Burden of illness among patients with severe aplastic anemia who have had insufficient response to immunosuppressive therapy: a multicenter retrospective chart review study

Annals of Hematology - This study assessed treatment patterns and healthcare resource utilization (HRU) of patients with severe aplastic anemia (SAA) with insufficient response to immunosuppressive...     

6-Mercaptopurine metabolism in Crohn's disease: correlation with efficacy and toxicity.

BACKGROUND: 6-Mercaptopurine (6-MP) has confirmed short and longterm efficacy in the treatment of IBD. However, the relation between its metabolism, efficacy, and side effects is not well understood. AIMS: To assay 6-MP metabolites and to correlate levels with drug compliance, disease activity, and adverse effects of treatment. PATIENTS: Heparinised blood was obtained prior to daily administration of 6-MP in 25 adolescent Crohn's disease patients (14 ileocolitis, 11 colitis) receiving 1.2 (range 0.4-1.6) mg/kg/day for a mean of 17 (range 4-65) months. METHODS: Erythrocyte free bases 6-thioguanine (6-TG) and 6-methyl-mercaptopurine (6-MMP) were measured (pmol/8 x 10(8) red blood cells) using reverse phase high performance liquid chromatography. RESULTS: Disease activity (modified Harvey-Bradshaw index) improved significantly with 6-MP (p = 0.001). Clinical remission was achieved in 72% of patients, who stopped taking prednisone, or were successfully weaned to a low alternate day dose (< 0.4 mg/kg/OD). Remission correlated well with erythrocyte 6-TG (p < 0.05), but not 6-MMP levels. Neutropenia was associated with 6-MP use (p < 0.005), but did not correlate with erythrocyte 6-MP metabolite levels. One patient refractory to 6-MP had 6-TG, but no measureable 6-MMP production, suggesting deficient thiopurine methyl-transferase activity or poor compliance. 6-MP induced complications (hepatitis, pancreatitis, and marrow suppression) were generally associated with increased 6-MMP levels. CONCLUSIONS: These results suggest that high performance liquid chromatography measurement of erythrocyte 6-MP metabolites may provide a quantitative assessment of patient responsiveness and compliance to treatment. The data support an immunosuppressive role for 6-TG, and potential cytotoxicity of raised 6-MMP levels.     

Activity and cross-reactivity of antibodies induced in mice by immunization with a group B meningococcal conjugate

The capsular polysaccharide of group B Neisseria meningitidis is composed of a linear homopolymer of alpha(2-8) N-acetyl neuraminic acid or polysialic acid (PSA) that is also carried by isoforms of the mammalian neural cell adhesion molecule (NCAM), which is especially expressed on brain cells during development. Here we analyzed the ability of antibodies induced by the candidate vaccine N-propionyl polysaccharide tetanus toxoid conjugate to recognize PSA-NCAM. We hyperimmunized mice to produce a pool of antisera and a series of immunoglobulin G monoclonal antibodies and evaluated their self-reactivity profile by using a battery of tests (immunoprecipitation, immunoblotting, and immunofluorescence detection on live cells and human tissue sections) chosen for their sensitivity and specificity to detect PSA-NCAM in various environments. We also searched for the effects of the vaccine-induced antibodies in two functional assays involving cell lysis or cell migration. Although they were highly bactericidal, all the antibodies tested showed very low or no recognition of PSA-NCAM, in contrast to PSA-specific monoclonal antibodies used as controls. Different patterns of cross-reactions were revealed by the tests used, likely due to affinity and specificity differences among the populations of induced antibodies. Furthermore, neither cell lysis nor perturbation of migration was observed in the presence of the tested antibodies. Importantly, we showed that whereas enzymatic removal of PSA groups from the surfaces of live cells perturbed their migration, blocking them with PSA-specific antibodies was not functionally detrimental. Taken together, our data indicated that this candidate vaccine induced antibodies that could not demonstrate an immunopathologic effect.     

A novel C202F mutation in the connexin26 gene (GJB2) associated with autosomal dominant isolated hearing loss

Mutations in the GJB2 gene encoding connexin26 (CX26) account for up to 50% of cases of autosomal recessive hearing loss. In contrast, only one GJB2 mutation has been reported to date in an autosomal dominant form of isolated prelingual hearing loss. We report here a novel heterozygous 605G→T mutation in GJB2 in all affected members of a large family with late childhood onset of autosomal dominant isolated hearing loss. The resulting C202F substitution, which lies in the fourth (M4) transmembrane domain of CX26, may impair connexin oligomerisation. Finally, our study suggests that GJB2 should be screened for heterozygous mutations in patients with autosomal dominant isolated hearing impairment, whatever the severity of the disease.


Keywords: C202F mutation; connexin26 gene (GJB2); autosomal dominant hearing loss     

Structural response and relative strength of a laminated composite hip prosthesis: effects of functional activity

To obtain a better appreciation for the structural performance of a laminated composite hip prosthesis (CP), we examined in situ prosthesis structural response and relative strengths as a function of walking and stair climbing using our previously developed analysis guidelines. Accordingly, we examined overall prosthesis structural response utilizing a global continuum level modeling approach and prosthesis relative strengths using a local microstructural (or ply-level) modeling approach. As a reference and control, we examined the structural performance of the intact natural femur (NAT) and a titanium alloy (Ti) based hip prosthesis. In terms of the overall structural response, i.e., the femur/prosthesis deformational response, stem/bone interfacial stress transfer, and calcar strain energy density restored, the performance of the CP prosthesis was moderately improved over that of the control Ti prosthesis and better approximates the NAT response. In terms of relative strength, we found that the neck of the CP prosthesis failed for all activities with the exception of the mid-stance phase of level walking. However, the prosthesis appears to have sufficient relative strength for function at positions distal to the neck of the prosthesis. While these results dampen enthusiasm for consideration of laminated composite hip prostheses designed with a shape based on a metal alloy implant, they indirectly support consideration of alternate hip prosthesis structural designs such as using a better supported prosthesis neck or utilizing metal/composite hybrid constructions. Importantly, our simulation and analysis approach could be utilized in the design of other laminated composite biomedical structural components.     

Presence of HLA-D/DR antigens on the membrane of breast tumour cells

HLA-D/DR (Ia) glycoproteins were identified in human breast carcinoma and normal mammary gland cells by means of an anti-Ia monoclonal antibody. Two techniques were used: (1) immunoperoxidase staining performed on histological sections and (2) Ia glycoproteins were isolated as follows: firstly by radioactive labelling of isolated cells, then by filtration on Sephadex G25, followed by Lens culinaris chromatography, and immune complex formation and then elution on protein A-Sepharose. Lastly, the immune complex was studied by chromatofocusing. Both techniques revealed that Ia expression was found in carcinoma cells, but not in normal cells.     

Identification, in mouse macrophages and in serum, of a soluble receptor for the Fc portion of IgG (Fc{gamma}R) encoded by an alternatively spliced transcript of the Fc{gamma}RII gene

Low affinity FcR are a heterogeneous group of glycoproteinswhich exist in transmembrane (TM) as well as in soluble forms.Two membrane isoforms of the murine type II FcR, FcRilb1 andFc;Rilb2, have been described. They result from the translationof alternatively spliced premRNA, FcRilb2 lacking sequencesof the first intracytoplasmic domain (IC1). Soluble forms ofFcR (sFcR) have previously been shown to result from proteolysisof membrane receptors. We report here the identification, inmacrophages, of a mRNA derived from the FCRll gene by splicingexons encoding the TM and IC1 domains, i.e. corresponding toa TM-deleted FcRllb2 mRNA. A soluble protein possibly encodedby this mRNA was identified in macrophage supernatants. In accordancewith FcR nomenclature, we propose to name this new FcRll IsoformFcRllb3. It is the most abundant 8FcR present in serum, as comparedwith 8FcR resulting from cleavage of membrane FcR.     

Effects of portal injection of 2,5-anhydro-D-mannitol on pancreatic hormone responses to exercise in rats

The fructose analogue 2,5-anhydro-D-mannitol (2,5-AM) has been shown to act specifically in liver by decreasing liver ATP and by blocking glycogenolysis and gluconeogenesis. The present investigation was designed to determine the effects of the administration of 2,5-AM on pancreatic hormone responses during a situation of increased energy demand such as physical exercise, and by comparison to the resting response, to test the possibility that the hormonal effects of 2,5-AM during exercise may be dissociated from a decrease in blood glucose levels. Adrenodemedullated rats were injected intraportally with a dose of 200 mg/kg of 2,5-AM (50 mg/ml) or by an equivalent volume of saline (0.9% NaCl) before being submitted to a 30-min treadmill run (26 m/min, 0% grade). Administration of 2,5-AM at rest resulted in a significant (P < 0.05) decrease of plasma glucose and insulin levels and an increase in beta-hydroxybutyrate concentrations. During exercise, administration of 2,5-AM, as compared to resting values, resulted in a larger decrease in glucose, a similar decrease in insulin, and a much larger increase in glucagon, glucagon/insulin molar ratio, and beta-hydroxybutyrate concentrations. It is concluded that exercise amplifies some of the metabolic and hormonal effects of 2,5-AM, and that these effects cannot all be explained by the decrease in blood glucose levels.