[Two different techniques combined with MIS-TLIF in the treatment of degenerative lumbar spondylolisthesis:a case-control study]

OBJECTIVE

To analyze the difference in clinical efficacy of minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) under Quadrant channel system combined with microscope and percutaneous pedicle screw in the treatment of degenerative lumbar spondylolisthesis.

METHODS

A total of 114 patients with single-segment degenerative lumbar spondylolisthesis from June 2015 to February 2019, were divided into three groups according to the surgical methods, such as the MIS-TLIF under the microscope surgery group ( microscope group), MIS-TLIF combined with percutaneous pedicle screw technique surgery group(percutaneous group) and posterior lumbar interbody fusion surgery group (open group). In the microscope group, there were 12 males and 26 females, aged from 42 to 83 years with an average of (63.29±9.09) years. In the percutaneous group, there were 16 males and 22 females, aged from 45 to 82 years with an average of (63.37±7.50) years. In the open group, there were 12 males and 26 females, aged from 51 to 82 years with an average of (63.76±8.21) years. The general conditions of operation, such as operation time, intraoperative blood loss, postoperative drainage, length of surgical incision, frequency of intraoperative fluoroscopy and postoperative time of lying in bed were recorded to analyze the differences in surgical related indicators. Visual analogue scale (VAS) of waist and leg pain in preoperative and postoperative period (3 days, 3 months, 6 months and 12 months) were recorded to evaluate pain remission;Oswestry Disability Index(ODI), Japanese Orthopaedic Association (JOA) score were recorded to evaluate the recovery of waist and leg function on preoperative and postoperative 12 months. The lumbar spondylolisthesis rate and intervertebral height at 12 months after operation were recorded to evaluate the reduction of spondylolisthesis. The Siepe intervertebral fusion standard was used to analyze the intervertebral fusion rate at 12 months after operation.

RESULTS

①All 114 patients were followed up more than 1 year, and no complications related to incision infection occurred. In the microscope group, there was 1 case of subcutaneous effusion 8 days after operation. After percutaneous puncture and drainage, waist compression, and then the healing was delayed. In the percutaneous group, 2 cases of paravertebral muscle necrosis occurred on the side of decompression, and the healing was delayed after debridement. In open group, there was 1 case of intraoperative dural tear, which was packed with free adipose tissue during the operation. There was no postoperative cerebrospinal fluid leakage and other related complications.① Compared with microscope group, percutaneous group increased in operation time, intraoperative blood loss, postoperative wound drainage, surgical incision length, intraoperative fluoroscopy times, and postoperative bed rest time. In open group, intraoperative blood loss, postoperative wound drainage, surgical incision length, and postoperative bed rest time increased, but the intraoperative fluoroscopy time decreased. Compared with percutaneous group, the intraoperative blood loss, wound drainage, surgical incision length, and postoperative bed rest time in open group increased, but operative time and the intraoperative fluoroscopy time decreased(P<0.05). ②ODI and JOA scores of the three groups at 12 months after operation were improved compared with those before operation (P<0.05), but there was no significant difference between the three group(P>0.05). ③Compared with microscope group, the VAS of low back pain in percutaneous group increased at 3 days after operation, and VAS of low back pain in open group increased at 3 days, and 12 month after operation. Compared with percutaneous group, the VAS low back pain score of the open group increased at 3 months after operation (P<0.05). ④ The lumbar spondylolisthesis rate of the three groups of patients at 12 months afrer operation was decreased compared with that before operation(P<0.05), and the intervertebral heigh was increased compared with that before operation(P<0.05), however, there was no significant difference among three groups at 12 months afrer operation(P>0.05). ⑤ There was no significant difference between three groups in the lumbar fusion rate at 12 months afrer operation(P>0.05).

CONCLUSION

The MIS-TLIF assisted by microscope and the MIS-TLIF combined with percutaneous pedicle screw are safe and effective to treat the degenerative lumbar spondylolisthesis with single-segment, and the MIS-TLIF assisted by microscope may be more invasive, cause less blood loss and achieve better clinical efficacy.

Computer-assisted cannulated screw internal fixation versus conventional cannulated screw internal fixation for femoral neck fractures: a systematic review and meta-analysis

Objective

To compare the effects between computer-assisted and traditional cannulated screw internal fixation on treating femoral neck fracture.

Methods

The search was conducted in Embase, Pubmed, Web of Science, Cochrane Library, China National Knowledge Infrastructure (CNKI) and Wanfang Database from the beginning to August 2020. RevMan5.4 software, which was provided by the International Cochrane Group, was used for the meta-analysis comparing the differences in operation time, intraoperative bleeding volume, fluoroscopy frequency, fracture healing time, total drilling times, Harris score, fracture healing rate, and femoral head necrosis rate between computer-assisted and traditional methods groups.

Results

A total of 1028 patients were included in 16 studies. Primary outcome indicators: Compared with the traditional method group, the computer-assisted group had less operative time (2RCTs, P < 0.00001; 8 non-RCTs, P = 0.009; Overall, P < 0.00001), intraoperative bleeding (1 RCTs, P < 0.00001; 9non-RCTs, P < 0.00001; Overall, P < 0.00001), femoral head necrosis rate (1 RCT, P = 0.11;7 non-RCTs, P = 0.09; Overall, P = 0.02) and higher Harris scores (1 RCT, P < 0.0001; 9 non-RCTs, P = 0.0002; Overall, P < 0.0001), and there were no significant differences in fracture healing rate between the two groups (5 non-RCTs, P = 0.17). Secondary outcomes indicators: The computer-assisted group had a lower frequency of intraoperative fluoroscopy and total number of drills compared with the traditional method group, while there was no significant difference in fracture healing time.

Conclusion

Compared with the traditional hollow screw internal fixation on the treatment of femoral neck fracture, computer-assisted percutaneous cannulated screw fixation can shorten the operation time and improve the operation efficiency and reduce the X-ray injury of medical staff and help patients obtain a better prognosis. Therefore, computer-assisted percutaneous cannulated screw fixation is a better choice for the treatment of femoral neck fracture.

Study registration PROSPERO registration number CRD42020214493.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-021-02806-7.

[Clinical study of modified one stage posterior approach total en block spondylectomy and spinal reconstruction in the treatment of invasive thoracic vascular tumor]

OBJECTIVE

To explore the surgical method and safety of modified one stage posterior approach total en block spondylectomy combined with pedicle screw fixation and titanium mesh reconstruction for the treatment of invasive thoracic vascular tumor.

METHODS

The clinical data of 12 patients with invasive thoracic vasculay tumor from December 2012 to May 2015 was retrospectively analyzed. There were 8 males and 4 females, aged from 40 to 62 years with an average of 51.2 years, the course of disease was 2 months to 8 years with an average of 3.4 years. The lesions involved vertebral bodies:1 case of T₂, 4 cases of T₄, 1 case of T₅, 2 cases of T₆, 2 cases of T₈, and 2 cases of T₁₀. According to Tomita classification, there were 3 cases of typeⅠ, 3 cases of typeⅡ, 1 case of type Ⅲ, and 5 cases of type Ⅳ. The Japanese Orthopaedic Association (JOA) score was 8.0±2.7 before operation. One patient with T₁₀ lesions had sensory dyskinesia below the umbilicus, and the muscle strength of both lower limbs was grade Ⅰ-Ⅱ, and the others 11 patients were grade Ⅲ-Ⅳ. All 12 patients underwent one stage posterior approach total en block spondylectomy and the pedicle screw fixation combined with titanium mesh reconstruction under general anesthesia and continuous motor evoked potential (MEP) spinal cord electrophysiological monitoring throughout the operation. The operation time, intraoperative blood loss and transfusion, postoperative pain and recovery of spinal cord function, bone graft fusion, tumor recurrence and other complications were followed up.

RESULTS

All the operations were successful. The average operation time, intraoperative blood loss and blood transfusion were 5.5 h (4.5 to 6.0 h), 1 850 ml (1 650 to 2 500 ml), 1 050 ml (600 to 1 500 ml), respectively. All 12 patients were followed up for 5 months to 2.5 years with an average of 21 months. Local pain and lower limb muscle strength were improved to varying, and the nerve compression symptoms disappeared. The JOA score at 6 months after operation was 12.0±3.4, which was statistically significant difference compared with the preoperative 8.0±2.7 (t=3.20, P<0.05). Titanium mesh bone grafts were all fused in phaseⅠ, with an average fusion time of 4.5 months (3 to 7 months). During the follow-up period, there was no tumor recurrence, loosening or breaking of nails, sinking and displacement of titanium mesh.

CONCLUSION

Modified one stage posterior approach total en block spondylectomy is an ideal surgical method for the treatment of invasive thoracic vascular tumors, which has a safe, reliable and long lasting efficacy.

PCAT6 may be a new prognostic biomarker in various cancers: a meta-analysis and bioinformatics analysis

Background

LncRNA prostate cancer-associated transcript 6 (PCAT6) has been reported to be dysregulated in several cancers and is associated with tumor progression. Here, we have performed a meta-analysis to assess the general prognostic role of PCAT6 in malignancies.

Methods

Four public databases (Embase, Pubmed, Web of Science, Cochrane Library) were used to identify eligible studies, then data was extracted and associations between prognostic indicators and clinical characteristics were combined to estimate hazard ratio (HR) or odds ratio (OR) with a 95% confidence interval (CI). Publication bias was measured using the Begg's test, and the stability of the combined results was measured using sensitivity analysis. Subsequently, results were validated using Gene Expression Profiling Interactive Analysis (GEPIA) and the National Genomics Data Center (NGDC).

Results

Ten studies were considered eligible for inclusion. In total, 937 patients and eight types of cancer were included. Our results revealed that overexpression of PCAT6 was significantly associated with a shorter OS (HR = 1.82; 95% CI, [1.40, 2.38]; P < 0.0001) and progression-free survival (PFS) (HR = 1.66; 95% CI, [1.22, 2.25]; P < 0.0001) in cancer patients, and that PCAT6 overexpression was significantly associated with individual tumor clinicopathological parameters, including TNM stage (OR = 0.29; 95% CI, [0.09, 0.94]; P = 0.04), gender (OR = 1.84; 95% CI, [1.31, 2.59]; P = 0.0005), and whether the tumor was metastatic (OR = 5.02; 95% CI, [1.36, 18.57]; P = 0.02). However, PCAT6 overexpression was not correlated with patient age and tumor differentiation. PCAT6 expression was significantly up-regulated in four types of cancer, which was validated using the GEPIA cohort. Combining OS and disease-free survival (DFS) of these four types of cancer revealed a shorter OS and DFS in patients with PCAT6 overexpression. PCAT6 expression in various types of cancer was also validated in NGDC. A total of eight cancers were analyzed and PCAT6 was highly expressed in all eight cancers. Further functional predictions suggest that PCAT6 is correlated with tumor prognosis, and that PCAT6 may be useful as a new tumor-specific marker.

Conclusions

LncRNA PCAT6 is highly expressed in multiple cancer types and its upregulation was significantly associated with patient prognosis and poorer clinical features, thereby suggesting that PCAT6 may be a novel prognostic factor in multiple cancer types.

[Application of apparent diffusion coefficient combined with serum tumor markers detection in evaluating neoadjuvant chemotherapy for osteosarcoma]

Objective: To discuss application of apparent diffusion coefficient (ADC) in diffusion weighted imaging (DWI) combined with serum alkaline phosphatase (ALP) and tumor specific growth factor (TSGF) in evaluating neoadjuvant chemotherapy for osteosarcoma. Methods: A total of 78 patients with osteosarcoma who were admitted to People's Hospital of Gansu from January 2016 to August 2018 were collected as study subjects. All the patients were treated with neoadjuvant chemotherapy. Before chemotherapy, at the end of 4 courses of chemotherapy, before and after surgery, MRI examination and detection of serum ALP and TSGF were performed. According to results of pathological examination, the 78 patients were divided into effective chemotherapy group (n=54) and ineffective chemotherapy group (n=24). ADC values, levels of serum ALP and TSGF, change rates of ADC values and levels of serum ALP and TSGF were compared between the two groups. The value of ADC value combined with serum ALP and TSGF in evaluating curative effect of neoadjuvant chemotherapy for osteosarcoma was analyzed with receiver operating characteristic curve (ROC). Results: After chemotherapy, ADC value in effective chemotherapy group increased significantly, while levels of serum ALP and TSGF decreased significantly (t=7.269, 18.778, 23.237, all P<0.05). Only after surgery, ADC value, levels of serum ALP and TSGF increased or decreased significantly in ineffective chemotherapy group (t=7.316, 15.083, 20.930, all P<0.05). Before and after chemotherapy, change rates of ADC values and levels of serum ALP and TSGF in effective chemotherapy group were all significantly higher than those in ineffective chemotherapy group (t=7.604, 5.482, 5.048, all P<0.05). ROC curve analysis showed that area under the curve (AUC) of ADC value combined with serum ALP and TSGF for evaluating curative effect of neoadjuvant chemotherapy was 0.912, which was higher than that of ADC value, ALP, TSGF, ADC value combined with ALP, ADC value combined with TSGF (0.847, 0.787, 0.701, 0.885, 0.876, respectively). Conclusion: ADC value combined with serum tumor markers ALP and TSGF is reliable in evaluating curative effect of neoadjuvant chemotherapy for osteosarcoma.

[Halo-pelvic traction combined with stageⅡsurgical correction for the treatment of severe and rigid scoliosis]

OBJECTIVE

To investigate the clinical effects of the Halo-pelvic traction combined with posterior instrumentation correction and internal fixation for the treatment of severe and rigid scoliosis.

METHODS

From January 2015 to 2019 May, 16 patients with severe and rigid scoliosis were treated by the Halo-pelvic traction combined with posterior instrumentation correction. There were 7 males and 9 females, aged 14 to 28 years with an average of 17.6 years, Cobb angle was 90° to 140° with an average of (108.84±17.93) °. Including congenital scoliosis in 10 cases (6 cases of dyssegmented scoliosis, 3 cases of dysplasia, 1 case of mixed scoliosis), idiopathic scoliosis in 4 cases and neurofibromatosis in 2 cases. All patients in group had scoliosis corrected by Halo-pelvic distraction combined with posterior instrumentation correction and internal fixation. Among them, 7 cases were treated with self-made guide device for iliac bone puncture, and the other cases with traditional bare hands. The height, scoliosis Cobb angle, kyphosis Cobb angle and correction rate of 16 patients before and after surgery were observed.

RESULTS

The body height was corrected from (144.88±6.32) cm to (154.56±7.87) cm ; Cobb angle of scoliosis was corrected from (108.84±17.93) ° to (42.12±7.29) °, Cobb angle of kyphosis was corrected from (64.18±16.39) ° to (33.81±6.06) °. After the Halo pelvic traction, the body height increase, Cobb angle of scoliosis and kyphosis were changed with the mean of (7.06± 5.65) cm, (41.50±9.09)%, (30.52±9.66)%, respectively. After the stage Ⅱ surgical correction, the body height increase, Cobb angle of scoliosis and kyphosis were changed with the mean of (2.63±1.78) cm, (32.47±10.80)%, (15.55±9.47)% (The baseline Cobb angle referenced by the correction rate was the Cobb angle of the previous treatment). The body height increase and correction rate of Cobb angle of scoliosis and kyphosis with staged traction combined with surgery was (9.69±5.42) cm, (61.09 ± 5.03)%, (46.07±8.60)%. There was significant difference in body height increase, correction rate of Cobb angle of scoliosis and kyphosis between before and after each period of treatment (P<0.05).

CONCLUSION

Treatment of severe and rigid scoliosis with Halo-pelvic traction combined with stage Ⅱ surgical correction can significantly correct deformities and improve appearance, and has fewer surgical complications and strong clinical operability.

[Minimal invasive surgery-transforaminal lumbar interbody fusion combined with expanded pedicle screw through Mast Quadrant channel for the treatment of senile pyogenic discitis and vertebral osteomyelitis]

OBJECTIVE

To investigate the feasibility and clinical efficacy of minimal invasive surgery-transforaminal lumbar interbody fusion (MIS-TLIF) combined with expanded pedicle screw (EPS) in the treatment of elderly patients with pyogenic discitis and vertebral osteomyelitis (PDVO).

METHODS

The clinical data of 11 elderly patients with pyogenic discitis and vertebral osteomyelitis treated from January 2016 to June 2017 were retrospectively analyzed, including 7 males and 4 females, aged from 59 to 79 years old with an average of (68.09±5.34) years. The MIS-TLIF technique was used assisted by the Quadrant channel under general anesthesia for the debridement and bone fusion of these 11 elderly patients. The posterior fixation was performed with EPS. The operation time, intraoperative blood loss, intraoperative blood transfusion, and postoperative time of out of bed, postoperative complications and erythrocyte sedimentation rate(ESR)were recorded. Visual analogue scale (VAS) was used to evaluate the clinical effects and the imaging data were used to observe lumbar fusion.

RESULTS

All the operations were successfully performed, the debridement was thorough, bone fusion was adequate, and no complications such as dural sac and nerve root injury were found. The operation time and intraoperative blood loss was(179.55±59.05) min and (174.55±49.22)ml, respectively. Concentrated red blood cells of (109.09±97.00) ml and plasma of (72.73±100.91) ml were given during operation. The time of out of bed was(1.19±0.83) d. All the incisions obtained healing at the first stage. The average follow-up time was(19.27±11.63) months. VAS scoring at 1 week and 6 months after surgery was 3.73±1.01 and 2.18±0.40;ESR at 6 weeks after surgery was(19.27±2.61) mm/h(decreased by more than 50%), at 6 months after surgery was (9.55±1.01) mm/h, both within normal range. During the follow-up period, all patients reached the clinical cure standard, and the bone fusion time was(5.54±1.51) months.

CONCLUSIONS

MIS-TLIF combined with EPS through Quadrant channel in the treatment of elderly patients with PDVO has achieved minimally invasive surgery. The feasibility of this method also has been verified and satisfactory clinical results have been achieved. It is a safe and reliable treatment for elderly patients with spinal suppurative osteomyelitis.

[Application of total en bloc spondylectomy in spinal tumors]

Total en bloc spondylectomy is a surgical technique cutting off tumors of spine and its satellite. Previous studies have shown that this technique could reduce postoperative recurrence rate of spinal tumor, but surgical indications are not unified. Wide application of spinal tumor surgical staging and life expectancy system make it more clear for surgery. However, it is difficult to carry out extensive operation for the characteristics of more bleeding, great difficulty and high risk. As for continuous improvement of TES technology, application of endoscopy and appearance of 3D printing artificial vertebral body could push the operation becoming mature.

[Progress on research of Madelung's deformity]

Madelung deformity is a rare deformity of forearm and wrist caused by growth disorders of distal radius ulnar and palmar epiphyseal. Current studies showed that its incidence mainly associated with trauma, epiphyseal developmental abnormalities, nutritional disorders and genetic deletion or mutation. The early clinical presentation is not typical, in middle and late time, wrist deformity and weak can appear. Plain film considered as the main means of diagnosis is often lack of early diagnosis significance. Although wrist joint magnetic resonance imaging showing early soft tissue and skeletal abnormalities were used for the early diagnosis of the disease, current domestic study in magnetic resonance imaging of this deformity is less. According to the size of the distal ulnar inclination angle and palm angle, this deformity can be divided into different types. The patients with severe deformity and symptoms usually need surgical intervention including ulna revision and osteotomy of the distal radius at present. Although the two operation can achieve good clinical results, the surgical trauma, infection and postoperative risk of joint activities are more.

[Intraosseous lipoma: retrospective analysis of 19 patients]

OBJECTIVE

To investigate the diagnostic and therapeutic procedures of intraosseous lipoma.

METHODS

From June 1986 to January 2016, 19 patients with intraosseous lipoma were treated including 12 males and 7 females, aged from 24 to 76 years, a predilection aged was from 40 to 50 years in 13 cases. Symptoms presented with pain or swelling in 15 patients, the lesions were found incidentally in 3 patients, another case was bone defect lipoma replacement after curettage of bone cyst for 4 years. On plain X-ray flims of all bones showed a well-circumscribed radiolucent area. Diagnosis was established with CT or MRI. Among them, 16 cases were treated by surgical operation, 3 cases were treated by concervative treatment. All patients' clinical data, histologic findings and X-ray, CT and MRI were analysed.

RESULTS

Total 19 patients were followed up from 9 to 42 months with an average of 15 months. There was no local tumor recurrence in 16 patients after excising the tumors, the remaining 3 patients showed no enlargement of the lesion.

CONCLUSIONS

Surgical intervention is considered as an unnecessary in the patients diagnosied intraosseous lipoma by MRI or CT. Patients with symptomatic should adopt surgical treatment with curettage and bone grafting.

The association between risk of limb fracture and type 2 diabetes mellitus

Background

Recently, increasing reports showed that the risk of fracture may be correlated with type 2 diabetes mellitus (T2DM). However, their results still remained controversial. Thus we performed a meta-analysis including 11 studies to estimate the risk factor of limb fracture in type 2 diabetes mellitus.

Materials and Methods

Databases including PubMed, Embase, Cochrane Library and Web of Science were searched to September, 2017. Risk Ratio (RR) with its 95% confidence intervals (CI) was used to evaluate the association between risk of limb fracture and type 2 diabetes mellitus. Two reviewers assessed the quality of all the included studies and extracted data for analysis independently.

Results

A total of 11 studies including 663,923 participants were included in this meta-analysis. Our analysis results showed that patients with type 2 diabetes mellitus had a significant association with risk of limb fracture (RR 1.18; 95% CI 1.02–1.35), including leg or ankle fracture (RR 1.80; 95% CI 1.13–2.87). Subgroup analysis showed individuals with type 2 diabetes had almost two-fold excessive risk of leg/ankle fracture in women and the pooled RR of leg/ankle fracture was 2.03 (95% CI 1.36–3.05; P = 0.0006).

Conclusions

The results of the present meta-analysis showed that individuals with type 2 diabetes mellitus had higher risk of limb fractures, and this relationship is more pronounced in leg or ankle fracture.

[Clinical application of anterior thoracoscopically assisted surgery with posterior one-stage total en block spondylectomy for thoracic spinal tumor]

OBJECTIVE

To investigate the clincial effects and feasibility of anterior thoracoscopically assisted surgery (TAS) with posterior one-stage total en block spondylectomy(TES) for thoracic spinal tumour.

METHODS

From October 2014 to January 2016, 4 patients with thoracic spinal tumour were treated by anterior thoracoscopically assisted surgery with posterior one-stage total en block spondylectomy. There were 2 males and 2 females, aged 16, 35, 46, 60 years. Courses of disease were 1, 4, 6, 9 months. The tumor occurred at T₄, T₆, T₁₃₀ segment in 1 case respectively, at double T7/T8 segments in 1 case. Preoperative visual analogue scores(VAS) were 4, 5, 6, 8 points. Frankel grade of neurologic function was grade B in 2, D in 1, and E in 1. SF-36 quality of life scores were 38, 65, 35, 29 points, including 2 cases of primary spinal tumors, 2 cases of metastatic spinal tumors. According to the classification of Tomita, 1 case was type III, 2 cases were type IV, 1 case was type VI. And according to the WBB staging, 4-9/ABCD was in 2 cases, 5-8/ABC compliated with 1-3 was in 1 case, 6-7/ABC was in 1 case. Surgical procedure: With lateral position, the thoracoscope channel was inserted. The involved intervertebral vessels and corresponding intercostal vessels were ligated, while the prevertebral large vessels were completely separated and protected. The front halves of superior and inferior involved vertebral discs were removed. Then the patients were changed to prone position, posterior one-stage total en block spondylectomy, titanium cage bone graft (allograft bone), pedicle screw fixation were performed.

RESULTS

All of the operations were successful and the patients were followed up for 34, 10, 11, 12 months. Pleural effusion occurred in 1 case after operation, and pleural closed drainage was done. All incisions got primary healing; and all patients showed significant pain relief (P<0.005), with the VAS score decreasing to 2(2 cases) and 3(2 cases) scores, 2 months after surgery. No nerve functional injury aggravated. SF-36 quality of life score obviously improved with postoperative scores for 88, 92, 71, 80 at 3 months after operation. No recurrent vertebral tumor, internal fixation lossening or breakage was found at follow-up points of 3, 6, 12 months. One patient with lung cancer died of multiple organ failure at 11 months after operation.

CONCLUSIONS

With anterior TAS, vertebral anterior vessels, intervertebral blood vessels, intercostal vessels were successfully separated or ligated, intraoperative bleeding was effectively controlled, lung and esophagus were effectively protected, and the tumor received wide excision. Anterior TAS and one-stage posterior TES could significantly reduce the surgical trauma and the risk of surgery.

Melt-metaphyseal and diphyseal osteotomy for correction of infantile Blount's disease: a long-term follow-up study

Blount's disease is an uncommon disorder of postero-medial proximal tibial physis. Blount described infantile and adolescent types. This study aims to describe using femur, tibia and fibula osteotomies to treat infantile Blount's disease. From May 1992 to May 2005, 7 patients of Blount's disease (3 males, 4 females) were included, whose age was range from 17 to 62 months. Femorotibial angle (FTA) was 31 ± 6° (range from 27° to 41°). Metaphyseal-diaphyseal angle (MDA) was 16 ± 4° (range from 13° to 24°). The femoral vara angle was 10 ± 4° (range from 2° to 23°). According to Langenskiold's classification, 3 patients were in stage II, 7 patients in stage III, and 2 patients in stage IV. Five cases were affected bilateral and 2 unilaterally, treated by famur, tibia and fibula valgus osteotomies, and a hip spica cast were used for 6 weeks after operation. Results indicated that all patients were followed up 3 to 16 years. FTA, MDA and femur diaphysis were measured, FTA was 2 ± 7°valgus (from 4° vara to 13° valgus). MDA was 1 ± 2°valgus (range from 0° to 12°). Femoral diaphyseal angle was 1 ± 3°valgus (range from 3° vara to 7° valgus). Six patients could walk without any knee pain, except for 1 patient with bilateral disorder feels his left genu uncomfortable after long time stand or work. His MDA was 12°, and FAT was -4°. In conclusion, femur, tibia and fibula osteotomies are useful for correction of Blount's disease. Recurrence and complication are less than those reported for Blount's disease.

Cell cycle transitions in early Xenopus development

Xenopus oocytes and embryos undergo two major maternally controlled cell-cycle transitions: oocyte maturation and the mid-blastula transition (MBT). During maturation, the essential order of events in the cell cycle is perturbed in that the M phases of Meiosis I and II occur consecutively without an intervening S phase. Use of U0126, a new potent inhibitor of MAPK kinase (MEK), shows that MAPK activation is essential to inhibit the anaphase-promoting complex and cyclin B degradation at the MI/MII transition. If MAPK is inactivated, cyclin B is degraded, S phase commences and meiotic spindles do not form. These events are restored in U0126-treated oocytes by a constitutively active form of the protein kinase p90Rsk. Thus all actions of MAPK during maturation are mediated solely by activation of p90Rsk. At the MBT, commencing with the 13th cleavage division, there are profound changes in the cell cycle. MBT events such as maternal cyclin E degradation and sensitivity to apoptosis are regulated by a developmental timer insensitive to inhibition of DNA, RNA or protein synthesis. Other events, such as zygotic transcription and the DNA replication checkpoint, are controlled by the nuclear:cytoplasmic ratio. Lengthening of the cell cycle at the MBT is caused by increased Tyr15 phosphorylation of Cdc2 resulting from degradation of the maternal phosphatase Cdc25A and continued expression of maternal Wee1. Ionizing radiation causes activation of a checkpoint mediating apoptosis when administered before but not after the MBT. Resistance to apoptosis is associated with increased p27Xic1, the relative fraction of Bcl-2 or Bax in pro- versus anti-apoptotic complexes, and the activity of the protein kinase Akt.

Spatial heterogeneity of calcium transient alternans during the early phase of myocardial ischemia in the blood-perfused rabbit heart

BACKGROUND

Optical mapping of cytosolic calcium transients in intact mammalian hearts is now possible using long-wavelength [Ca(2+)](i) indicators. We propose that beat-to-beat [Ca(2+)](i) transient alternans during ischemia may lead to spatial and temporal heterogeneity of calcium-activated membrane currents.

METHODS AND RESULTS

To test this hypothesis, isolated rabbit hearts were loaded with the fluorescent [Ca(2+)](i) indicator, rhod-2 AM, and imaged at 300 frames/sec during blood-perfused ischemic trials. High-quality [Ca(2+)](i) transients were recorded in each of 8 hearts.[Ca(2+)](i) transient alternans was never present in control records but occurred in each of the hearts during ischemia, with onset after 2 to 4 minutes. Alternans was confined to circumscribed regions of the heart surface 5 to 15 mm across. Multiple regions of alternans were found in most hearts, and regions that were out of phase with one another were found in 6 hearts. Quantitative maps of alternans were constructed by calculating an alternans ratio. This ratio behaved as a continuous variable that reached a maximum value in the center of the regions with alternans.

CONCLUSIONS

These results demonstrate marked spatial heterogeneity of the [Ca(2+)](i) transient during the early phase of ischemia, which could produce electrical instability and arrhythmias in large mammalian hearts.

The polo-like kinase Plx1 is required for activation of the phosphatase Cdc25C and cyclin B-Cdc2 in Xenopus oocytes

In the Xenopus oocyte system mitogen treatment triggers the G(2)/M transition by transiently inhibiting the cAMP-dependent protein kinase (PKA); subsequently, other signal transduction pathways are activated, including the mitogen-activated protein kinase (MAPK) and polo-like kinase pathways. To study the interactions between these pathways, we have utilized a cell-free oocyte extract that carries out the signaling events of oocyte maturation after addition of the heat-stable inhibitor of PKA, PKI. PKI stimulated the synthesis of Mos and activation of both the MAPK pathway and the Plx1/Cdc25C/cyclin B-Cdc2 pathway. Activation of the MAPK pathway alone by glutathione S-transferase (GST)-Mos did not lead to activation of Plx1 or cyclin B-Cdc2. Inhibition of the MAPK pathway in the extract by the MEK1 inhibitor U0126 delayed, but did not prevent, activation of the Plx1 pathway, and inhibition of Mos synthesis by cycloheximide had a similar effect, suggesting that MAPK activation is the only relevant function of Mos. Immunodepletion of Plx1 completely inhibited activation of Cdc25C and cyclin B-Cdc2 by PKI, indicating that Plx1 is necessary for Cdc25C activation. In extracts containing fully activated Plx1 and Cdc25C, inhibition of cyclin B-Cdc2 by p21(Cip1) had no significant effect on either the phosphorylation of Cdc25C or the activity of Plx1. These results demonstrate that maintenance of Plx1 and Cdc25C activity during mitosis does not require cyclin B-Cdc2 activity.

The critical role of the MAP kinase pathway in meiosis II in Xenopus oocytes is mediated by p90(Rsk)

BACKGROUND

During oocyte maturation in Xenopus, progesterone induces entry into meiosis I, and the M phases of meiosis I and II occur consecutively without an intervening S phase. The mitogen-activated protein (MAP) kinase is activated during meiotic entry, and it has been suggested that the linkage of M phases reflects activation of the MAP kinase pathway and the failure to fully degrade cyclin B during anaphase I. To analyze the function of the MAP kinase pathway in oocyte maturation, we used U0126, a potent inhibitor of MAP kinase kinase, and a constitutively active mutant of the protein kinase p90(Rsk), a MAP kinase target.

RESULTS

Even with complete inhibition of the MAP kinase pathway by U0126, up to 90% of oocytes were able to enter meiosis I after progesterone treatment, most likely through activation of the phosphatase Cdc25C by the polo-like kinase Plx1. Subsequently, however, U0126-treated oocytes failed to form metaphase I spindles, failed to reaccumulate cyclin B to a high level and failed to hyperphosphorylate Cdc27, a component of the anaphase-promoting complex (APC) that controls cyclin B degradation. Such oocytes entered S phase rather than meiosis II. U0126-treated oocytes expressing a constitutively active form of p90(Rsk) were able to reaccumulate cyclin B, hyperphosphorylate Cdc27 and form metaphase spindles in the absence of detectable MAP kinase activity.

CONCLUSIONS

The MAP kinase pathway is not essential for entry into meiosis I in Xenopus but is required during the onset of meiosis II to suppress entry into S phase, to regulate the APC so as to support cyclin B accumulation, and to support spindle formation. Moreover, one substrate of MAP kinase, p90(Rsk), is sufficient to mediate these effects during oocyte maturation.

Mitotic effects of a constitutively active mutant of the Xenopus polo-like kinase Plx1

During mitosis the Xenopus polo-like kinase 1 (Plx1) plays key roles in the activation of Cdc25C, in spindle assembly, and in cyclin B degradation. Previous work has shown that the activation of Plx1 requires phosphorylation on serine and threonine residues. In the present work, we demonstrate that replacement of Ser-128 or Thr-201 with a negatively charged aspartic acid residue (S128D or T201D) elevates Plx1 activity severalfold and that replacement of both Ser-128 and Thr-201 with Asp residues (S128D/T201D) increases Plx1 activity approximately 40-fold. Microinjection of mRNA encoding S128D/T201D Plx1 into Xenopus oocytes induced directly the activation of both Cdc25C and cyclin B-Cdc2. In egg extracts T201D Plx1 delayed the timing of deactivation of Cdc25C during exit from M phase and accelerated Cdc25C activation during entry into M phase. This supports the concept that Plx1 is a "trigger" kinase for the activation of Cdc25C during the G(2)/M transition. In addition, during anaphase T201D Plx1 reduced preferentially the degradation of cyclin B2 and delayed the reduction in Cdc2 histone H1 kinase activity. In early embryos S128D/T201D Plx1 resulted in arrest of cleavage and formation of multiple interphase nuclei. Consistent with these results, Plx1 was found to be localized on centrosomes at prophase, on spindles at metaphase, and at the midbody during cytokinesis. These results demonstrate that in Xenopus laevis activation of Plx1 is sufficient for the activation of Cdc25C at the initiation of mitosis and that inactivation of Plx1 is required for complete degradation of cyclin B2 after anaphase and completion of cytokinesis.

Purification and cloning of a protein kinase that phosphorylates and activates the polo-like kinase Plx1

The Xenopus polo-like kinase 1 (Plx1) is essential during mitosis for the activation of Cdc25C, for spindle assembly, and for cyclin B degradation. Polo-like kinases from various organisms are activated by phosphorylation by an unidentified protein kinase. A protein kinase, polo-like kinase kinase 1 or xPlkk1, that phosphorylates and activates Plx1 in vitro was purified to near homogeneity and cloned. Phosphopeptide mapping of Plx1 phosphorylated in vitro by recombinant xPlkk1 or in progesterone-treated oocytes indicates that xPlkk1 may activate Plx1 in vivo. The xPlkk1 protein itself was also activated by phosphorylation on serine and threonine residues, and the kinetics of activation of xPlkk1 in vivo closely paralleled the activation of Plx1. Moreover, microinjection of xPlkk1 into Xenopus oocytes accelerated the timing of activation of Plx1 and the transition from G2 to M phase of the cell cycle. These results define a protein kinase cascade that regulates several events of mitosis.

Activated polo-like kinase Plx1 is required at multiple points during mitosis in Xenopus laevis

Entry into mitosis depends upon activation of the dual-specificity phosphatase Cdc25C, which dephosphorylates and activates the cyclin B-Cdc2 complex. Previous work has shown that the Xenopus polo-like kinase Plx1 can phosphorylate and activate Cdc25C in vitro. In the work presented here, we demonstrate that Plx1 is activated in vivo during oocyte maturation with the same kinetics as Cdc25C. Microinjection of wild-type Plx1 into Xenopus oocytes accelerated the rate of activation of Cdc25C and cyclin B-Cdc2. Conversely, microinjection of either an antibody against Plx1 or kinase-dead Plx1 significantly inhibited the activation of Cdc25C and cyclin B-Cdc2. This effect could be reversed by injection of active Cdc25C, indicating that Plx1 is upstream of Cdc25C. However, injection of Cdc25C, which directly activates cyclin B-Cdc2, also caused activation of Plx1, suggesting that a positive feedback loop exists in the Plx1 activation pathway. Other experiments show that injection of Plx1 antibody into early embryos, which do not require Cdc25C for the activation of cyclin B-Cdc2, resulted in an arrest of cleavage that was associated with monopolar spindles. These results demonstrate that in Xenopus laevis, Plx1 plays important roles both in the activation of Cdc25C at the initiation of mitosis and in spindle assembly at late stages of mitosis.

Dual retinoblastoma-binding proteins with properties related to a negative regulator of ras in yeast

The retinoblastoma protein (Rb) interacts with multiple cellular proteins that mediate its cellular function. We have identified nine polypeptides that bind to the T-binding domains of Rb using an Rb affinity resin. RbAp48 and RbAp46 are quantitatively the major Rb-associated proteins purified by this approach. RbAp48 was characterized previously and was found to be related to MSI1, a negative regulator of Ras in the yeast Saccharomyces cerevisiae. Here we report the cloning and characterization of RbAp46. RbAp46 shares 89.4% amino acid identity with RbAp48. The internal WD repeats, which are found in a growing number of eukaryotic proteins, are conserved between RbAp46 and RbAp48. Like RbAp48, RbAp46 forms a complex with Rb both in vitro and in vivo and suppresses the heat-shock sensitivity of the yeast RAS2Val-19 strains. We have also isolated the murine cDNA homologs of RbAp48 and RbAp46. Although both mRNA can be detected in all mouse tissues, their mRNA levels vary dramatically between different tissues. No significant differences were observed in the expression patterns of these genes in most tissues except thymus, testis, and ovary/uterus, in which 2-fold differences were observed. Interestingly, the mouse and human RbAp48 amino acid sequences are completely identical, and the mouse and human RbAp46 differ only by one conserved amino acid substitution. These results suggest that RbAp48 and RbAp46 may have shared as well as unique functions in the regulation of cell proliferation and differentiation.

Identification of discrete structural domains in the retinoblastoma protein. Amino-terminal domain is required for its oligomerization

To characterize the protein product of the retinoblastoma tumor suppressor gene biochemically, a recombinant human protein was produced in an Escherichia coli expression system. The full-length protein, p110RB, and an amino-terminal truncated form, p56RB, were expressed and purified to near homogeneity by conventional chromatographic procedures. To probe the structural organization of the retinoblastoma protein the purified proteins were subjected to partial proteolysis by trypsin, chymotrypsin, and subtilisin. Four discrete structural domains were revealed in p110RB by this method. Two of these structural domains, found in both p56RB and p110RB, were mapped to the carboxyl-terminal half of the protein and corresponded to the SV40 large T binding domains defined previously by genetic methods. In addition two distinct domains in the amino-terminal half of the protein were also defined. A potential role for these newly defined amino-terminal domains was uncovered upon analysis of the purified proteins by nondenaturing polyacrylamide gel electrophoresis. p110RB revealed multiple bands by this method, suggesting the formation of oligomeric structures by the protein, while this property was not observed for p56RB. Electron microscopy of p110RB revealed linearly extended, macromolecular structures, further supporting the formation of homologous higher order structures by the full-length retinoblastoma protein. Analysis of the interactions between retinoblastoma protein molecules using the yeast two-hybrid system confirmed that the retinoblastoma protein could self-associate and that this association was mediated by interactions between the amino- and carboxyl-terminal ends of the protein. These observations suggest that the retinoblastoma protein contains multiple structural domains with the amino-terminal domains being required for oligomerization of the full-length protein.

A retinoblastoma-binding protein related to a negative regulator of Ras in yeast

The growth suppression function of the retinoblastoma protein (Rb) is though to be mediated by Rb binding to cellular proteins. p48 is one of the major proteins that binds to a putative functional domain at the carboxy terminus of the Rb protein. Here we report the isolation of a full-length complementary DNA (RbAp48) encoding p48. Complex formation between p48 and Rb occurs in vitro and in vivo, and apparently involves direct interaction between the proteins. Like Rb, p48 is a ubiquitously expressed nuclear protein. RbAp48 share sequence homology with MSI1, a negative regulator of the Ras-cyclic AMP pathway in the yeast Saccharomyces cerevisiae. Furthermore, like MSI1, human RbAp48 suppresses the heat-shock sensitivity of the yeast ira1 strains and RAS2Val19 strains. Interaction with p48 may be one of the mechanisms for suppression of growth mediated by Rb.

The retinoblastoma protein region required for interaction with the E2F transcription factor includes the T/E1A binding and carboxy-terminal sequences

Recent experiments in understanding the mechanism of the retinoblastoma protein (RB) function have revealed the existence of several cellular proteins that are complexed with RB. One of these cellular proteins is the E2F transcription factor, which was originally identified due to its inducibility by E1A during an adenovirus infection. The E2F recognition sequence is found in the promoters of several cellular genes involved in growth control, including several oncogenes. In this report, we provide evidence that the interaction of E2F and RB is mediated through a region on RB where viral oncogenes such as SV40 T antigen and adenovirus E1A bind and where tumorigenic mutations also cluster. Additional carboxy-terminal sequences are also required for the interaction with E2F. These observations provide evidence for a direct connection between tumor suppressor function and the gene expression program leading to cellular growth regulation.

Chemical synthesis, molecular cloning, and expression of the gene coding for the Trichosanthes trypsin inhibitor--a squash family inhibitor

The gene coding for a Trichosanthes trypsin inhibitor analog (Ala-6-TTI) in which methionine at position 6 was replaced by alanine was synthesized chemically. The synthetic gene was cloned into plasmid pWR590-1 and expressed in Escherichia coli as a fusion protein composed of beta-galactosidase fragment of 590 amino acid residues and (Ala-6)-TTI, with methionine as a connecting residue. After cyanogen bromide cleavage and reduction of the fusion protein, followed by refolding with trypsin-Sepharose 4B as a matrix and affinity chromatography on the immobilized enzyme, the fully active (Ala-6)-TTI was obtained. The trypsin inhibitory activity and amino acid composition of the recombinant (Ala-6)-TTI were consistent with those of the natural one. The (Ala-6)-TTI gene was also cloned into the secretion expression vector, pVT102U/alpha, in Saccharomyces cerevisiae. In order to make the reading frame of the gene compatible with the vector, a nucleotide was inserted into the (Ala-6)-TTI gene via site-directed mutagenesis. The secreted (Ala-6)-TTI was purified and found to be correctly processed at the junction between the alpha-factor leader peptide and (Ala-6)-TTI downstream. Of the two expression systems, the latter is more advantageous in the high yield (greater than 2 mg/liter), easy purification and needlessness of disulfide refolding.

The retinoblastoma gene product regulates progression through the G1 phase of the cell cycle

The RB gene product is a nuclear phosphoprotein that undergoes cell cycle-dependent changes in its phosphorylation status. To test whether RB regulates cell cycle progression, purified RB proteins, either full-length or a truncated form containing the T antigen-binding region, were injected into cells. Injection of either protein early in G1 inhibits progression into S phase. Co-injection of anti-RB antibodies antagonizes this effect. Injection of RB into cells arrested at G1/S or late in G1 has no effect on BrdU incorporation, suggesting that RB does not inhibit DNA synthesis in S phase. These results indicate that RB regulates cell proliferation by restricting cell cycle progression at a specific point in G1 and establish a biological assay for RB activity. Neither co-injection of RB with a T antigen peptide nor injection into cells expressing T antigen prevents cells from progressing into S phase, which supports the hypothesis that T antigen binding has functional consequences for RB.

Expression of the human retinoblastoma gene product pp110RB in insect cells using the baculovirus system

The product of the retinoblastoma susceptibility gene (RB) was overproduced in cultured insect cells using the baculovirus expression system. Upon insertion of the cloned human RB complementary DNA sequence into the viral genome downstream of the promoter of the polyhedrin gene, full-length RB protein with an apparent molecular weight of 110,000 was expressed in the insect cells. This protein was found to be phosphorylated, located in the nuclei of the infected cells, and immunologically indistinguishable from pp110RB of human cells as assayed by several anti-RB antibodies. Following cell disruption and a one-step immunoaffinity chromatographic purification, 6-12 mg of soluble pp110RB with approximately 95% purity were obtained per liter of infected suspension culture. Characterization of the two known biochemical properties of RB protein showed that this purified protein from insect cells behaved similarly to the authentic human pp110RB. First, it bound to DNA, and second, it could form a specific complex with SV40 T antigen in vitro. Prompt translocation of the protein from cytoplasm to nucleus after microinjection further indicated that the purified RB protein may be active. The availability of soluble, intact, and presumably active pp110RB in large quantity represents a significant advance for studying the biochemical and biophysical properties of the RB gene product as well as its potential biological function in cancer suppression.

Studies on natural and modified peptide Trichosanthes trypsin inhibitors

A peptide trypsin inhibitor was isolated and purified from the roots of Trichosanthes kirilowii (a Chinese medical herb) by using immobilized anhydro-trypsin affinity chromatography and HPLC C18 column reverse chromatography. It contains two major components, both consisting of 27 amino acid residues with three pairs of disulfide bonds. The sequence determination indicated that the difference between them is only in the ninth position, being Gln and Lys, respectively. The peptide bond of the inhibitor reactive site Arg-Ile (3-4) is easy to cleave at low pH by trypsin, resulting in a modified inhibitor. It might be the smallest naturally occurring protein inhibitor so far known. The modification reaction of the Trichosanthes inhibitor with trypsin is similar to the catalytic enzyme-substrate reaction. The dissociation constant of the modified inhibitor with trypsin is around fourfold that of the natural inhibitor.