Delta-opioid augments cardiac contraction through ß-adrenergic and CGRP-receptor co-signaling.

Cardiac epinephrine and calcitonin gene-related peptide (CGRP) are produced by intrinsic cardiac adrenergic cells (ICA cells) residing in human and animal hearts. ICA cells are neuroparicine cells expressing δ-opioid receptors (DOR). We hypothesized that δ-opioid stimulation of ICA cells enhances epinephrine and CGRP release, which results in the augmentation of heart contraction. Rats were injected with DOR-agonist DPDPE (100 µg/kg) with or without 10-min pretreatment with either ß-adrenergic receptor (ß-AR) blocker propranolol (2mg/kg) or CGRP-receptor (CGRPR) blocker CGRP(8-37) (300 µg/kg), or their combination. Hemodynamics were monitored with echocardiogram and systolic blood pressure (SBP) was monitored via a tail arterial catheter. Changes in left ventricular fraction-shortening (LVFS) and heart rate (HR) were observed at 5-min after DPDPE infusion. At 5-min DPDPE induced a 36 ± 18% (p<0.001) increase of the LVFS, which continues to increase to 51 ± 24% (p<0.0001) by 10 min, and 68 ± 19% (p<0.001) by 20 min. The increase in LVFS was accompanied by the decrease of HR by 9±5% (p<0.01) by 5 min and 11 ± 6% (p<0.001) by 15 min post DPDPE infusion. This magnitude of HR reduction was observed for the remainder of the 20 min. Despite the HR-reduction, cardiac output was increased by 17 ± 8% (p<0.05) and 28±5% (p<0.001) by 5- and 20-min post DPDPE administration, respectively. There was a modest (9 ± 9%, p=0.03) decrease in SBP that was not apparent until 20 min post DPDPE infusion. The positive inotropism of DPDPE was abrogated in animals pretreated with propranolol, CGRP(8-37), or combined propranolol+CGRP(8-37). Furthermore, in whole animal and cardiomyocyte cell culture preparations, DPDPE induced myocardial protein-kinase A (PKA) activation which was abrogated in the animals pretreated with propranolol+CGRP(8-37). DOR agonists augment myocardial contraction through enhanced ß-AR and CGRPR co-signaling.

Withdrawal of treatment in children.

With advances in medical technology, many critically ill children will die following withdrawal of treatment rather than failed resuscitation attempts. Legally the parents are surrogate decision makers. The authors review the ethical, legal and practical aspects of withdrawal of treatment and the complex interactions between them.

Should children's autonomy be respected by telling them of their imminent death?

Respect for an individual's autonomy determines that doctors should inform patients if their illness is terminal. This becomes complicated when the terminal diagnosis is recent and death is imminent. The authors examine the admission to paediatric intensive care of an adolescent with terminal respiratory failure. While fully ventilated, the patient was kept sedated and comfortable but when breathing spontaneously he was capable of non-verbal communication and understanding. Once resedated and reintubated, intense debate ensued over whether to wake the patient to tell him he was going to die. The authors discuss the ethical arguments that surrounded their decision.

Molecular regulation of CD40 gene expression in macrophages and microglia.

Inflammatory events in the central nervous system (CNS) contribute to the disease process in a variety of neuroinflammatory diseases such as multiple sclerosis (MS), Alzheimer's Disease (AD), and cerebral ischemia, and activated macrophages/microglia are central to this response. Immunological activation of these cells leads to the production of a wide array of cytokines, chemokines, matrix metalloproteinases and neurotoxins, and ultimately to glial/neuronal injury and death. The CD40 molecule has an important role in promoting inflammatory responses by macrophages/microglia, since interaction with its cognate ligand, CD154, leads to secretion of cytokines and neurotoxins. Aberrant CD40 expression by macrophages/microglia, induced by cytokines such as IFN-gamma and TNF-alpha, contributes to neuroimmunologic cascades in the CNS. Strategies to suppress CD40 expression may attenuate inflammation and neuronal damage within the CNS, which will ultimately be of benefit in neuroinflammatory diseases. The mediators that regulate expression of CD40 in macrophages/microglia (both induction and inhibition) function at the level of gene transcription. In this review, we present an overview of the molecular basis of CD40 expression in macrophages/microglia. The signal transduction pathways and transcription factors employed by IFN-gamma and TNF-alpha to induce CD40 expression are described, as are the cis-elements in the CD40 promoter that are critical for CD40 transcription. Information is provided on the mechanism(s) underlying suppression of CD40 in macrophages/microglia by immunomodulatory agents such as IL-4, TGF-beta, neuropeptides, neurotrophins, and statins. A comprehensive assessment of CD40 production and function in macrophages/microglia will establish the foundation for future therapeutic manipulation of this critical immunoregulatory protein.

Regulation and function of class II major histocompatibility complex, CD40, and B7 expression in macrophages and microglia: Implications in neurological diseases.

The ability of microglia, the brain's resident macrophage, to present antigen through the class II major histocompatibility complex (MHC) to T cells allows these normally quiescent cells to play a critical role in shaping the outcome of many neurological diseases. The expression of class II MHC antigens and the costimulatory molecules CD40 and B7 on microglia and infiltrating macrophages is regulated through a complex network of cytokines in the inflamed brain. In this review, we describe the molecular mechanisms underlying class II MHC, CD40 and B7 regulation in microglia and macrophages. Our focus is on the cis-elements in the promoters of their genes and the transcription factors activated by cytokines that bind them. The functional implications of aberrant class II MHC, CD40 and B7 expression by microglia and macrophages as related to the diseases of Multiple Sclerosis and Alzheimer's Disease are discussed.

Suppressor of cytokine signaling 1 inhibits cytokine induction of CD40 expression in macrophages.

CD40 is a type I membrane-bound molecule belonging to the TNFR superfamily that is expressed on various immune cells including macrophages and microglia. The aberrant expression of CD40 is involved in the initiation and maintenance of various human diseases including multiple sclerosis, arthritis, atherosclerosis, and Alzheimer's disease. Inhibition of CD40 signaling has been shown to provide a significant beneficial effect in a number of animal models of human diseases including the aforementioned examples. We have previously shown that IFN-gamma induces CD40 expression in macrophages and microglia. IFN-gamma leads to STAT-1alpha activation directly and up-regulation of NF-kappaB activity due to the secretion and subsequent autocrine signaling of TNF-alpha. However, TNF-alpha alone is not capable of inducing CD40 expression in these cells. Suppressor of cytokine signaling 1 protein (SOCS-1) is a cytokine-inducible Src homology 2-containing protein that regulates cytokine receptor signaling by inhibiting STAT-1alpha activation via a specific interaction with activated Janus kinase 2. Given the important role of CD40 in inflammatory events in the CNS as well as other organ systems, it is imperative to understand the molecular mechanisms contributing to both CD40 induction and repression. We show that ectopic expression of SOCS-1 abrogates IFN-gamma-induced CD40 protein expression, mRNA levels, and promoter activity. Additionally, IFN-gamma-induced TNF-alpha secretion, as well as STAT-1alpha and NF-kappaB activation, are inhibited in the presence of SOCS-1. We conclude that SOCS-1 inhibits cytokine-induced CD40 expression by blocking IFN-gamma-mediated STAT-1alpha activation, which also then results in suppression of IFN-gamma-induced TNF-alpha secretion and subsequent NF-kappaB activation.

Critical role of tumor necrosis factor-alpha and NF-kappa B in interferon-gamma -induced CD40 expression in microglia/macrophages.

CD40 is a member of the tumor necrosis factor (TNF) receptor superfamily. CD40 expression on antigen-presenting cells (including macrophages and microglia) is crucial for T-cell activation. Aberrant expression of CD40 has been associated with autoimmune inflammatory diseases such as multiple sclerosis and rheumatoid arthritis. We have recently shown that the cytokine interferon (IFN)-gamma is the most potent inducer of CD40 expression in macrophages and microglia, and this induction is mediated by the IFN-gamma-activated transcription factor STAT-1alpha and constitutively expressed PU.1 and/or Spi-B. In this study, we have discovered that a major component of IFN-gamma-induced CD40 expression involves the endogenous production of the cytokine TNF-alpha. The inclusion of anti-TNF-alpha-neutralizing antibody significantly inhibits IFN-gamma-induced CD40 mRNA and CD40 promoter activity. IFN-gamma-induced CD40 protein expression is attenuated in TNF-alpha-deficient microglia and can be restored with exogenous TNF-alpha. Site-directed mutagenesis studies demonstrate that three of the four NF-kappaB elements in the CD40 promoter are required for IFN-gamma-induced CD40 promoter activity. IFN-gamma treatment leads to the activation of NF-kappaB in a time-dependent manner, which is inhibited in the presence of anti-TNF-alpha-neutralizing antibody. These results indicate that IFN-gamma-induced TNF-alpha production and subsequent NF-kappaB activation are integral parts of the mechanism of IFN-gamma-induced CD40 expression.

Conservation of essential sequences in the major late promoter and tripartite leader of the simian adenovirus type 30.

We report here the cloning and sequencing of the major late promoter (MLP) and the tripartite leader (TPL) from simian adenovirus type 30 (sAd30) and the comparison of the sAd30 nucleotide (nt) sequence with that of human adenoviruses (hAd). The nt sequence homology between sAd30 and hAd2 is 75% from -66 to +190 relative to the cap site. This sAd30 MLP segment contains the upstream regulatory sequence element, TATA box, and downstream regulatory sequence elements that are homologous to hAd MLP. The sAd30 upstream regulatory sequence has a small palindromic DNA sequence GTCACGTGAC, and the TATA box contains the sequence of ATAAA instead of TATAAA. The sAd30 TPL was located on the sAd30 genome as identified by sequence homology with the hAd counterpart. The splice sites of TPL introns were confirmed by sequence analysis of cDNAs synthesized from sAd30-infected cells. There is a 74.2% nt sequence homology between the TPL of sAd30 and hAd2. The conservation of these sequence elements during evolution of Ad suggests that they are essential for the transcription and translation of Ad ML transcripts.

Therapeutic efficacy and pharmacokinetic properties of ciprofloxacin in intra-abdominal abscesses caused by Bacteroides fragilis and Escherichia coli.

Experimental intra-abdominal abscesses were produced in mice by intraperitoneal injections of Bacteroides fragilis and Escherichia coli. The therapeutic efficacy of ciprofloxacin was investigated in this mixed intra-abdominal abscess model and was compared with that of rifampicin. Treatment with ciprofloxacin at 0.2 to 20 mg/kg or rifampicin at 20 mg/kg prevented all mice from death, as compared to the 60% mortality rate observed in the vehicle-treated controls. Rifampicin concentrations at 10 and 20 mg/kg were effective in preventing abscess formation and eradicated bacterial abscess. Ciprofloxacin at all the levels tested neither reduced the incidence of abscess nor eradicated Bact. fragilis from abscesses. However, ciprofloxacin at levels of 20, 10, 5, and 1 mg/kg reduced significantly the number of E. coli cells in the abscess. The peak serum level of ciprofloxacin at the oral dose of 20 mg/kg was 0.43 mg/l which was well above the MIC values for E. coli but not for Bact. fragilis.

Experimental efficacy of apalcillin and cefpiramide compared with that of six other antipseudomonal agents in Pseudomonas aeruginosa burn infections.

The therapeutic efficacy of cefpiramide and apalcillin was evaluated and compared with that of six other antipseudomonal beta-lactam antibiotics in an experimental mouse burn infection due to Pseudomonas aeruginosa. Both cefpiramide and apalcillin were as potent as cefsulodin and more potent than carbenicillin, cefotaxime, cefoperazone, piperacillin and gentamicin in protecting the infected mice from fatal bacteraemia and in eradicating Ps. aeruginosa from the infected site.

Experimental efficacy and pharmacokinetic properties of cefpiramide, a new cephalosporin.

The in vivo therapeutic efficacy of cefpiramide was investigated and compared with that of cefoperazone. Cefpiramide was more potent than cefoperazone against infections produced by both beta-lactamase-producing and non-beta-lactamase-producing S. aureus. The protective activity of cefpiramide against experimental infections with selected members of Enterobacteriaceae was lower than that of cefoperazone. Against carbenicillin-resistant P. aeruginosa infections, cefpiramide was as active as gentamicin and aztreonam and three times more potent than cefoperazone, cefotaxime and piperacillin. The pharmacokinetic properties of cefpiramide in mice and rats were superior to those of cefotaxime and cefoperazone. The peak serum concentrations of cefpiramide, administered subcutaneously at a dose of 50 mg/kg, were 76 micrograms/ml in mice and 174 micrograms/ml in rats and the corresponding serum half-lives of cefpiramide were 87 min and 49 min in mice and rats respectively.

Nafcillin and oxacillin: comparative antistaphylococcal activity in mice.

The therapeutic properties of nafcillin, oxacillin and erythromycin were determined in mice infected with a strain (Evans) of Staphylococcus aureus shown to be tolerant to the bactericidal action of penicillinase-resistant derivatives of penicillin. The therapeutic activity of these agents was also correlated with the extent of colonization of kidneys by resistant clones of S. aureus Evans. The CD50 values or potency ratios proved that nafcillin was highly active against this organism, whereas oxacillin and erythromycin were capable of protecting the animals to a lesser degree. Of the agents studied, only nafcillin was capable of preventing or interfering with the colonization of the kidneys by S. aureus Evans. Although the exact interpretation and application of these data in the management of clinical problems remains to be determined, the observations suggest important differences between nafcillin and oxacillin in vivo and that it is difficult to predict the antibacterial efficacy of these drugs solely from MIC and MBC data.

Amide Penicillin Wy-12,556: therapeutic activity in animals subjected to repeated bacterial infection.

Amide penicillin Wy-12,556 and DBED penicillin were studied for their antibacterial effect in CD-1 mice repeatedly infected with Streptococcus pyogenes C203 and/or Staphylococcus aureus Smith. Animals infected with S. aureus Smith failed to show a difference between the therapeutic activity of DBED penicillin and Wy-12,556. Wy-12,556 was significantly more effective than DBED penicillin in protecting the animals challenged repeatedly with S. pyogenes C203. Wy-12,556 provoked a positive transient chemotactic response in uninfected mice. 24 h after intraperitoneal challenge the exudate showed a high neutrophilic count.