Immune responses, and autoimmune outcome, during virus infection of the central nervous system

A combined role of a virus infection of the central nervous system (CNS) and an autoimmune response to myelin basic protein (MBP), an autoantigen of the CNS, is suggested in the pathogenesis of multiple sclerosis (MS). SJL mice are highly susceptible while B6 mice are less susceptible to the induction of experimental autoimmune encephalomyelitis (EAE), the autoimmune model of MS. Peripheral inoculation of Semliki forest virus (SFV) into SJL and B6 mice resulted in: (1) Higher viral titers, more severe clinical disease, and hence a stronger nonspecific and SFV-specific lymphoproliferation, and production of IFN-gamma and TNF/LT was observed by splenocytes (SPL) of B6 than by those of SJL mice, on Day 7 postinfection. (2) Following viral clearance, however, proliferation to SFV, and to MBP, and the production of IFN-gamma and TNF/LT by SPL of SFV-infected SJL mice were significantly higher, while the production of TGF-beta was significantly lower than by those of B6 mice. In conclusion, the immune responses to SFV, and to MBP, which were triggered by SFV infection were significantly higher and more prolonged in the SPL of SJL mice, the EAE-susceptible mice, than by those of B6 mice after the infection was cleared.

Transcatheter delivery of c-myc antisense oligomers reduces neointimal formation in a porcine model of coronary artery balloon injury

BACKGROUND

Smooth muscle cell proliferation and extracellular matrix accumulation are the principal mechanisms leading to vascular restenosis. We have previously demonstrated the growth-inhibitory effect of antisense oligomers targeting the c-myc proto-oncogene in human smooth muscle cells. The goal of this study was to investigate whether c-myc antisense oligomers reduce neointimal formation in balloon-denuded porcine coronary arteries.

METHODS AND RESULTS

First, type I collagen synthesis, which reflects synthetic function, was markedly reduced following c-myc antisense oligomers in porcine vascular smooth muscle cells independent of the growth inhibition. These effects in vitro provided the rationale for assessing c-myc antisense oligomers in the prevention of neointima in vivo. Second, the efficiency of single transcatheter delivery of oligomers into denuded porcine coronary arteries was determined. Despite rapid plasma clearance following local delivery, oligomers persisted at the site of injection for at least 3 days, exceeding by severalfold their concentration in peripheral organs. Third, morphometric analyses were carried out in balloon-denuded coronary arteries at 1 month after transcatheter c-myc antisense oligomer administration. Maximal neointimal area was reduced from 0.80 +/- 0.17 mm2 in the control group (n = 12) to 0.24 +/- 0.06 mm2 in the antisense-treated group (n = 13, P < .01). Likewise, a significant reduction in maximal neointimal thickness was observed in the antisense-treated group (P < .01). These changes in vascular remodeling following denuding injury resulted in an increase in residual lumen from 64 +/- 6% in the control group to 81 +/- 5% in the antisense-treated group (P < .05).

CONCLUSIONS

(1) Single transcatheter administration allowed for endoluminal delivery of oligomers to the site of coronary arterial injury. (2) C-myc antisense oligomers reduced the formation of neointima in denuded coronary arteries, implying a therapeutic potential of this approach for the prevention of coronary restenosis. (3) It is postulated that the c-myc proto-oncogene is involved in the process of vascular remodeling, regulating smooth muscle cell proliferation and extracellular matrix synthesis.

DNA fragmentation is an early event in cytokine-induced islet beta-cell destruction

The cytokines, interleukin 1, tumour necrosis factor, and interferon gamma are cytotoxic to islet beta cells, however, their mechanisms of beta-cell killing are not fully characterized. Since DNA damage is a mechanism of cytokine-induced cell death in some cell types, we sought evidence for cytotoxic effects of cytokines at a nuclear level in islet beta cells by measuring DNA fragmentation in rat islets and islet beta-cell lines. The individual cytokines, interleukin 1 (10 U/ml), tumour recrosis factor (10(3) U/ml) and interferon gamma (10(3) U/ml) inhibited insulin release from rat islets, but did not cause DNA fragmentation or destroy islet cells; by contrast, combination of the three cytokines induced DNA fragmentation and islet-cell death. Cytokine-induced DNA fragmentation preceded cell lysis in islet beta-cell lines (RINm5F, rat insulinoma cells; and NIT-1, NOD/Lt mouse transgenic beta cells), whereas in non-islet cell lines (GH-3, rat pituitary; and PC-12, rat adrenal) the cytokines induced cell lysis and no or late DNA fragmentation. Nicotinamide prevented both DNA fragmentation and destruction of RINm5F islet cells by the cytokines. These findings identify DNA as an early target of cytokine action in islet beta cells, and implicate DNA fragmentation as a mechanism of cytokine-induced beta-cell destruction.

Higher autoantibody levels and recognition of a linear NH2-terminal epitope in the autoantigen GAD65, distinguish stiff-man syndrome from insulin-dependent diabetes mellitus

The smaller form of the GABA-synthesizing enzyme glutamic acid decarboxylase (GAD65) is a major autoantigen in two human diseases that affect its principal sites of expression. Thus, destruction of pancreatic beta cells, which results in insulin-dependent diabetes mellitus (IDDM), and impairment of GABA-ergic synaptic transmission in Stiff-Man syndrome (SMS) are both characterized by circulating autoantibodies to GAD65. Anti-GAD65 autoantibodies in IDDM are predominantly directed to conformational epitopes. Here we report the characterization of humoral autoimmune responses to GAD65 in 35 SMS patients, of whom 13 (37%) also had IDDM. All SMS patients immunoprecipitated native GAD65 and the main titers were orders of magnitude higher than in IDDM patients. Furthermore, in contrast to the situation in IDDM, autoantibodies in 35 of 35 (100%) of SMS patients recognized denatured GAD65 on Western blots. Two major patterns of epitope specificity were identified on Western blots. The first pattern, detected in 25 of 35 SMS patients (71%), of whom 11 had IDDM (44%), was predominantly reactive with a linear NH2-terminal epitope residing in the first eight amino acids of GAD65. Nine of nine individuals who were HLA-haplotyped in this group carried an IDDM susceptibility haplotype and HLA-DR3, DQw2 was particularly abundant. The second pattern, detected in 10 of 35 patients (29%) of whom two had IDDM (20%), included reactivity with the NH2-terminal epitope plus strong reactivity with one or more additional epitope(s) residing COOH-terminal to amino acid 101. The second epitope pattern may represent epitope spreading in the GAD65 molecule, but may also include some cases of epitope recognition associated with IDDM resistant HLA-haplotypes. The principal NH2-terminal linear epitope in GAD65 distinguishes the reactivity of SMS and IDDM autoantibodies and may be a determinant of pathogenicity for GABA-ergic neurons. The greater magnitude and distinct specificity of the humoral response to GAD65 in SMS may reflect a biased involvement of the T helper cell type 2 (Th2) subset of CD4+ T cells and antibody responses, whereas IDDM is likely mediated by the Th1 subset of CD4+ T cells and cytotoxic T cell responses.

Defective production of anti-inflammatory cytokine, TGF-beta by T cell lines of patients with active multiple sclerosis

Activated T lymphocytes play an important role in the pathogenesis of multiple sclerosis (MS). These T cells secrete both pro- and anti-inflammatory cytokines. We have studied the production of these two kinds of cytokines by PBL of patients with MS and compared it with normal controls and other autoimmune diseases (OAD). PBL of 29 patients with MS, 14 patients with OAD, and 14 healthy normal controls were cultured for 5 wk. PBL of MS patients produced more pro-inflammatory cytokines, IL-2, IFN-gamma and TNF/lymphotoxin, and less anti-inflammatory cytokine, TGF-beta, during wk 2 to 4 in culture than PBL of normal controls. PBL of MS patients also produced more IL-2 and TNF/lymphotoxin than PBL of OAD patients. Decreased TGF-beta production by lymphocytes of patients with MS correlated directly with disease activity. MS patients with active disease produced less TGF-beta than MS patients with stable disease. The cells producing TGF-beta were primarily CD8+ T cells and CD45RA+T cells. These findings emphasize the complexity of immune response in MS patients and suggest that the increased production of pro-inflammatory cytokines by lymphocytes of patients with MS, combined with the decreased production of TGF-beta (anti-inflammatory cytokine), may play an important role in the mechanisms and manifestations of MS.

Defective production of anti-inflammatory cytokine, TGF-beta by T cell lines of patients with active multiple sclerosis

Activated T lymphocytes play an important role in the pathogenesis of multiple sclerosis (MS). These T cells secrete both pro- and anti-inflammatory cytokines. We have studied the production of these two kinds of cytokines by PBL of patients with MS and compared it with normal controls and other autoimmune diseases (OAD). PBL of 29 patients with MS, 14 patients with OAD, and 14 healthy normal controls were cultured for 5 wk. PBL of MS patients produced more pro-inflammatory cytokines, IL-2, IFN-gamma and TNF/lymphotoxin, and less anti-inflammatory cytokine, TGF-beta, during wk 2 to 4 in culture than PBL of normal controls. PBL of MS patients also produced more IL-2 and TNF/lymphotoxin than PBL of OAD patients. Decreased TGF-beta production by lymphocytes of patients with MS correlated directly with disease activity. MS patients with active disease produced less TGF-beta than MS patients with stable disease. The cells producing TGF-beta were primarily CD8+ T cells and CD45RA+T cells. These findings emphasize the complexity of immune response in MS patients and suggest that the increased production of pro-inflammatory cytokines by lymphocytes of patients with MS, combined with the decreased production of TGF-beta (anti-inflammatory cytokine), may play an important role in the mechanisms and manifestations of MS.

[Molecular cytogenetic study of Turner's syndrome with the 45, X/46,X,r(?) karyotype]

Two small marker chromosomes were identified as X-derived ring chromosomes by using the high-resolution banding technique and in situ hybridization with a radioactively labelled human X-chromosome-specific satellite DNA probe. This procedure clearly determined the origin of the marker chromosome, which had been impossible using conventional cytogenetic techniques. The clinical significance of this work is briefly discussed.

[The treatment of lenticular magnetic foreign body using tri-combined operation]

Fourteen patients with lenticular magnetic foreign bodies are reported. All received magnetoperation extraction of foreign bodies combined with extracapsular cataract extraction and primary posterior chamber IOL implantation. Of them, 3 patients underwent a suture fixation of haptic in ciliary sulcus during operation due to tear of posterior capsule of lens. The operation we performed can effectively resolve the problems of the wounders' monocular blindness caused by lenticular foreign bodies and recover their binocular vision simultaneously. The results indicate that this method is good for lenticular foreign bodies. The operative method, opportunity, complication and its management are also discussed.

The mutant Escherichia coli F112W cyclophilin binds cyclosporin A in nearly identical conformation as human cyclophilin

The periplasmic Escherichia coli cyclophilin is distantly related to human cyclophilin (34% sequence identity). Peptidyl-prolyl isomerase activity, cyclosporin A binding, and inhibition of the calcium-dependent phosphatase calcineurin are compared for human and E. coli wild-type and mutant proteins. Like human cyclophilin, the E. coli protein is a cis-trans peptidyl-prolyl isomerase. However, while the human protein binds cyclosporin A tightly (Kd = 17 nM), the E. coli protein does not (Kd = 3.4 microM). The mutant F112W E. coli cyclophilin has enhanced cyclosporin binding (Kd = 170 nM). As for the human protein, the complex of the E. coli mutant with cyclosporin A inhibits calcineurin. Here we describe the structure at pH 6.2 of cyclosporin A bound to the mutant E. coli cyclophilin as solved with solution NMR methods. Despite the low overall sequence identity, the structure of the bound cyclosporin A is virtually identical in both proteins. To assess differences of the cyclosporin binding site, the solution structure of wild-type E. coli cyclophilin was compared with structures of uncomplexed human cyclophilin A and with cyclosporin bound. Despite the structural similarity of bound cyclosporin A, the architecture of the binding site in the E. coli protein is substantially different at the site most distant to tryptophan 121 (human sequence). This site is constructed by a five-residue insertion in a loop of the E. coli protein, replacing another loop in the human protein.

A direct sensitivity matrix approach for fast reconstruction in electrical impedance tomography

In electrical impedance imaging, several proposed reconstruction algorithms have employed the concept of a sensitivity matrix, which can be used to relate the magnitude of a boundary voltage change of a 2D object to the change in conductivity inside the object that has given rise to it. The search for an appropriate inversion of the sensitivity matrix is the key to these algorithms. In this work, a method called the direct sensitivity matrix (DSM) approach for fast image reconstruction is proposed. Both theoretical and experimental results showing the efficiency of this proposed method are also presented.

Comparing ethnic group-specific DAI equations with the standard DAI

The Standard DAI is an orthodontic index based on public perceptions of dental aesthetics in the USA and is a regression equation linking the relative social acceptability of dental appearance and the objective, physical measurements of ten occlusal traits. It can be used in surveys of need for orthodontic treatment and as a screening tool in public programmes providing orthodontic care. To determine if the Standard DAI could be used internationally, 200 stimuli (photographs of dental configurations) were rated for dental aesthetics by 413 Chinese students, 418 Latvian students and 428 Native Americans. To develop ethnic group-specific DAI equations these ratings were linked by regression procedures to the occlusal trait measurements available for each of the 200 stimuli. Using these equations, group-specific DAI scores were calculated for the 200 stimuli. At all levels on the DAI scale the percentage agreements, sensitivities and specificities ranged from 73 to 100 per cent indicating that the Standard DA can be used without modification to calculate DAI scores among Chinese, Latvians and Native Americans.

Clinical observation of treatment of hypertension with calcium

The effect of oral calcium supplementation (1000 mg/day) on hypertension was studied in 57 borderline and mild-to-moderate hypertensive patients in a randomized, double-blind, placebo-controlled study for 14 weeks. Twenty-five patients from the above groups (11 from the calcium-treated group and 14 from the placebo group) were studied in a crossover fashion for 14 more weeks. The high calcium intake lowered systolic blood pressure by 17 mm Hg (P < .01), and diastolic blood pressure by 11 mm Hg (P < .01). Fifty percent of the calcium-treated patients showed a significant antihypertensive effect and were termed calcium responders. In the crossover study, serum sodium was lower after taking calcium than after placebo intake (P < .05). Pretreatment plasma free calcium content of the calcium-responsive patients was significantly lower (P < .05) than in the calcium nonresponsive patients, and was highly significantly increased (P < .01) after administering calcium. The result showed that oral calcium supplementation can lower blood pressure in a significant fraction of essential hypertensive subjects, and that the free calcium level in plasma may help identify calcium-responsive individuals. While the mechanism by which increased calcium intake lowers blood pressure in hypertension is still undetermined, these data support an underlying relationship between hypertension and calcium and possibly sodium metabolism.

Expression of recombinant human casein kinase II and recombinant heat shock protein 90 in Escherichia coli and characterization of their interactions

To assess the interaction of human casein kinase II (CKII) with the heat shock protein 90 (HSP90) class of chaperone proteins, human CKII alpha and beta subunits and beta S2A mutant were expressed and purified separately or from a tandem coexpression construct in Escherichia coli. Recombinant human HSP90 beta and recombinant yeast HSP90 as His6 constructs were also expressed in and purified from E. coli. The rhCKII S2A mutant removed the regulatory beta subunit autophosphorylation site but had no effect on catalytic efficiency with peptide or protein substrates. As a CKII substrate, recombinant hHSP90 beta displayed a Km of 9.8 microM and a kcat of 4.1 min-1 and was phosphorylated to 1.5 mol/mol, whereas ryHSP90, lacking the known serine CKII sites of hHSP90, was phosphorylated at a 19-fold lower kcat/Km ratio to levels of 0.8 mol/mol. The endoplasmic reticulum HSP90 family member Grp94 was phosphorylated to 1.4 mol/mol but, in contrast, HSC70 and FKBP25 chaperones were phosphorylated to < 0.01 mol/mol. Neither phospho nor dephospho forms of hHSP90 showed significant activation of CKII toward the peptide substrate RRREEETEEE in contrast to a previous report that activation was observed at high molar ratios of chaperone to kinase.

Amino acid residues 24-31 but not palmitoylation of cysteines 30 and 45 are required for membrane anchoring of glutamic acid decarboxylase, GAD65

The smaller isoform of the GABA synthesizing enzyme glutamic acid decarboxylase, GAD65, is synthesized as a soluble protein that undergoes post-translational modification(s) in the NH2-terminal region to become anchored to the membrane of small synaptic-like microvesicles in pancreatic beta cells, and synaptic vesicles in GABA-ergic neurons. A soluble hydrophilic form, a soluble hydrophobic form, and a hydrophobic firmly membrane-anchored form have been detected in beta cells. A reversible and hydroxylamine sensitive palmitoylation has been shown to distinguish the firmly membrane-anchored form from the soluble yet hydrophobic form, suggesting that palmitoylation of cysteines in the NH2-terminal region is involved in membrane anchoring. In this study we use site-directed mutagenesis to identify the first two cysteines in the NH2-terminal region, Cys 30 and Cys 45, as the sites of palmitoylation of the GAD65 molecule. Mutation of Cys 30 and Cys 45 to Ala results in a loss of palmitoylation but does not significantly alter membrane association of GAD65 in COS-7 cells. Deletion of the first 23 amino acids at the NH2 terminus of the GAD65 30/45A mutant also does not affect the hydrophobicity and membrane anchoring of the GAD65 protein. However, deletion of an additional eight amino acids at the NH2 terminus results in a protein which is hydrophilic and cytosolic. The results suggest that amino acids 24-31 are required for hydrophobic modification and/or targeting of GAD65 to membrane compartments, whereas palmitoylation of Cys 30 and Cys 45 may rather serve to orient or fold the protein at synaptic vesicle membranes.

Role of tumor necrosis factor in neonatal sepsis

In order to assess the role of tumor necrosis factor (TNF) in neonatal sepsis, plasma TNF levels were determined by a method using L929 cells at the time of septic work-up in 67 neonates. Thirty-three patients with sepsis were found to have significantly higher TNF levels (533.33 +/- 468.74 U/ml; 1 U corresponding to 1.67 pg recombinant TNF) as compared with 34 non-sepsis patients (100.0 +/- 188.97 U/ml) and 30 healthy newborns (27.33 +/- 16.17 U/ml, P < 0.05, respectively). The upper limit of normal plasma TNF levels was 60 U/ml and the best cutoff value for predicting neonatal sepsis was 160 U/ml. This had remarkable sensitivity (88%), specificity (82%), positive predictive value (83%), and negative predictive value (88%). Plasma TNF levels were significantly associated with the occurrence of shock, organ failure, scleroma and outcome. Thus, anti-TNF antibodies might be used in protecting newborns from septic death.

Measurement of the Mueller scattering matrix by use of optical beats from a Zeeman laser

A two-frequency beam from a Zeeman laser scatters elastically from an isotropic medium, such as randomly oriented viruses or other particles suspended in water. The Zeeman effect splits the laser line by 250 kHz, and beats can be seen electronically in the signal from a phototube that views the scattered light. There are independently rotatable half-wave and quarter-wave retardation plates in the incident beam and a similar pair in the observed scattered beam, plus a fixed linear polarizer directly in front of the detector. Each of the four retarders has two angular positions, providing a total of 16 possible polarization cases. For each of the 16 cases, there are three data to be collected: (1) the average total intensity of the scattered light, (2) the amplitude of the beats in the scattered light, and (3) the phase shift between the beats of the scattered light and those of a reference signal from the laser. When a singular value decomposition technique is used, these threefold redundant data are rapidly ransformed into a best-fit 4 × 4 Mueller scattering matrix. We discuss several different measurement strategies and their systematic and statistical errors. We present experimental results for two kinds of particle of wavelength size: polystyrene spheres and tobacco mosaic virus. In both cases the achiral retardation element M(34) of the Mueller matrix is easily measurable.

Role of DNA fragmentation in T cell activation-induced apoptosis in vitro and in vivo

Apoptotic cell death, characterized by DNA fragmentation and morphologic changes, has previously been shown to occur in immature thymocytes and some T cell hybridomas after activation. Like some other forms of apoptosis, DNA fragmentation during activation-induced cell death precedes the morphologic events. For apoptosis to proceed, activation of the cells must persist at least to the time of DNA fragmentation, before which the cells can remain viable if the activation signal is removed. Aurintricarboxylic acid (ATA) blocks activation-induced apoptotic cell death in a T cell hybridoma, and kinetic studies show that this inhibition occurs at or near the time of DNA fragmentation in the cells. Taken together with the ability of ATA to inhibit DNA fragmentation in isolated nuclei exposed to Ca2+ and Mg2+, these data strongly suggest that ATA prevents apoptosis via its ability to inhibit endogenous endonuclease activity, and, conversely, that this activity is required for this form of cell death. In vivo, ATA inhibits thymocyte depletion and DNA fragmentation induced by anti-CD3 Ab. Further, specific loss of V beta 8+ thymocytes after administration of staphylococcal enterotoxin B is blocked by administration of ATA. These observations support an essential role for DNA fragmentation as an irreversible step in activation-induced apoptosis in T cell hybridomas and during T cell development. This is contrasted with heat shock-induced cell death, in which inhibition of DNA fragmentation does not prevent loss of cell viability.

Role of DNA fragmentation in T cell activation-induced apoptosis in vitro and in vivo

Apoptotic cell death, characterized by DNA fragmentation and morphologic changes, has previously been shown to occur in immature thymocytes and some T cell hybridomas after activation. Like some other forms of apoptosis, DNA fragmentation during activation-induced cell death precedes the morphologic events. For apoptosis to proceed, activation of the cells must persist at least to the time of DNA fragmentation, before which the cells can remain viable if the activation signal is removed. Aurintricarboxylic acid (ATA) blocks activation-induced apoptotic cell death in a T cell hybridoma, and kinetic studies show that this inhibition occurs at or near the time of DNA fragmentation in the cells. Taken together with the ability of ATA to inhibit DNA fragmentation in isolated nuclei exposed to Ca2+ and Mg2+, these data strongly suggest that ATA prevents apoptosis via its ability to inhibit endogenous endonuclease activity, and, conversely, that this activity is required for this form of cell death. In vivo, ATA inhibits thymocyte depletion and DNA fragmentation induced by anti-CD3 Ab. Further, specific loss of V beta 8+ thymocytes after administration of staphylococcal enterotoxin B is blocked by administration of ATA. These observations support an essential role for DNA fragmentation as an irreversible step in activation-induced apoptosis in T cell hybridomas and during T cell development. This is contrasted with heat shock-induced cell death, in which inhibition of DNA fragmentation does not prevent loss of cell viability.

YY1 is the cellular factor shown previously to bind to regulatory regions of several leaky-late (beta gamma, gamma 1) genes of herpes simplex virus type 1

We have recently reported that a cellular factor, the leaky-late binding factor (LBF), binds to sites in a number of leaky-late (beta gamma or gamma 1) genes of herpes simplex virus type 1 and that an LBF site is essential for maximum viral transactivation of the major capsid protein (VP5) gene. The results of binding competition, partial proteolysis, and monoclonal antibody inhibition assays presented here establish that LBF is identical to the transcription factor YY1. This, along with our previous observations, suggests that YY1 plays a role in herpes simplex virus type 1 gene regulation.

Cloning, sequencing, and expression in Escherichia coli of the gene encoding a 45-kilodalton protein, elongation factor Tu, from Chlamydia trachomatis serovar F

The gene encoding a 45-kDa protein (45K) of Chlamydia trachomatis serovar F was cloned, sequenced, and overexpressed in Escherichia coli. Alignment of the deduced peptide sequence with E. coli elongation factor Tu (EF-Tu) demonstrated 69% identity. The 45K was recognized by a Chlamydia genus-specific monoclonal antibody GP-45 and cross-reacted with a monospecific polyclonal antibody to E. coli EF-Tu. Purified recombinant 45K has the capability to bind GDP, and the binding was enhanced in the presence of E. coli elongation factor Ts (EF-Ts). The GDP binding was specifically inhibited by the monoclonal antibody GP-45. These data suggest that the 45K is a chlamydial EF-Tu, and it forms a functional complex with E. coli EF-Ts protein.