1.Treatment strategy and curative effect analysis of os odontoideum complicated with atlantoaxial joint dislocation.
Xu-Dong HU ; Wei-Yu JIANG ; Yun-Lin CHEN ; Nan-Jian XU ; Chao-Yue RUAN ; Wei-Hu MA
China Journal of Orthopaedics and Traumatology 2021;34(4):321-327
OBJECTIVE:
To explore the treatment strategy and clinical efficacy for os odontoideum complicated with atlantoaxial dislocation.
METHODS:
The clinical data of 17 patients with os odontoideum complicated with atlantoaxial dislocation surgically treated from January 2006 to January 2015 were retrospectively analyzed, including 7 males and 10 females, aged 17 to 53 (43.1±11.3) years old;course of disease was 3 to 27(10.2±6.9) months. All patients received cranial traction before operation, 12 of 14 patients with reducible dislocation were treated by posterior atlantoaxial fixation and fusion, and 2 patients with atlantooccipital deformity were treated by posterior occipitocervical fixation and fusion;3 patients with irreducible alantoaxial dislocation were treated by transoral approach decompression combined with posterior atlantoaxial fixation and fusion. The operation time, intraoperative blood loss and perioperative complications were recorded. Visual analogue scale (VAS) and Japanese Orthopaedic Association (JOA) score were used to evaluate the change of neck pain and neurological function. Atlantoaxial joint fusion rate was evaluated by CT scan.
RESULTS:
The operation time of posterior fixation and fusion ranged from 86 to 170 (92.2±27.5) min, and the intraoperative blood loss was 200-350 (250.7±65.2) ml. No vertebral artery injury and spinal cord injury were recorded. Among the patients underwent atlantoaxial fixation and fusion, 1 patient with reducible dislocation fixed by C
CONCLUSION
Surgical treatment of os odontoideum complicated with atlantoaxial dislocation can achieve satisfactory results, improve the patient's neurological function and improve the quality of life, however the surgical options needs to be individualized.
Adolescent
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Adult
;
Atlanto-Axial Joint/surgery*
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Axis, Cervical Vertebra
;
Female
;
Humans
;
Joint Dislocations/surgery*
;
Male
;
Middle Aged
;
Quality of Life
;
Retrospective Studies
;
Spinal Fusion
;
Treatment Outcome
;
Young Adult
2.Comparison of the effects of injured vertebra pedicle fixation combined with vertebroplasty and vertebra pedicle screw fixation combined with vertebroplasty in the treatment of osteoporotic thoracolumbar burst fractures.
Wei-Yu JIANG ; Guo-Ping PAN ; Dan-Guo CHEN ; Xu-Dong HU ; Yun-Lin CHEN ; Nan-Jian XU ; Chao-Yue RUAN ; Yang WANG ; Wei-Hu MA
China Journal of Orthopaedics and Traumatology 2020;33(5):440-444
OBJECTIVE:
To assess the curative effects of injured vertebra pedicle fixation combined with vertebroplasty and short-segment pedicle screw fixation combined with vertebroplasty in treatment of osteoporotic thoracolumbar burst fractures.
METHODS:
Seventy patients with osteoporotic thoracolumbar burst fractures who met the inclusion criteria were collected in the study from January 2015 to December 2017. Among them, 35 patients were treated with injured vertebra pedicle fixation combined with vertebroplasty (group A), including 20 males and 15 females, aged from 55 to 74 years with an average of (64.03± 7.82) years. Twenty-six cases were type A3 and 9 cases were type A4 according to the AO typing;another 35 patients were treated with short segment pedicle screw fixation combined with vertebroplasty (group B), including 18 males and 17 females, aged from 54 to 72 years with an average of (62.78±6.40) years. Twenty-eight cases were type A3 and 7 cases were type A4 according to AO typing. Operation length, intraoperative bleeding volume, complication, imaging parameters and clinical effects were compared between the two groups.
RESULTS:
All the patients were followed up for at least 12 months. There were no significant differences in gender, age, injury site, preoperative VAS, Cobb angle, and injured vertebral height before surgery. There were no significant differences in operation length, intraoperative bleeding volume between two groups. In terms of VAS scores before surgery, 1 week after surgery, and at the final follow up, group A was 5.5 ±2.5, 1.8 ±0.8, 0.9 ±0.4, group B was 5.4 ± 2.3, 1.7±0.6, 1.2±1.8, respectively;injured vertebral height was (40.4±8.8)%, (92.0±4.9)%, (87.1±3.8)% in group A, and (41.2±6.6)%, (93.2±4.6)%, (80.0±4.3)% in group B;Cobb angle was (18.4±6.9) °, (2.8±2.2) °, (4.2±2.6) ° in group A, and (16.8±7.2) °, (2.7±2.5) °, (6.0±2.4) ° in group B. There were significant differences in the 3 parameters above before the operation and at the final follow up in all groups (<0.05). There were significant differences in the Cobb angle and injured vertebral height between 1 week after operation and at the final follow up (<0.05). At the final follow up, injured vertebral height in group A was obviously better than that in group B (<0.05). Internal fixation failure occurred in 2 cases from the group A, and occurred in 4 cases from the group B. There were no neurological complications in both groups.
CONCLUSION
For osteoporotic thoracolumbar vertebral burst fractures, injured vertebra pedicle fixation combined with vertebroplasty and vertebra pedicle screw fixation combined with vertebroplasty can achieve good clinical effects. However, injured vertebra pedicle fixation combined with vertebroplasty is better at maintaining postoperative vertebral height and sagittal arrangement, and reducing internal fixation related complications. The treatment strategy is worthy of application and promotion.
Aged
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Female
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Fracture Fixation, Internal
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Humans
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Lumbar Vertebrae
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Male
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Middle Aged
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Pedicle Screws
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Spinal Fractures
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Thoracic Vertebrae
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Treatment Outcome
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Vertebroplasty
3.Optimized AAV package and experimental application of recombinant AAV8/hFⅧ for gene therapy on hemophilia A mice.
Jian Hua MAO ; Yan SHEN ; Qiang WANG ; Yun WANG ; Zheng RUAN ; Xiao Dong XI
Chinese Journal of Hematology 2020;41(1):34-39
Objective: To evaluate the effects of adeno-associated virus (AAV) carrying hFⅧ by serotype 8 (AAV8/hFⅧ) on hemophilia A (HA) mice by gene therapy strategy. Methods: pAAV-CB-EGFP, pH22 (serotype 2) and pfΔ6 (adenovirus helper) were used to package AAV into HEK-293 cells in different conditions (ratios of cells to plasmids). The efficiency of transfection and infection were evaluated using immunofluorescence microscope to seek an optimized package condition. pAAV-TTR-hFⅧ, pH 28 (serotype 8) and pfΔ6 were applied to package AAV8/hFⅧ in HEK-293 cells using the optimized package condition. The purified AAV8/hFⅧ were intravenously injected into HA mice and the effects of gene therapy were estimated. Results: The efficiency of package was evaluated according to the amount and intensity of enhanced green fluorescent protein (EGFP) under immunofluorescence microscope. Four package conditions including 10 cm-dish to transfect 10 μg plasmids, 20 cm-dish to 20 μg, 30 μg and 40 μg plasmids were employed, and the condition of 20 cm-dish to transfect 20 μg plasmids reached the highest transfection efficiency at 24 h, 48 h and 72 h after transfection. The small scale AAV-EGFP was packaged using the optimized condition and an AAV crude extract was harvested by a freeze-thaw method. HEK-293 and 16095 cells were infected by the AAV crude extract, and the preferential infection efficiency was recognized in 16095 cells under immunofluorescence microscope. Then, AAV8/hFⅧ was packaged and purified based on the optimized transfection condition, and the high purity of AAV8/hFⅧ was detected by Western blot. Fractions of AAV8/hFⅧ at the dose of 8×10(12) vg/kg were injected into HA mice through tail vein, an eye-bleeding was performed at every two weeks, and the activity of FⅧ was measured by aPTT assay. Results showed that the activity of FⅧ maintained at the therapeutic level and lasted up to 12 weeks after injection. Conclusion: The purified AAV8/hFⅧ based on the optimized package condition could play a role in HA mice gene therapy, and the long-term therapeutic effects of AAV8/hFⅧ were observed in vivo.
Animals
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Dependovirus
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Genetic Therapy
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Genetic Vectors
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HEK293 Cells
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Hemophilia A
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Humans
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Mice
4.Effect of Amino Acid Motifs in Integrin β3 Cytoplasmic Tail on αⅡbβ3-Mediated Cell function in 293T cell models.
Dong-Ya LI ; Jian-Hua MAO ; Wei ZHANG ; Xin-Jie CHEN ; Bing XIAO ; Zheng RUAN ; Yun WANG ; Guo-Xiong JIANG ; Xiao-Feng SHI ; Xiao-Dong XI
Journal of Experimental Hematology 2019;27(1):227-232
OBJECTIVE:
To establish 293T cell lines stably expressing Calpain-cleavage related α3 cytoplasmic tail mutants, and to explore the effect of amino acid motifs in integrin β3 cytoplasmic tail on αⅡbβ3-mediated cell function.
METHODS:
293T cell lines stably co-expressing human wild type integrin αⅡb and full length β3 or mutant β3, including β3-ΔNITY (β3 cytoplasmic tail NITY motif deleted), β3-Δ754 (β3 cytoplasmic tail TNITYRGT motif deleted) and β3-Δ759 (β3 cytoplasmic tail RGT motif deleted) were established. Spreading and adhesion of these stable cell lines on immobilized fibrinogen were tested.
RESULTS:
293T-αⅡbβ3ΔNITY, 293T-αⅡbβ3Δ754, 293T-αⅡbβ3Δ759 and 293T-αⅡbβ3 cell lines were successfully established. Compared with the 293T cells, 293T-αⅡbβ3 cells which expressed full β3, possessed well adhesion and spread ability on immobilized fibrinogen, suggesting it can be as a surrogate for platelet. Compared with 293T-αⅡbβ3 cells, the 293T-αⅡbβ3ΔNITY cells showed a partial impairment of adhesion and spreadability on immobilized fibrinogen. while the 293T-αⅡbβ3Δ754 cells and 293T-αⅡbβ3Δ759 cells failed to adhere or spread on immobilized fibrinogen.
CONCLUSION
To the cell spreading function mediated by integrin β3, RGT motif is vital, while NITY can be dispensable. These established 293T cell lines stably expressing different β3 mutants provide a solid basis for a further analysis of mass spectrometry.
Amino Acid Motifs
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Animals
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CHO Cells
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Cell Adhesion
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Cricetinae
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Cricetulus
;
HEK293 Cells
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Humans
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Integrin beta3
;
genetics
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metabolism
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Platelet Glycoprotein GPIIb-IIIa Complex
;
genetics
;
metabolism
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Signal Transduction
5.Percutaneous pedicle screw fixation combined with limited-open decompression technique for thoracolumbar fractures with neurologic deficit.
Xu-Dong HU ; Wei-Hu MA ; Wei-Yu JIANG ; Yun-Lin CHEN ; Chao-Yue RUAN
China Journal of Orthopaedics and Traumatology 2018;31(1):62-66
OBJECTIVETo evaluate the clinical effects of percutaneous pedicle screw fixation combined with limited open decompression technique for the treatment of thoracolumbar fractures with neurologic deficit.
METHODSThe clinical data of 76 patients with thoracolumbar fractures with neurologic deficit underwent percutaneous pedicle screw fixation combined with limited open decompression technique from June 2010 to June 2014 were retrospectively analyzed. There were 45 males and 31 femals, aged from 17 to 56 years with an average of 32.5 years old. According to the classification of Denis, 33 cases were type A, 26 cases were type B, 17 cases were type C. According to the criterion of American Spinal Injury Association(ASIA), 13 cases were grade A, 9 cases were grade B, 21 cases were grade C, 33 cases were grade D. The operative time, intraoperative blood loss, postoperative internal fixation lossening and breakage were recorded. The informations of the Cobb angle, the anterior height of injured vertebra, canal stenosis were observed before operation, 3 days after operation, and the final follow-up. The improvement of neurologic function were analyzed at final follow-up.
RESULTSAll the patients were followed up from 13 to 47 months with an average of 32.1 months. The mean operative time was 159 min (136 to 218 min) and the intraoperative blood loss was 225 ml(150 to 360 ml). The anterior height of injured vertebra was increased from (52.0±5.9)% before operation to (87.2±1.8)% at 3 days after operation, and (86.1±1.5)% at final follow-up (=45.27,=0.000); the Cobb angle was decreased from (29.7±8.2)° before operation to (5.7±2.9)° at 3 days after operation, and (5.9±3.6)° at final follow-up (=34.62,=0.000); the canal stenosis was decreased from (37.5±7.2)% before operation to (12.3±3.3)% at 3 days after operation, and (11.9±3.1)% at final follow-up(=37.02,=0.000); there was no significant differences between postoperative 3 days and the final follow-up about the above parametres(>0.05). According to ASIA criterion, the spinal cord function was classified as grade A in 13 cases, grade B in 0 cases, grade C in 10 cases, grade D in 21 cases and grade E in 32 cases at final follow-up. Internal fixation lossening and breakage occurred in 2 cases.
CONCLUSIONSPercutaneous pedicle screw fixation combined with limited open decompression technique can obtain satisfactory clinical effect for patients with thoracolumbar fractures with neurologic deficit, and have a good recovery of nerve function can be observed.
6.Case-control study of pedicle screw fixation combined with vertebroplasty and injured vertebra pedicle fixation in treatment of osteoporotic thoracolumbar burst fractures.
Wei-Yu JIANG ; Wei-Hu MA ; Hua-Guo ZHAO ; Xu-Dong HU ; Yun-Ling CHEN ; Nan-Jian XU ; Chao-Yue RUAN
China Journal of Orthopaedics and Traumatology 2018;31(8):703-708
OBJECTIVETo compare the curative effect of short-segment pedicle screw fixation combined with vertebroplasty and injured vertebra pedicle fixation in treating osteoporotic thoracolumbar burst fractures.
METHODSA retrospective study was performed for 52 patients with thoracolumbar burst fractures from August 2010 to August 2015. Among them, 27 patients(group A) were treated with short-segment pedicle screw fixation combined with vertebroplasty, including 17 males and 10 females, aged from 54 to 68 years old with an average of(61.01±5.41) years, 16 cases were type A3 and 11 cases were type A4 according the new AO typing. Other 25 patients (group B) were treated with short-segment pedicle screw fixation combined with injured vertebra pedicle fixation, including 12 males and 13 females, aged from 55 to 66 years old with an average of (59.28±6.12) years, 18 cases were type A3 and 7 cases were type A4 according the new AO typing. Operation time, intraoperative bleeding volume, complication, image data and clinical effect were compared between two groups.
RESULTSAll the patients were followed up for 12 to 15 months with an average of (12.4±2.1)months. There was no significant difference in general data(including gender, age, injured site, preoperative VAS score, Cobb angle, injured vertebral anterior border height) between two groups. There was no significant differences in operation time, intraoperative bleeding volume between two groups. Preoperative, one week after operation and final follow-up, VAS scores were 5.2±0.5, 1.2±0.2, 0.8±0.1 respectively in group A and 5.0±0.6, 2.5±0.4, 1.3±0.2 in group B; injured vertebral anterior border height were (49.4±6.8)%, ( 94.5±1.2)%, ( 94.1±3.7)% respectively in group A and (48.2±7.0)%, ( 94.3±4.1)%, ( 90.0±2.3)% in group B;Cobb angles were (20.4±5.2) °, (2.5±1.8) °, (4.4±1.7)° respectively in group A and (19.8±6.8)°, (2.4±1.7)°, (7.0±1.2)° in group B. At final follow-up, VAS, Cobb angle, injured vertebral anterior border height in two groups were obviously improved(<0.05). Postoperative at 1 week and final follow-up, VAS score of group A was lower than that of group B(<0.05);and there was no significant difference in Cobb angle between two groups(>0.05); there was significant difference in injured vertebral anterior border height between two groups(<0.05). The complication of internal fixation failure had 1 case in group A and 4 cases in group B.
CONCLUSIONSFor the treatment of single osteoporotic thoracolumbar burst fractures, short-segment pedicle screw fixation combined with vertebroplasty is better than combined with injured vertebra pedicle fixation in clinical effect, it can relieve pain, maintain injured vertebral height and sagittal alinement, reduce the complications associated with internal fixation, and be worth spread in clinic.
7.The shor-term clinical outcomes and safety of extreme lateral interbody fusion combined with percutaneous pedicle screw fixation for the treatment of degenerative lumbar disease.
Xu-Dong HU ; Wei-Hu MA ; Wei-Yu JIANG ; Chao-Yue RUAN ; Yun-Lin CHEN
China Journal of Orthopaedics and Traumatology 2017;30(2):147-151
OBJECTIVETo evaluate the early efficacy and safety of extreme lateral interbody fusion (XLIF) combined with percutaneous pedicle screw fixation for lumbar degenerative disease.
METHODSFrom January 2013 to June 2014, 13 patients with degenerative lumbar disease were treated with XLIF combined with percutaneous pedicle screw fixation, including 8 cases of lumbar instability, 5 cases of mild to moderate lumbar spondylolisthesis;there were 5 males and 8 females, aged from 56 to 73 years with an average of 62.1 years. All patients were single segment fusion. Operation time, perioperative bleeding and perioperative complications were recorded. Visual analogue scale (VAS) and Oswestry Disability Index (ODI) were used to evaluate the clinical efficacy. Interbody fusion rate was observed and the intervertebral foramen area changes were compared preoperation and postoperation by X-rays and CT scanning.
RESULTSThe mean operation time and perioperative bleeding in the patients respectively was(62.8±5.2) min and(82.5±22.6) ml. One case occurred in the numbness of femoribus internus and 1 case occurred in the muscle weakness of hip flexion after operation, both of them recovered within 2 weeks. All the patients were followed up from 12 to 19 months with an average of 15.6 months. VAS was decreased from preoperative 7.31±0.75 to 2.31±0.75 at final follow-up(<0.05); ODI was decreased from preoperative (42.58±1.55)% to (12.55±0.84)% at final follow-up(<0.05). At final follow-up, CT scanning confirmed 8 cases completely fused and 5 cases partly fused;the intervertebral foramen area was increased from preoperative (94.86±2.44)mm2 to (150.70±7.02)mm2(<0.05).
CONCLUSIONSExtreme lateral interbody fusion combined with percutaneous pedicle screw fixation is an ideal method and can obtain early good clinical effects in treating lumbar degenerative disease.
8.French door segmented laminectomy decompression for severe cervical ossification of posterior longitudinal ligament complicated with spinal cord injury.
Wei-Yu JIANG ; Wei-Hu MA ; Yong-Jie GU ; Liu-Jun ZHAO ; Xu-Dong HU ; Liang YU ; Chao-Yue RUAN ; Yun-Lin CHEN ; Yue-Ling FENG
China Journal of Orthopaedics and Traumatology 2017;30(9):844-848
OBJECTIVETo evaluate the clinical effects of French door segmented laminectomy decompression for severe cervical OPLL complicated with spinal cord injury.
METHODSThe clinical data of 38 patients with serious cervical OPLL complicated with spinal cord injury were retrospectively analyzed and these patients were treated with French door segmented laminectomy decompression and internal fixation from June 2012 to June 2014. There were 25 males and 13 females, aged from 42 to 78 years with an average of 58.2 years. Of them, 35 cases suffered from aggravating neurological symptoms with a definite precipitating factor. Spinal cord injury was related to minor injury of the neck, such as hyperextension of the neck in 3 cases. Preoperative Japanese Orthopaedic Score (JOA) was 8.1±1.7 and Neck Disability Index (NDI) was 19.8±4.4. Preoperative CT scans showed the range of OPLL was more than three segments. The spinal canal was occupied 50% to 85% with an average of 70.7%.
RESULTSAll the patients were followed up for 10 to 24 months with an average of 15.6 months. The operative time was 90 to 150 min with an average of 120 min and blood loss was 300 to 800 ml with an average of (480±80) ml. At final follow-up, NDI and JOA were 7.5±2.5 and 13.5±2.0, respectively, and they were obviously improved compared with preoperation. Preoperative cervical Cobb angle was (8.10±2.70)° and at final follow-up was (15.60±1.80)°, and there was significant difference between preoperative and postoperative (<0.05). Deep infection occurred in 1 case, epidural hematoma in 1 case, C₅ nerve root palsy in 3 cases, and axial symptom in 8 cases after operation. No serious complications, such as vertebral artery injury, cerebrospinal fluid leakage, deterioration of neurological dysfunction, or internal fixation failure was found.
CONCLUSIONSFrench door segmented laminectomy decompression is safe and feasible for severe cervical OPLL complicated with spinal cord injury, and it is worth to be popularized in future.
9.Liver and cardiac iron overload is harmful to HLA-identical hematopoietic stem cell transplantation in thalassemia children: an MRI detection
jing Wen YANG ; yun Jian LIAO ; yun Jian WEN ; sheng Yong RUAN ; bai Li CHEN ; lin Yue HE ; fu Chun LI ; dong Xue WU
Chinese Journal of Tissue Engineering Research 2017;21(33):5293-5298
BACKGROUND: The majority of children with β-thalassemia major have iron overload, and iron overload may have negative effects on hematopoietic stem cell transplantation. OBJECTIVE: To assess the effects of liver and cardiac iron overload detected by magnetic resonance imaging (MRI) T2* on HLA-identical allogeneic hematopoietic stem cell transplantation in children with β-thalassemia major. METHODS: Eighty-one children with β-thalassemia major who were over 3 years of age and could cooperate with MRI detection were subjected to liver and heart MRI T2* tests before or after HLA-identical allogeneic hematopoietic stem cell transplantation. According to the test results, we calculated the liver and cardiac iron content, defined as an indicator of liver and heart iron overload. Then, there was a correlation analysis between the liver and cardiac iron content and serum ferritin, time of hematopoietic reconstitution, mortality rate, implantation rate and the morbidity of transplantation related complications, such as graft-versus-host disease, infections, autoimmune hemolysis, pancytopenia, hepatic veno-occlusive disease, septicemia. RESULTS AND CONCLUSION: The liver iron content was positively correlated with the time of hemoglobin implantation (r=0.229, P=0.043), and the cardiac iron content were positively correlated with the mortality rate (r=0.266, P=0.017); the serum ferritin level was negatively correlated with the implantation rate (r=-0.289, P=0.009), and positively correlated with the morbidity of septicemia (r=0.251, P=0.024) and pancytopenia (r=0.276, P=0.013). Therefore, iron overload exerts negative effects on HLA-identical allogeneic hematopoietic stem cell transplantation in β-thalassemia major children, and it is necessary to detect serum ferritin level and assess liver and cardiac iron overload before cell transplantation.
10.Epidemiological survey of asthma among children aged 0-14 years in 2010 in urban Zhongshan, China.
Juan HUANG ; Dong-Ming HUANG ; Xiao-Xiong XIAO ; Si-Mao FU ; Cui-Mei LUO ; Guan ZENG ; Ye-Hong WANG ; Ke-Ming WANG ; Jian RUAN ; Bo-Qiang ZHEN ; Min LI ; Lan LI ; Bi-Yun CUI ; Gui-Zhen HUANG ; Gui-Lan WANG ; Jia-Yan RONG ; Jian-Mei HUANG ; Qiong-Qing XIAO ; Xiao-Ling GUO
Chinese Journal of Contemporary Pediatrics 2015;17(2):149-154
OBJECTIVETo investigate the prevalence, current treatment, and clinical characteristics of asthma, as well as the risk factors for this disease, among children aged 0-14 years in 2010 in urban Zhongshan, China.
METHODSA total of 10 336 children aged 0-14 years were selected from urban Zhongshan by cluster random sampling. The Third National Childhood Asthma Epidemiological Questionnaire 2010 was used to analyze the prevalence, current treatment, and clinical characteristics of childhood asthma, as well as the risk factors for this disease.
RESULTSAsthma was diagnosed in 179 cases (1.73%). The prevalence of asthma in male children was significantly higher than that in female children (2.25% vs 1.16%; P<0.01). Of the 179 patients, severe attacks were common in 104 cases (58.1%), 110 cases (61.5%) had slow onset, 102 cases (57.0%) had gradually relieved conditions, 61 cases (34.1%) suffered from asthma during seasonal transition, and 150 cases (83.8%) developed asthma due to respiratory tract infection. Among all asthmatic children, 71.5% had been treated with inhaled corticosteroids, and 71.5% had been treated with bronchodilator. The multivariate logistic regression analysis showed that a history of penicillin allergy, a family history of allergy, food allergy, eczema, allergic rhinitis, cesarean delivery, family mould, and perinatal passive smoking were independent risk factors for childhood asthma.
CONCLUSIONSThe prevalence of childhood asthma in urban Zhongshan is on a high level, and is associated with gender. The treatment of asthma has been standardized, but still needs further improvement. The onset of asthma attack is influenced by various factors.
Adolescent ; Asthma ; epidemiology ; etiology ; Child ; Child, Preschool ; China ; epidemiology ; Female ; Humans ; Infant ; Infant, Newborn ; Male ; Risk Factors ; Seasons ; Time Factors

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