A comparison of DNA vaccines for the rabies-related virus,Mokola

Mokola virus, a rabies-related virus, has been reported to date from the African continent only. Like rabies virus, it is highly pathogenic, causes acute encephalitis, and zoonotic events have been documented. Although believed to be rare, there has been an unexplained increase in the number of isolations of the virus in South Africa in recent years. We have cloned and sequenced the glycoprotein (G) and nucleoprotein (N) genes from a South African Mokola virus, and used these in the construction of different DNA vaccines for immunization against Mokola virus. Four vaccines, utilizing different promoters and DNA backbone compositions, were generated and compared for efficacy in protection against Mokola virus. In one of these, both the Mokola virus G and N genes were co-expressed. Two of the single G-expressing DNA vaccines (based on pSG5 and pCI-neo, respectively) protected laboratory mice against lethal challenge, despite major differences in their promoters. However, neither vaccine was fully protective in a single immunization only. Serological assays confirmed titers of virus-neutralizing antibodies after immunization, which increased upon booster vaccine administration. A third construct (based on pBudCE4) was less effective in inducing a protective immune response, despite employing a strong CMV enhancer/promoter also used in the pCI-neo plasmid. Dual expression of Mokola virus G and N genes in pBudCE4 did not enhance its efficacy, under the conditions described. In addition, no significant utility could be demonstrated for a combined prime-boost approach, as no cross-protective immunity was observed against rabies or Mokola viruses from the use of pSG5-mokG or vaccinia-rabies glycoprotein recombinant virus vaccines, respectively, even though both vaccines provided 60-100% protection against homologous virus challenge.     

Impact of pathogen burden in patients with coronary artery disease in relation to systemic inflammation and variation in genes encoding cytokines

The number of infectious pathogens to which an individual has been exposed (pathogen burden) has been linked to the development and the prognosis of coronary artery disease (CAD). The interaction among infection, genetic host susceptibility, and CAD remains unclear. This study was aimed at evaluating the modulation of the association between CAD and pathogen burden, by serum levels of inflammatory markers and polymorphisms of the interleukin (IL)-6 and tumor necrosis factor (TNF)-alpha genes. Immmunoglobulin (Ig) G or IgA antibodies to 8 pathogens were determined in 991 patients with CAD and 333 control subjects. Serum levels of high-sensitivity C-reactive protein, fibrinogen, IL-6, and TNF-alpha were also measured. All subjects were genotyped for the IL-6/G-174C, the TNF/C-851T, and the TNF/G-308A polymorphisms. Analysis of single pathogens demonstrated a positive relation to the presence of CAD for some (Chlamydia pneumoniae, cytomegalovirus, Helicobacter pylori, and herpes virus simplex type 1), but not all pathogens. A strong association between increasing pathogen burden and CAD was confirmed, even after adjustment for risk factors. The prevalence of a high pathogen burden (>/=4 pathogens) was 50% in patients and 21% in controls (p <0.0001). A high pathogen burden was associated with decreased high-density lipoprotein cholesterol levels (p <0.001). The association between CAD and pathogen burden was modulated by the IL6/G-174C polymorphism, the odds ratio being higher in heterozygotes than in both types of homozygotes (p <0.05). This interaction appeared to be mediated by variations in serum IL-6 levels. No such interaction was detected with any of the 2 TNF-alpha polymorphisms.     

Fondaparinux and enoxaparin in comparison to unfractionated heparin in preventing thrombus formation on mechanical heart valves in an ex vivo rabbit model

The aim of the present study was to investigate the efficacy of three different parenterally administered anticoagulants for the prevention of thrombus formation on artificial heart valves in an experimental rabbit model. Unfractionated heparin was administered intravenously in group I (n = 10), Enoxaparin subcutaneously in group II (n = 10), fondaparinux intravenously in group III (n = 10), and no medication was administered to group IV (n = 9). Leaflets from Sulzer Carbomedics bileaflet mechanical heart valves were placed in a flow chamber. The flow chamber was filled with blood in a continuous circulation between the carotid artery and the jugular vein. In group IV the flow chamber was clotted after a median of 15 minutes of circulation. Weight analysis before and after 1 h of perfusion showed that the median thrombus weight was 18.0 mg in group I, 17.7 mg in group II, 20.3 mg in group III, and 30.8 mg in group IV. Further analysis by electron microscopy showed similar results regarding deposition of fibrin, platelets, and erythrocytes on leaflet surfaces. Fondaparinux and subcutaneously administered enoxaparin were as effective as intravenously administered unfractionated heparin in preventing thrombus formation on artificial heart valve leaflets in our investigation. This rabbit model, in which the heart valve leaflets were exposed to rabbit blood for a short time under laminar flow, should be further evaluated with respect to whether it can provide information about anti-thrombotic regimens in patients after mechanical heart valve replacement.     

Antidepressants are functional antagonists at the serotonin type 3 (5-HT3) receptor

Antidepressants are commonly supposed to enhance serotonergic and/or noradrenergic neurotransmission by inhibition of neurotransmitter reuptake through binding to the respective neurotransmitter transporters or through inhibition of the monoamine oxidase. Using the concentration-clamp technique and measurements of intracellular Ca2+, we demonstrate that different classes of antidepressants act as functional antagonists at the human 5-HT3A receptor stably expressed in HEK 293 cells and at endogenous 5-HT3 receptors of rat hippocampal neurons and N1E-115 neuroblastoma cells. The tricyclic antidepressants desipramine, imipramine, and trimipramine, the serotonin reuptake inhibitor fluoxetine, the norepinephrine reuptake inhibitor reboxetine, and the noradrenergic and specific serotonergic antidepressant mirtazapine effectively reduced the serotonin-induced Na(+)- and Ca(2)(+)-currents in a dose-dependent fashion. This effect was voltage-independent and, with the exception of mirtazapine, noncompetitive. Desipramine, imipramine, trimipramine, and fluoxetine also accelerated receptor desensitization. Moclobemide and carbamazepine had no effect on the serotonin-induced cation current. By analyzing analogues of desipramine and carbamazepine, we found that a basic propylamine side chain increases the antagonistic potency of tricyclic compounds, whereas it is abolished by an uncharged carboxamide group. The antagonistic effects of antidepressants at the 5-HT3 receptor did not correlate with their effects on membrane fluidity. In conclusion, structurally different types of antidepressants modulate the function of this ligand-gated ion channel. This may represent a yet unrecognized pharmacological principle of antidepressants.     

The role of inflammation and infection in acute coronary syndrome

INFLAMMATORY PROCESS: Within the vessel wall is considered to be crucial for initiation and progression of atherosclerosis. As response to endothelial injury a focal inflammatory response arises which can lead to plaque vulnerability and rupture and a consecutive acute coronary syndrome. Systemic markers of inflammation like C-reactive protein (CRP) or interleukin (IL) 6 are elevated in stable angina and acute coronary syndrome and are associated with future cardiovascular events even in initially healthy people. Alongside classical risk factors infectious agents like cytomegalovirus or Chlamydia pneumoniae are discussed to be involved in the local and systemic inflammatory response. Seroepidemiological studies revealed disparate results of the association between antibody titers against Chlamydia pneumoniae or cytomegalovirus and prevalence of coronary artery disease or future cardiovascular events. In animal models Chlamydia pneumoniae and cytomegalovirus increase accelerated neointimal response, however, molecular mechanisms are not entirely clear. CONCLUSION: Whereas local and systemic inflammatory processes play a crucial role in atherogenesis and prognosis the causal role of infection in atherogenesis remains controversial.     

The incurable wound revisited: progress in human rabies prevention?

Rabies is the most important viral zoonosis from a global perspective. Modern human postexposure prophylaxis consists of potent vaccines and local infiltration of rabies immune globulins (RIGs), but the latter biologicals are not widely available or affordable. Monoclonal antibodies (Mabs) offer several theoretical advantages over RIGs. To this end, several human and equine RIGS, alone or in combination with vaccine, were investigated for postexposure efficacy in a Syrian hamster model, compared with a single neutralizing murine Mab. Preliminary results suggest that: (1) animal models continue to provide utility as human surrogates in the demonstration of product efficacy against rabies; (2) RIG preparations differ substantially in experimental effectiveness and clearance; and (3) relevant alternatives, such as Mabs, should be pursued for future improvements to human rabies prevention.     

Gamma-knife radiosurgery for trigeminal neuralgia

Gamma knife was installed at the PD Hinduja National Hospital and Medical Research Centre, Mumbai, India, in January 1997. In the first year of gamma-knife radiosurgery to January 1998, we treated 110 patients, of whom six had medically refractory trigeminal neuralgia. Seven treatments were administered to this group of six patients (one had bilateral neuralgia). This report evaluates the effectiveness of radiosurgery treatment in these patients. The median age of the patients was 56 years and there were five males and one female. Following Leksell stereotactic frame fixation, a magnetic resonance imaging scan was done in all. The Leksell gamma plan was used for planning. A radiosurgery dose of 70–80 Gy was delivered to the trigeminal root entry zone, 2–4 mm anterior to the junction of the pons and trigeminal nerve with a single 4 mm collimator helmet. Complete pain relief was achieved in four patients. Two had partial relief. No patient developed any radiosurgery related morbidity during the follow-up period of 5–16 months. Radiosurgery seems to be an effective approach for medically or surgically refractory trigeminal neuralgia.     

Hypoaldosteronism in three sibs due to 18-dehydrogenase deficiency

Three sibs all presented in the early neonatal period with a salt-losing syndrome. The salt-losing form of congenital adrenal hyperplasia was diagnosed and appropriate treatment with glucocorticosteroids, mineralocorticosteroids, and additional dietary salt started. Although early life was maintained with difficulty, with age all 3 children required decreasing amounts of replacement steroids to maintain normal plasma electrolyte balance. They were reinvestigated at the ages of 15 years and 8 years (twins), when cortisol synthesis and metabolism proved normal, but aldosterone synthesis was blocked by deficiency of 18-dehydrogenase. Rational treatment of these cases of a salt-losing syndrome in which aldosterone synthesis alone is blocked due to lack of the enzyme 18-dehydrogenase requires the administration of a mineralocorticosteroid drug only. Since deoxycorticosterone (acetate or pivalate) requires intramuscular administration, as life-long therapy oral fludrocortisone is preferable. Although fludrocortisone has glucocorticoid activity, the "hydrocortisone equivalent" effect of the small dosage used was unlikely to inhibit either pituitary corticotrophin or growth hormone production.     

Centrilobular emphysema: CT-pathologic correlation

Over a 5-year period, 25 patients who had undergone chest computed tomography (CT) died and were autopsied. Their lungs were fixed in the inflated state and were assessed for the presence and severity of centrilobular emphysema (CLE). Three radiologists independently evaluated the CT scans for nonperipheral low-attenuation areas, peripheral low-attenuation areas, pulmonary vascular pruning, pulmonary vascular distortion, and pulmonary density gradient. The CT criterion that best correlated with the presence and severity of CLE was the nonperipheral low-attenuation area. With this CT criterion, lung destruction was correctly identified in 13 of 15 cases. The absence of this criterion resulted in correct identification of eight of ten normal lungs. These preliminary data suggest that CLE can be reliably identified and quantified with current CT scanners.