Ragweed pollen in France: origin, diffusion, exposure.

PURPOSE OF THE STUDY: To detect the origin of ragweed pollen and to measure the impact of this pollen exposure on allergic patients, so their sensitivity can be noted (using specific IgE production: sIgEw1) in order to inform the population about an "allergy" against those ragweed pollen grains. MATERIAL AND METHODS: To measure population exposure to ragweed pollen, the R.N.S.A (National Aerobiological Monitoring Network, a French association) has a pollen trap network located in urban areas. These traps allow continuous recording of airborne pollen, the light microscope analysis (with a bi-hourly time step) allows one to know the daily concentrations of ragweed grains and the circadian rhythm of grains impaction. It is thus possible to follow the evolution of pollination during each day ofeach season and to compare seasons and years at each station. Biomnis is a biological laboratory which performs more than 85% of ragweed specific IgE assay in France. It seems to be clear that when allergists ask ragweed IgE for a patient, it is because they think that this patient seems to be allergic to this specific pollen. The statistical analysis of results about specific IgE (for ragweed) from the Allergology laboratories Biomnis (located in Lyon and Paris) can determine the number ofpatients sensitized to ragweed in French departments. RESULTS: The distribution ofsensitized patients to ragweed is compared to ragweed pollen distribution studied by the R.N.S.A from the year 2005 to 2008 in France, whatever the ragweed plant' origin: local (closed topollen trap) or imported (by wind). CONCLUSION: The biological database (Health impact) allows a correlation between the geographical distribution ofragweed pollen and the number ofpatients with specific IgE against ragweed (sIgEw1), i.e., whose sensitization is due to local plants. That also permits one to estimate the expected number of allergy cases in the next years, because the sensitivity precedes the allergy.

Stability of anterior vertebral body screws after kyphoplasty augmentation. An experimental study to compare anterior vertebral body screw fixation in soft and cured kyphoplasty cement.

The goal of this cadaver study was to compare the stability of anterior vertebral body screws after implantation in soft or cured kyphoplasty cement. Anterior vertebral body screws were inserted in a total of 30 thoracolumbar vertebrae of ten different human specimens: ten screws were implanted in non-augmented vertebrae (group 1), ten screws were placed in soft cement (group 2), and ten screws were placed in cured cement (group 3). The screws were then tested for biomechanical axial pullout resistance. Mean axial pullout strength was 192 N (range: 10-430 N) in group 1, 364 N (range: 65-875 N) in group 2, and 271 N (range: 35-625 N) in group 3. The paired Student's t-test demonstrated a significant difference between pullout strength of groups 1 and 2 (p= 0.0475). No significant difference was seen between pullout strength of groups 1 and 3 (p= 0.2646) and between groups 2 and 3 (p= 0.3863). We achieved a 1.9 times higher pullout strength with kyphoplasty augmentation of osteoporotic vertebrae compared with the pullout strength of non-augmented vertebrae. Implantation of anterior vertebral body screws in cured cement is a satisfactory method. With this method we found a 1.4 times higher pullout strength than non-augmented vertebrae.

Anaphylaxis to the 23-valent pneumococcal vaccine in child: a case-control study based on immediate responses in skin tests and specific IgE determination.

Injections of the 23-valent pneumococcal vaccine are usually well tolerated. Skin tests (prick and intradermal) and a self-made RAST with pneumococcal vaccine and phenol were performed in a child reporting a severe anaphylactic reaction induced by a 23-valent pneumococcal vaccine, and in ten control children, including one child with a well-tolerated vaccination, and nine non-vaccinated children. Skin tests and RAST with the vaccine were positive in the child reporting anaphylaxis, and negative in nine of the control children. Intradermal test with the vaccine was slightly positive in a non-vaccinated child with negative RAST. Skin tests and RAST with phenol were negative in all the children. These results suggest that immediate responses in skin tests and specific IgE determination have a good diagnostic value in children reporting severe reactions suggestive of IgE-dependent hypersensitivity to pneumococcal vaccine.

Serum eosinophil cationic protein measurements in the management of perennial and periodic asthma: a prospective study.

We performed a prospective study in order: 1) to determine whether a correlation could be found between serum eosinophil cationic protein (ECP) levels and clinical and functional status in perennial asthmatics during a 5 month prospective study; and 2) to evaluate the relationship between allergic exposure and ECP levels in periodic asthmatics. Two groups of asthmatic patients were selected: a group of acutely ill perennial asthmatics and a group of periodic asthmatics. The acutely ill perennial asthmatics (n=22, mean age=39.4 yrs) were included on the basis of hospitalization for acute asthma. At the end of the hospitalization, there was a 5 month follow-up of clinical, functional and medication scores, as well as eosinophil counts and ECP levels. The periodic asthmatic group was composed of asthmatics sensitized to birch and tree pollens (n=10, mean age=33.8 yrs). The same measurement were performed on this group, before, during and after the pollen season. Under corticosteroid treatment in the acutely ill patients, there was a significant decrease in serum ECP levels between the first day of hospitalization and the day of discharge (mean: 23.2 microg x L(-1) and 9.5 microg x L(-1), respectively; p=0.006). No correlation was found between the clinical status, functional status and serum ECP levels during the 5 month follow-up. A significant increase in ECP levels was found in periodic asthmatics during the pollen season. Our results suggest that serum eosinophil cationic protein is a useful marker of allergen exposure and of acute asthma treatment. This could be of importance in the prevention and follow-up of allergic asthma; the value of serum eosinophil cationic protein measurements in the day-to-day management of adult asthmatics needs to be further clarified.

Variable estimates of cytokine levels produced by commercial ELISA kits: results using international cytokine standards.

Commercially available ELISA kits now make it possible to measure cytokines in biological samples and cell culture supernatants. We have compared the levels of IL-1 beta, IL-6, IL-8 and TNF-alpha in various pathological plasma and synovial fluids, and in supernatants of human monocytes activated by lipopolysaccharide (LPS). Measurements were performed using ELISA kits from different companies. A wide variation in values was obtained when measurements were deduced from the standard curves formed with the standard provided by the manufacturers. We also performed calibration curves for all ELISA kits, using the international standards provided by the NIBSC (UK). The coefficients of variation were then significantly improved for IL-6 and IL-8 measurements but not for IL-1 beta and TNF alpha assays. However, despite this attempt to obtain uniform measurements, none of the kits gave similar values for individual samples. These results suggest that the nature of the different pairs of monoclonal antibodies employed in each ELISA does not permit comparable recognition of cytokines in samples. Further work with the various kits is required to establish whether (i) denaturation of the recognized epitope within the natural cytokine, (ii) fragmentation of the cytokine following enzymatic cleavage, (iii) depolymerization, (iv) binding of cytokines to undefined ligands, (v) variable glycosylation of the natural cytokines (vi) recognition of precursor forms, interferes with the measurements.

Excretion of platelet activating factor-acetylhydrolase and phospholipase A2 into nasal fluids after allergenic challenge: possible role in the regulation of platelet activating factor release.

Platelet activating factor (PAF), a proinflammatory mediator synthesized through a phospholipase A2 (PLA2)-dependent reaction, is hydrolyzed into its inactive metabolite, lyso-PAF, by a specific acetylhydrolase. Previous studies have shown that allergen challenge of patients with allergic rhinitis leads to an increase of the concentrations of lyso-PAF in nasal lavage fluid (NLF), whereas PAF is detected only marginally. PAF-hydrolyzing enzymes are expected to be released on allergenic challenge, to account for the reduced concentrations of PAF in NLF. Here, we show that allergen challenge of patients with allergic rhinitis induces an increase of acetylhydrolase-like activity in NLF, which peaks within 10 minutes and returns to basal values 1 hour later. Acetylhydrolase hydrolyzed exogenous PAF with a complete loss of its ability to induce platelet aggregation. Allergen challenge also led to a parallel release of a PLA2 in nasal fluids. This enzyme preferentially hydrolyzes negatively charged phospholipids (phosphatidic acid monomethyl ester and phosphatidylgylcerol) versus phosphatidylcholine. More interestingly, the hydrolysis of phosphatidic acid monomethyl ester and phosphatidylglycerol by NLF was completely abolished by the addition of ethylenediaminetetraacetic acid which had no effect on the hydrolysis of PAF, indicating that the PLA2 secreted in nasal fluids is not involved in the degradation of PAF. Finally, our results show that allergen-induced increase in the concentrations of lyso-PAF and prostaglandin D2 occurred with a kinetic similar to that of tosyl-L-arginine-methyl-ester esterase, suggesting that mast cells are implicated in this process. Although no direct relationship was demonstrated between the absence of PAF and the increase of acetylhydrolase levels in NLF, we suggest a potential role for this enzyme in the inactivation of PAF if the latter is released in the nasal lumen.

Onset and development of cyclosporin A effects on lymphocytes of cardiac patients before heart transplantation.

The effects of cyclosporin A (CSA) in low dosage (4 mg/kg/24 h i.v.) were studied in 17 patients awaiting heart transplantation. The lymphocyte subsets were typed, enumerated, and their proliferation measured before CSA perfusion, after infusion (over 24 h), and then again after two further 24 h intervals (T0 h, T24 h, T48 h, and T72 h). No significant change was found in T or B enumerations although lymphocyte function was markedly modified. For all 17 patients, there was a significant decrease in lymphocyte proliferation that was, however, re-established after 72 h for 14 of the patients, but not for the remaining 3. Inhibition of the proliferative response was found to occur rapidly, to be potent although rapidly reversible in most cases, while yet subject to wide interindividual variability. These four features suggest that (a) CSA in fixed doses may later the balance between helper and suppressor cells in varying degrees according to the patient, and that (b) CSA given immediately or shortly after heart transplantation could be beneficial.

How chronically administered valproate increases chlordiazepoxide transfer through the blood-brain barrier.

Sodium valproate (VPA) is a drug widely used in the treatment of epileptics often in association with benzodiazepines. Recent animal studies have shown that the addition of valproate increases diazepam levels in the cortex and the cerebellum (Hariton et al, 1985). The aim of our study was to determine the effect of VPA on the transfer of benzodiazepines through the blood-brain barrier. They were investigated using the intracarotid injection technique in rats as described by Oldendorf (1971). Our results show that the 14C-chlordiazepoxide brain extraction is significantly higher in rats on prolonged valproate treatment than in controls. With regard to plasma protein binding effects on chlordiazepoxide transport, our data indicate that a fraction of the protein-bound chlordiazepoxide could transfer from the intracapillary space to the brain tissue space because of enhanced drug dissociation from albumin in the brain microcirculation (Kd in vitro = 74.1 microM; Kd in vivo = 793.7 microM). Two distinct mechanisms can be deduced from this study: 1) chlordiazepoxide is displaced from HSA by valproate, 2) in addition, this fatty acid could increase drug permeation through the blood brain barrier (PS/F (chlordiazepoxide) = 0.60 in controls, PS/F (chlordiazepoxide) = 0.97 in treated rats). On the contrary, the washout of the benzodiazepine from the rat brain does not seem to be modified by the addition of valproate.

[Value of cyclosporin A in dermatomyositis in a child]. / Intérêt de la cyclosporine A dans la dermatomyosite de l'enfant.

Cyclosporin A was used in a 3 1/2 year-old child with dermatomyositis exhibiting severe junctional impairment and intolerance to steroids. After a few weeks, marked clinical improvement was observed allowing a reduction of the doses of steroids. After 9 months, the clinical status was satisfactory: the calcifications had lost their inflammatory characteristics. No side effect of cyclosporin A was observed at the dose used (4.4 mg/kg/d) which maintained effective blood concentrations between 80 and 220 ng/ml.

Distribution of cyclosporin A between blood cells and plasma of cardiac and renal transplant recipients.

The relationship between blood cells and plasma concentrations of cyclosporin A (Cy A) determined by radioimmunoassay, was investigated in 12 heart and 12 kidney transplant recipients. The decision between a linear and nonlinear model was made according to a standardized residuals plot. We observed high blood cells-plasma concentration ratios in the two groups, indicating a high affinity of Cy A for blood cells. The distribution of Cy A between blood cells and plasma was ascribed to a nonlinear saturable model in the two groups. According to our results we have simulated the blood-plasma concentration ratio of Cy A as a function of plasma Cy A concentration and hematocrit.

Binding in vitro of pipequaline (45319 RP) onto plasma proteins and blood cells in man.

Serum binding of pipequaline, a new anxiolytic drug, was studied in vitro by equilibrium dialysis. The percent binding in serum is high, 96.3%, and remains constant within the range of therapeutic concentrations. Investigations performed on isolated proteins with a wide range of concentrations showed one site with a high affinity constant (Ka = 450,000 M-1) for alpha 1-acid glycoprotein and two sites with a lower affinity constant (Ka = 58,000 M-1) for human serum albumin. Binding to lipoproteins was saturable, with an affinity constant of 22,000 less than or equal to Ka less than or equal to 35,000 M-1. Over the range of therapeutic concentrations, the ratio of pipequaline concentrations in serum and red blood cells remained constant (14.4%) and was shown to be dependent on the free fraction of pipequaline in serum.

Effect of erythrocytes and plasma protein binding on the transport of progabide and SL 75102 through the rat blood-brain barrier.

Brain extraction of two antiepileptic compounds, progabide and its acid metabolite, SL 75102, was investigated using the carotid injection technique in the rat. The extent to which drug binding to plasma proteins could inhibit the brain extraction was measured. Equilibrium dialysis at 4 degrees showed that both drugs were highly bound to human serum proteins, mainly to serum albumin. Progabide is also bound to red blood cells and to lipoproteins. The free dialyzable drug fraction was inversely related to the protein concentration. Similarly, the brain extraction of the drugs in the presence of either albumin, or red blood cells for progabide was inversely related to their respective concentrations. However, the rat brain extraction of both drugs was higher than expected from the in vitro measurement of dialyzable fraction. Furthermore, despite a significant degree of progabide binding to lipoproteins, no significant reduction in the brain extraction of the drug was observed. These data indicate that the amount of circulating progabide or SL 75102 available for penetration in a peripheral tissue such as brain exceeds the dialyzable fraction of drug. However, the in vivo exchangeable drug fraction still parallels the dialyzable fraction, except if the drug is lipoprotein-bound.

Progabide and SL 75102 binding to plasma proteins and red blood cells in humans.

The binding of progabide and its metabolite, SL 75102, was studied in vitro by equilibrium dialysis. The progabide binding percentage in serum remained constant (approximately equal to 96%) over a wide range of concentrations. Binding of progabide was characterized by one class of sites to human serum albumin (HSA) (n = 3.8 +/- 0.2; K = 2.5 X 10(4) M-1). The binding to alpha 1 acid glycoprotein (AAG) was also shown to be saturable with n = 1.7 +/- 0.2 and K = 3.1 X 10(4) M-1. Progabide was bound to a lesser extent to red blood cells (RBC), lipoproteins and gamma-globulins. The SL 75102 binding percentage in serum remained constant (approximately equal to 98%), over a range of concentrations exceeding therapeutic levels. SL 75102 showed two saturable classes of binding sites to HSA: the first one with n1 = 0.8 +/- 0.1 and K1 = 10(6) M-1 and the second one with n2 = 7.9 +/- 0.2 and K2 = 8.1 X 10(3) M-1. The binding to AAG was also shown to be saturable with n = 0.7 +/- 0.1 and K = 1.6 X 10(4) M-1. SL 75102 was bound to a lesser extent to RBC, lipoproteins and gamma-globulins. The binding parameters were used to calculate the distribution of progabide and SL 75102 among the components in whole blood over the therapeutic range. The calculations showed that serum albumin was the major binding component for the parent drug and its metabolite.

Binding of bornaprolol to human serum proteins and blood cells.

The binding of 14C-bornaprolol to human serum proteins and to blood cells and platelets was studied by equilibrium dialysis and centrifugation. Bornaprolol binding to alpha 1-acid glycoprotein (n = 1.89, K = 433,900 M-1) was found to be a saturable phenomenon. By contrast, a non-saturable binding was observed with serum albumin (nK = 6.4 X 10(3) M-1), HDL (nK = 205 X 10(3) M-1), LDL (nK = 1,530 X 10(3) M-1), VLDL (nK = 2,342 X 10(3) M-1) and gamma globulins (nK = 25 X 10(3) M-1). The binding to blood cells was negligible. All the binding parameters were used to simulate the distribution of bornaprolol between serum proteins and blood cells over the range of therapeutic concentrations and showed that serum albumin, red blood cells and alpha 1 acid glycoprotein were the major binding components.

[In vitro study of ceftriaxone binding to blood]. / Etude in vitro de la fixation sanguine de la ceftriaxone.

Binding of ceftriaxone, a new third generation cephalosporin, to blood was studied in vitro. Steady state dialysis with 14C-ceftriaxone was used. Percentages of ceftriaxone bound to plasma within the range of therapeutic concentrations (10 to 1,000 microM) varied widely (80 to 50%). Indicating that the binding process is saturable, investigations performed with various isolated plasma proteins in physiologic concentrations show that ceftriaxone binds mainly to albumin, and marginally or not at all to alpha-1-acid glycoprotein, gammaglobulins, transferrin, haptoglobin, and lipoproteins. Albumin has a single binding site (n = 0.7) with moderate affinity (Ka = 72,000 M-1) for ceftriaxone. The presence of this site explains why ceftriaxone binds to plasma according to a saturable process. Only a small proportion (5%) of ceftriaxone (75-450 microM) binds to red blood cells in whole blood with a 50% hematocrit. A strongly significant inhibition of ceftriaxone (520 microM) binding to plasma was found with high bilirubin levels (230 microM) (24% decrease; p less than 0.01). A small but significant decrease in ceftriaxone (380 microM) binding to plasma was found with high serum oleic acid (1014 microM) or uric acid (1,800 microM) concentrations (2% decrease; p less than 0.05).

In vitro binding study of gemfibrozil to human serum proteins and erythrocytes: interactions with other drugs.

The binding of gemfibrozil to human serum, isolated proteins and erythrocytes was studied in vitro by equilibrium dialysis. Our results show that this drug is highly bound to serum (99%) at therapeutic levels. Human serum albumin was shown to be mainly responsible for this binding (98.6%) with a saturable process characterized by two binding sites with a moderate affinity. Like many acidic drugs with a carboxylic acidic group, gemfibrozil showed none or negligible binding to alpha 1 acid glycoprotein, lipoproteins and gamma-globulins. The drug binding to erythrocytes is very low (0.8%). The unbound fraction in blood remains constant (0.8%) within the range of therapeutic concentrations. Moreover, interactions were studied with bilirubin and palmitic acid at pathophysiological concentrations and acenocoumarol, salicylic acid, valproic acid, furosemide, phenylbutazone, tolbutamide, warfarin and sulfamethoxazol at therapeutic concentrations. Neither endogenous compounds nor the other drugs studied altered gemfibrozil binding in serum. Likewise, the binding of warfarin to serum and to human serum albumin (600 microM) is not influenced by gemfibrozil.