Objective:To investigate the diagnostic value and imaging characteristics of MRI combined with 18F-fluorodeoxyglucose (FDG) positron-emission tomography (PET)/CT in focal cortical dysplasia (FCD) complicated with refractory epilepsy. Methods:A retrospective analysis was performed on 42 patients with FCD complicated with refractory epilepsy who were admitted to the Affiliated Hospital of Jining Medical University from January 2017 to December 2022. All patients underwent preoperative MRI and 18F-FDG PET/CT, and PET/MRI fusion was performed on the images. Chi-square test and Kappa consistency test were used to compare the localization diagnostic efficacy of PET/CT, MRI and PET/MRI fusion for epileptic foci. The patients were categorized based on gender, lesion location, pathological type, seizure type, and efficacy. Independent sample t-test and analysis of variance were used to compare maximum standardized uptake (SUVmax) values and asymmetry index (AI) of the patients between different groups. Results:Among the 42 patients, the positive rates of MRI, PET/CT, PET/MRI fusion examinations were 85.7%(36/42), 95.2%(40/42), 100.0%(42/42), the lateral localization rates were 71.4%(30/42), 92.9%(39/42), 95.2%(40/42), and the localization rates were 57.1%(24/42), 81.0%(34/42), 88.1%(37/42), respectively. There were significant differences in the lateral localization rates and localization rates of epileptogenic foci between MRI and PET/CT (χ 2=6.574, P=0.010; χ 2=5.570, P=0.018). There were significant differences in the positive rates of lesions, the lateral localization rates and the localization rates of epileptogenic foci between MRI and PET/MRI fusion (χ 2=6.385, P=0.012; χ 2=8.571, P=0.003; χ 2=10.118, P=0.001). There were no significant differences in the positive rates of lesions between MRI and PET/CT, and in the positive rates of lesions, the lateral localization rates and localization rates of epileptogenic foci between PET/CT and PET/MRI fusion (χ 2=2.184, P=0.139; χ 2=2.024, P=0.155; χ 2=0.210, P=0.647; χ 2=0.819, P=0.365). The Kappa consistency test of PET/CT and PET/MRI fusion imaging was performed for the location of epileptogenic foci, and the Kappa=0.721 was obtained, indicating that they were consistent in the location of epileptogenic foci. The SUVmax values of patients with temporal lobe epilepsy were lower, and the AI values were higher than that of patients with extra temporal lobe epilepsy (7.4±1.3 vs 9.6±1.6, 15.5±2.6 vs 12.9±2.4; t=5.154, 6.083; P=0.001, 0.001). The SUVmax values of patients with good efficacy (according to the Engel efficacy grading system, grades Ⅰ-Ⅱ indicating good efficacy) were higher, and the AI values were lower than that of patients with poor efficacy (according to the Engel efficacy grading system, grades Ⅲ-Ⅳ indicating poor efficacy; 9.5±1.9 vs 7.9±2.1, 13.5±3.3 vs 14.8±3.0; t=2.789, 3.722; P=0.042, 0.029). There were no significant differences in SUVmax and AI values among different genders, pathological types and seizure types (all P>0.05). Conclusions:The imaging characteristics of patients with different types of FCD complicated with refractory epilepsy are different. PET/MRI fusion is better than MRI in the diagnosis of FCD complicated with refractory epilepsy, and is consistent with PET/CT in the location of epileptogenic foci.

Objective To investigate the clinical application of perioperative human serum albumin(HSA)in cardiac surgery in multiple regions in China,and to evaluate the rationality of its clinical application in conjunction with the clinical guidelines,in order to provide a reference for promoting the rational application of HSA.Methods The medical records of patients who underwent cardiac surgery from April to June 2019 in eight hospitals across the country were retrospectively collected.The statistical information on patients'general information,the dosage,course of treatment,and cost of HSA,and the serum albumin level before and after medication was analyzed to evaluate the use of HSA.Relevant evaluation criteria were established,and the rationality of its medication was evaluated.Results Data from a total of 449 patients were included for analysis,the appropriate rate of medication was 81.1％.The course of medication was mostly＞2-5 days and the total amount of HSA was mostly 50-99 g.The main purpose of medicaiton were improving colloid osmotic pressure,reducing exudation to improve interstitial edema,postoperative volume expansion.Conclusion Clinical attention should be paid to ensure the rational application of HSA in cardiac surgery during the perioperative period and prevent the abuse of blood products.

Traumatic fractures and stress fractures are common orthopedic diseases,and there is great potential in researching bone turnover,repair,and promotion of fracture healing.Basic medical experiments often use animal models of long bone fractures in limbs to study the mechanisms of various interventions on fracture healing.Fracture healing is a complex process influenced by multiple factors and involves multiple molecules and pathways.Therefore,to explore the mechanisms more deeply,accelerate the translation of results,and improve the clinical efficacy,it is particularly important to choose the appropriate animal fracture modeling methods in experimental research.Based on this,this paper conducts a literature review of animal species and modeling methods commonly used for long bone fracture models in experimental research.It summarizes five methods:bone defect method,physical impact method,mechanical bending method,open osteotomy method,and drilling method.A side-by-side comparison of their advantages,disadvantages,and scope of application is made,aiming to provide suitable fracture models for studyingthe mechanisms of fracture healing interventions.

Objective:To evaluate the clinical efficacy of Huolong moxibustion combined with Shaofu Zhuyu ointment acupoint application in the treatment of sequelae of pelvic inflammatory disease with cold coagulation and stasis syndrome.Methods:Randomized controlled trial study was performed. 102 patients with pelvic inflammatory disease in our hospital from June 2021 to June 2023 were selected as the observation subjects. They were divided into two groups according to random number table method, with 51 cases in each group. The control group was treated with conventional Western medicine therapy, with 10 days as one course of treatment, for a total of 3 courses of treatment. The observation group was treated with Huolong Moxibustion combined with Shaofu Zhuyu Ointment acupoint application, once every 3 days, with 5 sessions as a course of treatment, for a total of 3 menstrual cycles. TCM syndrome scores were performed before and after treatment; doppler ultrasound diagnostic instrument was used to detect the maximum systolic blood flow velocity (PSV), end diastolic blood flow velocity (EDV), pulsatile index (PI), and resistance index (RI) of the uterine artery; ELISA was used to detect levels of β - endorphin (β - EP), prostaglandin F2α(PGF2α), and serum substance P (SP). Adverse reactions during treatment were recorded, and clinical efficacy was evaluated.Results:The total effective rate of the observation group was 92.16% (47/51), while that of the control group was 76.47% (39/51),the difference between the two groups was statistically significant ( χ2=4.74, P=0.029).After treatment, the observation group had lower abdominal pain refusal to press (1.76 ± 0.45 vs. 2.12 ± 0.54, t=3.66),limb coldness and chills (1.85 ± 0.47 vs. 2.21 ± 0.60, t=3.37), menstrual disorders (1.93 ± 0.56 vs. 2.31 ± 0.58, t=3.37), tongue purple coating white score (2.04 ± 0.55 vs. 2.52 ± 0.50, t=4.25) and total score (7.58 ± 1.56 vs. 9.16 ± 1.92, t=4.56) than the control group ( P<0.01); the EDV [(18.86 ± 3.65) cm/s vs. (14.45 ± 3.51) cm/s, t=6.23] and PSV [(37.94 ± 5.19) cm/s vs. (32.21 ± 4.97) cm/s, t=5.70] of the uterine artery were higher than those in the control group ( P<0.01); the RI [(72.62 ± 7.56)% vs. (78.31 ± 6.58)%, t=4.05], PI [(41.94 ± 5.90)% vs. (47.52 ± 5.59)%, t=4.90] were lower than those in the control group ( P<0.01);the levels of β-EP [(49.86 ± 5.87) μg/L vs. (55.41 ± 5.91) μg/L, t=4.76], PGF2α [(71.94 ± 8.13) μg/L vs. (78.21 ± 8.97) μg/L, t=3.70], and SP [(19.12 ± 3.98) μg/L vs. (22.34 ± 3.81) μg/L, t=4.17] were lower than those in the control group ( P<0.05).The incidence of adverse reactions during treatment was 11.76% (6/51) in the observation group and 3.9% (2/51) in the control group, with no statistically significant difference between the two groups ( χ2=0.44, P=0.505). Conclusion:The combination of Huolong Moxibustion and Shaofu Zhuyu Ointment acupoint application can effectively improve the microcirculation status of the uterine artery in patients with pelvic inflammatory disease sequelae of cold coagulation and blood stasis syndrome, reduce the level of pain factors, alleviate the main symptoms of patients, improve clinical efficacy, and have good safety.

Objective:To investigate respiratory virus infection in children with septic shock in pediatric care units (PICU) in China and its influence on clinical outcomes.Methods:The clinical data of children with septic shock in children′s PICU from January 2018 to December 2019 in 10 Chinese hospitals were retrospectively collected. They were divided into the pre-COVID-19 and post-COVID-19 groups according to the onset of disease, and the characteristics and composition of respiratory virus in the 2 groups were compared. Matching age, malignant underlying diseases, bacteria, fungi and other viruses, a new database was generated using 1∶1 propensity score matching method. The children were divided into the respiratory virus group and non-respiratory virus group according to the presence or absence of respiratory virus infection; their clinical characteristics, diagnosis, and treatment were compared by t-test, rank sum test and Chi-square test. The correlation between respiratory virus infection and the clinical outcomes was analyzed by logistic regression. Results:A total of 1 247 children with septic shock were included in the study, of them 748 were male; the age was 37 (11, 105) months. In the pre-and post-COVID-19 groups, there were 530 and 717 cases of septic shock, respectively; the positive rate of respiratory virus was 14.9% (79 cases) and 9.8% (70 cases); the seasonal distribution of septic shock was 28.9% (153/530) and 25.9% (185/717) in autumn, and 30.3% (161/530) and 28.3% (203/717) in winter, respectively, and the corresponding positive rates of respiratory viruses were 19.6% (30/153) and 15.7% (29/185) in autumn, and 21.1% (34/161) and 15.3% (31/203) in winter, respectively. The positive rates of influenza virus and adenovirus in the post-COVID-19 group were lower than those in the pre-COVID-19 group (2.1% (15/717) vs. 7.5% (40/530), and 0.7% (5/717) vs. 3.2% (17/530), χ2=21.51 and 11.08, respectively; all P<0.05). Rhinovirus virus were higher than those in the pre-Covid-19 group (1.7% (12/717) vs. 0.2% (1/530), χ2=6.51, P=0.011). After propensity score matching, there were 147 cases in both the respiratory virus group and the non-respiratory virus group. Rate of respiratory failure, acute respiratory distress, rate of disseminated coagulation dysfunction, and immunoglobulin usage of the respiratory virus group were higher than those of non-respiratory virus group (77.6% (114/147) vs. 59.2% (87/147), 17.7% (26/147) vs. 4.1% (6/147), 15.6% (25/147) vs. 4.1% (7/147), and 35.4% (52/147) vs. 21.4% (32/147); χ2=11.07, 14.02, 11.06 and 6.67, all P<0.05); and PICU hospitalization of the former was longer than that of the later (7 (3, 16) vs. 3 (1, 7)d, Z=5.01, P<0.001). Univariate logistic regression analysis showed that the presence of respiratory viral infection was associated with respiratory failure, disseminated coagulation dysfunction, the use of mechanical ventilation, and the use of immunoglobulin and anti-respiratory viral drugs ( OR=2.42, 0.22, 0.25, 0.56 and 1.12, all P<0.05). Conclusions:The composition of respiratory virus infection in children with septic shock is different between pre and post-COVID-19. Respiratory viral infection is associated with organ dysfunction in children with septic shock. Decreasing respiratory viral infection through respiratory protection may improve the clinical outcome of these children.

Objective:To investigate the clinical features, pathogen composition, and prognosis of septic shock in pediatric intensive care units (PICU) in China.Methods:A multicenter retrospective cohort study. A retrospective analysis was conducted on the clinical data of children with septic shock from 10 hospitals in China between January 2018 and December 2021. The clinical features, pathogen composition, and outcomes were collected. Patients were categorized into malignant tumor and non-malignant tumor groups, as well as survival and mortality groups. T test, Mann Whitney U test or Chi square test were used respectively for comparing clinical characteristics and prognosis between 2 groups. Multiple Logistic regression was used to identify risk factors for mortality. Results:A total of 1 247 children with septic shock were included, with 748 males (59.9%) and the age of 3.1 (0.9, 8.8) years. The in-patient mortality rate was 23.2% (289 cases). The overall pathogen positive rate was 68.2% (851 cases), with 1 229 pathogens identified. Bacterial accounted for 61.4% (754 strains) and virus for 24.8% (305 strains). Among all bacterium, Gram negative bacteria constituted 64.2% (484 strains), with Pseudomonas aeruginosa and Enterobacter being the most common; Gram positive bacteria comprised 35.8% (270 strains), primarily Streptococcus and Staphylococcus species. Influenza virus (86 strains (28.2%)), Epstein-Barr virus (53 strains (17.4%)), and respiratory syncytial virus (46 strains (17.1%)) were the top three viruses. Children with malignant tumors were older and had higher pediatric risk of mortality (PRISM) Ⅲ score, paediatric sequential organ failure assessment (pSOFA) score (7.9 (4.3, 11.8) vs. 2.3 (0.8, 7.5) years old, 22 (16, 26) vs. 16 (10, 24) points, 10 (5, 14) vs. 8 (4, 12) points, Z=11.32, 0.87, 4.00, all P<0.05), and higher pathogen positive rate, and in-hospital mortality (77.7% (240/309) vs. 65.1% (611/938), 29.7% (92/309) vs. 21.0% (197/938), χ2=16.84, 10.04, both P<0.05) compared to the non-tumor group. In the death group, the score of PRISM Ⅲ, pSOFA (16 (22, 29) vs. 14 (10, 20) points, 8 (12, 15) vs. 6 (3, 9) points, Z=4.92, 11.88, both P<0.05) were all higher, and presence of neoplastic disease, positive rate of pathogen and proportion of invasive mechanical ventilation in death group were also all higher than those in survival group (29.7% (87/289) vs. 23.2% (222/958), 77.8% (225/289) vs. 65.4% (626/958), 73.7% (213/289) vs. 50.6% (485/958), χ2=5.72, 16.03, 49.98, all P<0.05). Multiple Logistic regression showed that PRISM Ⅲ, pSOFA, and malignant tumor were the independent risk factors for mortality ( OR=1.04, 1.09, 0.67, 95% CI 1.01-1.05, 1.04-1.12, 0.47-0.94, all P<0.05). Conclusions:Bacterial infection are predominant in pediatric septic shock, but viral infection are also significant. Children with malignancies are more severe and resource consumptive. The overall mortality rate for pediatric septic shock remains high, and mortality are associated with malignant tumor, PRISM Ⅲ and pSOFA scores.

Objective To assess the screening efficacy of a novel esophageal cell collector and esophageal exfoliated cell cytology examination for esophageal cancer and investigate risk factors associated with cytological examination results in the Han and Mongolian ethnic groups.Methods ①A total of 1196 high-risk individuals with esophageal cancer were selected for treatment at the Second Affiliated Hospital of Baotou Medical College.Esophageal cells were collected,and endoscopic examination and mucosal biopsy of the esophagus were performed.The pathological examination of the digestive tract endoscopic biopsy tissue was used as the gold standard to verify the diagnostic efficacy of cytological examination.① In this study,9256 Han and 572 Mongolian individuals who participated in esophageal cancer screening in the Baotou area were selected as the research subjects.General information,dietary habits,lifestyle habits,and other information of the subjects were collected through a questionnaire survey.Esophageal cells were collected using a new type of esophageal cell collector,and logistic regression analysis was used to identify the risk factors for positive cytology in Han and Mongolian populations.Results ① The novel esophageal cell collector and esophageal exfoliated cell cytology examination demonstrated excellent screening capabilities for esophageal cancer,with sensitivity(92.86％),specificity(99.58％),positive predictive value(PPV)of 72.22％,negative predictive value(NPV)of 99.92％,positive likelihood ratio(PLR)of 221.10,negative likelihood ratio(NLR)of 0.07,Youden index of 0.92,and an area under the ROC curve of 0.961(0.923-1.0).The optimal cutoff value was 2.50,yielding a sensitivity of 92.90％and specificity of 88.20％.②The cytological positivity rate among the Mongolian population(2.27％)was higher than that among the Han population(1.12％).The proportion of alcohol drinkers,those with a preference for hot and spicy foods,and those consuming pickled foods was higher in the Mongolian population than in the Han population.Logistic regression analysis revealed risk factors for the Han population:gender(OR=0.381,95％CI:0.256-0.568),age(OR=1.091,95％CI:1.067-1.116),alcohol consumption(OR=1.693,95％CI:1.150-2.492),and smoking(OR=2.127,95％CI:1.439-3.143).Risk factors for the Mongolian population were gender(OR=0.174,95％CI:0.047-0.638),age(OR=1.124,95％CI:1.052-1.200),and alcohol consumption(OR=3.945,95％CI:1.074-14.489).Conclusion ①The novel type of esophageal cell collector-esophageal exfoliative cytology examination has good screening efficacy for esophageal cancer.② Gender,age,alcohol consumption,and hot eating habits are the main risk factors for positive cytological diagnosis in the Mongolian population,while gender,age,alcohol consumption,and smoking are the main risk factors for positive cytological diagnosis in the Han population.

Objective:To explore the diagnostic value of 18F-FDG PET/CT imaging in etiology of patients with hemophagocytic lymphohistiocytosis (HLH). Methods:Retrospective analysis was performed on 49 patients newly diagnosed as HLH (32 males, 17 females; age 19-61 years) who received 18F-FDG PET/CT imaging in Affiliated Hospital of Jining Medical University from January 2017 to January 2023. PET/CT images and clinical parameters were observed and recorded. Based on the pathological examination and clinical follow-up results, diagnostic efficacies for HLH etiology of PET/CT, PET and CT imaging were calculated. χ2 test, independent-sample t test and Mann-Whitney U test were used to compare the differences between hematologic tumors associated HLH and non-hematologic tumor associated HLH. Multivariate logistic regression was used to analyze the predictors of secondary HLH in hematologic tumors. ROC curve analysis was used to calculate AUCs and optimal threshold of lymph node SUV max and soluble CD25 (sCD25) to predict secondary HLH in patients with hematologic tumors. Results:The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of PET/CT, PET and CT in the etiological diagnosis of HLH were 85.7%(30/35), 8/10, 84.4%(38/45), 93.8%(30/32), 8/13; 77.1%(27/35), 6/10, 73.3%(33/45), 87.1%(27/31), 6/14; 62.9%(22/35), 5/10, 60.0%(27/45), 81.5%(22/27), 5/18, respectively. There were differences in lymph node distribution and boundary, liver and spleen and bone lesions, SUV max of lymph node and liver and spleen and bone, gender, age, WBC, neutrophil (ANC), PLT, lactate dehydrogenase (LDH), total bilirubin (TBIL), C-reactive protein (CRP) and sCD25 between different etiology groups ( χ2 values: 3.91-9.66, t values: 3.75-7.90, z values: 3.82-4.01, all P<0.05). SUV max of lymph nodes and sCD25 were predictive factors for secondary HLH of hematological tumors (odds ratio ( OR): 1.28 (95% CI: 1.09-1.72), 1.56 (95% CI: 1.17-2.49), P values: 0.004, 0.013). The optimal thresholds were 12.6 and 40 028 ng/L, with the AUC of 0.87 and 0.76, with the sensitivity and specificity of 88.6%(31/35) and 8/10, 65.7%(23/35) and 7/10, respectively. The combined AUC was 0.83 and the sensitivity and specificity were 74.3% (26/35) and 9/10. Conclusions:18F-FDG PET/CT imaging is of high value for the diagnosis of the cause of HLH. SUV max of lymph node and sCD25 are predictive factors for secondary HLH of hematologic tumors.

Objective To investigate the mechanism of Chonghe soft extract on ulcer wound healing in diabetic rats through protein kinase B(Akt)/mammalian Sirolimus target protein(mTOR)-mediated nucleotides binding oligomeric acid domain-like receptor protein 3(NLRP3)inflammasome inactivation.Methods Thirty six SD rats with diabetic ulcer,which were established by feeding with high glucose and high fat diet and injecting intraperitoneally with streptozocin(STZ)combined with skin defect,were randomly divided into model group,Chonghe soft extract group and growth factor group,with twelve rats in each group.Another twelve SD rats were injected an equal dose of citric acid-sodium citrate buffer solution and used as blank group.The blank group and the model group were not received drug intervention,but the Chonghe soft extract group and the growth factor group were externally applied Chonghe soft extract and growth factor gel,respectively.The wound healing of each group was observed and recorded.After 7 days and 14 days of treatment,the histopathology of wound were observed by HE staining and the number of fibroblasts were counted.The levels of IL-1β,IL-18 and TNF-α in serum were detected by ELISA.The expression of autophagy-related protein Beclin-1 and LC3Ⅱ in granulation tissue was detected by immunohistochemistry.The expression of NLRP3,apoptosis-associated speck-like protein containing a caspase recruitment domain(ASC),Caspase1,Pro-Caspase1 and Akt/mTOR autophagy pathway-related proteins Akt,p-Akt,mTOR and p-mTOR were detected by Western Blot.Results Compared with the blank control group,the pathological wound repair of the model group was delayed on the 7th day and 14th day,the number of fibroblasts per unit area was decreased(P<0.01).The levels of IL-1β,IL-18 and TNF-α were increased(P<0.01).The expression levels of ASC,Pro-Caspase1,Caspase1,and NLRP3 were increased in the wound tissues(P<0.01),while the expression levels of Beclin-1,LC3-Ⅱ,mTOR,p-mTOR,Akt and p-Akt were decreased in the wound tissues(P<0.01).Compared with the model group,the pathological injury in Chonghe soft extract group and growth factor group was significantly improved on the 7th day and 14th day.The number of fibroblasts per unit area was significantly increased(P<0.01).The levels of IL-1β,IL-18 and TNF-α were significantly decreased(P<0.01).The expression levels of ASC,Pro-Caspase1,Caspase1,and NLRP3 in the wound tissues were decreased(P<0.01),while the expression levels of Beclin-1,LC3-Ⅱ,mTOR,p-mTOR,Akt and p-Akt were increased(P<0.01,P<0.05).Conclusion Chonghe soft extract can reduce inflammatory reaction,promote the generation of fibro,regulate the Akt/mTOR-mediated NLRP3 inflammasome inactivation,improve the level of autophagy in wound,and promote ulcer wound healing in diabetic rats.

Vascular wall-resident stem cells (VW-SCs) play a critical role in maintaining normal vascular function and regulating vascular repair. Understanding the basic functional characteristics of the VW-SCs will facilitate the study of their regulation and potential therapeutic applications. The aim of this study was to establish a stable method for the isolation, culture, and validation of the CD34⁺ VW-SCs from mice, and to provide abundant and reliable cell sources for further study of the mechanisms involved in proliferation, migration and differentiation of the VW-SCs under various physiological and pathological conditions. The vascular wall cells of mouse aortic adventitia and mesenteric artery were obtained by the method of tissue block attachment and purified by magnetic microbead sorting and flow cytometry to obtain the CD34⁺ VW-SCs. Cell immunofluorescence staining was performed to detect the stem cell markers (CD34, Flk-1, c-kit, Sca-1), smooth muscle markers (SM22, SM MHC), endothelial marker (CD31), and intranuclear division proliferation-related protein (Ki-67). To verify the multipotency of the isolated CD34⁺ VW-SCs, endothelial differentiation medium EBM-2 and fibroblast differentiation medium FM-2 were used. After culture for 7 days and 3 days respectively, endothelial cell markers and fibroblast markers of the differentiated cells were evaluated by immunofluorescence staining and q-PCR. Furthermore, the intracellular Ca²⁺ release and extracellular Ca²⁺ entry signaling were evaluated by TILLvisION system in Fura-2/AM loaded cells. The results showed that: (1) High purity (more than 90%) CD34⁺ VW-SCs from aortic adventitia and mesenteric artery of mice were harvested by means of tissue block attachment method and magnetic microbead sorting; (2) CD34⁺ VW-SCs were able to differentiate into endothelial cells and fibroblasts in vitro; (3) Caffeine and ATP significantly activated intracellular Ca²⁺ release from endoplasmic reticulum of CD34⁺ VW-SCs. Store-operated Ca²⁺ entry (SOCE) was activated by using thapsigargin (TG) applied in Ca²⁺-free/Ca²⁺ reintroduction protocol. This study successfully established a stable and efficient method for isolation, culture and validation of the CD34⁺ VW-SCs from mice, which provides an ideal VW-SCs sources for the further study of cardiovascular diseases.
Mice ; Animals ; Endothelial Cells ; Cell Differentiation/physiology* ; Stem Cells ; Adventitia ; Fibroblasts ; Cells, Cultured ; Antigens, CD34/metabolism*