Non-invasive prediction of preeclampsia using the maternal plasma cell-free DNA profile and clinical risk factors.

Background: Preeclampsia (PE) is a pregnancy complication defined by new onset hypertension and proteinuria or other maternal organ damage after 20 weeks of gestation. Although non-invasive prenatal testing (NIPT) has been widely used to detect fetal chromosomal abnormalities during pregnancy, its performance in combination with maternal risk factors to screen for PE has not been extensively validated. Our aim was to develop and validate classifiers that predict early- or late-onset PE using the maternal plasma cell-free DNA (cfDNA) profile and clinical risk factors. Methods: We retrospectively collected and analyzed NIPT data of 2,727 pregnant women aged 24-45 years from four hospitals in China, which had previously been used to screen for fetal aneuploidy at 12 + 0 ~ 22 + 6 weeks of gestation. According to the diagnostic criteria for PE and the time of diagnosis (34 weeks of gestation), a total of 143 early-, 580 late-onset PE samples and 2,004 healthy controls were included. The wilcoxon rank sum test was used to identify the cfDNA profile for PE prediction. The Fisher's exact test and Mann-Whitney U-test were used to compare categorical and continuous variables of clinical risk factors between PE samples and healthy controls, respectively. Machine learning methods were performed to develop and validate PE classifiers based on the cfDNA profile and clinical risk factors. Results: By using NIPT data to analyze cfDNA coverages in promoter regions, we found the cfDNA profile, which was differential cfDNA coverages in gene promoter regions between PE and healthy controls, could be used to predict early- and late-onset PE. Maternal age, body mass index, parity, past medical histories and method of conception were significantly differential between PE and healthy pregnant women. With a false positive rate of 10%, the classifiers based on the combination of the cfDNA profile and clinical risk factors predicted early- and late-onset PE in four datasets with an average accuracy of 89 and 80% and an average sensitivity of 63 and 48%, respectively. Conclusion: Incorporating cfDNA profiles in classifiers might reduce performance variations in PE models based only on clinical risk factors, potentially expanding the application of NIPT in PE screening in the future.

Treatment of Early Undifferentiated Chronic Monoarthritis of the Wrist by Arthroscopic Wrist Synovectomy Combined with Partial Denervation.

OBJECTIVE: Undifferentiated chronic monosecarthritis (UCMA) is a group of inflammatory joint diseases that has the potential to progress to other diseases and can seriously affect patients' quality of life. There is yet no unified consensus regarding treatment of UCMA. This study aimed to investigate the efficacy of arthroscopic synovectomy combined with partial wrist denervation in treating Larsen 1-3 UCMA. METHODS: In this case series, we reviewed 14 patients with UCMA treated by arthroscopic synovectomy combined with partial denervation from February 2017 to June 2020. The mean duration of symptoms was 17.4 months (range, 4-60 months), and the mean follow-up was 13.3 months (range, 6-23 months). The anterior and posterior interosseous nerves were severed at the distal forearm, and the radiocarpal, midcarpal, and distal radial ulnar joint synovial membranes were arthroscopically resected at the wrist. The clinical evaluation indices included the visual analogue scale score (VAS) for pain, grip strength, range of (active) motion of the wrist, total active motion, and Mayo wrist score. Larsen's scoring method was used as the imaging evaluation index. RESULTS: At the last follow-up, significant clinical improvements were observed in the visual analogue scale (VAS) score for pain (6.0 (5.0-6.3) vs 1.0 (1.0-2.3), P = 0.001) and Mayo wrist score (42.1 ± 9.7 vs 61.8 ± 12.3, P < 0.0001). No significant changes were found in grip strength (15.9 ± 4.5 vs 16.6 ± 4.7, P = 0.230) or the flexion-extension arc (58.9 ± 39.0 vs 64.3 ± 36.5, P = 0.317), although the mean and median did show positive changes. Among the three patients who showed progress in imaging, there was no significant difference in their pain and functional scores compared to those who did not progress. One patient underwent total wrist fusion 17 months after the operation. CONCLUSION: Arthroscopic wrist synovectomy combined with partial wrist denervation can provide sustained pain relief and functional recovery for patients with Larsen 1-3 UCMA.

Aberrant expression of circular RNA DHPR facilitates tumor growth and metastasis by regulating the RASGEF1B/RAS/MAPK axis in hepatocellular carcinoma.

BACKGROUND: Circular RNAs (circRNAs) are noncoding RNAs. Accumulating evidence suggests that circRNAs play a critical role in human biological processes, especially tumorigenesis, and development. However, the exact mechanisms of action of circRNAs in hepatocellular carcinoma (HCC) remain unclear. METHODS: Bioinformatic tools and RT-qPCR were used to identify the role of circDHPR, a circRNA derived from the dihydropteridine reductase (DHPR) locus, in HCC and para-carcinoma tissues. Kaplan-Meier analysis and the Cox proportional hazard model were used to analyze the correlation between circDHPR expression and patient prognosis. Lentiviral vectors were used to establish stable circDHPR-overexpressing cells. In vitro and in vivo studies have shown that tumor proliferation and metastasis are affected by circDHPR. Mechanistic assays, including Western blotting, immunohistochemistry, dual-luciferase reporter assays, fluorescence in situ hybridization, and RNA immunoprecipitation, have demonstrated the molecular mechanism underlying circDHPR. RESULTS: CircDHPR was downregulated in HCC, and low circDHPR expression was associated with poor overall survival and disease-free survival rates. CircDHPR overexpression inhibits tumor growth and metastasis in vitro and in vivo. Further systematic studies revealed that circDHPR binds to miR-3194-5p, an upstream regulator of RASGEF1B. This endogenous competition suppresses the silencing effect of miR-3194-5p. We confirmed that circDHPR overexpression inhibited HCC growth and metastasis by sponging miR-3194-5p to upregulate the expression of RASGEF1B, which is regarded as a suppressor of the Ras/MAPK signaling pathway. CONCLUSIONS: Aberrant circDHPR expression leads to uncontrolled cell proliferation, tumorigenesis, and metastasis. CircDHPR may serve as a biomarker and therapeutic target for HCC.

FGF23 promotes proliferation, migration and invasion by regulating miR-340-5p in osteosarcoma.

BACKGROUND: Increasing evidences have been indicated that FGF23 is associated with the biological behavior of malignant tumors, but its role in osteosarcoma and the specific mechanism need to be elucidated. The purpose of this study is to investigate the effects of FGF23 on the proliferation, migration and invasion of osteosarcoma cells, and the possible molecular mechanisms. METHODS: Western blot was used to detect differences in FGF23 expression in osteosarcoma cells MG-63 and U2-OS and osteoblasts hFOB1.19. FGF23-overexpressing adenoviruses and FGF-silencing plasmids were transfected into osteosarcoma cells, and transfection efficiency was verified using Western blot. MTT and colony formation assays were performed to detect osteosarcoma cell proliferation. Cell cycle was measured by flow cytometry. Scratch assay, holographic imaging cell analyzer Holomonitor ® M4 and transwell were applied to detect cell migration and invasion. Dual-luciferase reporter assay was performed to validate the interaction between FGF23 and miR-340-5p. Changes in miR-340-5p mRNA levels were measured by QRT-PCR. RESULTS: FGF23 is highly expressed in osteosarcoma cells compared to hFOB1.19. Overexpression of FGF23 significantly promoted the proliferation, migration and invasion of MG-63 and U2-OS cells. MiR-340-5p is a target of FGF23. Transfection of miR-340-5p mimics reversed the promoting effects of FGF23 on proliferation, migration and invasion of MG-63 and U2-OS cells. CONCLUSION: FGF23 promotes osteosarcoma cell proliferation, migration and invasion by targeting miR-340-5p gene expression.

Two-Year Clinical Outcomes after Arthroscopic Re-Excision of Recurrent Dorsal Wrist Ganglion Cyst.

OBJECTIVES: Arthroscopic excision of dorsal wrist ganglion (DWG) cysts has recently become an alternative to open surgery, with the advantage of lower recurrence. However, in recurrent cases, whether re-excision using an arthroscopic approach would achieve favorable outcomes has not been determined. This study aimed to evaluate the clinical outcomes of function evaluation and recurrence rate after arthroscopic excision of recurrent DWG cysts. METHODS: A total of 11 consecutive patients with clinically diagnosed recurrent DWG cysts were retrospectively reviewed between November 2017 and March 2020. Extensive re-excision of the ganglion cyst and its surrounding pathological capsule was performed using an arthroscopic approach. Magnetic resonance imaging (MRI) was routinely performed before surgery to identify the location and limits of the cyst. All patients were followed up for a minimum of 2 years. A second recurrence was recorded if a mass reappeared at the same site with a positive transillumination test. Pain during activity was evaluated using the visual analog scale (VAS). The active range of motion (ROM) of the wrist was measured using a goniometer, and the hand grip strength was measured using a digital dynamometer. Comparative analysis between the pre- and postoperative indexes was performed using Student's t-test. RESULTS: After a mean follow-up period of 29.3 months (range, 24-34 months), no second recurrence of the cyst was recorded. The VAS score improved from 1.4 to 0.3 (t = 3.833, p = 0.003), and residual pain was reported by three patients (VAS score = 1 for each). Active wrist flexion increased from 73.6° to 78.2° (t = 2.887, p = 0.016). No significant changes were found in active wrist extension or hand grip strength (p > 0.05). No major complications occurred during the study. CONCLUSION: Arthroscopic excision of a recurrent DWG cyst yielded satisfactory results with no second recurrence, significant pain relief, and good wrist function at a minimum of 2-year follow-up. Clear identification of the location and limits of the ganglion based on preoperative MRI could be helpful to achieve complete excision and therefore prevent a second recurrence.

SIRT6 Prevents Glucocorticoid-Induced Osteonecrosis of the Femoral Head in Rats.

Objective: Glucocorticoid-induced osteonecrosis of the femoral head is one of the most common causes of nontraumatic osteonecrosis of the femoral head, but its exact pathogenesis remains unclear. The aim of this study was to investigate the role of SIRT6 in the maintenance of bone tissue morphology and structure, intravascular lipid metabolism, and its potential molecular mechanism in glucocorticoid-induced osteonecrosis of the femoral head. Methods: SIRT6 adenovirus was transfected into GIONFH in rats. The microstructure of rat bone was observed by micro-CT and histological staining, and the expression of bone formation-related proteins and angiogenesis-related factors was determined through western blot and immunohistochemistry. Alkaline phosphatase activity, alizarin red staining, and the expression levels of Runx2 and osteocalcin were used to evaluate the osteogenic potential. And in vitro tube formation assay and immunofluorescence were used to detect the ability of endothelial cell angiogenesis. Results: Dexamethasone significantly inhibited osteoblast differentiation, affected bone formation, and destroyed microvessel formation, increased the intracellular Fe2+ and ROS levels and induced the occurrence of ferroptosis. SIRT6 can inhibit ferroptosis and restore the ability of bone formation and angiogenesis. Conclusion: SIRT6 can inhibit the occurrence of ferroptosis, reduce the damage of vascular endothelium, and promote osteogenic differentiation, so as to prevent the occurrence of osteonecrosis of the femoral head.

Anatomical and clinical study of a new mallet fracture classification method.

BACKGROUND: Mallet fracture is avulsion of the terminal extensor tendon from the base of the distal phalangeal bone with a bony fragment. This study was performed to evaluate the anatomical characteristics of mallet fractures, investigate a new mallet fracture classification system using anatomical and imaging methods, and discuss the treatment schemes for different types of mallet fracture. METHODS: Sixty-four fresh cadaveric fingers were divided into four groups, and models of different types of mallet fracture with distal interphalangeal joint instability were established by dissecting 25%, 50%, 75%, and 100% of the bilateral collateral ligaments. The effect of mallet fractures on the stability of the distal interphalangeal joint was then observed. The lateral radiographs of mallet fractures in 168 patients were analyzed and classified according to the involvement of the joint surface in the fracture, the thickness of fracture, the untreated time after injury, and the complication of distal interphalangeal joint palmar subluxation. Forty-seven patients were surgically treated by reconstruction of extensor tendon insertion, the Ishiguro method, or single Kirschner wire fixation. RESULTS: The established mallet fracture model showed that the distal interphalangeal joint was stable when the bilateral collateral ligaments were cut off by 25% (t = -0.415, P = 0.684) and significantly unstable when this range was ≥50% (50% transection: t = -6.363, P < 0.001; 75% transection: t = -17.036, P < 0.001; 100% transection: t = -30.977, P < 0.001, respectively). The mallet fractures were divided into Types I, II, and III (fracture involving <20%, 20%-50%, and >50% of the joint surface, respectively). Type II was further divided into Types IIa and IIb according to whether the course of injury was < or ≥2 weeks, respectively. The mean post-operative flexion of the distal interphalangeal joint was 63.4°â€Š±â€Š7.9°, and the mean extension lag was 6.7°â€Š±â€Š4.6°. CONCLUSIONS: The lateral collateral ligament is the main factor that maintains the stability of the distal interphalangeal joint. Classification that combines the involvement of the joint surface in the fracture, the thickness of the fracture, and the untreated time after injury is reasonable and will help to choose an appropriate operational method.

Role of Pigment Epithelium-Derived Factor in Arsenic-Induced Vascular Endothelial Dysfunction in a Rat Model.

Water-borne arsenicosis is caused by the consumption of excess levels of inorganic arsenic from drinking water and is a worldwide public health issue. Arsenic exposure has recently attracted extensive attention due to its damage to the cardiovascular system. Vascular endothelial dysfunction (VED) is recognized as an important cause of cardiovascular diseases. Pigment epithelium-derived factor (PEDF) plays an important role in maintaining endothelial function, and our previous studies suggested that PEDF may have role in arsenic-induced damage. In the present study, we established subchronic arsenic exposure (3 months) rat model from drinking water at doses of 0, 2 mg/L, 10 mg/L, and 50 mg/L, respectively. The results showed that the endothelial cells of the aortic arch were obviously damaged, the apoptosis rate increased, the vWF and iNOS levels increased, and the NO and TNOS levels significantly decreased in the arsenic exposure groups. Regardless of serum or aortic arch endothelium, PEDF levels in the arsenic exposure groups decreased compared to the control group. The oxidative stress level and key proteins associated with apoptosis such as Fas, FasL, P53, and p-p38 were then detected to explore the detailed mechanisms. The results showed that the P53 and p-p38 levels significantly increased in the 10 mg/L and 50 mg/L groups compared to the control group. The MDA content in the arsenic exposure groups increased markedly, whereas the SOD activity decreased significantly with the increased arsenic dose. Taken together, our study is the first to find that PEDF plays a protective role in arsenic-induced endothelial dysfunction through anti-oxidation and anti-apoptosis, and p38 and P53 may be promising target proteins.

Insulin treatment prevents the increase in D-serine in hippocampal CA1 area of diabetic rats.

PURPOSE: Diabetes is a high risk factor for dementia. Employing a diabetic rat model, the present study was designed to determine whether the content of D-serine (D-Ser) in hippocampus is associated with the impairment of spatial learning and memory ability. METHODS: Diabetes was induced by a single intravenous injection of streptozotocin (STZ). The insulin treatment began 3 days after STZ injection. RESULTS: We found that both water maze learning and hippocampal CA1 long-term potentiation (LTP) were impaired in diabetic rats. The contents of glutamate, D-Ser, and serine racemase in the hippocampus of diabetic rats were significantly higher than those in the control group. Insulin treatment prevented the STZ-induced impairment in water maze learning and hippocampal CA1-LTP in diabetic rats and also maintained the contents of glutamate, D-Ser, and serine racemase at the normal range in hippocampus. CONCLUSIONS: These results suggest that insulin treatment has a potent protection effect on CA1-LTP, spatial learning and memory ability of the diabetic rats in vivo. Furthermore, insulin may take effect by inhibiting the overactivation of N-methyl-d-aspartate receptors, which play a critical role in neurotoxicity.

Closed reduction external fixator fixation versus open reduction internal fixation in the patients with Bennett fracture dislocation.

BACKGROUND: The Bennett fracture is either a common or a challenging problem to hand surgeons. It is still debated whether closed or open reduction gives optimal results. This study aimed to describe and assess a closed reduction and mini-external fixator fixation technique for the treatment of Bennett's fracture dislocation and to compare this technique versus open reduction and internal fixation. METHODS: From October 2002 to December 2012, 56 patients with Bennett's fracture dislocation were treated by closed reduction and mini-external fixator fixation and 32 patients were treated by open reduction and internal fixation in Jishuitan Hospital. Patients with an articular step-off of more than 1 mm were excluded. All patients were assessed at a mean follow-up of 7 years (range 2-10 years) and the two groups were compared with pain levels, active range of trapeziometacarpal motion, grip strength and pinch strength, arthritic changes, and adduction deformity. RESULTS: Based on primary closed reduction maintained , the rate of anatomic reduction is 63.6%. Radiographic fracture union was achieved in all patients at a mean time of 5 weeks. At the final follow-up, there was no difference between the two groups in mean union time and pain levels (P = 0.2). There was also no difference between the two groups regarding the active range of trapeziometacarpal motion (P = 0.3), grip stength (P = 0.6), pinch strength (P = 0.2), arthritic change and loss of reduction (P = 0.2). There was a significant correlation between adduction deformity and the development of arthritis (P = 0.02). CONCLUSION: Closed reduction mini-external fixator fixation should be first tried to apply in the treatment of Bennett's fracture dislocation, and open reduction internal fixation should only be performed for irreducible fractures.

Ligament reconstruction with tendon interposition arthroplasty for first carpometacarpal joint osteoarthritis.

BACKGROUND: Ligament reconstruction tendon interposition (LRTI) is the most commonly performed surgical procedure for first carpometacarpal joint osteoarthritis. The purpose of this study was to examine the radiographic and clinical outcomes of LRTI arthroplasty and document the clinical results based on metacarpal subsidence. METHODS: From January 2008 to January 2011, 19 patients (21 thumbs) underwent surgery for thumb carpometacarpal arthritis using ligament reconstruction tendon interposition arthroplasty with flexor carpi radialis (FCR) in Kleinert Kutz Hand Care Center of Louisville University, USA. The follow-up period was an average of 13.9 months. Pain, grip strength, tip pinch strength, range of motion, and radiographic measurements were recorded. Based on first metacarpal subsidence, the cases were classified in to mild, moderate, and severe. Clinical outcomes of the groups were evaluated and compared. RESULTS: Grip strength improved from 18.6 kg to 20.5 kg, and tip pinch strength increased from 4.4 kg to 4.5 kg after the surgery. Radial abduction and palmar abduction improved after surgery. Radial abduction increased from 55.7° to 60.6° and palmar abduction improved from 56.7° to 63.5° after the procedure. Visual analogue scores (VAS) were significantly reduced, from 6.6 to 0.5. Compared with the preoperative radiographs the first metacarpal had subsided about 54.6% of the arthroplasty space. The height of arthroplasty space and index of the arthroplasty space significantly decreased from 12.4 mm to 5.6 mm and from 0.27 to 0.12 respectively. Between the various groups (mild, moderate and severe metacarpal subsidence), there was no difference in grip strength, tip pinch strength, thumb range of motion, and VAS. CONCLUSIONS: Ligament reconstruction tendon interposition arthroplasty resulted in excellent relief of pain and increase in range of motion. However, LRTI cannot maintain the arthroplasty space. Compared with the preoperative radiographs, the metacarpal subsided more than 50%. The amount of first metacarpal subsidence has no bearing on the results.

[Dorsal intercarpal ligament capsulodesis for chronic static scapholunate dissociation].

OBJECTIVE: To investigate the radiographic and clinical outcomes of dorsal intercarpal ligament capsulodesis (DILC) procedure for chronic static scapholunate dissociation. METHODS: Between January 2008 and January 2011, 12 patients with chronic static scapholunate dissociation were treated with DILC. Of 12 cases, 10 were male and 2 were female with an average age of 42 years (range, 20-66 years). All injuries were caused by falling. The interval from injury to surgery was 3-19 months (mean, 8 months). Physical examination at admission showed wrist tenderness and limited range of motion (ROM). Radiological examination showed that scapholunate gap was greater than 3 mm on posteroanterior view, and scapholunate angle more than 60° on the lateral view. Before operation, the grip strength was (25.4 ± 8.2) kg; the wrist ROM was (56.7 ± 11.5)° in flexion and (52.0 ± 15.2)° in extension; visual analogue scale (VAS) score was 6.3 ± 1.4; and disabilities of arm, shoulder & hand (DASH) score was 39.5 ± 7.4. According to Garcia-Elias staging criteria, all cases were rated as stage 4, indicating that the scapholunate interosseous ligament was completely injured and reduction could easily be obtained. Eight patients had wrist instability. RESULTS: Primary healing of incision was achieved, no complication was found. All patients were followed up 13-34 months (mean, 15.9 months). During surgery, all deformities were corrected completely, but 7 patients (58%) recurred at 1 month after Kirschner wire removal. Compared with preoperative ones, the scapholunate gap, scapholunate angle, radiolunate angle, lunocapitate angle, and wrist height ratio at 1 month after Kirschner wire removal and last follow-up showed no significant difference (P > 0.05); the wrist flexion and extension ROM were significantly decreaed to (46.8 ± 7.2)° and (42.0 ± 9.0)° at last follow-up (P < 0.05); the grip strength was significantly increased to (32.7 ± 9.6) kg at last follow-up (P < 0.05); VAS score and DASH score were improved to 1.7 ± 1.0 and 8.1 ± 8.7 (P < 0.05). CONCLUSION: Carpal collapse will recur in short time after DILC. DILC is not the best way to treat chronic static scapholunate dissociation.

[Epidemiological features of acute hand injuries in daily life in Beijing area].

OBJECTIVE: To study the composition, distribution, and influencing factors of acute hand injuries in daily life in the Beijing area by analyzing the clinical data from patients with acute hand injuries. METHODS: Between April 1st 2005 to September 30th 2005, 2575 patients with acute hand injuries in daily life from Beijing area were investigated by questionnaire. The epidemiological factors were analyzed, including gender, age, injury time, injury cause, accident place, injury mechanism, and location. RESULTS: The 2 575 patients injuried in daily life accounted for 49.2% of all. Most of them were young males, and the male to female ratio was 3.3:1. Most of the patients were 21-30 years old. The most common accident place was resting place (43.3%), and next was outdoors (28.8%) and leisure place (20.0%). Accidental injury was the major injury cause, accounted for 51.0%, followed by injury after drinking (16.1%) and violence (15.5%). The major injury mechanism was cutting (52.23%), followed by collision (16.04%) and falling (15.18%). A total of 2 405 patients were right hander, and handedness affected the distribution of injured hands significantly. Open injuries accounted for 70.7% of the patients, and the tissues in deep layer were involved in the injury in 54.4% of all. CONCLUSION: Hand injury in daily life is a common problem, which has its own epidemiological features. More appropriate measures should be taken to decrease the incidence.

Management of intra-articular fracture of the fingers via mini external fixator combined with limited internal fixation.

BACKGROUND: Intra-articular fractures of the fingers are common problems to emergency physicians and hand surgeons. Inappropriate management of these injuries may result in chronic pain, stiffness, deformity, or post traumatic arthritis. Ideal treatment necessitates the restoration of a stable and congruent joint that will allow early mobilization. The purpose of this study was to investigate the results of intra-articular fracture of the fingers by mini external fixator combined with limited internal fixation. METHODS: From May 2005 to May 2007, a total of 26 patients with intra-articular fracture of the fingers were treated by mini external fixator combined with limited internal fixation. Of the 26 cases, 11 involved in metacarpophalangeal joint, and 15 interphalangeal joint in proximal interphalangeal. Kirschner wire, mini wire and absorbable suture were used for limited internal fixation. All patients were followed up and patients were accomplished with total active motion (TAM) of fingers. RESULTS: All patients were reviewed by an independent observer. The mean follow up was 13 months (range 9 to 24 months). Subjective, objective and radiographic results were evaluated. X-ray films revealed fracture union and the average radiographic union time was 7 weeks with a range of 5 - 12 weeks and the phalange shortening or rotation in 2 cases, joint incongruity (less than 1 mm) and joint space narrowing in 3 cases respectively. Phalangeal shortening or rotation was observed in 2 cases and joint incongruity or joint space narrowing was observed in 3 cases. An artificial implant was performed on one case for traumatic arthritis 1.5 years after surgery. Based on TAM the overall good-excellent rate of joint motion function was 80.8%. CONCLUSION: Mini external fixator combined with limited internal fixation is a reliable and effective method for treatment of intra-articular fracture of the fingers.

Early pre-implantation lethality in mice carrying truncated mutation in the RNA polymerase 1-2 gene.

Ribosomal DNA (rDNA) transcription by RNA polymerase I (Pol I) is an important initial step for the production of ribosomes. The RNA polymerase 1-2 (Rpo1-2) gene is comprised of 15 exons and encodes 1135 amino acids (aa) of the second largest subunit in Pol I. In a gene trap screen, we have identified an insertional mutation (Rpo1-2(Gt)) in the 14th exon of Rpo1-2, resulting in a truncation of 312aa from the C-terminal. In Rpo1-2(Gt/Gt) embryos, the synthesis of rRNA was severely impaired. Rpo1-2(Gt/Gt) embryos could develop to the morula stage, and thereafter displayed nucleolus disruption and apoptotic cell death. These results indicate that the loss of rDNA transcription induced nucleolar structure disorganization and apoptosis in preimplantation embryos.

[Antegrade intramedullary fixation of the neck and subcapital fractures of the fifth metacarpal].

OBJECTIVE: To investigate the treatment of the displaced neck and subcapital fractures of the fifth metacarpal. METHODS: Thirty-one patients with the neck and subcapital fractures of the fifth metacarpal had been operated on with antegrade intramedullary fixation between January and August 2005. There was 11 subcapital fractures (group A), and 20 neck fractures (group B). Following closed reduction of the fracture, a blunt 2.0 mm diameter K-wire, which was pre-bent into 20 degrees at the distal end, was inserted into the medullary canal of the fifth metacarpal and fixed the fractures. Postoperatively, patients in group A were immobilized in a short arm plaster splint for 4 weeks, and the ones in group B were treated with unrestricted mobilization. RESULTS: Operative time was 18 min averagely (range 5 to 30 min). Twenty-nine of 31 patients obtained anatomic reduction, and 2 patients had 2/3 apposition of bone end and no rotational deformity. Follow-up was available for all patients. The average follow-up interval was 4 months, with a range of 3 - 6 months. The head/shaft angle of the fifth metacarpal in group A was 63.4 degrees +/- 14.5 degrees preoperatively, and 15.0 degrees +/- 2.5 degrees postoperatively, and 15.4 degrees +/- 2.6 degrees in 3 months postoperatively. The difference between preoperative and postoperative angles was highly significant. The range of motion of the metacarpal joint was 89.5 degrees +/- 4.3 degrees postoperatively, which was not significantly different compared with that of uninjured side. The head/shaft angle in group B was 59.1 degrees +/- 10.0 degrees preoperatively, and 15.9 degrees +/- 2.5 degrees postoperatively, and 15.5 degrees +/- 2.8 degrees in 3 months postoperatively. The difference between preoperative and postoperative angles was highly significant. The range of motion of the metacarpal joint was 88.6 degrees +/- 3.6 degrees postoperatively, which was not significantly different compared with that of uninjured side. CONCLUSIONS: The technique is technically easy to perform, minimally invasive, low-cost, allowing early hand mobilization, with good functional results and low morbidity, and it has been proved to be an ideal method.