Immune Cells and Molecular Networks in Experimentally Induced Pulpitis.

Dental pulp is a dynamic tissue able to resist external irritation during tooth decay by using immunocompetent cells involved in innate and adaptive responses. To better understand the immune response of pulp toward gram-negative bacteria, we analyzed biological mediators and immunocompetent cells in rat incisor pulp experimentally inflamed by either lipopolysaccharide (LPS) or saline solution (phosphate-buffered saline [PBS]). Untreated teeth were used as control. Expression of pro- and anti-inflammatory cytokines, chemokine ligands, growth factors, and enzymes were evaluated at the transcript level, and the recruitment of the different leukocytes in pulp was measured by fluorescence-activated cell-sorting analysis after 3 h, 9 h, and 3 d post-PBS or post-LPS treatment. After 3 d, injured rat incisors showed pulp wound healing and production of reparative dentin in both LPS and PBS conditions, testifying to the reversible pulpitis status of this model. IL6, IL1-ß, TNF-α, CCL2, CXCL1, CXCL2, MMP9, and iNOS gene expression were significantly upregulated after 3 h of LPS stimulation as compared with PBS. The immunoregulatory cytokine IL10 was also upregulated after 3 h, suggesting that LPS stimulates not only inflammation but also immunoregulation. Fluorescence-activated cell-sorting analysis revealed a significant, rapid, and transient increase in leukocyte levels 9 h after PBS and LPS stimulation. The quantity of dendritic cells was significantly upregulated with LPS versus PBS. Interestingly, we identified a myeloid-derived suppressor cell-enriched cell population in noninjured rodent incisor dental pulp. The percentage of this population, known to regulate immune response, was higher 9 h after inflammation triggered with PBS and LPS as compared with the control. Taken together, these data offer a better understanding of the mechanisms involved in the regulation of dental pulp immunity that may be elicited by gram-negative bacteria.

Dysregulation of energy homeostasis in mice overexpressing insulin-like growth factor-binding protein 6 in the brain.

AIMS/HYPOTHESIS: IGFs, IGF receptors and IGF binding proteins (IGFBPs) are widely expressed in the central nervous system. To investigate the physiological significance of IGFBP-6 in the brain we established two transgenic mouse lines overexpressing human (h)-IGFBP-6 under the control of glial fibrillary acidic protein promoter. Increasing evidence suggests that insulin/IGF signalling pathways could be implicated in the neuroendocrine regulation of energy homeostasis. We explored the impact of brain IGFBP-6 overexpression on the regulation of food intake and energy balance. METHODS: Transgenic mice were fed either a control diet or a high-fat diet for up to 3 months. Glucose and insulin tolerance tests were carried out before and after the diet period. Plasma parameters (insulin, leptin, glucose, NEFAs and triglycerides) were measured, and uncoupling protein 1 (UCP-1) expression was quantified in brown adipose tissue. Oxygen consumption was also measured in both groups. RESULTS: The transgenic mice fed a high-fat diet for 3 months developed obesity, showing increases in plasma leptin, glucose and insulin levels and mild insulin resistance. As compared with wild-type mice, no significant differences were found in the quantity of food intake. However, UCP-1 expression was down-regulated in the brown adipose tissue of the transgenic mice. CONCLUSIONS/INTERPRETATION: Our results show that brain IGFBP-6 has an impact on the regulation of energy homeostasis. These transgenic h-IGFBP-6 mice may be considered a new tool for studies of the involvement of the brain IGF system in metabolism control and obesity.

Insulin-like growth factor binding protein-6 inhibits neuroblastoma cell proliferation and tumour development.

In neuroblastoma cells, survival and proliferation are dependent upon the insulin-like growth factor (IGF) system. IGFs actively participate in cell growth, whereas IGFBP-6, is associated with the arrest of growth. With a view to blocking IGF-II action, we produced recombinant human IGFBP-6 capable of binding IGFs with affinities between 1.23 and 6.36 x 10(9) M(-1). Ex vivo mitogenic activities were tested on two human neuroblastoma cell lines, in which 100 ng/ml IGFBP-6 completely abolished the effects of both endogenous and exogenous IGF-II. In vivo, nude mice previously injected with neuroblastoma cells were submitted to either 15 daily injections of 4-20 microg IGFBP-6 or implantation of mini-pumps diffusing 20-100 microg IGFBP-6 over 2 weeks. The result was an average 18% reduction in the incidence and development of tumours. Delivery of the IGFBP-6 via mini-pumps also delayed tumour appearance by 6-15 days. Our results therefore show the involvement of IGFBP-6 in neuroblastoma cell growth, both ex vivo in terms of proliferation and in vivo in terms of tumour development.

Vascular endothelial growth factor in pleural fluid.

STUDY OBJECTIVES: The purpose of this study was to analyze the relationship of the pleural fluid vascular endothelial growth factor (VEGF) level with the diagnostic category and with the pleural fluid characteristics in a group of 70 patients. DESIGN: The VEGF levels of consecutive patients undergoing therapeutic thoracentesis were determined with an enzyme-linked immunosorbent assay. SETTING: University-affiliated tertiary care center. RESULTS: The median level of pleural fluid VEGF in the patients with congestive heart failure (150 pg/mL) was significantly (p < 0.05) lower than the median level in the patients with coronary artery bypass grafting (357 pg/mL), which in turn was significantly lower (p < 0.05) than the median levels in the patients with malignancy (1,097 pg/mL). The overlap between groups, however, limits the diagnostic usefulness of pleural fluid VEGF levels. The VEGF level was most closely correlated with the lactate dehydrogenase level (r = 0.42, p < 0.001) and was also significantly correlated with the total pleural fluid protein level. The median VEGF levels in the pleural fluid of patients with breast cancer were significantly lower (p = 0.017) than in those with lung cancer. The VEGF level was very high (3,294 pg/mL) in the one patient with pulmonary embolism. CONCLUSIONS: We conclude that the VEGF levels in pleural fluid differ significantly from one diagnostic category to another with the highest median levels occurring in patients with malignant pleural effusions. We speculate that VEGF may be responsible for the pleural fluid accumulation in at least some situations.

Ultimate performance of QEM classifiers.

Supervised learning of classifiers often resorts to the minimization of a quadratic error, even if this criterion is more especially matched to nonlinear regression problems. It is shown that the mapping built by a quadratic error minimization (QEM) tends to output the Bayesian discriminating rules even with nonuniform losses, provided the desired responses are chosen accordingly. This property is for instance shared by the multilayer perceptron (MLP). It is shown that their ultimate performance can be assessed with finite learning sets by establishing links with kernel estimators of density.

Pharmacokinetics, pharmacodynamics, and minimum effective clinical dose of intravenous nicardipine.

Nicardipine hydrochloride was administered intravenously to two groups of hypertensive patients: one group of 37 patients with mild to moderate hypertension and one group of 20 patients with severe hypertension. In the first group, doses of 0.5, 1, 2, and 4 mg/hr, as well as placebo, were infused for 48 hours in a double-blind fashion. Blood pressure and heart rate were monitored for this period and for the 24 hours after the infusion was discontinued. Significant decrements in blood pressure were noted with all doses; 4 mg/hr produced lowering that was greater than all other doses; 1 and 2 mg/hr produced lowering that was greater than 0.5 mg/hr but that were not different from each other. Excellent correlation of blood pressure reduction and plasma level was observed and linear kinetics existed. In the severe hypertensive patients, 1, 2, 4, 5, and 8 mg/hr were infused to established minimal and ineffective doses. One milligram per hour was an ineffective dose; 4, 5, and 8 mg/hr all produced significant reductions over the course of the study that were undistinguishable from each other. Two milligrams per hour produced modest reductions in blood pressure. Blood pressure reduction also correlated with plasma levels in the severe hypertensive group.

Nicardipine in severe hypertension: oral therapy following intravenous treatment.

Nicardipine is an investigational dihydropyridine calcium-channel blocker. In the present study, 21 patients with severe hypertension were treated with oral nicardipine, alone or in combination with beta-blockers and diuretics for 4-5 weeks, following initial control of their blood pressure with intravenous nicardipine. Each of the 21 patients had a satisfactory response to intravenous nicardipine which was administered as an infusion following initial blood pressure lowering. At 1 h prior to discontinuation of the intravenous treatment, oral nicardipine therapy was begun as a 40 mg dose. Oral nicardipine, 40 mg t.i.d., was continued for the remainder of hospitalization and for a 4-5-week outpatient follow-up period. The dose of oral nicardipine was downtitrated and additional antihypertensive drugs, beta-adrenergic blocking agents and/or diuretics, were added to maintain blood pressure in an acceptable range. Compared to baseline, mean supine systolic blood pressure was lowered significantly (p less than 0.001) by 57 mmHg at the end of intravenous maintenance and by 50 mmHg at the end of oral treatment. Likewise, significant (p less than 0.001) decreases in diastolic blood pressure of 43 and 32 mmHg, respectively, were observed for the same time periods. At the end of oral treatment, 6 patients remained on nicardipine monotherapy, 8 patients were on two-drug therapy and 7 patients required three-drug therapy. Side-effects were mild except for a moderate headache reported in one patient during intravenous treatment. From these observations we conclude that oral nicardipine is a useful new agent for initial, single treatment of chronic severe hypertension, although a significant number of patients eventually need additional antihypertensive therapy.

Changes of plasma renin activity and atrial natriuretic factor during intravenous nicardipine treatment of severe hypertension.

Intravenous nicardipine was given to 32 severe hypertensive patients in an increasing dose, titration fashion. Samples for plasma renin activity and plasma atrial natriuretic factor concentration were obtained at the following times: before treatment, at the time of titration response and at the end of a maintenance period. The mean time required to achieve the titration response was 29 min. Plasma renin activity was increased by 32% (p less than 0.05) at the titration response and 181% (p less than 0.005) at the end of an 8-12 h maintenance nicardipine infusion. Atrial natriuretic factor concentration was unchanged from baseline at titration response and was decreased by 25% (p less than 0.005) at the end of maintenance. Mean plasma nicardipine dose was 6.95 mg/h at the titration response and 8.76 mg/h at the end of maintenance. These results suggest that alterations in plasma renin activity and atrial natriuretic factor concentrations may be associated with blood pressure reduction rather than with a direct drug action on release mechanisms.

Intravenous nicardipine in severe systemic hypertension.

Sixty-six patients with severe hypertension were treated with intravenous nicardipine in 3 separate protocols. Each protocol had a common end point: Diastolic blood pressure would either reduce 25 mm Hg or measure below 95 mm Hg. Each of the 66 patients studied attained the desired clinical response end point. Intravenous nicardipine produced a gradual reduction in blood pressure, was effective in maintaining blood pressure control during constant infusion and had few undesirable effects. These observations suggest that intravenous nicardipine maybe a useful addition to a limited number of therapeutic agents currently available to the physician for treatment of hypertensive urgencies.

Intravenous nicardipine for the treatment of severe hypertension.

PURPOSE: Severe hypertension responds to treatment with nifedipine given orally or sublingually. Nicardipine hydrochloride, a water soluble dihydropyridine analogue similar to nifedipine, has less of a negative ionotropic effect and produces less reflex tachycardia than nifedipine. Our purpose was to assess the antihypertensive efficacy and safety of intravenous nicardipine in a group of patients with severe hypertension (defined as a supine diastolic blood pressure of more than 120 mm Hg). PATIENTS AND METHODS: Eighteen patients with severe hypertension received treatment with intravenous nicardipine. Nicardipine titration was performed using doses of 4 to 15 mg/hour to achieve therapeutic goal (diastolic blood pressure 95 mm Hg or less or decrease in diastolic blood pressure of more than 25 mm Hg). After this therapeutic end-point was reached, patients received maintainance therapy with nicardipine for varying lengths of time: one hour (Group I), six hours (Group II), or 24 hours. When blood pressure control was lost, patients in Groups I and II entered a second maintenance period lasting a maximum of 24 hours. Onset and offset of action of nicardipine at various infusion rates and times of infusion were measured. RESULTS: Onset time to achieve therapeutic response was rapid at 15 mg/hour (0.31 +/- 0.13 hours) when compared with lower doses (1.11 +/- 0.36 hours at 4 mg/hour; 0.54 +/- 0.09 hours at 5 mg/hour; 0.52 +/- 0.09 hours at 7 to 7.5 mg/hour). Those who showed a therapeutic response received maintenance infusions with nicardipine for one (n = 7), six (n = 6), or 24 (n = 5) hours. Sustained blood pressure control at a constant rate of nicardipine infusion was seen in all patients during the maintenance period. After discontinuation of nicardipine, the time for offset of action (increase in diastolic blood pressure of 10 mm Hg or more) was independent of duration of infusion. Decreases in both systolic and diastolic pressures correlated well with plasma nicardipine levels. Heart rate increased by about 10 beats/minute, but this increase did not correlate with plasma nicardipine levels. Side effects were minimal, consisting of headache and flushing. In seven patients, local phlebitis developed at the site of infusion. This occurred after at least 14 hours of infusion at a single site, and the incidence can probably be reduced by shortening the infusion time at a single site. CONCLUSION: Nicardipine appears to be a safe and effective drug for intravenous use in the treatment of severe hypertension.