Management of bone defects due to infected non-union or chronic osteomyelitis with autologous non-vascularized free fibular grafts.

OBJECTIVES: Bone defects as a result of infected non-union or chronic osteomyelitis are difficult to manage. The purpose of this study was to present the results of treatment of bone defects of < 6 cm due to a previous infected non-union or chronic osteomyelitis with autologous non-vascularized fibular grafts in a 2-stage surgery. PATIENTS AND METHODS: The records of patients who were treated with autologous non-vascularized fibular grafts for bone defects of < 6 cm due to a previous infected non-union or chronic osteomyelitis between 2008 and 2013 were retrospectively reviewed. Primary complete bone union was the primary outcome. Time until fracture union, and return to normal daily activities or previous work were recorded. Radiographs were evaluated for graft hypertrophy as well as for stress fracture and other complications. RESULTS: A total of 27 cases were included. The mean length of the bone defects was 4.4 cm (range 2 - 6 cm). Complete union and healing occurred in 25/27 patients (primary success rate of 92.6%). Non-union was present in two patients with suboptimal soft tissue condition 10 months after surgery, one patient was subsequently treated with a vascularized free fibular graft from the contralateral fibula, and the other patient was treated with distraction osteogenesis, bone union was achieved after the second surgery. Average time to return to normal daily activity after surgery was 7.82 months (6 ~ 11 months). Graft hypertrophy occurred in 15 cases 15/25 (60%) two years post-surgery. There were no other surgical or postoperative complications. CONCLUSIONS: With careful evaluation of soft-tissue condition surrounding bone defect, management of infected bone defects with autologous non-vascularized fibular grafts technique has a high success rate with few complications.

Hypoxia-induced activation of specific members of the NF-kB family and its relevance to pulmonary vascular remodeling.

BACKGROUND AND OBJECTIVE: Pulmonary Hypertension (pH) is a chronic progressive disease. Endothelial cells (EC) play a central and critical role in the initiation and progression of pH. The NF-κB family (NF-κB1 (p50/p105), NF-κB2 (p52/p100), RelA (p65), RelB, and C-Rel) regulates a wide array of genes involved in inflammatory responses, cell proliferation, and survival. The involvement of specific NF-κB family members in the pathogenesis of hypoxia-induced pH remains to be determined. The objective of this study was to assess the specific role of individual NF-κB family members in mediating endothelial cell responses to hypoxia and its downstream effect on smooth muscle cell proliferation. METHODS AND RESULTS: NF-κB family members' expression were selectively reduced by siRNA in human pulmonary microvascular endothelial cells. Cells were then exposed to hypoxia (1%) for 24h. Endothelin1, ICAM1 gene expression and Stat1 and Stat3 phosphorylation were assessed. Smooth muscle cells (SMC) proliferation was assessed by culturing them with EC conditioned media. Reduction of either NF-κB2 or RelA in EC, led to a significant decrease in Endothelin1 and ICAM1 gene expression. C-Rel knockdown resulted in a significant increase in phosphorylated STAT1; both C-Rel and RelA knockdown significantly decreased phosphorylated STAT3 in EC. There was a significant reduction in SMC proliferation, and AKT/ERK phosphorylation in SMC, when cultured in RelA knockdown, EC conditioned media. CONCLUSION: RelA in EC plays crucial role in hypoxia induced vascular remodeling and development of pH. Targeting RelA in EC alleviates SMC proliferation as well as inflammation related processes.

Factors That Regulate the Generation of Antibody-Secreting Plasma Cells.

The generation of antigen-specific neutralizing antibodies and memory B cells is one of the most important immune protections of the host and is the basis for successful vaccination strategies. The protective antibodies, secreted by preexisting long-lived plasma cells and reactivated antigen-experienced memory B cells, constitute the main humoral immune defense. Distinct from the primary antibody response, the humoral memory response is generated much faster and with greater magnitude, and it produces antibodies with higher affinity and variable isotypes. Humoral immunity is critically dependent on the germinal center where high-affinity memory B cells and plasma cells are generated. In this chapter, we focus on recent advances in our understanding of the molecular mechanisms that govern fate decision for memory B cells and plasma cells and the mechanisms that maintain the long-lived plasma-cell pool, with emphasis on how the transcription factor Blimp-1 (B lymphocyte-induced maturation protein-1) helps regulate the above-mentioned immunoregulatory steps to ensure the production and maintenance of antibody-secreting plasma cells as well as how it directs memory cell vs plasma-cell fate. We also discuss the molecular basis of Blimp-1 action and how its expression is regulated.

Aiolos collaborates with Blimp-1 to regulate the survival of multiple myeloma cells.

The transcriptional repressor B lymphocyte-induced maturation protein-1 (Blimp-1) has crucial roles in the control of plasma cell differentiation and in maintaining survival of plasma cells. However, how Blimp-1 ensures the survival of plasma cell malignancy, multiple myeloma (MM), has remained elusive. Here we identified Aiolos, an anti-apoptotic transcription factor of MM cells, as a Blimp-1-interacting protein by mass spectrometry. ChIP coupled with DNA microarray was used to profile the global binding of Aiolos and Blimp-1 to endogenous targets in MM cells, which revealed their co-binding to a large number of genes, including apoptosis-related genes. Accordingly, Blimp-1 and Aiolos regulate similar transcriptomes in MM cells. Analysis of the binding motifs for Blimp-1 and Aiolos uncovered a partial motif that was similar across sites for both proteins. Aiolos promotes the binding of Blimp-1 to target genes and thereby enhances Blimp-1-dependent transcriptional repression. Furthermore, treatment with an anti-MM agent, lenalidomide, caused ubiquitination and proteasomal degradation of Blimp-1, leading to the de-repression of a new Blimp-1 direct target, CULLIN 4A (CUL4A), and reduced Aiolos levels. Accordingly, lenalidomide-induced cell death was partially rescued by reintroduction of Blimp-1 or knockdown of CUL4A. Thus, we demonstrated the functional impacts and underlying mechanisms of the interaction between Aiolos and Blimp-1 in maintaining MM cell survival. We also showed that interruption of Blimp-1/Aiolos regulatory pathways contributes to lenalidomide-mediated anti-MM activity.

B lymphocyte-induced maturation protein 1 (BLIMP-1) attenuates autoimmune diabetes in NOD mice by suppressing Th1 and Th17 cells.

AIMS/HYPOTHESIS: Recent reports indicate that B lymphocyte-induced maturation protein 1 (BLIMP-1), encoded by the Prdm1 gene, expands its control over T cells and is associated with susceptibility to colitis in mice with T cell-specific BLIMP-1 deficiency. In this study, we aimed to investigate the potential role of BLIMP-1 in regulating autoimmune diabetes and T helper type 17 (Th17) cells. METHODS: We generated T cell-specific Blimp1 (also known as Prdm1) transgenic (Tg) or conditional knockout (CKO) NOD mice, in which Blimp1 is overexpressed or deleted in T cells, respectively. By side-by-side analysing these Tg or CKO mice, we further dissected the potential mechanisms of BLIMP-1-mediated modulation on autoimmune diabetes. RESULTS: Overproduction of BLIMP-1 in T cells significantly attenuated insulitis and the incidence of diabetes in NOD mice. Consistent with these results, the diabetogenic effect of splenocytes was remarkably impaired in Blimp1 Tg mice. Moreover, overproduction of BLIMP-1 repressed the proliferation and activation of lymphocytes and enhanced the function of regulatory T cells (Tregs) in NOD mice. In contrast, mice lacking BLIMP-1 in T cells markedly increased Th1 and Th17 cells, and developed highly proliferative and activated lymphocytes. Strikingly, overexpansion of Th1 and Th17 cells in CKO mice was significantly reduced by introducing a Blimp1 transgene, reinforcing the emerging role of BLIMP-1 in autoimmunity. CONCLUSIONS/INTERPRETATION: We conclude that BLIMP-1 orchestrates a T cell-specific modulation of autoimmunity by affecting lymphocyte proliferation and activation, Th1 and Th17 cell differentiation, and Treg function. Our results provide a theoretical basis for developing BLIMP-1-manipulated therapies for autoimmune diabetes.

Handedness in diplegic cerebral palsy.

OBJECTIVE: To determine if the frequency of left-handedness is high in children with spastic cerebral diplegia. DESIGN: Case-control study. METHODS: One hundred and eleven children with spastic diplegic cerebral palsy and 444 age- and gender-matched controls were studied. The handedness of each child was assigned on the basis of responses to questions on the hand preference for writing and drawing, feeding and throwing a ball. The data were analysed by conditional logistic regression and computing the odds ratio and 95% confidence intervals for left handedness. RESULTS: Of the 111 children with spastic diplegic cerebral palsy, 45 were left-handed, while 13 of 444 normal children were left-handed. The odds ratio for left-handedness in children with diplegic cerebral palsy as compared to normal children was 27.33 (95% CI = 11.63, 64.25). CONCLUSION: The study shows that left-handedness is very frequently encountered in children with spastic diplegic cerebral palsy.

The effect of posterior cervical distraction on foraminal dimensions utilizing a screw-rod system.

STUDY DESIGN: Cadaveric human cervical spine anatomic study using posterior lateral mass screw-rod instrumentation to assess foraminal enlargement via distraction techniques. OBJECTIVES: To determine the role of posterior cervical distraction on foraminal dimensions and to ascertain the impact of this technique on segmental kyphosis. SUMMARY OF BACKGROUND DATA: Management of cervical spondylotic radiculopathy includes removal of offending compressive structures and enlarging the neuroforamen via anterior discectomy with interbody fusion or posterior laminoforaminotomy. METHODS: Six human cervical spines were prepared and posterior exposure performed. Lateral mass screws were inserted from C5 to C7 and a longitudinal rod attached. Distraction was applied between the screw heads at 2 mm intervals and accuracy confirmed with digitized calipers. Pre- and postdistraction computed tomography was performed including axial and reformatted images. Foraminal area, height, and width and sagittal alignment and disc heights were evaluated. RESULTS: The results suggest that minimal posterior distraction of 4 to 6 mm at C5-C6 and C6-C7 may enlarge the neuroforamen by 10 to 18 mm. Foraminal height and width increased minimally from baseline to maximum distraction; however, these measurements did not reach statistical significance at either level. A decrease of segmental lordosis at C5-C6 was noted from baseline to 8 mm of distraction. Statistically significant kyphosis from baseline was present at 6 mm of distraction leading to overall 5.2 +/- 1.4degrees change in alignment. At C6-C7, statistically significant kyphosis was not present until 8 mm of distraction (4.62 +/- 2.23degrees). CONCLUSIONS: This study suggests that posterior cervical instrumented distraction in the setting of foraminal stenosis is a reasonable supplement to direct laminoforaminotomy and nerve root decompression. Distraction leads to minimal segmental kyphosis, allowing this technique to serve as an adjunct for additional foraminal enlargement.