Radiographic and complication evaluation of 2 different bioresorbable pins in hallux valgus corrective surgery.

Osteotomies to correct hallux valgus are usually secured using metal implants. Their main disadvantage is the need for a repeat surgery for removal of implanted material. Bioresorbable implants would make it possible to overcome this complication. Few studies analyse the results of using bioresorbable pins. The primary objective of this study is to compare hallux valgus correction radiographic results with the use of two types of bioresorbable pins. The secondary objectives are to screen for possible complications related to the use of these bioresorbable pins. This is a descriptive, retrospective, single-centre study carried out between May 2018 and May 2022 in the orthopaedic surgery department of the Centre Chirurgical Emile Gallé at the CHRU in Nancy (France). The study involved 105 hallux valgus (98 patients) operated on by open double metatarsal and phalangeal osteotomy. Osteotomies were stabilised with resorbable polylactic acid (PLLA) pins (Arthrex® TRIM-IT® drill pin) in 57 cases (53 patients), and with resorbable polylactic acid-polyglycolic acid copolymer (PGLA) pins (Bioretec® ActivaPins®) in 48 cases (45 patients). The efficacy of hallux valgus correction was analysed in terms of changes in preoperative and postoperative radiographic parameters at 1 and 6 months on a weight-bearing foot. Descriptive statistics were used to describe the demographic and radiological parameters of each group. The mean age was 59.7 years (range 25-81 years) in the PLLA group and 56 years (range 23-78 years) in the PGLA group. The mean preoperative HVA was 30° (range 15-63°) in the PLLA group and 30.8° (range 15-57°) in the PGLA group. The mean preoperative IMA was 14.4° (range 7-30°) in the PLLA group and 13.8° (range 7-20°) in the PGLA group. There was a statistically significant correction of hallux valgus in the PLLA (p=5.24 X 10-15 ) and PGLA (p=3.56 X 10-13 ) groups. The mean correction for the hallux valgus angle was 13° in the PLLA group and 12° in the PGLA group. There was no statistically significant difference in hallux valgus correction between the PLLA and PGLA groups, particularly in terms of hallux valgus severity. There was no radiological or clinical complication in the groups related to bioresorbable pins. The use of bioresorbable pins allows effective stabilisation of osteotomies to correct hallux valgus. There was no significant difference in correction between PLLA and PGLA implants, regardless of the severity of the hallux valgus. We did not observe any obvious clinical or radiological complications related to their use. The use of bioresorbable osteosynthesis material in forefoot surgery seems to offer interesting advantages, providing patients with safer and less invasive treatment solutions.

Treatment of presumed aseptic non-union of the humeral shaft by osteosynthesis combining intramedullary nailing and screw plate.

In 2020, the most common treatment for presumed aseptic non-union of the humeral shaft seems to be decortication, often associated with bone autografting, and stabilized by a screw plate. We propose to evaluate an original technique of rigid osteosynthesis combining intramedullary nailing and screw plate. Between January 2004 and January 2020, 45 patients underwent treatment of presumed aseptic non-union of the humeral shaft by osteosynthesis combining intramedullary nailing and a screw plate. The minimum radio-clinical follow-up was one year postoperatively. The series included 19 men and 26 women with a mean age of 53 years (range 19-84 years). Bone consolidation was achieved in 43 patients, a rate of 95.5%. Comparing patients who achieved bone consolidation with the two failed consolidations did not reveal any statistically significant factor. Interobserver agreement was almost perfect (k=0.93) for the use of the RUST for humeral shaft fractures treated with intramedullary nailing and screw plate. In our study, the treatment of presumed aseptic non- union of the humeral shaft with an osteosynthesis combining intramedullary nailing and screw plate gives, with 95.5% of bone consolidation, results equal to or even superior to the different treatments currently described in the literature.

Rat monoclonal antibodies. III. A simple method for facilitation of hybridoma cell growth in vivo.

Hybridoma cells that did not grow when injected subcutaneously or intraperitoneally in histocompatible or Rnu/Rnu rats were injected intravenously into histocompatible recipients. Eight of the 9 cell lines injected in this way grew in several organs of the recipient 3-7 weeks later. Hybridoma cells proliferated mainly in the liver. When the liver homogenate of these animals was injected intraperitoneally into histocompatible recipients, hybridoma cells grew readily giving rise to ascites containing the expected monoclonal antibody for 6 of the 9 cell lines.

Discordant heart xenografts in the rat. Additional effect of plasma exchange and cyclosporine, cyclophosphamide, or splenectomy in delaying hyperacute rejection.

Natural antidonor antibodies are known to play a prominent role in hyperacute xenograft rejection. The aim of this work was to devise an experimental protocol to prolong the survival time of guinea pig heart xenografts transplanted into rats. A technique of continuous plasma exchange adapted to small animals was used to remove the natural cytotoxic antibodies from the recipient prior to the transplantation. In some experiments, cyclosporine (CsA), cyclophosphamide (CY), or splenectomy were associated with the plasma exchange. In this highly discordant xenogenic donor-recipient combination, the mean graft survival time in nontreated rats was 16 min. When an exchange of 1.5 plasma volume was performed 24 hr before the transplantation, no prolongation of the graft survival time was observed. When CsA, CY, or splenectomy were associated with the plasma exchange, the graft survival time was significantly increased by more than 2500% (up to 418 min with CsA). When used isolately, none of these 3 immunosuppressive methods was able to prolong the graft survival time. Natural cytotoxic antibodies were monitored by a complement-mediated cytotoxicity assay. After a plasma exchange, the titers decreased from 1:16-1:32 to 1:1-1:2. When no immunosuppressive method was associated with the plasma exchange, the antibodies returned to their initial level within the 24 hr that preceded the transplantation, and the graft was rejected as in nontreated animals. When an immunosuppressive method was associated with the plasma exchange, and particularly in the case of CsA, the titers remained low, and the hyperacute rejection was delayed. Therefore, it can be concluded that plasma exchanges, associated with CsA, are an efficient experimental protocol in the rat to increase the survival time of guinea pig heart xenografts. The effect of the treatment is correlated with the decrease in natural cytotoxic antidonor antibodies.

Effect of cyclosporine A on mercury-induced autoimmune glomerulonephritis in the Brown Norway rat.

To test the effect of cyclosporine A (CsA) in mercuric chloride (HgCl2)-induced nephritis in the Brown-Norway (BN) rat, we treated groups of intoxicated rats with varying doses of CsA for a period of 2 months. All manifestations of HgCl2-induced disease were prevented in rats treated concurrently with CsA at either 7 or 10 mg/kg/day. Partial suppression was evident at lower daily doses, but not with bi-weekly CsA administration. The initial phase of HgCl2-induced nephritis could be completely suppressed with a short, 15 day course of CsA. The later phase of the disease could be tempered by CsA administration starting on day 10 after the first HgCl2 injection. The optimal regimen of 7 mg/kg/day for 60 days was not associated with any evidence of CsA toxicity. CsA appears to interfere with the polyclonal activation of B cells observed in HgCl2-induced autoimmune disease, accounting for its striking preventive and curative effect in this model.

Cell adhesion molecule expression in murine lupus-like nephritis induced by lipopolysaccharide.

BACKGROUND: Intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule (VCAM) are thought to play important roles in leukocyte recruitment to the kidney. We therefore chose to study mesangial cell adhesion molecule expression in vitro, and the role of these molecules in experimental lupus-like nephritis. METHODS AND RESULTS: When cultured murine mesangial cells were stimulated with interferon-gamma (IFgamma) and tumor necrosis factor-alpha (TNFalpha), mRNA levels for ICAM-1 and VCAM markedly increased. These molecules were detected at the cell surface by flow cytometry. Since lipopolysaccharide (LPS) stimulates TNFalpha and IFgamma production in vivo, we treated mice with Streptococcus minnesota LPS in order to study renal adhesion molecule expression. LPS treatment induced mesangial proliferative glomerulonephritis characterized by leukocyte infiltration, and increases in total glomerular cellularity, volume and matrix area. mRNA levels for ICAM-1 and VCAM were increased in the kidneys of LPS-treated versus control mice. ICAM-1 and VCAM molecules were constitutively expressed in renal vascular endothelium. At 3 and 5 weeks, this vascular staining intensified, and some ICAM-1 and VCAM expression was induced in the glomerular mesangium. ICAM-1 and VCAM induction occurred early and correlated in time with leukocyte infiltration. CONCLUSION: Interactions between cell adhesion molecules expressed by intrinsic glomerular cells and infiltrating leukocytes play a role in the initiation of LPS-induced lupus-like nephritis. These observations are potentially relevant to the understanding and treatment of certain types of human glomerulonephritis.

Effects of vitamin D3 and cyclosporin A on HgCl2-induced autoimmunity in brown Norway rats.

BACKGROUND: Mercuric chloride (HgCl2) induces a lymphoproliferative disorder and autoimmune glomerulonephritis in Brown Norway (BN) rats. This syndrome is the consequence of T cell-dependent polyclonal B cell activation and autoantibody production. We have previously shown that HgCl2-induced autoimmune perturbations can be prevented in BN rats by the administration of cyclosporin A (CsA). The most potent vitamin D3 metabolite 1,25(OH)2 D3 (Vit D3) shares certain immunomodulatory properties with CsA. We therefore chose to compare the effects of Vit D3 to those of CsA in BN rats treated with HgCl2 in order to establish whether Vit D3 either alone or in combination with CsA can attenuate an autoimmune syndrome in vivo. METHODS: BN rats were treated with HgCl2 according to a standard protocol. Subgroups of rats were also given CsA alone, Vit D3 or synthetic analogues of Vit D3 alone, or combinations of both agents. Different doses and routes of administration were compared. The following markers of disease activity were evaluated: mortality, peak proteinuria, serum IgE concentrations, and renal immunoglobulin deposition. RESULTS: Disease activity was markedly attenuated in all rats treated with CsA alone. Vit D3 and certain of its synthetic analogues administered alone also tempered the autoimmune process, but to a lesser extent than did CsA. The effect of CsA alone was so potent, that no additive or synergistic effects could be demonstrated when CsA was administered in combination with Vit D3. CONCLUSIONS: Despite similar described immunomodulatory effects in vitro, CsA is clearly more effective than Vit D3 in preventing HgCl2 autoimmune disease in BN rats. This suggests that there is a difference in the cellular targets of these two agents in vivo, and/or a difference in the potency with which HgCl2-triggered immune activation is suppressed.

Production of monoclonal anti-glomerular basement membrane antibodies during autoimmune glomerulonephritis.

Monoclonal anti-glomerular basement membrane (GBM) antibodies were obtained by fusing spleen cells from Brown-Norway (BN) rats injected with mercuric chloride with IR 983 F, a nonsecreting rat myeloma cell line. These antibodies showed the same pattern of fixation on renal basement membranes by indirect immunofluorescence. One of them was developed. It reacted both in vivo and in vitro with GBM but failed to react with collagenase-digested GBM, laminin, and collagen IV. This monoclonal antibody which resembles the kidney acid eluate obtained from BN rats injected with mercuric chloride induced a weak and transient proteinuria when intravenously injected into normal BN rats.

Plasma exchange in a rat model of autoimmune glomerulonephritis.

Using an original technique permitting repeated plasma exchange in the rat, we have tested this therapeutic approach in animals actively immunised with horseradish peroxidase, and in rats with HgCl2-induced autoimmune glomerulonephritis. Plasma exchange effectively removes circulating IgG anti-horseradish peroxidase antibodies from the sera of immunised rats. When applied to the model of HgCl2-induced antiglomerular basement membrane glomerulonephritis in Brown-Norway rats, this technique is also remarkably effective. In these rats, proteinuria is abolished during the plasma exchange treatment period and no circulating antiglomerular basement membrane antibodies can be detected. These antibodies are, however, found in the ultrafiltrates of exchanged rats. Serum IgE, characteristically elevated in HgCl2-treated rats, is also markedly diminished in exchanged rats. Control rats treated with infusions of fresh frozen plasma or with heparin alone did not show any improvement in disease severity. These results suggest that plasma exchange alone can attenuate antiglomerular basement membrane nephritis in HgCl2-treated rats. This observation may be of relevance for the treatment of human antiglomerular-basement membrane-mediated glomerulonephritis.