Utility of the indium 111-labeled human immunoglobulin G scan for the detection of focal vascular graft infection

The ability to diagnose and localize vascular graft infections has been a major challenge. Recent studies in animal models and humans with focal bacterial infection have shown that radiolabeled, polyclonal, human immunoglobulin G accumulates at the site of inflammation and can serve as the basis for an imaging technique. This study investigated this new technique for the diagnosis and localization of vascular graft infections. Twenty-five patients with suspected vascular infections involving grafts (22), atherosclerotic aneurysms (2), and subclavian vein thrombophlebitis (1) were studied. Gamma camera images of the suspected area were obtained between 5 and 48 hours after intravenous administration of 1.5 to 2.0 mCi (56 to 74 mBq) of indium 111-labeled, human, polyclonal immunoglobulin G. Scan results were interpreted without clinical information about the patient and were subsequently correlated with surgical findings, other imaging modalities, and/or clinical follow-up. In 10 of 10 patients found to have positive scan results, localized infections were confirmed at the involved sites. In 14 of 15 patients whose scan results were interpreted as negative, no vascular infections were identified at follow-up. The patient with false-negative results and recurrent bacteremia from an aortoduodenal fistula was found to have a negative scan outcome at a time when his disease was quiescent. These data suggest that nonspecific, human, indium 111-labeled immunoglobulin G scanning can be a useful noninvasive means of localizing vascular infections.     

On the thymus in the differentiation of "H-2 self-recognition" by T cells: evidence for dual recognition?

In the thymus, precursor T cells differentiate recognition structures for self that are specific for the H-2K, D, and I markers expressed by the thymic epithelium. Thus recognition of self-H-2 differentiates independently of the T cells H-2 type and independently of recognition of nonself antigen X. This is readily compatible with dual recognition by T cells but does not formally exclude a single recognition model. These conclusions derive from experiments with bone marrow and thymic chimeras. Irradiated mice reconstituted with bone marrow to form chimeras of (A X B)F1 leads to A type generate virus-specific cytotoxic T cells for infected targets A only. Therefore, the H-2 type of the host determines the H-2-restricted activity of killer T cells alone. In contrast, chimeras made by reconstituting irradiated A mice with adult spleen cells of (A X B)F1 origin generate virus-specific cytotoxic activity for infected A and B targets, suggesting that mature T cells do not change their self-specificity readily. (A X B)F1 leads to (A X C)F1 and (KAIA/DC) leads to (KAIA/DB) irradiation bone marrow chimeras responded against infected A but not B or C targets. This suggests that cytotoxicity is not generated against DC because it is abscent from the host's thymus epithelium and not against DB because it is not expressed by the reconstituting lymphoreticular system. (KBIB/DA) leads to (KCIC/DA) K, I incompatible, or completely H-2 incompatible A leads to B chimeras fail to generate any measurable virus specific cytotoxicity, indicating the necessity for I-specific helper T cells for the generation of killer T cells. Finally adult thymectomized, irradiated and bone marrow reconstituted (A X B)F1 mice, transplanted with an irradiated thymus of A origin, generate virus-specific cytotoxic T cells specific for infected A targets but not for B targets; this result formally demonstrates the crucial role of thymic epithelial cells in the differentiation of anti-self-H-2 specificities of T cells.     

Familial Nephropathic Non-neuropathic Amyloidosis: Clinical Features, Immunohistochemistry and Chemistry

Classification of familial amyloidosis by the chemical natureof the fibrillar protein has become possible. Most such amyloidogenicproteins so far recognized are variant transthyretins, but twokindreds with the same apolipoprotein AI modification have beenreported. We describe the clinical features of another suchfamily in whom petechial skin rash appeared to be a marker forthe disease, which was non-neuropathic and of the Ostertag-type.Immunohistochemistry showed the protein to be apolipoproteinAI, but allele-specific DNA amplification indicated that itwas not the Arg²⁶ variant previously identified.     

Effect of glucoprivation on serotonin neurotoxicity induced by substituted amphetamines

The present studies were conducted to further explore the potential role of metabolic compromise in substituted amphetamine-induced serotonin (5-HT) neurotoxicity. To this end, we examined the glucoprivic effects of 2-deoxy-D-glucose (2-DG) on the 5-HT neurotoxic effects of fenfluramine (FEN) and methylenedioxymethamphetamine (MDMA). Rats were treated with either FEN or MDMA, alone and in combination, with doses of 2-DG known to produce glucoprivic effects at either 22 +/- 1 or 28 +/- 1 degrees C. At 22 +/- 1 degrees C, FEN produced hypothermia, MDMA induced hyperthermia, and both drugs produced significant long-term reductions in regional brain 5-HT neuronal markers. 2-DG did not enhance 5-HT neurotoxicity induced by either FEN or MDMA; indeed, in some instances, it afforded partial neuroprotection. Although 2-DG afforded partial protection from both FEN and MDMA-induced 5-HT neurotoxic changes, it also caused significant hypothermia, raising the possibility that protection was due to a lowered temperature. Increasing the ambient temperature to 28 +/- 1 degrees C largely eliminated drug-induced hypothermia and eliminated the neuroprotective effects of 2-DG. Thus, even without the confounding effect of temperature, 2-DG still did not potentiate FEN or MDMA-induced 5-HT neurotoxicity. These findings suggest that the role of metabolic compromise in amphetamine-induced 5-HT neurotoxicity merits further study.     

Pharmacokinetics of 18F-labeled fleroxacin in rabbits with Escherichia coli infections, studied with positron emission tomography.

18F-labeled fleroxacin was used to measure the pharmacokinetics of fleroxacin in healthy and infected animals by positron emission tomography (PET) and tissue radioactivity measurements. In all experiments, a pharmacological dose of unlabeled drug (10 mg/kg) was coinjected with the tracer. The pharmacokinetics of [18F]fleroxacin was measured in groups of healthy mice (n = six per group) at 10, 30, 60, and 120 min after injection and in groups of rats with Escherichia coli thigh infections (n = six per group) at 60 and 120 min after injection by radioactivity measurements in excised tissues. In healthy rabbits (n = 4) and in rabbits with E. coli thigh infections (n = 4), tissue concentrations of drug were determined by serial PET imaging over 2 h; after the final image was acquired, animals were sacrificed and concentrations measured by PET were compared with the results of tissue radioactivity measurements. In all three species, there was rapid equilibration of [18F]fleroxacin to significant concentrations in most peripheral organs; low concentrations of drug were detected in the brain. Accumulations of radiolabeled drug in infected and healthy thigh muscles were similar. Peak concentrations of drug of more than three times the MIC for 90% of members of the family Enterobacteriaceae (greater than 100-fold for most organisms) were achieved in all tissues except brain and remained above this level for more than 2 h. Especially high peak concentrations were achieved in the kidney (greater than 75 micrograms/g), liver (greater than 50 micrograms/g), blood (greater than 25 micrograms/g), and bone and lung (greater than 10 micrograms/g).Since the MICs for 90% of all Enterobacteriaceae are <2 micrograms/ml, fleroxacin should be particularly useful in treating gram-negative infections affecting these tissues. In contrast, the low concentration of drug delivered to the brain should limit the toxicity of the drug for the central nervous system.     

Attenuation of murine collagen-induced arthritis by a novel, potent, selective small molecule inhibitor of IkappaB Kinase 2, TPCA-1 (2-[(aminocarbonyl)amino]-5-(4-fluorophenyl)-3-thiophenecarboxamide), occurs via reduction of proinflammatory cytokines and antigen-induced T cell Proliferation

Demonstration that IkappaB kinase 2 (IKK-2) plays a pivotal role in the nuclear factor-kappaB-regulated production of proinflammatory molecules by stimuli such as tumor necrosis factor (TNF)-alpha and interleukin (IL)-1 suggests that inhibition of IKK-2 may be beneficial in the treatment of rheumatoid arthritis. In the present study, we demonstrate that a novel, potent (IC(50) = 17.9 nM), and selective inhibitor of human IKK-2, 2-[(aminocarbonyl)amino]-5-(4-fluorophenyl)-3-thiophenecarboxamide (TPCA-1), inhibits lipopolysaccharide-induced human monocyte production of TNF-alpha, IL-6, and IL-8 with an IC(50) = 170 to 320 nM. Prophylactic administration of TPCA-1 at 3, 10, or 20 mg/kg, i.p., b.i.d., resulted in a dose-dependent reduction in the severity of murine collagen-induced arthritis (CIA). The significantly reduced disease severity and delay of disease onset resulting from administration of TPCA-1 at 10 mg/kg, i.p., b.i.d. were comparable to the effects of the antirheumatic drug, etanercept, when administered prophylactically at 4 mg/kg, i.p., every other day. Nuclear localization of p65, as well as levels of IL-1beta, IL-6, TNF-alpha, and interferon-gamma, were significantly reduced in the paw tissue of TPCA-1- and etanercept-treated mice. In addition, administration of TPCA-1 in vivo resulted in significantly decreased collagen-induced T cell proliferation ex vivo. Therapeutic administration of TPCA-1 at 20 mg/kg, but not at 3 or 10 mg/kg, i.p., b.i.d., significantly reduced the severity of CIA, as did etanercept administration at 12.5 mg/kg, i.p., every other day. These results suggest that reduction of proinflammatory mediators and inhibition of antigen-induced T cell proliferation are mechanisms underlying the attenuation of CIA by the IKK-2 inhibitor, TPCA-1.     

Anaphylaxis after treatment with recombinant factor VIII

BACKGROUND: Treatment of hemophilia patients with recombinant factor VIII concentrates has not previously been associated with anaphylaxis. STUDY DESIGN AND METHODS: A 5-week-old boy with severe hemophilia A developed dyspnea, cyanosis, hypotension, and a diffuse urticarial rash following treatment with a recombinant factor VIII (Recombinate). To identify the cause of anaphylaxis in this patient, the vial lot was examined for the presence of endotoxin, and a checkerboard immunoblotting technique was used to test serum and/or plasma samples from the patient and mother for the presence of antibodies (IgA, IgG, IgE, and IgM) to Recombinate-related antigens (recombinant factor VIII, von Willebrand factor, human serum albumin, Chinese hamster ovary proteins, bovine serum albumin, mouse monoclonal anti-human factor VIII, polyethylene glycol 3350), and to ethylene oxide, the agent used to sterilize the infusion equipment. RESULTS: No immune response directed against the Recombinate-related antigens or ethylene oxide that could be associated with the anaphylactic reaction was identified. Endotoxin was not present upon rabbit pyrogen testing of the therapeutic product. CONCLUSION: These studies failed to show any association between Recombinate and the onset of the allergic reaction. This seems to be the first reported case of anaphylaxis following the infusion of a recombinant form of factor VIII concentrate.     

Discrepancies in reverse ABO typing due to prozone

Three group O sera manifesting prozone in reverse ABO tests are reported. All were implicated in erroneous blood typing results. One sample failed to react with A1 red cells (RBCs) in immediate-spin (IS) tests, had anti-A and -B titers of 8192 and 2048, respectively, by indirect antiglobulin technique (IAT), and was from a diabetic patient; the parenteral administration of A substance present in porcine insulin is a possible cause of hyperimmunity in this case. The second sample was from the recipient of a single unit of group B fresh-frozen plasma; the serum anti-A and -B titers were 10,240 by IAT, but only weak reactions with A1 and B RBCs were noted in routine IS reverse typing tests; the hyperimmunity in the patient concerned was likely due to crossreacting anti-A, B stimulated by B-active glycoproteins and/or glycolipids in the transfused plasma. The third serum also had anti-A and anti-B IAT titers of 10,240 but did not react with A1 and B RBCs by IS; the hyperimmunity in this case may be related to sepsis from intestinal flora carrying A- and/or B-like antigens. These antibodies lysed A1 and/or B RBCs in tests incubated at room temperature (RT) and strongly agglutinated those RBCs by IS when diluted 10-fold with saline. The absence of the prozone phenomenon in tests with RBCs suspended in diluents containing EDTA is consistent with the previously published mechanism for anti-A prozone: namely, the steric hindrance of agglutination by the C1 component of human complement.(ABSTRACT TRUNCATED AT 250 WORDS)     

The 67-kD elastin/laminin-binding protein is related to an enzymatically inactive, alternatively spliced form of beta-galactosidase.

We and others have previously shown that a 67-kD cell surface elastin/laminin-binding protein (EBP) is responsible for cell adhesion to elastin and laminin and for mediating the process of elastin fiber assembly, but the nature of this protein was unknown. In this report we provide evidence that a 67-kD catalytically inactive form of beta-galactosidase produced by alternative splicing demonstrates immunological and functional similarity and sequence homology to the 67-kD EBP, suggesting that the two might be the same. Antibody prepared to a synthetic peptide, N-Ac-GSPSAQDEASPL, corresponding to a frame-shift-generated sequence unique to the alternatively spliced form of human beta-galactosidase, also recognized sheep EBP both on Western blotting and in aortic tissue. Furthermore, this synthetic peptide (S-GAL) binds to elastin and laminin, but not to fibronectin, collagen I, or collagen III. Moreover, both tropoelastin and laminin which bind to S-GAL peptide affinity columns can be specifically eluted from them with an excess of free S-GAL peptides. In addition, sequence homology among this splice variant of human beta-galactosidase, sheep EBP, and NH2-terminal sequences of some elastases suggests that these proteins share a common ligand-binding motif that has not been previously recognized.