[Establishment of a platelet production model by bone marrow cavity transplantation of mouse primary megakaryocytes].

Objective: To establish an intramedullary transplantation model of primary megakaryocytes to evaluate the platelet-producing capacity of megakaryocytes and explore the underlying regulatory mechanisms. Methods: Donor megakaryocytes from GFP-transgenic mice bone marrow were enriched by magnetic beads. The platelet-producing model was established by intramedullary injection to recipient mice that underwent half-lethal dose irradiation 1 week in advance. Donor-derived megakaryocytes and platelets were detected by immunofluorescence staining and flow cytometry. Results: The proportion of megakaryocytes in the enriched sample for transplantation was 40 to 50 times higher than that in conventional bone marrow. After intramedullary transplantation, donor-derived megakaryocytes successfully implanted in the medullary cavity of the recipient and produce platelets, which showed similar expression of surface markers and morphology to recipient-derived platelets. Conclusion: We successfully established an in vivo platelet-producing model of primary megakaryocytes using magnetic-bead enrichment and intramedullary injection, which objectively reflects the platelet-producing capacity of megakaryocytes in the bone marrow.

Establishment of a platelet production model by bone marrow cavity transplantation of mouse primary megakaryocytes / 中华血液学杂志

Objective: To establish an intramedullary transplantation model of primary megakaryocytes to evaluate the platelet-producing capacity of megakaryocytes and explore the underlying regulatory mechanisms. Methods: Donor megakaryocytes from GFP-transgenic mice bone marrow were enriched by magnetic beads. The platelet-producing model was established by intramedullary injection to recipient mice that underwent half-lethal dose irradiation 1 week in advance. Donor-derived megakaryocytes and platelets were detected by immunofluorescence staining and flow cytometry. Results: The proportion of megakaryocytes in the enriched sample for transplantation was 40 to 50 times higher than that in conventional bone marrow. After intramedullary transplantation, donor-derived megakaryocytes successfully implanted in the medullary cavity of the recipient and produce platelets, which showed similar expression of surface markers and morphology to recipient-derived platelets. Conclusion: We successfully established an in vivo platelet-producing model of primary megakaryocytes using magnetic-bead enrichment and intramedullary injection, which objectively reflects the platelet-producing capacity of megakaryocytes in the bone marrow.

Relationship between blood loss of proximal femoral nail anti-rotation fixation and local use combined with intravenous injection of tranexamic acid / 中国组织工程研究

BACKGROUND: Tranexamic acid has been shown to effectively reduce dominant and hidden blood loss in patients undergoing proximal femoral nail antirotation fixation, and it is safe and effective. At present, the use of tranexamic acid in this operation is mainly divided into intravenous infusion and local intramedullary perfusion; intravenous infusion can be divided into single use or multiple uses, and most of the local use is single use. For the combined local use with intravenous infusion is rarely reported. However, the combined use of tranexamic acid in hip and knee arthroplasties has been proven to be safe and effective. OBJECTIVE: To explore the effectiveness and safety of intravenous combined with local application of tranexamic acid on the perioperative blood loss in proximal femoral nail antirotation. METHODS: Ninety patients with intertrochanteric fracture who underwent proximal femoral nail antirotation in Shantou Hospital of Traditional Chinese Medicine from January 2016 to December 2018 were enrolled, and randomly divided into combined, intravenous and local groups (n=30/group). All patients signed the informed consents and the study was approved by the hospital ethical committee. In the combined group, tranexamic acid (20 mg/kg dissolved in 20 mL normal saline) was injected intravenously at 30 minutes before surgery, followed by femoral intracavitary injection of tranexamic acid (1 g, dissolved in 20 mL normal saline) after proximal femoral nail antirotation. Intravenous group only underwent intravenous injection of tranexamic acid. Local group only received femoral intracavitary injection of tranexamic acid. The total blood loss, dominant blood loss, hidden blood loss, International Normalized Ratio, prothrombin time, activated partial thromboplastin time, blood transfusion rate and the incidence of deep venous thrombosis were counted and compared in the three groups. RESULTS AND CONCLUSION: (1) The total blood loss in the combined group was significantly less than that in the intravenous and local groups (P 0.05). (2) The hidden blood loss in the combined group was significantly less than that in the intravenous and local groups (P 0.05). (3) There was no significant difference in the dominant blood loss among groups (P > 0.05). (4) The International Normalized Ratio, prothrombin time, and activated partial thromboplastin time before and after surgery showed no significant difference among groups (P > 0.05). (5) The blood transfusion rate showed no significant difference among groups (P > 0.05). (6) None presented with deep venous thrombosis. (7) These results suggest that compared with single intravenous and intracavitary injection of tranexamic acid, their combination can obviously reduce total and hidden blood loss of proximal femoral nail antirotation without increasing the risk of deep venous thrombosis. In addition, single intravenous and intramedullary injection of tranexamic acid has no significant difference in total or hidden blood loss.

Growth factor-mediated augmentation of long bones: evaluation of a BMP-7 loaded thermoresponsive hydrogel in a murine femoral intramedullary injection model.

BACKGROUND: Due to our aging population, an increase in proximal femur fractures can be expected, which is associated with impaired activities of daily living and a high risk of mortality. These patients are also at a high risk to suffer a secondary osteoporosis-related fracture on the contralateral hip. In this context, growth factors could open the field for regenerative approaches, as it is known that, i.e., the growth factor BMP-7 (bone morphogenetic protein 7) is a potent stimulator of osteogenesis. Local prophylactic augmentation of the proximal femur with a BMP-7 loaded thermoresponsive hydrogel during index surgery of an osteoporotic fracture could be suitable to reduce the risk of further osteoporosis-associated secondary fractures. The present study therefore aims to test the hypothesis if a BMP-7 augmented hydrogel is an applicable carrier for the augmentation of non-fractured proximal femurs. Furthermore, it needs to be shown that the minimally invasive injection of a hydrogel into the mouse femur is technically feasible. METHODS: In this study, male C57BL/6 mice (n = 36) received a unilateral femoral intramedullary injection of either 100 µl saline, 100 µl 1,4 Butan-Diisocyanat (BDI)-hydrogel, or 100 µl hydrogel loaded with 1 µg of bone morphogenetic protein 7. Mice were sacrificed 4 and 12 weeks later. The femora were submitted to high-resolution X-ray tomography and subsequent histological examination. RESULTS: Analysis of normalized CtBMD (Cortical bone mineral density) as obtained by X-ray micro-computed tomography analysis revealed significant differences depending on the duration of treatment (4 vs 12 weeks; p < 0.05). Furthermore, within different anatomically defined regions of interest, significant associations between normalized TbN (trabecular number) and BV/TV (percent bone volume) were noted. Histology indicated no signs of inflammation and no signs of necrosis and there were no cartilage damages, no new bone formations, or new cartilage tissues, while BMP-7 was readily detectable in all of the samples. CONCLUSIONS: In conclusion, the murine femoral intramedullary injection model appears to be feasible and worth to be used in subsequent studies that are directed to examine the therapeutic potential of BMP-7 loaded BDI-hydrogel. Although we were unable to detect any significant osseous effects arising from the mode or duration of treatment in the present trial, the effect of different concentrations and duration of treatment in an osteoporotic model appears of interest for further experiments to reach translation into clinic and open new strategies of growth factor-mediated augmentation.

[Intramedullary injection with tethered cord : Case report of a rare complication during spinal anesthesia]. / Intramedulläre Injektion bei "tethered cord" : Fallbericht einer seltenen Komplikation bei Spinalanästhesie.

Although very rare, severe neurological complications can occur when undergoing spinal anesthesia. This report describes and analyses a case of spinal injury due to an undiagnosed tethered cord (TC) during spinal anesthesia for a cesarean section of a 31-year-old woman expecting twins. As a consequence of spinal dysraphism during embryogenesis, an atypically low conus level can occur and increase the risk of injury during neuraxial anesthesia, especially in the absence of symptoms. Injuries can be caused by mechanical trauma from direct needle injury, hematoma or neurotoxicity from local anesthetics. Special attention should therefore be paid to frequent symptoms, such as a hairy nevus on the back, deformities of the feet or bladder and bowels, voiding and micturition dysfunction in order to reduce the risk of complications.

THERAPEUTIC EFFECT OF INTRAMEDULLARY INJECTION OF FETAL LIVER CELL SUSPENSION ON THE LETHALLY IRRADIATED MICE / 第二军医大学学报

This paper describes the study on intramedullary injection of fetal liver cell suspension into the lethally irradiated mice. The results show that the therapeutic effect of intramedullary injection is better than that of intravenous one.It is suggested that the fetal liver cells injected into the bone marrow cavity can settle down and proliferate here and the volume of injection should be limited.