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Biomedical subjects

L D Anderson

Publications and source records attributed to L D Anderson.

At least 19 recordsLinked to original sources
PubMed2001

Bone marrow transplant conditioning intensified with liposomal clodronate to eliminate residual host antigen presenting cells fails to ameliorate GVHD and increases PERI-BMT mortality.

BACKGROUND: Graft versus host disease (GVHD) mediated by allogeneic donor T cells may be initiated and/or exacerbated by residual host antigen presenting cells (APC) which survive the transplant conditioning regimen. We examined whether the depletion of hepatic and splenic APC could reduce the severity of hepatic GVHD after bone marrow transplantation (BMT). METHODS: Recipient mice were depleted for hepatic and splenic phagocytic APCs by i.v. injection of clodronate- (dichloromethylene diphosphonate) containing liposomes before fully allogeneic or MHC-matched, minor Ag-mismatched BMT. Severity of hepatic GVHD was scored on histological sections 2, 3, 4, or 9 weeks after BMT. RESULTS: No differences in the severity of GVHD were observed between APC-depleted mice and control mice. APC-depleted mice had increased peritransplant mortality due to sepsis. Bacterial clearance assays showed that APC-depleted mice were unable to efficiently clear bacteria, although nondepleted, transplanted mice were able to clear bacteria as quickly as naive control mice. CONCLUSIONS: Residual host phagocytic APC do not appear to play a role in the induction of GVHD after BMT. They are, however, essential for prevention of sepsis in the transplant host.

Animals↗
PubMed2000

Pretransplant tumor antigen-specific immunization of allogeneic bone marrow transplant donors enhances graft-versus-tumor activity without exacerbation of graft-versus-host disease.

Allogeneic bone marrow transplantation (BMT) causes a beneficial graft-versus-tumor (GVT) immune response that is often associated with graft-versus-host disease (GVHD). There is substantial interest in developing therapeutic strategies that augment GVT without GVHD. We have demonstrated recently that immunization of BMT donors with cellular tumor vaccines leads to curative GVT but induces unacceptable GVHD because of the presence of recipient minor histocompatibility antigens (mHAgs) in whole-cell tumor vaccines. This study tested the hypothesis that immunization of BMT donors against a defined tumor-specific antigen with a vaccine not containing recipient mHAgs would help to separate the two responses by enhancing GVT activity without exacerbating GVHD, even when cellular vaccines were used after BMT. Recipient strain C57BL/6 fibrosarcoma cells engineered to express the well-characterized model tumor antigen, influenza nucleoprotein (NP), were used in these studies. C3H.SW donors were immunized against NP prior to BMT, and cytolytic T cells were transferred along with bone marrow into irradiated H-2-matched, mHAg-mismatched C57BL/6 recipients with established micrometastatic 205-NP tumors. Donor immunization led to a significant increase in GVT activity, as measured by reduction in tumor growth and enhanced survival. However, deaths in recipients of tumor antigen-specific immune BMT ultimately occurred because of the growth of antigen-loss variants; such tumor growth did not occur in animals receiving BMT from donors treated with whole-cell vaccines. Donor immunization did not lead to an exacerbation of GVHD, even when BMT recipients received additional immunization after BMT with a 205-NP "whole" tumor cell vaccine (which was shown to induce fatal GVHD when used for donor immunization). In conclusion, immunization of allogeneic BMT donors against a tumor-specific antigen significantly enhances GVT activity without an associated exacerbation of GVHD.

Animals↗
PubMed2000

Immunization of allogeneic bone marrow transplant recipients with tumor cell vaccines enhances graft-versus-tumor activity without exacerbating graft-versus-host disease.

Allogeneic bone marrow transplantation (BMT) induces 2 closely associated immune responses: graft-versus-tumor (GVT) activity and graft-versus-host disease (GVHD). We have previously shown that pretransplant immunization of allogeneic BMT donors with a recipient-derived tumor cell vaccine increases both GVT activity and lethal GVHD because of the priming of donor T cells against putative minor histocompatibility antigens (mHAgs) on the tumor vaccine cells. The work reported here tested the hypothesis that tumor cell vaccination after BMT would produce an increase in GVT activity without exacerbating GVHD. C3H.SW donor bone marrow and splenocytes were transplanted into major histocompatibility complex-matched, mHAg-mismatched C57BL/6 recipients. One month after BMT, recipients were immunized against either a C57BL/6 myeloid leukemia (C1498) or fibrosarcoma (205). Immunized recipients had a significant increase in survival and protection against tumor growth in both tumor models, and significant tumor protection was seen even in recipients with preexisting micrometastatic cancer before immunization. Alloreactivity appeared to contribute to the in vitro anti-tumor cytolytic activity, but in vivo immunity was tumor specific, and no exacerbation of GVHD was observed. Although the immunodominant mHAg B6(dom1) was shown to be expressed by all B6 tumors tested and was largely responsible for the alloreactivity resulting from tumor immunization of donors, the in vitro alloreactivity of immune recipients was more restricted and was not mediated by recognition of B6(dom1). In conclusion, post-transplant tumor immunization of allogeneic BMT recipients against either a leukemia or a solid tumor can increase GVT activity and survival without exacerbating GVHD.

Animals↗
PubMed2000

Lead effects on protamine-DNA binding.

BACKGROUND: Lead impairs male fertility and may affect offspring of exposed males, but the mechanisms for this impairment are not completely clear. Protamine P1 and P2 families pack and protect mammalian sperm DNA. Human HP2 is a zinc-protein and may have an important role in fertility. As lead has affinity for zinc-containing proteins, we evaluated its ability in vitro to bind to HP2 and its effects on HP2-DNA binding. Methods and Results UV/VIS spectroscopic data indicated that HP2 binds both Pb(2+) and Zn(2+)(as chloride salts). They also provided evidence that thiol groups mainly participate for Zn(2+)-binding; however, HP2 has additional binding sites for Pb(2+). The mobility shift assay showed that lead interaction with HP2 caused a dose-dependent decrease on HP2 binding to DNA, suggesting that lead may alter chromatin stability. CONCLUSIONS: These in vitro results demonstrate that lead can interact with HP2 altering the DNA-protamine binding. This chemical interaction of lead with protamines may result in chromatin alterations, which in turn may lead to male fertility problems and eventually to DNA damage.

Chromatin↗
PubMed2000

Lead interaction with human protamine (HP2) as a mechanism of male reproductive toxicity.

During spermatogenesis, histones are replaced by protamines, which condense and protect sperm DNA. In humans, zinc contributes to sperm chromatin stability and binds to protamine P2 (HP2). Chemical interactions with nuclear protamines, which prevent normal sperm chromatin condensation, may induce changes in the sperm genome and thus affect fertility and offspring development. Since lead has a high affinity for zinc-containing proteins, we investigated lead interactions with HP2 as a novel mechanism of its toxicity to sperm. UV/vis and CD spectroscopy results indicated that HP2 binds Pb(2+) at two different sites, causing a conformational change in the protein. They also provided evidence that thiol groups are primarily involved in Zn(2+) and Pb(2+) binding to HP2 and that HP2 may have additional binding sites for Pb(2+) not related to Zn(2+). HP2 affinities for Pb(2+) and Zn(2+) were very similar, suggesting that Pb(2+) can compete with or replace Zn(2+) in HP2 in vivo. This interaction of lead with HP2 resulted in a dose-dependent decrease in the extent of HP2-DNA binding, although lead interaction with DNA also contributed to this effect. Therefore, the ability of lead to decrease the level of HP2-DNA interaction may result in alterations to sperm chromatin condensation, and thus in reduced fertility.

Animals↗
PubMed1999

Enhancement of graft-versus-tumor activity and graft-versus-host disease by pretransplant immunization of allogeneic bone marrow donors with a recipient-derived tumor cell vaccine.

Allogeneic bone marrow transplantation (BMT) can be accompanied by a beneficial T cell-mediated antitumor immune response known as graft-versus-tumor (GVT) activity. However, BMT donor T cells are not exposed to target antigens of GVT activity until transfer to the host, where tumor antigen presentation may be suboptimal. This study tested in a murine model the hypothesis that immunization of MHC-matched allogeneic donors with a recipient-derived tumor cell vaccine would substantially increase GVT activity and extend survival of BMT recipients with preexisting micrometastatic tumor. C3H.SW and C57BL/10 mice were immunized against a C57BL/6-derived fibrosarcoma or leukemia, and they were used as BMT donors. Recipients were H-2-matched, minor histocompatibility antigen-mismatched C57BL/6 mice with previously established micrometastatic tumors. Donor immunization led to a significant increase in GVT activity that was T cell dependent and cell dose dependent. In some settings, donor immunization also prolonged survival of recipients with preexisting micrometastatic tumors. However, donor immunization significantly increased the incidence of fatal graft-versus-host disease such that long-term survival was uncommon. In vitro cytotoxicity assays indicated that donor immunization induced both tumor-selective and alloreactive cytolytic T-cell populations. In vivo cross-protection assays showed that a substantial portion of the GVT effect was mediated by alloreactive cells not specific for the immunizing tumor. In conclusion, immunization of allogeneic BMT donors with a recipient-derived whole tumor cell vaccine substantially increases GVT activity but also exacerbates graft-versus-host disease.

Animals↗
PubMed1999

HER-2/neu peptide specificity in the recognition of HLA-A2 by natural killer cells.

Although natural killer (NK) cells have been described as non-MHC-restricted, new evidence suggests that NK activity can be either up- or down-regulated after interaction with the peptide-MHC-class-I complex expressed on target cells. However, the epitope(s) recognized by NK cells have remained ill-defined. We investigated NK cell recognition of synthetic peptides representing a portion of a self-protein encoded by the HER-2/neu (HER-2) proto-oncogene and presented by HLA-A2. HER-2 nonapeptides C85, E89, and E75 were found partially to protect T2 targets from lysis by freshly isolated and interleukin-2(IL-2)-activated NK cells (either HLA-A2(+) or A2(-)). This inhibition was not solely due to changes in the level of HLA-A2 expression or conformation of serological HLA-A2 epitopes. Using single-amino-acid variants at position 1 (P1) of two HER-2 peptides, we observed that protection of targets was dependent on the sequence and the side-chain. These results suggest similarities in the mechanism of target recognition by NK and T cells. This information may be important for understanding the mechanisms of tumor escape from immunosurveillance and could help explain the aggressiveness of HER-2-overexpressing tumor cells.

Cells, Cultured↗
PubMed1996

Ultrasonography in the management of painful hips in children.

The decision to aspirate a painful hip joint is often based on history, physical, and laboratory findings. The purpose of this study is to determine whether ultrasound is helpful in making decisions to aspirate a painful hip joint in children. The anterior capsular distance was determined in 10 children with painful or irritable hips. This anterior capsular distance is 2 to 4 mm in most hips. A side difference of 2 mm or more is considered a significant capsular distension. Based on these criteria and clinical parameters, 3 hips were aspirated, and 7 were observed without aspiration. None of the 7 hips subsequently required further diagnostic workup or treatment and all have had a satisfactory outcome. Ultrasound is a reliable method to detect capsular distension or joint effusion. It helps significantly in making the decision as to "when to aspirate" a painful or irritable hip joint.

Adolescent↗
PubMed1995

Vein, silastic, and polyglycolic acid fine mesh: a comparative study in peripheral nerve repair.

We investigated three sheathing materials (autogenous vein, silastic, and polyglycolic acid fine mesh) using the rat model. Forty rats were divided into five groups of eight animals each. Group A animals underwent transection of the sciatic nerve but had no repair. In Group B, a standard epineural repair was performed. In Groups C, D, and E, the nerve was repaired as in Group B with the addition of autogenous vein, Silastic, and polyglycolic acid fine mesh sheaths, respectively. Nerve regeneration and function were assessed using sciatic functional index, nerve conduction studies, and light microscopy. Sheathing methods showed no statistically significant advantage to standard epineural repair without a sheath.

Animals↗
PubMed1994

Percutaneous intramedullary fixation of lateral malleolus fractures: technique and report of early results.

Twenty-four patients with Weber B and low Weber C displaced lateral malleolus fractures who underwent closed reduction and percutaneous internal fixation with an intramedullary, fully threaded, self-tapping screw were retrospectively reviewed. Nineteen of these patients were followed for an average of 63.4 weeks. A good radiographic reduction was obtained in 87.5% of patients, a fair reduction in 8.3%, and a poor reduction in 4.2%. The reduction that was obtained was maintained in all patients. Fracture union was achieved in 95.5% of patients, with an average time to union of 8.2 weeks. In all patients the average time to full weight bearing was 6.8 weeks, whereas that in patients with isolated lateral malleolus fractures was 4.5 weeks. There were no deep wound infections or complaints of painful hardware. At latest follow-up, functional results were excellent in 42.1%, good in 42.1%, fair in 5.3%, and poor in 10.5% of patients. If reduction of the lateral malleolus fracture can be obtained in a closed fashion (with the aid of an image intensifier), we believe that fixation may be performed with an axial screw percutaneously. This technique requires minimal soft-tissue dissection, thereby decreasing wound complications and painful hardware sites that are occasionally observed after open techniques. This closed technique also eliminates screw penetration of the ankle joint and damage to the peroneal tendons, which can be risks when a plate or lag screws are employed as internal fixation. Surgical time is also reduced and tourniquet use is optional. If an acceptable reduction cannot be obtained using this technique, open reduction and internal fixation should be performed.

Adolescent↗
PubMed1994

Intramedullary screw fixation of lateral malleolus fractures.

A biomechanical evaluation of intramedullary versus buttress plate and lag screw fixation of lateral malleolus fractures is combined with a clinical evaluation of 44 patients with lateral malleolus fractures who underwent intramedullary screw fixation. The biomechanical study was performed in experimentally produced, Weber B, supination-eversion ankle fractures. The fractures were fixed with one of the two above fixation methods and then placed under a torsional load to failure. Sixteen cadaver ankles were tested as compared with native bone. The intramedullary screw provided 66.5% the resistance of torsion, and the buttress plate and lag screw provided 61.5% the resistance to torsion. There was no statistical difference between these two groups. The 44 fractures treated with an intramedullary screw were reviewed retrospectively. There was one failure of fixation, and one prominent hardware problem. Time to full weightbearing averaged 7.2 weeks. These results suggest that intramedullary screw fixation of noncomminuted lateral malleolus fractures provides stable fixation with good clinical results. This technique has the advantages of providing dynamic intramedullary fixation with limited surgical dissection and no subcutaneous hardware.

Adolescent↗
PubMed1992

A preliminary experience with the Russell-Taylor reconstruction nail for complex femoral fractures.

Eleven cases of complex femoral fractures were seen from November 1987 to November 1989; five ipsilateral femoral neck and shaft fractures and six comminuted subtrochanteric fractures. High-energy accidents accounted for most of these injuries. There were numerous associated injuries, many requiring operative procedures. All of the fractures were treated with Russell-Taylor reconstruction nails. All fractures united, but there were two delayed unions. There was no delay in diagnosis of the femoral neck fractures, and all healed without avascular necrosis. Malalignment occurred in one case, shortening of the femur occurred in two cases, and in two cases only one screw could be placed in the femoral head. In three patients technical errors related to nail insertion led to fracture complications. The use of the Russell-Taylor reconstruction nail is technically demanding. However, we conclude that in complex femoral fractures, this device offers superior stabilization over other currently used methods of internal fixation.

Adult↗
PubMed1992

Incidence of deep vein thrombosis in major adult spinal surgery.

Deep vein thrombosis and pulmonary embolus are well known complications of lengthy orthopaedic procedures. Historically spine surgery has been associated with few thrombotic complications. Recent widespread use of instrumentation in adult cases led to concern regarding the incidence of deep vein thrombosis and pulmonary embolus. Forty-one patients underwent posterior spinal procedures using either pedicular or segmental instrumentation. One day before discharge all patients underwent noninvasive testing using color duplex Doppler imaging to rule out deep vein thrombosis. Six patients were noted to have tests results compatible with deep vein thrombosis. The incidence of deep vein thrombosis during this study (14%) reveals a group of patients who would have been discharged with ongoing thrombosis and potential pulmonary embolism.

Adult↗
PubMed1992

Chondromyxoid fibroma.

Chondromyxoid fibroma (CMF) is the least common cartilage-producing tumor. In Dahlin and Unni's series of 8,542 bone tumors, 39 of which were CMF, none were found in the femoral shaft. In this case, a CMF in the femoral shaft presented initially as a pathologic fracture. Attempts at curettage and autogenous bone graft failed, and en bloc resection and segmented allograft reconstruction were eventually required.

Adolescent↗
PubMed1992

Cat-scratch disease: orthopaedic presentation.

Although cat-scratch disease is not uncommonly treated by pediatricians, it is rarely seen by orthopaedists. In this review of cat-scratch disease, two cases with orthopaedic manifestations are high-lighted. One patient had a positive bone scan in the distal humerus that simulated osteomyelitis on presentation. The second patient presented with a rapidly enlarging soft-tissue mass in the arm that resembled a soft-tissue sarcoma. The diagnosis of cat-scratch disease eventually was made late in the course of management in both cases. Both patients underwent surgical drainage and evacuation of the suppurated lymph node and recovered without sequelae.

Adolescent↗