Midazolam for the Successful Treatment of Refractory Spinal-Anesthesia-Associated Hypothermia After Cesarean Delivery

Cesarean deliveries receiving spinal anesthesia with intrathecal morphine are associated with post-operative hypothermia. Lorazepam has been proposed as a reversal agent for treating intrathecal morphine-associated post-cesarean hypothermia. Midazolam is a benzodiazepine familiar to most anesthesia providers and is frequently administered in the perioperative period. We present a post-cesarean delivery spinal anesthesia-associated hypothermia patient successfully treated with intravenous midazolam.

Abl kinase but not PI3-kinase links to the cytoskeletal defects in Bcr-Abl transformed cells

OBJECTIVE

The purpose of this study was to investigate the contribution of Abl kinase and phosphatidylinositol 3-kinase (PI3-kinase) to the altered adhesive properties and cytoskeletal defects in a Bcr-Abl transformed fibroblast cell model. MATERIALS ANID METHODS: Two fibroblast cell lines stably transfected with Bcr-Abl were compared to their parental counterparts for alterations in their adhesive properties in an attachment assay and for abnormalities in their cytoskeletal architecture by immunofluorescence microscopy. Cells then were treated with specific inhibitors of either the Abl kinase CGP57148 or the PI3-kinase LY294002 to determine whether these treatments would restore normal cytoarchitecture and adhesion.

RESULTS

[corrected] Significant defects in cytoskeletal architecture were observed using this fibroblast model of Bcr-Abl expression. Specific changes include loss of stress fibers and focal adhesions, which correlated with an adhesive defect. [corrected] Treatment of Bcr-Abl expressing cells with CGP57148, but not LY294002, resulted in reversion of cells to a near-normal phenotype, as assessed by immunofluorescence and attachment of Bcr-Abl transformed fibroblasts.

CONCLUSIONS

Our studies demonstrate that Bcr-Abl tyrosine kinase but not PI3- kinase activity is required for maintenance of cytoskeletal rearrangements resulting from Bcr-AbI expression. Further, inhibition of Abl kinase restored normal adhesive properties to the Bcr-Abl-expressing cells, demonstrating the contribution of Bcr-Abl kinase activity to abnormal cytoskeletal function.

The transferrin receptor cytoplasmic domain determines its rate of transport through the biosynthetic pathway and its susceptibility to cleavage early in the pathway

The soluble human transferrin receptor (TfR) found in blood is the result of a proteolytic cleavage occurring in the ectodomain of the receptor close to the transmembrane domain at Arg-100. We have discovered another cleavage site between Gly-91 and Val-92 even closer to the transmembrane domain. Cleavage at Gly-91 differs markedly from the normal cleavage site. It occurs when the entire cytoplasmic portion or the proximal 31 amino acids of the transmembrane domain are deleted. A soluble disulfide-bonded dimer of the TfR is released into the medium in contrast to the cleavage at Arg-100 where a dimer lacking intersubunit disulfide bonds is released. Whereas the cleavage at Arg-100 is generated by cycling through the endosomal system, pulse-chase experiments indicate that cleavage at Gly-91 occurs predominantly during the biosynthesis of the receptor. Pulse-chase analysis of the biosynthesis of mutant TfRs that lack the membrane-proximal cytoplasmic domain show that they exit the endoglycosidase H-sensitive compartment at a slower rate than the wild type TfR. These results suggest that the cytoplasmic domain influences the trafficking of the TfR either by influencing the folding of the ectodomain or by providing a positive signal for its transport through the biosynthetic pathway.

The human immunodeficiency virus-1 nef gene product: a positive factor for viral infection and replication in primary lymphocytes and macrophages

Considerable controversy and uncertainty have surrounded the biological function of the Human Immunodeficiency Virus (HIV)-1 nef gene product. Initial studies suggested that this early, nonstructural viral protein functioned as a negative regulatory factor; thus, it was proposed to play a role in establishing or maintaining viral latency. In contrast, studies in Simian Immunodeficiency Virus (SIV)mac-infected rhesus monkeys have suggested that Nef is not a negative factor but rather plays a central role in promoting high-level viral replication and is required for viral pathogenesis in vivo. We sought to define a tissue culture system that would approximate the in vivo setting for virus infection in order to assess the role of HIV-1 Nef in viral replication. We show that infection of mitogen-activated peripheral blood mononuclear cells (PBMC) with Nef+ HIV results in enhanced replication as evidenced by earlier gag p24 expression when compared with infections performed with nef mutant viruses. Moreover, when unstimulated freshly isolated PBMC are infected with Nef+ and Nef- viruses and then subsequently activated with mitogen, the Nef-induced difference in viral replication kinetics is even more pronounced, with the Nef- viruses requiring much more time in culture for appreciable growth. A positive effect of Nef on viral replication was also observed in primary macrophages infected with a recombinant of YU-2, a patient-derived molecular clone with macrophage tropism. These positive effects of Nef on viral replication are dependent on the initial multiplicity of infection (MOI), in that infections of unstimulated PBMC at low MOI are most dependent upon intact nef for subsequent viral growth. We now provide evidence that the Nef+ HIV is more infectious than Nef- HIV from both a tissue culture infectious dose analysis, and a single-cell HIV infection assay. In the latter case, we demonstrate that infection with equivalent doses of HIV based on virion-associated gag p24 yields five- to sixfold more infected cells if Nef+ viral stocks were used. Furthermore, we find that the differential infectivity is not dependent on CD4 down-regulation as Nef+ virus produced from transfected COS cells lacking CD4 is also more infectious. However, normalization of PBMC infections to equivalent infectivity between that of the Nef+ and Nef- viruses continues to reveal delayed viral replication in the absence of Nef, suggesting that secondary viral spread in PBMC is also enhanced in Nef+ infections. We demonstrate this directly by showing a 13-15-fold increase in infectivity of PBMC-derived Nef+ HIC.(ABSTRACT TRUNCATED AT 400 WORDS)

Peptides derived from the CDR3-homologous domain of the CD4 molecule are specific inhibitors of HIV-1 and SIV infection, virus-induced cell fusion, and postinfection viral transmission in vitro. Implications for the design of small peptide anti-HIV therapeutic agents

Peptides 12-25 amino acids in length from the V1J1 region of the CD4 molecule (residues 1-120) were synthesized as randomly derivatized, deliberately derivatized, or pure peptide products, and tested for their ability to inhibit HIV-1-induced cell fusion, HIV-1 and SIV infection of CD4-positive human cells, HIV-1 envelope glycoprotein binding to the CD4 molecule, CD4-neutralizing antibody binding to the CD4 holoreceptor, and CD4-dependent cellular immune function in the mixed lymphocyte and cytotoxic T-cell bioassays. Only peptides derived from the complementarity-determining region 3 (CDR3)-homologous domain of CD4, in particular CD4(81-92) and CD4(81-101), were effective antiviral agents. Within the CD4(81-92) series, R-group derivatization of selective amino acid residues was an absolute requirement for biological activity. The prototype compound T1C4E5-tribenzyl-K10-acetyl-TYICEVEDQKEE inhibited HIV-1-induced cell fusion at 32 microM, HIV-1 infection of CEM-SS cells at 10 microM, SIV infection of CEM-174 cells at less than 125 microM, gp120/CD4 binding at 60 microM, and postinfection cell-mediated viral transmission at 10-15 microM. Compounds of identical structure and derivatization, but of altered primary sequence, were substantially less active, or without activity, in these assays. These data indicate that the effect of amino acid derivatization of the CD4(81-92) peptide was most likely restriction of the flexible underivatized peptide backbone to a conformation closely approximating that of the CDR3-homologous gp120 binding site of the native CD4 molecule. Peptide antiviral activity was specific, as judged by lack of cytotoxicity, lack of inhibition of HTLV-1-induced cell fusion, and lack of inhibition of CD4-dependent cellular immune function in vitro. Further derivatization of the prototype compound involving the production of cyclic congeners yielded peptides with submicromolar potency to block HIV-1 infection, strengthening the hypothesis that previous peptide derivations accomplished partial restriction of the conformation of CD4(81-92) to one favorable for interaction with gp120. Concentrations of the original prototype compound T1C4E5-tribenzyl-CD4(81-92) that inhibited infection in vitro more than 50% could be achieved for several hours by intravenous infusion in primates and were well-tolerated at these levels. The peptide was not efficacious to inhibit establishment of viral infection at these doses; however, peptide treatment did lower average viral antigenemia and delay the cumulative time to morbidity relative to the control group.

Effects of GLQ223 on HIV replication in human monocyte/macrophages chronically infected in vitro with HIV

GLQ223 is a formulated version of tricosanthin, a single-chain ribosome-inactivating protein that was shown in earlier studies to inhibit human immunodeficiency virus (HIV) replication in T-lymphoblastoid cells and to decrease HIV p24 levels in HIV-infected monocyte-derived macrophages as measured by flow cytometry. The current studies were performed to test the selectivity of the observed inhibitory effects on HIV replication in chronically infected macrophages infected in vitro. Peripheral blood-derived monocyte/macrophages were infected in vitro and cultivated in suspension for at least two weeks prior to GLQ223 treatment. Anti-HIV effects were quantitated by measurement of cytoplasmic HIV p24, by both enzyme-linked immunosorbent assay (ELISA) and flow cytometry and HIV RNA levels were measured by slot blot analysis. Incorporation of [3H]leucine into trichloroacetic acid- (TCA) precipitable protein was also evaluated as an index of nonspecific inhibitory effects mediated by the compound in infected and uninfected cultures. Five days after a single 3-h treatment with GLQ223 there was a concentration-dependent decrease in all measurable HIV parameters within infected cultures. The anti-HIV effects persisted at least 28 days without evidence for increasing HIV expression. GLQ223 treatment of parallel uninfected macrophage cultures showed no significant inhibition of tritiated leucine uptake. These experiments demonstrate that a single pulsed exposure with GLQ223 of macrophages infected with HIV in vitro caused a sustained, concentration-dependent decrease in both HIV p24 antigen levels as well as HIV RNA without causing measurable toxicity in uninfected cultures.

Anti-idiotypic antisera raised against monoclonal antibody specific for a p24 gag region epitope detects a common interspecies idiotype associated with anti-HIV responses

One potential strategy for the control of human immunodeficiency virus (HIV) infection is immune network manipulation using anti-idiotypic antibodies: this study was undertaken to demonstrate experimentally the potential of such an approach which, in a more highly evolved form, could be used for the treatment of the acquired immune deficiency virus (AIDS) and related disorders. Anti-idiotypic antibodies were generated in rabbits against a murine monoclonal antibody identifying an epitope on the p24 gag core protein of HIV. After extensive absorption on affinity columns to remove isotype- and allotype-specific antibodies, the purified anti-idiotypic antibody preparation was shown to have specific complementarity with the immunizing mouse monoclonal antibody. This anti-idiotypic antibody was also shown to recognize a common idiotype associated with HIV-specific antibodies from both humans and chimpanzees infected with the AIDS virus. In addition a group of rats immunized with the anti-Id responded with significant antibody titers to recombinant derived p24 gag. These data indicate that at least a subpopulation of these polyclonal anti-Id antibodies structurally mimics an HIV gag region epitope and suggest that immunoregulation by anti-idiotypic antibodies may have therapeutic utility for the AIDS epidemic.

GLQ223: an inhibitor of human immunodeficiency virus replication in acutely and chronically infected cells of lymphocyte and mononuclear phagocyte lineage

GLQ223 is a highly purified, formulated preparation of trichosanthin, a 26-kDa plant-derived ribosome-inactivating protein with potent inhibitory activity against human immunodeficiency virus (HIV) in vitro. The compound produced concentration-dependent inhibition of HIV replication in acutely infected cultures of T-lymphoblastoid cells (VB cell line). Treatment with GLQ223 selectively reduced levels of detectable viral proteins compared to total cellular protein synthesis and produced a selective decrease in levels of viral RNA relative to total cellular RNA in acutely infected cells. Substantial inhibition of viral replication was observed at concentrations of GLQ223 that showed little inhibition of parallel uninfected cultures. Selective anti-HIV activity was also observed in cultures of primary monocyte/macrophages chronically infected with HIV in vitro. When freshly drawn blood samples from HIV-infected patients were treated with a single 3-hr exposure to GLQ223. HIV replication was blocked for at least 5 days in subsequently cultured monocyte/macrophages, without further treatment. The anti-HIV activity of GLQ223 in both acutely and chronically infected cells and its activity in cells of both lymphoid and mononuclear phagocytic lineage make it an interesting candidate as a potential therapeutic agent in HIV infection and AIDS.

Long-term observation of baboons, rhesus monkeys, and chimpanzees inoculated with HIV and given periodic immunosuppressive treatment

Baboons, rhesus monkeys, and chimpanzees were injected with the human immunodeficiency virus (HIV) and monitored for up to 4 years. Various immunosuppressive regimens were used during this time in attempts to induce development of the acquired immune deficiency syndrome (AIDS). No infectious virus was recovered or anti-HIV antibodies detected in the baboons and rhesus monkeys. Virus has been recovered from lymphocyte cultures of all five of the chimpanzees at intermittent periods following inoculation. The chimpanzees developed anti-HIV antibodies from 1 to 5 months after virus inoculation and had circulating antibodies that neutralized HIV. All the infected animals were capable of in vitro lymphocyte blastogenic responses to recombinant envelope and core HIV antigens. Despite immunosuppressive therapies and evidence of some immunologic abnormalities, none of the five chimpanzees has yet developed AIDS or a related disorder.

Human monoclonal antibody directed against gag gene products of the human immunodeficiency virus

Tonsillar B lymphocytes from an asymptomatic individual infected with HIV were transformed with EBV. A cloned lymphoblastoid cell line was obtained that secreted human mAb (IgG4 subtype) against the known gag gene products of 55,000 and 25,000 Da and a protein of 40,000 Da. The latter p40 protein appears to be a HIV gag-related gene product that is also recognized immunologically by individuals infected by HIV. Although the mAb detects infection of cells by different HIV isolates, it does not neutralize HIV or show activity in an antibody-dependent cytotoxicity assay.

Human monoclonal antibody directed against gag gene products of the human immunodeficiency virus

Tonsillar B lymphocytes from an asymptomatic individual infected with HIV were transformed with EBV. A cloned lymphoblastoid cell line was obtained that secreted human mAb (IgG4 subtype) against the known gag gene products of 55,000 and 25,000 Da and a protein of 40,000 Da. The latter p40 protein appears to be a HIV gag-related gene product that is also recognized immunologically by individuals infected by HIV. Although the mAb detects infection of cells by different HIV isolates, it does not neutralize HIV or show activity in an antibody-dependent cytotoxicity assay.