Immunogenicity and safety of AS03-adjuvanted H1N1 pandemic vaccines in children and adolescents

Vaccines with acceptable efficacy profile against the H1N1 A/California/7/2009 virus are needed for use in children. The two studies presented here evaluated the immunogenicity and the reactogenicity/safety of A/H1N1/2009 vaccines containing either 3.75 μg haemagglutinin antigen (HA) and AS03(A)-adjuvant (3.75 μg HA/AS03(A) study) (N=210 [53, 57 and 100 in the 3-5, 6-9 and 10-17 years age strata, respectively]) or 1.9 μg HA and AS03(B)-adjuvant (1.9 μg HA/AS03(B) study) (N=244 [61, 65 and 118 in the 3-5, 6-9 and 10-17 years age strata, respectively]), given as two-dose series. Although the haemagglutination inhibition antibody titres were higher in the 3.75 μg HA/AS03(A) study, both vaccine dosages were highly immunogenic and exceeded regulatory acceptance criteria after the first and the second doses. Seroprotection rates reached 100% and seroconversion rates ranged from 98.2% to 99.1% after each dose of both vaccine dosages. Geometric mean titres increased from 456.5 to 1538.5 and from 297.9 to 1106.7 between the first and the second doses in the 3.75 μg HA/AS03(A) study and the 1.9 μg HA/AS03(B) study, respectively. Despite an observed slight increase of the reactogenicity following the second dose in the 3.75 μg HA/AS03(A) study, the vaccines safety profiles were considered clinically acceptable. In conclusion, both dosages of the AS03-adjuvanted A/H1N1/2009 pandemic influenza vaccines were highly immunogenic and well-tolerated in children and adolescents.

Microstructure and macroscopic properties of bioactive CaO-SiO2-PDMS hybrids

CaO-SiO2-PDMS (polydimethylsiloxane) hybrid materials were synthesized as crack-free monoliths presenting in vitro bioactivity, i.e. able to be coated with a calcium phosphate-rich layer after having been soaked in simulated body fluid (SBF). A wide physical-chemical characterization of these materials was carried out to relate their microscopic structure and macroscopic properties. The effect of PDMS and the amounts of water used for the tetraethoxysilane (TEOS) hydrolysis on the mechanical properties of hybrid materials was investigated by three-point bending tests. For a given amount of water, as PDMS content in hybrids increased, the elastic modulus decreased. Furthermore, keeping the PDMS content constant, when the amount of H2O decreased, the elastic modulus increased. Regarding in vitro bioactivity and mechanical properties, the hybrid material obtained with molar ratios H2O/TEOS = 2 and TEOS/PDMS = 3.5 proved to be the best candidate for either soft tissue substitution or metallic implant coating since the hybrid material would promote bond to bone formation, simultaneously dampening the mechanical charges.

Magnetic properties of ZnO nanoparticles

We experimentally show that it is possible to induce room-temperature ferromagnetic-like behavior in ZnO nanoparticles without doping with magnetic impurities but simply inducing an alteration of their electronic configuration. Capping ZnO nanoparticles ( approximately 10 nm size) with different organic molecules produces an alteration of their electronic configuration that depends on the particular molecule, as evidenced by photoluminescence and X-ray absorption spectroscopies and altering their magnetic properties that varies from diamagnetic to ferromagnetic-like behavior.

Budesonide/formoterol maintenance and reliever therapy: an effective asthma treatment option?

This 12-month dose-titration study assessed the effectiveness of budesonide/formoterol for maintenance plus relief with a control group using salmeterol/fluticasone for maintenance plus salbutamol for relief. Adolescents and adults (n = 2,143; mean forced expiratory volume in one second (FEV1) 73% predicted; mean inhaled corticosteroid (ICS) 884 microg.day(-1)) were randomised to budesonide/formoterol 160/4.5 microg two inhalations b.i.d. plus additional inhalations as needed, or salmeterol/fluticasone 50/250 microg b.i.d. plus salbutamol as needed. Treatment was prescribed open label; after 4 weeks, physicians could titrate maintenance doses in accordance with normal clinical practice. Maintenance plus as-needed budesonide/formoterol prolonged the time to first severe exacerbation versus salmeterol/fluticasone (25% risk reduction). The total number of severe exacerbations was significantly reduced in the budesonide/formoterol group (255 versus 329). Both regimens provided sustained improvements in symptoms, as-needed use, quality of life and FEV1, with differences in favour of the budesonide/formoterol group for as-needed use (0.58 versus 0.93 inhalations.day(-1)) and FEV1 (post-beta2-agonist values). Mean ICS dose during treatment was similar in both groups (653 microg budesonide.day(-1) (maintenance plus as-needed) versus 583 microg fluticasone.day(-1)). The simplified strategy using budesonide/formoterol for maintenance and reliever therapy is feasible, safe and at least as effective as salmeterol/fluticasone plus salbutamol.

The content of glycogen phosphorylase and glycogen in preparations of sarcoplasmic reticulum-glycogenolytic complex is enhanced in diabetic rat skeletal muscle

AIMS/HYPOTHESIS

We have examined the effect of diabetes and pharmacological insulin treatment on the content of glycogen phosphorylase and glycogen associated with the sarcoplasmic reticulum-glycogenolytic complex from rat skeletal muscle.

METHODS

Diabetes was induced in rats by streptozotocin injection. Enzymatic activities were measured using spectrophotometric methods. Glycogen phosphorylase was determined measuring the pyridoxal-5' -phosphate content and using polyacrylamide gel electrophoresis. Glycogen content was measured by enzymatic and the phenol sulfuric methods.

RESULTS

The content of glycogen phosphorylase associated with the sarcoplasmic reticulum glycogenolytic complex gradually arises after diabetes induction. The content of glycogen phosphorylase was restored to a control value by pharmacological insulin treatment. In addition, the content of glycogen in preparations of sarcoplasmic reticulum-glycogenolytic complex of diabetic animals was also increased, whereas the content of glycogen in total muscle of diabetic rats was similar to that of the control rats. The absolute and relative amount of glycogen associated with sarcoplasmic reticulum seemed to increase in diabetic animals. These effects on the compartmentalisation of glycogen were suppressed by insulin treatment. Additionally, the rate of conversion of glycogen phosphorylase b to a, an index of the phosphorylase kinase activity, was 50 % lower in diabetic rats, increasing the dephosphorylated form of glycogen phosphorylase and, as a consequence, its association with sarcoplasmic reticulum membranes.

CONCLUSION/INTERPRETATION

These results suggest that under diabetic conditions, both glycogen phosphorylase and a small percentage of muscle glycogen are relocalized in the sarcoplasmic reticulum-glycogenolytic complex.

Microbiology of pediatric primary pulmonary tuberculosis

OBJECTIVE

To determine the sensitivity of bacteriologic studies in pediatric pulmonary tuberculosis.

PATIENTS AND METHODS

Between January 1988 and December 1996, 104 consecutive patients aged 0 to 18 years received a diagnosis of primary pulmonary tuberculosis at our institution. Demographic, clinical, laboratory, and bacteriologic data were collected. Clinical specimens were studied for acid-fast bacilli detection by Ziehl-Neelsen stain and cultured for Mycobacterium recovery by Lowenstein-Jensen culture medium. Statistical analysis was performed utilizing chi(2), t tests, and multivariate logistic regression analysis.

RESULTS

Bacteriologic results were available for 57 patients (54.8%). A positive smear or culture result for Mycobacterium tuberculosis was obtained in 9 of 54 patients (16.6%) and 25 of 50 patients (50%), respectively. Confirmation of M tuberculosis disease was achieved in 28 patients (49.1%). Ziehl-Neelsen stain and Lowenstein-Jensen culture recovery rates were 10.3% (14 of 135) and 52% (48 of 92) of specimens studied, respectively. Sputum, pleural fluid, and biopsy material cultures yielded M tuberculosis in 55%, 75%, and 63% of patients, respectively. Mean +/- SD age (13.7 +/- 4.5 years vs 9.6 +/- 4.5 years) and number of samples submitted for culture (1.93 +/- 0.94 vs 1.31 +/- 0.97) were significantly higher in the confirmed tuberculosis disease group (p < 0.05). The presence of a pleural effusion was also more commonly found in the confirmed tuberculosis disease group (p < 0.05).

CONCLUSION

The sensitivity of bacteriologic studies in pediatric pulmonary tuberculosis disease was 49.1%. Age is the main factor associated with the positivity of culture results.

Identification of an aspartic residue in the P-loop of the vanilloid receptor that modulates pore properties

Vanilloid receptor subunit 1 (VR1) is a nonselective cation channel that integrates multiple pain-producing stimuli. VR1 channels are blocked with high efficacy by the well established noncompetitive antagonist ruthenium red and exhibit high permeability to divalent cations. The molecular determinants that define these functional properties remain elusive. We have addressed this question and evaluated by site-specific neutralization the contribution on pore properties of acidic residues located in the putative VR1 pore region. Mutant receptors expressed in Xenopus oocytes exhibited capsaicin-operated ionic currents akin to those of wild type channels. Incorporation of glutamine residues at Glu(648) and Glu(651) rendered minor effects on VR1 pore attributes, while Glu(636) slightly modulated pore blockade. In contrast, replacement of Asp(646) by asparagine decreased 10-fold ruthenium red blockade efficacy and reduced 4-fold the relative permeability of the divalent cation Mg(2+) with respect to Na(+) without changing the selectivity of monovalent cations. At variance with wild type channels and E636Q, E648Q, and E651Q mutant receptors, ruthenium red blockade of D646N mutants was weakly sensitive to extracellular pH acidification. Collectively, our results suggest that Asp(646) is a molecular determinant of VR1 pore properties and imply that this residue may form a ring of negative charges that structures a high affinity binding site for cationic molecules at the extracellular entryway.

Arginine-rich peptides are blockers of VR-1 channels with analgesic activity

Vanilloid receptors (VRs) play a fundamental role in the transduction of peripheral tissue injury and/or inflammation responses. Molecules that antagonize VR channel activity may act as selective and potent analgesics. We report that synthetic arginine-rich hexapeptides block heterologously expressed VR-1 channels with submicromolar efficacy in a weak voltage-dependent manner, consistent with a binding site located near/at the entryway of the aqueous pore. Dynorphins, natural arginine-rich peptides, also blocked VR-1 activity with micromolar affinity. Notably, synthetic and natural arginine-rich peptides attenuated the ocular irritation produced by topical capsaicin application onto the eyes of experimental animals. Taken together, our results imply that arginine-rich peptides are VR-1 channel blockers with analgesic activity. These findings may expand the development of novel analgesics by targeting receptor sites distinct from the capsaicin binding site.

A multidimensional modeling of predictors influencing the adjustment to a colostomy

PURPOSE

Factors contributing to the postoperative adjustment of patients who had undergone permanent colostomy surgery were studied.

DESIGN

Cross-sectional study.

SETTING AND SUBJECTS

Sixty patients who underwent colostomy surgery at 5 hospitals in Santiago, Chile, between 1987 and 1995 were evaluated. Subjects were between the ages of 27 and 89 and underwent colostomy surgery from 4 months to 19 years before data collection. METHODS AND INSTRUMENTS: A demographic questionnaire and a semistructured interview were used to elicit information concerning psychosocial reactions to a colostomy and perceptions about the changes in lifestyle created by the ostomy. Medical records were reviewed for information about disease-related characteristics and an ostomy self-care scale measured coping skills. Adjustment to the colostomy procedure was measured by means of the Olbrisch ostomy adjustment scale.

RESULTS

Patient adaptation to a colostomy is primarily affected by the following factors: (1) the level of ostomy self-care, (2) psychological support, and (3) social support from family and significant others.

CONCLUSION

Successful adjustment to a permanent colostomy is most likely to occur if the patient receives adequate instruction in self-care and has the appropriate psychological support to integrate the new physical changes into a healthy body image. This includes continued acceptance from family and the patient's social network.

pH and ligand binding modulate the strength of protein-protein interactions in the Ca(2+)-ATPase from sarcoplasmic reticulum membranes

The Ca(2+)-ATPase from sarcoplasmic reticulum (SR) membranes couples the Ca(2+) transport to ATP hydrolysis through phosphorylation in its cytoplasmic catalytic domain. Interactions between protein domains and the role of monomer-monomer interactions remain unclear. Here, we report a differential scanning calorimetric study of the thermal unfolding of this protein. In the pH range 6-8, thermal unfolding of the Ca(2+)-ATPase in glycogen phosphorylase-free SR membranes shows a major endothermic peak with a critical temperature midpoint ranging between 51 and 55 degrees C, depending on pH, Ca(2+), Mg(2+)-ADP and KCl concentrations. The enthalpy change of the overall unfolding process ranged between 250 and 300 kcal/mol of Ca(2+)-ATPase monomer. Thermal denaturation of the Ca(2+)-ATPase in SR membranes is well fitted to an irreversible process that can be rationalized in terms of a non-two state process, N (native)right harpoon over left harpoon I (intermediate)-->D (denatured). Thermodynamic analysis show that this protein has a compact structure, implying a tight structural interconnection between catalytic and Ca(2+) transport domains. The apparent cooperative unit, defined by the van 't Hoff enthalpy to the overall unfolding enthalpy ratio, increased from 1.1 at pH 6 to 1.8 at pH 8, showing that monomer-monomer interactions are stronger at weakly basic pH than at weakly acidic pH. While micromolar Ca(2+) concentrations had only a weak effect on the cooperativity of the unfolding process, this is clearly increased by millimolar Mg(2+)-ADP. In addition, high ionic strength lowered the apparent cooperative unit to approximately 1.0 in the pH range 6-8. Taken together, these results suggest that protein-protein interactions are altered by variables that modulate the catalytic activity of this enzyme.

Plausible stoichiometry of the interacting nucleotide-binding sites in the Ca(2+)-ATPase from sarcoplasmic reticulum membranes

The Ca(2+),Mg(2+)-ATPase from sarcoplasmic reticulum couples ATP hydrolysis to Ca(2+) transport toward the lumen of the muscular vesicular system. Combined structural and functional studies suggest that the Ca(2+) binding sites are formed by six amino acids of the same polypeptide and that cation translocation may take place through a channel inside a monomer of the ATPase. However, calorimetric, fluorescent, and kinetic studies suggest that the ATPase may assemble into functional oligomers of as yet unknown stoichiometry. We have addressed this question and attempted to determine the ATPase stoichiometry using a biophysical approach based on the analysis of the ATPase inhibition by fluorescein 5'-isothiocyanate in the presence of increasing ATP concentrations. For native SR membranes, our inhibition data are well described by a model consisting of two interacting nucleotide-binding sites per oligomer. This stoichiometry was disrupted in detergent C(12)E(8)-solubilized ATPase. Thus, these findings suggest that interacting nucleotide binding sites of the ATPase may appear as dimers, and imply that interactions of the globular cytoplasmic domains would play a modulatory role of the protein enzymatic activity.

[Factors which determine the psychological adjustment to permanent colostomies. An empirical study in Santiago, Chile]

BACKGROUND

The acceptance of a colostomy by a patient requires a great amount of psychological resources and social support.

AIM

To identify factors that influence the postoperative adaptation to a colostomy.

PATIENTS AND METHODS

Sixty patients subjected to a colostomy in 5 hospitals in Santiago were interviewed. The adaptation to the procedure was assessed using the Olsbrisch Ostomy Adjustment Scale. Three regression equations were elaborated to determine the main predictors associated to adaptation. Control variables such as sex, age and the lapse between the interview and the surgical procedure, were included in the model.

RESULTS

The model used identified the simultaneous and combined effects of socioeconomic variables such as education and income on the adaptation to colostomy. A generalized detriment of the self image was detected. Patients valued the social support given by the family and friends. Multiple regression analysis determined that the main predictor of the patient's adaptation to colostomy was the level of self care developed.

CONCLUSIONS

The better adaptation to a colostomy could be achieved by training the patient for an adequate self care and providing him with psychological and social support.

Tuberculous pleural effusion in children

STUDY OBJECTIVES

To describe the age distribution, clinical, laboratory, radiographic, and bacteriologic findings of pediatric patients with tuberculous pleural effusion.

DESIGN

A retrospective study.

PATIENTS AND METHODS

We have identified all cases of primary pulmonary tuberculosis in children < 18 years, reported to the health department. We have collected information from medical records regarding demographics, clinical findings, bacteriologic results, and evolution. Chest radiographs obtained at the time of initial evaluation were reviewed independently by two groups of radiologists who were blind to the clinical and epidemiologic data.

RESULTS

Between January 1983 and December 1996, 175 children < 18 years were diagnosed as having primary pulmonary tuberculosis. Among them, 39 patients (22.1%) showed pleural effusion on chest radiograph. The mean age of patients with tuberculous pleural effusion was significantly higher (13.52+/-0.5 years vs 6.97+/-0.42 years). The sensitivity of the tuberculin test is 97.4% for an induration > or = 5 mm. Pleural fluid analysis shows a lymphocytic exudative effusion. Chest radiograph review showed unilateral pleural effusion in all cases. Pleural effusion was the sole radiographic manifestation in 41% of cases. Parenchymal disease is associated in 23 cases (59%). Bacteriologic confirmation of tuberculosis was achieved in 22 cases (56.4%). Cultures of pleural fluid and biopsy material both yielded Mycobacterium tuberculosis in 15 of 34 (44.1%) and 12 of 18 (66.6%), respectively, for samples under study. Pleural biopsy specimens showed granulomatous inflammation in 18 of 23 cases (78.3%). Antituberculous therapy for 6 to 9 months was effective in all cases. Transient side effects occurred in 1 of 39 patients (2.9%).

CONCLUSIONS

Pleural effusion accounts for 22.1% of cases of pediatric pulmonary tuberculosis. Parenchymal consolidation is the most common associated radiographic finding. Bacteriologic confirmation was achieved in 56.4% of cases. A short course of chemotherapy is effective.

Structural determinants of the blocker binding site in glutamate and NMDA receptor channels

Glutamate receptor channels of the NMDA-type (N-methyl-D-aspartate) and non-NMDA-type (GluR) differ in their pore properties. The N-site in the M2 transmembrane segment of NMDA receptors (NMDAR), or the corresponding Q/R-site in GluRs, is a pivotal structural determinant of their permeation and blockade characteristics. Substitutions at a second site in M2, the L-site (L577) in GluR1, drastically alter the receptor selectivity to divalent cations. Here we report that M2 mutants carrying an asparagine or a threonine residue at the Q-site of GluR1, along with a tryptophan residue at the L-site, form homomeric GluR1 channels that are highly sensitive to structurally diverse, uncompetitive NMDA antagonists such as arylcyclohexylamines, dibenzocycloheptenimines, and to morphinian and adamantane derivatives. Analysis of the voltage dependence of channel blockade locates the blocker binding site approximately 0.65 partway into the transmembrane electric field in both GluR1 mutants and NMDAR channels. Our results suggest that the homomeric GluR1 double mutants, L577W/Q582N and L577W/Q582T, fairly approximate the pore properties of the heteromeric NMDA receptor and support the structural kinship of their permeation pathways.

Selected peptides targeted to the NMDA receptor channel protect neurons from excitotoxic death

Excitotoxic neuronal death, associated with neurodegeneration and stroke, is triggered primarily by massive Ca2+ influx arising from overactivation of glutamate receptor channels of the N-methyl-D-aspartate (NMDA) subtype. To search for channel blockers, synthetic combinatorial libraries were assayed for block of agonist-evoked currents by the human NR1-NR2A NMDA receptor subunits expressed in amphibian oocytes. A set of arginine-rich hexapeptides selectively blocked the NMDA receptor channel with IC50 approximately 100 nM, a potency similar to clinically tolerated blockers such as memantine, and only marginally blocked on non-NMDA glutamate receptors. These peptides prevent neuronal cell death elicited by an excitotoxic insult on hippocampal cultures.

Structural changes of the sarcoplasmic reticulum Ca(II)-ATPase nucleotide binding domain by pH and La(III)

The Ca(2+)-ATPase from sarcoplasmic reticulum couples the hydrolysis of one molecule of ATP to the transport of two Ca2+ ions in skeletal muscle fibers. Here, we study the accessibility of the fluorescein covalently attached to the Lys515 at the nucleotide binding domain of the ATPase to the small collisional quencher iodide at pH 6 and 8, as well as the effect of ligand binding (La3+, La(3+)-nucleotide, and Ca2+). Our results indicate that bound fluorescein is significantly more accessible at pH 6 than at pH 8, suggesting that pH modulates the structure of the nucleotide binding domain of the ATPase. This notion was further substantiated by the finding that La(3+)-nucleotide only interacted with the catalytic center at acidic pH. Notably, the differential accessibility of the nucleotide binding domain at acidic and basic pH cannot be rationalized in terms of the ATPase E1/E2 conformational equilibrium since a shift of the ATPase toward the E1 (plus Ca2+) or E2 (plus EGTA) did not affect the accessibility of fluorescein-labeled ATPase to the quencher. Taken together, these findings show the presence of structural flexibility in the FITC binding site and suggest a structural modulation of the Ca(2+)-ATPase nucleotide binding domain by pH and La3+ binding through long-range link-age mechanisms.

[Bronchiolitis: conceptual review]

Bronchiolitis is a term which brings together several processes which may confuse anyone who is not familiar with the subject. We will review these processes by focusing on the most common types.

Pediatric experience with autologous peripheral blood progenitor cell transplantation: influence of CD34+ cell dose in engraftment kinetics

The aim of this study was to analyze factors affecting mobilization and engraftment in 40 children undergoing autologous peripheral blood progenitor cell transplantation for different malignancies: 19 patients with haematological malignancies and 21 patients with solid tumors. Patients received 4-5 days of rhG-CSF (12 micrograms/kg/day) subcutaneously. Apheresis was performed by continuous flow blood cell separation beginning on the fifth day of rhG-CSF. For patients weighing < or = 25 kg, the extracorporeal line was primed with irradiated red blood cells. After myeloablative conditioning regimens, patients were grafted with 7.21 +/- 7.8 x 10(6)/kg CD34+ cells. Days to achieve an absolute neutrophil count > 0.5 x 10(9)/1 and a platelet count > 20 x 10(9)/1 without platelet support were 9.50 +/- 1.2 (range 7-13) and 18.1 +/- 8.3 (range 9-37), respectively. The number of CD34+ cells infused was highly correlated with engraftment kinetics (P = 0.0001). The patient's body weight and the number of previous chemotherapy courses had a negative influence on CD34+ cells collected.

Complicated pulmonary aspergillosis with pneumothorax and pneumopericardium in a child with acute lymphoblastic leukemia

Invasive aspergillosis is a fungal infection that is being observed increasingly in immunocompromised patients due to the use of more aggressive chemotherapeutic regimens. To our knowledge, no case of pneumothorax and pneumopericardium associated with invasive pulmonary aspergillosis has been reported to date. High-dose amphotericin B (1 to 1.5 mg/kg/day) is the treatment of choice, although severe side effects, especially hypokalemia, are very common. Itraconazole is considered to be a therapeutic alternative for invasive pulmonary aspergillosis in immunocompromised patients. A rare combination of pneumothorax and pneumopericardium associated with systemic aspergillosis in a child with acute lymphoblastic leukemia is described. Treatment with low-dose amphotericin B and itraconazole achieved complete resolution of the foregoing complications.

Mg(2+)-ADP protects against inactivation of sarcoplasmic reticulum Ca2+,Mg(2+)-ATPase by N-cyclohexyl-N'-(4-dimethylamino-alpha-naphthyl) carbodiimide

N-cyclohexyl-N'-(4-dimethylamino-alpha-naphthyl) carbodiimide (NCD-4) inactivates the sarcoplasmic reticulum Ca(2+)-ATPase by covalent labelling at or near the high affinity (transport) Ca2+ sites. Mg(2+)-ADP protects against the inactivation of the Ca(2+)-ATPase produced by NCD-4, with a K0.5 of Mg(2+)-ADP of 28 +/- 6 microM for purified Ca(2+)-ATPase. With native and solubilized sarcoplasmic reticulum membranes millimolar Mg(2+)-ADP concentrations are needed to produce an effective protection of the Ca(2+)-ATPase against inactivation by NCD-4. These results suggest a tight structural interconnection between catalytic and transport Ca2+ sites in the Ca(2+)-ATPase, modulated by protein-protein interactions in the SR membrane.

[Mediastinal chordoma]

We describe a patient with chordoma located in the mid-posterior mediastinum whose first clinical symptoms were respiratory. This, together with the patient's age at presentation, made this case unusual.

Thermal unfolding of monomeric Ca(II), Mg(II)-ATPase from sarcoplasmic reticulum of rabbit skeletal muscle

The thermal unfolding of monomeric and delipidated Ca(2+)-ATPase, solubilized in C12E8, can be appropriately described as a non-two-state irreversible denaturation, with only one endothermic peak. In the Ca2+ concentration range (0-0.5 mM) which stimulates the ATPase activity of solubilized monomeric ATPase, Ca2+ shifts the critical temperature midpoint of the denaturation process (Tm) from 42 to 50 degrees C without segregation of the endothermic peak into two separate components. Because 20 mM Mg2+ only shifts the Tm from 42 to 44 degrees C, we conclude that the effect of Ca2+ upon the Tm is likely to be due to binding to the high affinity Ca2+ sites in the ATPase. The effect of Ca2+ upon the enthalpy of denaturation is biphasic, suggesting the presence of low affinity Ca2+ sites (K0.5 in the millimolar range) in monomeric and solubilized ATPase.

[The prevalence of anemia in the children and adolescents of Madrid]

Iron deficiency and iron deficiency anemia are very important disorders in childhood because, during this stage of life, the confluence of different factors can lead to iron deficiency. During childhood, there are rapid growth periods in which the need for iron increases and these needs are not always compensated for by a sufficient iron intake. We have studied a sample of 2,224 schoolchildren, both males and females, between the ages of 2 and 18 years, from five different schools in the Community of Madrid. The prevalence of anemia was studied by determining the hemoglobin, MCV and MCHC, whereas iron deficiency was assessed by measurement of serum iron. In our study population, the prevalence of iron deficiency was 4.94% and the rate of iron deficiency anemia was 0.94%. This disorder is predominant in 13 to 15 year olds (3.7% of the males and 3.53% of the females showed hemoglobin values below the reference range). In addition 6.73% of this group were iron deficient. The MCV was decreased in 2.69% of the subjects, after the exclusion of six children with thalassemia trait.

[Diagnosis of anaerobic infection of the pleural fluid using gas-liquid chromatography]

BACKGROUND

An assessment of the efficacy of the detection of volatile and non-volatile fatty acids that are produced by microorganisms aimed at the possible diagnosis of pleural empyema.

METHODS

106 pleural fluids were examined by gas-liquid chromatography in contrast to conventional aerobic and anaerobic cultures. The sample previously prepared (1 microliter) was injected in an Hewlett-Packard 5890 chromatograph, that was equipped with a fused silica capillary column and a flame ionization detector.

RESULTS

Growth of aerobic or anaerobic microorganisms was obtained in 13 (12.3%) of the samples, and volatile or non-volatile fatty acids were detected in all of them (sensitivity = 1). No growth was obtained in the 93 samples, but volatile or non-volatile fatty acids were detected in 64 (68.8%) of them (specificity = 0.31). A positive predictive value of 0.17 and a negative predictive value of 1 were obtained. Growth of anaerobic microorganisms was obtained in 9 samples (8.5%) and volatile fatty acids were detected in all of them (sensitivity = 1). Anaerobic microorganisms did not grow in 97 samples, however volatile fatty acids were detected in 2 (2.1%) of them. A positive predictive value of 0.82 and a negative of 1 were obtained.

CONCLUSIONS

Referring to pleural fluid samples, the detection of volatile and non-volatile fatty acids by gas-liquid chromatography is a highly sensitive method, that may be used to quickly reject negative samples in about 30 mins. Furthermore, when anaerobic microorganisms exist, the high specificity of gas-liquid chromatography will make it possible to confirm their presence in the sample, mainly if there is a clinical suspect of anaerobic infection. Thus, the utilization of this sensitive method may also change the therapeutic behaviour.

[Non-Hodgkin's lymphoma associated with human immunodeficiency virus infection in children]

A 3-year-old boy with infection by the human immunodeficiency virus (HIV) developed stage IV Burkitt's lymphoma. Complete remission was achieved with the BFM-86 protocol. One month after finishing treatment, and still in complete remission, fever appeared and seropositivity to HIV was found. The child was diagnosed of AIDS (P2-E1) and died 10 days later. Although the association of HIV infection and Burkitt's lymphoma is well known in adults, it is extremely rare in children. The routine HIV screening is suggested for children with non-Hodgkin's lymphoma.

[Cytokines-endothelium interaction: its role in the thrombotic process]

The in vivo relationship between the immune and the coagulation systems is a well documented fact. In a number of pathological conditions, thrombosis is not understood isolately, but in the context of inflammation and immunity. The mediators in these complex multidirectional interactions are the cytokines, a group of soluble peptides which act on surface cellular receptors, with immunoregulatory properties. These molecules influence negatively the physiological antithrombogenic situation by two different mechanisms. They are involved in processes which disrupt the endothelial integrity, and at the same time, they are capable of activating the endothelium in a prothrombotic manner, by stimulating procoagulant activities and by inhibiting different anticoagulants.

Processing dominance of global and local information in visual patterns

The processing dominance of global and local levels of visual patterns was studied using two tasks: speeded classification and identification. Stimuli were presented with spatial certainty and controlled eccentricity. The results with both procedures showed global advantage: RTs to global level were faster than those to local level. In the same way, the interference effect was bidirectional between the global and local levels, the amount of interference being larger from the global level to the local one than vice versa.