A computerised sampling strategy for therapeutic drug monitoring of lithium provides precise estimates and significantly reduces dose-finding time

Abstract: The clinical benefit of implementing Bayesian approach for lithium drug monitoring was evaluated. Intervention group (N = 42) and historical control group (N = 55) patients were each divided into two groups: Dosage with immediate‐release lithium carbonate or a sustained‐release formulation, lithium citrate. Bayesian approach was performed in the intervention groups, and estimation of lithium steady‐state trough concentration was obtained from non‐steady‐state blood sample, collected about 12 hr after the first lithium study dose. The estimate was compared with the actually measured steady‐state concentration. In the control group, lithium monitoring was traditionally performed as steady‐state blood sampling. Predicted and measured lithium concentrations were comparable. The desired lithium dose was reached significantly faster in the intervention group compared to control; 2.47 ± 2.22 days versus 9.96 ± 11.24 days (mean ± S.D.) (p = 0.0003). Bayesian approach was an advantage for the clinicians as a fast and safe aid to obtain the optimal lithium treatment dose.     

Anticarbohydrate Antibody Repertoires in Patients Transplanted with Fetal Pig Islets Revealed by Glycan Arrays

Ten patients with type I diabetes were transplanted with porcine fetal islet-like cell clusters (ICC) between 1990 and 1993. A significant rise in the anti-α-Gal antibody titers was seen posttransplant, but also non-α-Gal-specific antibodies were detected in some patients. We have reanalyzed the carbohydrate specificity of antibodies in the sera from seven of these patients taken before transplantation, 1, 6 and 12 months posttransplantation using a glycan array with 200 structurally defined glycans. The main findings were: (i) prepig ICC transplantation patients had antibodies reactive with terminal α-GalNAc (e.g. the Forssman antigen, but not the blood group A determinant in blood group A patients), α-Gal (except blood group B determinants in B individuals), β3-linked Gal especially Galβ1,3GlcNAc even if terminally sulfated or sialylated, β-GlcNAc except if β1,3-linked and oligomannosyl compounds; (ii) the titers of all carbohydrate-specific antibodies detected before transplantation rose after transplantation; (iii) the kinetics of the antibody responses differed between patients; (iv) in some patients antibodies reacting with Galα1,3Le^x and several structures terminated with Neu5Gc appeared after transplantation. In conclusion, anti-α-Gal antibodies are the predominant anticarbohydrate antibodies detected after porcine ICC transplantation, with some patients also developing Neu5Gc-specific antibodies. Their clinical significance needs to be established.     

Anti-LFA-1 improves pig islet xenograft function in diabetic mice when long-term acceptance is induced by CTLA4Ig/anti-CD40L

BACKGROUND: It has been previously demonstrated that addition of anti-LFA-1 to a combination of CTLA4Ig and anti-CD40L induces the permanent acceptance of dopaminergic fetal pig xenografts when transplanted into the brain of wild-type mice. The purpose of this study was to test whether this costimulation blockade also can induce acceptance of adult pig islets transplanted to C57BL/6 mice with streptozotocin-induced diabetes. METHODS: Recipients were treated with CTLA4Ig/anti-CD40L+/-anti-LFA-1 or isotype control antibodies during the first week after transplantation. Half of the costimulation blockade-treated recipients had their grafts removed after 8 weeks. The other half was observed up to 5 months. RESULTS: Recipients treated with CTLA4Ig/anti-CD40L/anti-LFA-1 had significantly lower blood glucose and gained more weight than CTLA4Ig/anti-CD40L-treated recipients. CTLA4Ig/anti-CD40L-treated recipients exhibited unstable blood glucose. IPGTT of these recipients revealed a slow recovery to normal blood glucose levels at week 4. In comparison, CTLA4Ig/anti-CD40L/anti-LFA-1 treated recipients exhibited a significantly superior glucose clearance. CTLA4Ig/anti-CD40L+/-anti-LFA-1 treated recipients did not produce anti-pig IgG, whereas control antibody-treated mice did. CD4+ T cells from costimulation blockade-treated recipients proliferated less than CD4+ T cells from control antibody-treated mice when co-cultured with syngeneic antigen presenting cells loaded with pig islet antigens. CONCLUSIONS: CTLA4Ig/anti-CD40L/anti-LFA-1-treated recipients had superior islet function compared with CTLA4Ig/anti-CD40L-treated recipients. However, both costimulation blockade regimens led to islet graft acceptance up to 5 months after a 1-week treatment.     

Long-term gene expression and metabolic control exerted by lentivirus-transduced pancreatic islets

BACKGROUND: Genetic modification of non-human islets before transplantation may provide means by which they can escape immunity and, thus, be used in a human host. To accomplish this, efficient gene transfer methods are needed. Lentiviral vectors are transgene vehicles capable of stably transducing a variety of primary, post-mitotic cells including islets. METHODS: We investigated whether lentiviral transduction impaired rat pancreatic islet function long term. Following transduction, the gross morphology, viability and in vitro functionality of islets were evaluated by microscopy, adenylate nucleotide and insulin secretion assays, respectively. Further, in vivo functionality of transduced islets was assessed by transplanting the islets under the kidney capsule of diabetic nude mice. RESULTS: All transduced islets contained green fluorescent protein (GFP)-positive cells. In single cell suspensions prepared from transduced islets, 33+/-8% (n = 3) of dispersed islet cells were GFP-positive. The ADP/ATP ratio was 0.07+/-0.01 for transduced islets and 0.06+/-0.01 for controls (normal range <0.11). No morphological changes were observed in transduced islets. Further, basal insulin secretion was comparable between the two islet groups. When transduced and non-transduced islets were challenged with insulin secretagogues, they showed similar increases in insulin release. Transduced and non-transduced islets were equally effective in normalizing blood glucose when transplanted into diabetic nude mice. Euglycemia was maintained for 8 weeks until the graft-bearing kidney was removed. Intense green fluorescence was seen in removed islet grafts. Histology revealed preserved islet morphology, with abundant insulin-producing cells, few apoptotic cells and infiltrating leukocytes in both transduced and non-transduced grafts. CONCLUSIONS: Lentivirus transduction does not affect islet morphology or function. Lentiviral vectors will allow genetic modifications to be performed in islets before transplantation--modifications that can improve engraftment and/or prevent xenograft rejection.     

Different G2/M accumulation in M059J and M059K cells after exposure to DNA double-strand break-inducing agents

PURPOSE: To investigate and compare the cell cycle progression in relation to cell death in the human glioma cell lines, M059J and M059K, after exposure to DNA double-strand break-inducing agents. METHODS AND MATERIALS: The M059J and M059K cells, deficient and proficient in the catalytic subunit of the DNA-dependent protein kinase, respectively, were exposed to 1 and 4 Gy of photons or accelerated nitrogen ions. In addition, M059J and M059K cells were treated with 10 and 40 mug/mL of bleomycin for 30 min, respectively. Cell cycle progression, monitored by DNA flow cytometry, was measured up to 72 h after treatment. RESULTS: M059J, but not M059K, cells displayed G(2)/M accumulation after low linear energy transfer irradiation. High linear energy transfer radiation exposure however, resulted in a substantial increase of M059K cells in the G(2)/M phase detected at 48 h. At 72 h, the number of cells in the G(2)/M phase was equivalent to its control. M059J cells accumulated mainly in S phase after high linear energy transfer irradiation. In contrast to M059K, M059J cells were still blocked at 72 h. Bleomycin induced G(2)/M accumulation for both M059J and M059K cells detected 24 h after treatment. At 48 h, the percentage of bleomycin-treated M059J cells in G(2)/M phase remained high, and the number of M059K cells had decreased to control levels. Neither cell line showed cell cycle arrest (< or =10 h) after exposure to these agents. CONCLUSION: Distinct cell cycle block and release is dependent on the complexity of the induced DNA damage and the presence of the DNA-dependent protein kinase catalytic subunit.     

Adsorption of chain type–specific ABO antibodies on Sepharose‐linked A and B tetrasaccharides

BACKGROUND: Antigen‐specific removal of anti‐A and anti‐B on immunoadsorption columns carrying the blood group A and B trisaccharides is one important component of some protocols used in ABO‐incompatible organ transplantation. Because ABO antibodies exist requiring parts of the core saccharide chain for binding, the anti‐A and ‐B–binding capacity of individual and combined, Sepharose‐linked Types 1 through 4 A and B tetrasaccharides with that of the A and B trisaccharides was compared. STUDY DESIGN AND METHODS: Sepharose‐linked A and B tri‐ and tetrasaccharides were used to adsorb anti‐A and ‐B from pooled blood group O serum. Remaining chain type–specific anti‐A and ‐B were detected and quantified in enzyme‐linked immunosorbent assays using wells coated with neoglycoproteins or recombinant mucins carrying A and B determinants on defined core saccharide chains. RESULTS: Significantly more anti‐A Type 3‐ and 4‐specific immunoglobulin (Ig)G remained after adsorption on the A trisaccharide and the A Type 1 and A Type 2 tetrasaccharide than after adsorption on the A Types 3 and 4 tetrasaccharides. Selective adsorption of chain type–specific IgG anti‐B was detected on Sepharose‐linked B tetrasaccharides. In contrast, there were no chain type–specific IgM anti‐A or ‐B. A combination of the A or B tetrasaccharides adsorbed a larger fraction of the IgG anti‐A and ‐B repertoires than the corresponding trisaccharides. CONCLUSION: There are chain type–specific anti‐A and anti‐B IgG, and an adsorber based on a combination of Types 1 through 4 A or B tetrasaccharides will be a more efficient adsorber than an adsorber based on the A or B trisaccharides.     

Anti-Gal IgG potentiates natural killer cell migration across porcine endothelium via endothelial cell activation and increased natural killer cell motility triggered by CD16 cross-linking

Xenoreactive antibodies (Ab) are important for the development of acute vascular rejection (AVR) of xenografts characterized by monocytes, natural killer (NK) cells and neutrophils infiltrating the graft. The mechanisms by which anti-galactose alpha 1,3galactose (alpha-Gal) IgG influence NK cell migration across porcine aortic endothelium (PAEC) were investigated. NK cell migration across PAEC increased in the presence of anti-alpha-Gal IgG. Anti-alpha-Gal IgG exposure activated PAEC as shown by an increased expression of CD62E and CD106. NK cells adhered, spread and showed motile forms on plastic surfaces coated with human IgG, IgG Fc and on mAb against CD16, but not on mouse IgG or BSA, suggesting that CD16 cross-linking can mediate increased adhesiveness. Increased NK cell motility was observed on Boyden filters coated with human IgG, IgG Fc, and mAb against CD16 and the alpha 4, alpha 5, alpha L, beta 1 and beta 2 integrin chains. No motile response was seen on mouse IgGor CD7, CD56 and alpha 6 integrin mAb. NK cell migration on human IgG and anti-CD16 Ab was blocked by anti-CD16 or anti-beta 2, but not anti-beta 1 Ab, implying that the motile response triggered by CD16 cross-linking is mediated via beta 2 integrins. Preformed or induced anti-alpha-Gal IgG may therefore contribute to AVR by stimulating innate immune cell infiltration of the graft.