Anti-C1s monoclonal antibody BIVV009 in late antibody-mediated kidney allograft rejection-results from a first-in-patient phase 1 trial.

The classical pathway (CP) of complement may contribute to the pathogenesis of antibody-mediated rejection (ABMR). Selective CP blockade may be a promising strategy to counteract rejection. The objective of this first-in-patient phase 1b trial was to evaluate the safety/tolerability and CP-blocking potential of 4 weekly doses (60 mg/kg) of the anti-C1s antibody BIVV009 in complement-mediated disorders. Here we describe the results in a cohort of 10 stable kidney transplant recipients (median of 4.3 years posttransplantation) with late active ABMR and features of CP activation, such as capillary C4d or complement-fixing donor-specific antibodies (DSA). During 7 weeks follow-up, no severe adverse events were reported, and BIVV009 profoundly inhibited overall and DSA-triggered CP activation in serum. Five of 8 C4d-positive recipients turned C4d-negative in 5-week follow-up biopsies, while another 2 recipients showed a substantial decrease in C4d scores. There was, however, no change in microcirculation inflammation, gene expression patterns, DSA levels, or kidney function. In conclusion, we demonstrate that BIVV009 effectively blocks alloantibody-triggered CP activation, even though short-course treatment had no effect on indices of activity in late ABMR. This initial trial provides a valuable basis for future studies designed to clarify the therapeutic value of CP blockade in transplantation. ClinicalTrials.gov NCT#02502903.

Effect of the Anti-C1s Humanized Antibody TNT009 and Its Parental Mouse Variant TNT003 on HLA Antibody-Induced Complement Activation-A Preclinical In Vitro Study.

The classic pathway (CP) of complement is believed to significantly contribute to alloantibody-mediated transplant injury, and targeted complement inhibition is currently considered to be a promising approach for preventing rejection. Here, we investigated the mode of action and efficacy of the humanized anti-C1s monoclonal antibody TNT009 and its parental mouse variant, TNT003, in preclinical in vitro models of HLA antibody-triggered CP activation. In flow cytometric assays, we measured the attachment of C1 subcomponents and C4/C3 split products (C4b/d, C3b/d) to HLA antigen-coated flow beads or HLA-mismatched aortic endothelial cells and splenic lymphocytes. Anti-C1s antibodies profoundly inhibited C3 activation at concentrations >20 µg/mL, in both solid phase and cellular assays. While C4 activation was also prevented, this was not the case for C1 subcomponent attachment. Analysis of serum samples obtained from 68 sensitized transplant candidates revealed that the potency of inhibition was related to the extent of baseline CP activation. This study demonstrates that anti-C1s antibodies TNT009 and TNT003 are highly effective in blocking HLA antibody-triggered complement activation downstream of C1. Our results provide the foundation for clinical studies designed to investigate the potential of TNT009 in the treatment or prevention of complement-mediated tissue injury in sensitized transplant recipients.

Inhibition of tissue factor pathway inhibitor by the aptamer BAX499 improves clotting of hemophilic blood and plasma.

BACKGROUND: Tissue factor pathway inhibitor (TFPI) is the major inhibitor of tissue factor-initiated coagulation, making it an interesting and novel therapeutic target in hemophilia treatment. The aptamer BAX499 (formerly ARC19499) is designed to improve hemostasis by specifically inhibiting TFPI. OBJECTIVES: The aim of the study was to examine the concentration-dependent augmentation of clotting by BAX499. METHODS: Whole blood clot formation was quantified by rotational thromboelastometry and thromboelastography, and thrombin generation in platelet-poor plasma was assessed with the calibrated automated thrombogram, in samples from patients with congenital hemophilia A (N=55) and B (N=11), patients with acquired hemophilia A (N=1), and healthy controls (N=37). RESULTS: BAX499 significantly improved clotting of samples from hemophilic patients in a concentration-dependent manner, resulting in clotting profiles in samples from patients with severe hemophilia that were similar to those of healthy controls. CONCLUSION: BAX499 improved ex vivo clotting parameters in blood and plasma from patients with hemophilia A and B with different severity of disease, and also in a patient with acquired hemophilia. These results further support the contention that anti TFPI strategies may be an effective treatment for hemophilic patients.

Improvement of spatial fibrin formation by the anti-TFPI aptamer BAX499: changing clot size by targeting extrinsic pathway initiation.

BACKGROUND: Tissue factor pathway inhibitor (TFPI) is a major regulator of clotting initiation and a promising target for pro- and anticoagulation therapy. The aptamer BAX499 (formerly ARC19499) is a high-affinity specific TFPI antagonist designed to improve hemostasis. However, it is not clear how stimulation of coagulation onset by inactivating TFPI will affect spatial and temporal clot propagation. OBJECTIVE: To examine the BAX499 effect on clotting in a spatial, reaction-diffusion experimental system in comparison with that of recombinant activated factor VII (rVIIa). METHODS: Clotting in plasma activated by immobilized tissue factor (TF) was monitored by videomicroscopy. RESULTS: BAX499 dose-dependently improved coagulation in normal and hemophilia A plasma activated with TF at 2 pmole m(-2) by shortening lag time and increasing clot size by up to ~2-fold. The effect was TFPI specific as confirmed by experiments in TFPI-depleted plasma with or without TFPI supplementation. Clotting improvement was half-maximal at 0.7 nm of BAX499 and reached a plateau at 10 nm, remaining there at concentrations up to 1000 nm. The BAX499 effect decreased with TF surface density increase. RVIIa improved clotting in hemophilia A plasma activated with TF at 2 or 20 pmole m(-2) , both by shortening lag time and increasing spatial velocity of clot propagation; its effects were strongly concentration dependent. CONCLUSIONS: BAX499 significantly improves spatial coagulation by inhibiting TFPI in a spatially localized manner that is different to that observed with rVIIa.

[Propositions of interpretative comments for thyroid function tests]. / Propositions de commentaires interprétatifs pour les bilans biologiques thyroïdiens.

In the field of thyroid disease, a number of governmental organisms or professional associations have published practice guidelines containing laboratory-related recommendations, eg the Haute autorité de la santé (HAS), or the American Thyroid Association (ATA). Among the physicians who prescribe thyroid function tests, all have not read and memorized all these recommendations. In order to help them to better integrate these recommendations in their practice, we have composed a thesaurus of ready-made interpretative comments, trying to adapt our proposed comments to each possible combination of results of TSH and/or free T4 and/or free T3. The laboratorians who would prefer to use only the comments based strictly on the recommendations of HAS and/or ATA, will be able to select among our comments what is really validated by these two organizations. In addition, our work aims at enabling the patients who want it, to benefit from written information, which may be complementary to the more often spoken information provided by the clinicians.

[Disseminated tuberculosis and profound thrombopenia]. / Tuberculose disséminée et thrombopénie profonde.

Thrombocytopenia within the context of disseminated tuberculosis can lead to complications requiring rapid treatment. Although the origin is generally central, thrombocytopenia can arise from an immune disorder. We hereby report a case of disseminated tuberculosis associated with thrombocytopenia, which required, in addition to antituberculosis therapy initiated before bacteriological proof, corticosteroid treatment and multiple platelet transfusions. The discovery of anti-platelet antibodies along with the success of immunomodulator therapy confirmed the auto-immune origin of this thrombocytopenia.

The use of a bioactive skin substitute decreases length of stay for pediatric burn patients.

BACKGROUND: To optimize burn care for children, the authors introduced a protocol incorporating the use of a bioactive skin substitute, TransCyte (Advanced Tissue Sciences, La Jolla, CA). This study was designed to determine whether this management plan was safe, efficacious, and decreased hospital inpatient length of stay (LOS) compared with conventional burn management in children. METHODS: All pediatric burns greater than 7% total body surface area (TBSA) that occurred after October 1999 underwent wound closure with TransCyte (n = 20). These cases were compared with the previous 20 consecutive burn cases greater than 7% TBSA that received standard therapy. Standard therapy consisted of application of antimicrobial ointments and hydrodebridement. The following information was obtained: burn mechanism, age, size of burn, requirement of autograft, and LOS. Data were analyzed using the student's t test. RESULTS: Data for age, percent TBSA burn and LOS are reported as means +/- SEM. The children who received standard therapy were 2.99 +/- 0.7 years compared with those receiving TransCyte were 3.1 +/- 0.8 years. There was no difference between the treatment groups with regard to percent TBSA burn: standard therapy, 14.3 +/- 1.4% TBSA versus TransCyte, 12.7 +/- 1.3% TBSA. There was no difference in the type of burns in each group, the majority were liquid scald type, 70% in the standard therapy group versus 90% in the TransCyte group. Only 1 child in the TransCyte group required autografting (5%) compared with 7 children in the standard therapy group (35%). Children treated with TransCyte had a statistically 6 significant decreaed LOS compared with those receiving standard therapy, 5.9 +/- 0.9 days versus 13.8 +/- 2.2 days, respectively (P =.002). CONCLUSIONS: This is the first study using TransCyte in children. The authors found that this protocol of burn care was safe, effective, and significantly reduced the LOS. This new approach to pediatric burn care is effective and improves the quality of care for children with burns.

Does early ultrasonography affect management of pediatric appendicitis? A prospective analysis.

BACKGROUND: Appendicitis remains a difficult diagnosis in children. Ultrasonography is increasingly used for the diagnosis of appendicitis, although the proper clinical role for this test remains unclear. METHODS: To evaluate the clinical utility of ultrasonography in appendicitis, the authors analyzed prospectively all children evaluated for possible appendicitis from January 1 through December 31, 1997. Children with a high clinical suspicion of appendicitis were referred for surgery (n = 122). Children with equivocal findings of appendicitis were referred for early ultrasonography (EUS) and formed the study cohort (n = 103). An initial management plan was made to operate or observe each patient, and a risk of appendicitis (doubtful, possible, probable) was assigned by a pediatric surgery fellow. EUS was then performed, and its effect on management was assessed. RESULTS: Using clinical judgment to operate at initial presentation, the sensitivity was 38% and specificity was 95%. Using EUS alone, the sensitivity was 87% and specificity was 88%. The management of 30 of 103 patients (30%) was changed after EUS, including a decision to operate in 28 patients and a decision not to operate in two patients. CONCLUSIONS: EUS appears to have substantial clinical utility in children with equivocal findings of appendicitis, and its use complements the clinical management. The use of EUS can improve patient care and reduce hospital resource utilization.

Follow-up imaging studies in children with splenic injuries.

We undertook a retrospective study of pediatric blunt splenic injuries treated nonoperatively at our institution from 1990 to 1995 (n = 72) to assess the impact of serial computed tomography (CT) scans on the outcome. Median number of studies per child was three. The result showed that the appearance of the splenic injury remained unchanged or improved in 95% of the imaging studies obtained (116 of 122). Only one of five patients with an image suggesting a worsening splenic injury required operative intervention. There were no instances of missed injuries, delayed ruptures, or readmissions. We conclude that serial CT scans have limited follow-up value and should be used selectively.

Minor pediatric injuries.

Injuries are a common source of childhood morbidity and mortality. The initial evaluation should follow in a sequential fashion to determine the extent of injuries. Most minor injuries can be treated safely and cost-effectively in an office setting. The principles of wound care include adequate hemostasis, tissue debridement, removal of imbedded foreign bodies, and appropriate closure or coverage of the wound to optimize healing. Appropriate use of antibodies, tetanus prophylaxis, and rabies immunization will minimize complications. With proper selection and treatment, the outcome of children with minor injuries should be excellent.

Cervical ECMO cannula placement in infants and children: recommendations for assessment of adequate positioning and function.

BACKGROUND/PURPOSE: Cervical extracorporeal membrane oxygenation (ECMO) cannula position is often difficult to confirm by chest x-ray alone. Malposition requires a second surgery to rectify the problem. Reoperation places the patient at risk for infection, bleeding, or death. This study analyzes indications for cannula repositioning and suggests an alternative standard for intraoperative evaluation of catheter function as it relates to position. METHODS: The authors reviewed charts of 73 patients placed on arterio-venous ECMO through cervical vascular access. Reasons for repositioning of either cannula at the initial surgery or postoperatively were recorded. RESULTS: Of 73 patients, 18 (24.6%) required either arterial cannula or venous cannula repositioning. In 10 (55%) of these patients, cannula malposition was not detected by chest x-ray during the initial cannulation, and they therefore required a second cervical exploration for repositioning. CONCLUSIONS: Chest x-ray is not sensitive in demonstrating malpositioned cervical ECMO cannulae. Two-dimensional ECHO before wound closure, may be a superior, more cost effective means of assessing cannula placement and function than x-ray alone. Confirmation of cannula position and function, before wound closure, would reduce the risks involved with cervical reexploration.

Impact of bicycle helmet safety legislation on children admitted to a regional pediatric trauma center.

PURPOSE: The regional pediatric trauma center in Buffalo, NY, has been active in pediatric injury prevention programs, including community education and distribution of bicycle helmets, since 1990. Since June 1, 1994, the use of bicycle safety helmets for children under 14 years of age has been mandated by a state law in New York. The authors undertook this study to assess the impact of this legislation on the frequency of helmet use in children involved in bicycle crashes presenting to the regional pediatric trauma center, and to assess the impact of helmet use on the number and severity of head injuries. METHODS: Bicycle crash victims (n = 208) admitted to a regional pediatric trauma center from 1993 to 1995 were studied retrospectively. Head injuries were classified as concussion alone, skull fractures, intracranial hemorrhages (ie, epidural, subdural, and subarachnoid), cerebral contusions, or diffuse cerebral edema alone (without any other intracranial injury). Helmeted children (HC) were compared with nonhelmeted children (NHC) using chi2 and Fisher's Exact test. P value less than .05 was considered significant. RESULTS: Only 31 children (15%) wore helmets at the time of the crash. Helmet use increased from 2%, during the period of education alone, to 26% after the legislation went into effect (P < .00001). The proportion of children suffering head injuries was similar in both groups (HC, 68%; NHC, 61%; P = NS). However, the type of head injury was different. HC were more likely to sustain concussion alone (HC, 65%; NHC, 44%; P < .03). HC were less likely to have skull fractures (HC, 0%; NHC, 13%; P < .02), and exhibited a trend toward less intracranial hemorrhages (HC, 0%; NHC, 9%; P = NS), cerebral contusions (HC, 3%; NHC, 5%; P = NS), and cerebral edema (HC, 0%; NHC, 0.6%; P = NS). Excluding the isolated concussions, head injuries were noted in only one HC, compared with 30 NHC (P < .04). None of the three children who died wore helmets at the time of the crash, and all died of multiple head injuries. CONCLUSIONS: The bicycle helmet safety law resulted in a 13-fold increase in the use of bicycle helmets among the children admitted to a regional pediatric trauma center after bicycle crashes, but the helmet use remains inadequate. Helmet use reduced the severity of head injuries, and might have prevented deaths caused by head injuries.

Risk of hemorrhage and appropriate use of blood transfusions in pediatric blunt splenic injuries.

OBJECTIVE: To define changes in hematocrit (Hct) and the indications for blood transfusion in pediatric blunt splenic injury. DESIGN: Retrospective case series MATERIALS AND METHODS: All children with blunt splenic injuries from 1990 to 1995 were studied (n = 74). Transfusion practices were reviewed for the whole group. Thirty children with isolated splenic injuries who were not transfused were analyzed to document Hct changes (mean +/- 95% confidence intervals). MEASUREMENTS AND RESULTS: The Hct at presentation was 37 +/- 2%, which rapidly dropped to 31 +/- 2% (p < 0.05) within 24 hours. After remaining stable at that level for the next 5 days, the Hct rose to 33 +/- 4% on day 6 (p = not significant), 35 +/- 4% on day 7 (p = not significant), and 38 +/- 2% (p = not significant) on day 13 +/- 3. Fifteen children received transfusions, all but one of whom had suffered multiple injuries. The transfusion rate declined from 38% of children in 1990 to 10% in 1995. CONCLUSIONS: After the initial drop within the first 24 hours, the Hct remains stable and rises with time to reach the baseline by day 6. Transfusion rates have declined over time, and transfusions are now used almost exclusively in severely injured children with multiple injuries.

Temperature determination in the frozen region during cryosurgery of rabbit liver using MR image analysis.

Cryosurgery currently is being used clinically to treat tumors in internal organs such as the liver and prostate. Although performed at present under ultrasound monitoring, magnetic resonance imaging (MRI)-guidance of these procedures not only permits monitoring of the frozen region during cryosurgery but also makes it possible to determine the temperature distribution in the frozen region, which is not possible using ultrasound monitoring. A good estimate of the region of destruction in the tissue can be obtained from correlating the temperature distribution and the time course of the freezing with the image of the frozen region. Unfortunately, MR pulse sequence-based temperature determination techniques such as diffusion, relaxation time, and chemical shift cannot be used for measuring the temperature in the frozen region because the T2 of the frozen regions is so short that there is effectively no RF signal from the frozen region. This paper describes a numerical technique for determining the two dimensional temperature distribution in the frozen region during MR image-guided cryosurgery of normal liver in rabbits. The technique involves solving the energy equation numerically in the frozen region to determine the temperature distribution there. The boundary conditions needed to solve the equation are determined from MR images of the frozen tissue during cryosurgery and from the measured temperature of the cryoprobe. The calculated temperature in the frozen region is then correlated with the damaged region (cryolesion) determined from post mortem histologic evaluation.

Video-assisted thoracic surgery (VATS) for children with pulmonary metastases from osteosarcoma.

BACKGROUND: Video-assisted thoracic surgery (VATS) may complement open thoracotomy in children with osteosarcoma requiring pulmonary metastasectomy. METHODS: The records of children with metastatic pulmonary osteosarcoma considered for initial VATS intervention (n = 9) were reviewed. RESULTS: Two children did not have VATS exploration: one child with multiple bilateral nodules and another child with a deep parenchymal nodule. VATS provided diagnostic biopsy material in all cases when used (n = 7). Two children had benign inflammatory lesions; four children had VATS-directed wedge resections of solitary malignant lesions; and one child had VATS biopsy of diffuse parenchymal and pleural pulmonary disease not amenable to resection. The mean operative time and hospital length of stay were 1.78 +/- 0.54 h and 3.5 +/- 1.8 days, respectively. There were two complications of VATS: bleeding in a child, requiring a transfusion, and a latent pneumothorax in a patient after removal of the chest tube. CONCLUSION: VATS is safe, serves as an excellent diagnostic modality, complements the open thoracotomy, and may enable the surgeon to avoid more extensive procedures in selected cases.

Right diaphragmatic eventration simulating a congenital diaphragmatic hernia.

We describe an infant with severe eventration of the right diaphragm and pulmonary hypoplasia who presented like a newborn with congenital diaphragmatic hernia complicated by persistent pulmonary hypertension. Surgical correction while on extracorporeal life support was unsuccessful due to attachments of the liver which prevented reduction into the abdominal cavity and our inability to distinguish the true defect from complete agencies of the right hemidiaphragm. At autopsy the pulmonary remnant and the fibrous membrane separating it from the liver were identified.

An integrated probe for magnetic resonance imaging monitored skin cryosurgery.

Cryosurgery of the skin is a common treatment for both benign and malignant skin cancers. Monitoring the depth of the frozen lesion during cryosurgery, either by estimation based on the lateral spread of freeze at the skin surface or via thermocouples, may be inaccurate because of the heterogeneous nature of tissue. We describe an integrated cryosurgical probe and magnitude resonance imaging probe which we use to obtain high resolution MR images of skin, subcutaneous muscle and the frozen lesion during cryosurgery.

Differential time course for desensitization to muscarinic effects on K+ and Ca2+ channels.

The time course of muscarinic effects on K and Ca currents was investigated at 22-24 degrees C in guinea-pig atrial myocytes, using the whole-cell voltage clamp. At a holding potential of -40 or -50 mV, short exposures to 100 microM acetylcholine (ACh) or carbachol (CCh) reproducibly induced outward K currents (IK,ACh). During long exposures to these agonists, IK,ACh faded with time. In cells not dialysed with guanosine triphosphate (GTP), IK,ACh could dissipate completely following 15-20 min of agonist exposure. After agonist washout, lost sensitivity was not recovered. In cells dialysed with GTP (0.2-1 mM), IK,ACh still faded but normal sensitivity to agonists was restored with washout. Fade of IK,ACh was not prevented by intracellular heparin or dextran, excluding the involvement of either beta-adrenergic or muscarinic receptor kinase. IK,ACh induced by bethanechol or adenosine also faded, and subsequent CCh application after washout revealed a diminished response. Intracellular guanosine-5'-o-(3-thiotriphosphate (GTP gamma S) induced IK,ACh which faded, and subsequent exposure to CCh was without effect. Equally, after full desensitization with CCh, GTP gamma S failed to induce IK,ACh. The Ca current (ICa) was activated by voltage steps to 0 mV and increased with 1-3 microM isoproterenol. This increase could be reversed by CCh, even when IK,ACh had completely faded. Prolonged muscarinic agonist exposure sometimes also caused fade of the effect on ICa, which always occurred after loss of IK,ACh. The results show that desensitization is heterologous and may involve the guanine nucleotide-binding (G) protein. The differential desensitization to the effects on IK,ACh and ICa suggests the involvement of two different signalling pathways in the muscarinic control of K and Ca channels.