Validation of electrodeposited 241Am alpha-particle sources for use in liquified gas detectors at cryogenic temperatures.

This paper describes a procedure for the validation of alpha-particle sources (exempt unsealed sources) to be used in experimental setups with liquefied gases at cryogenic temperatures (down to -196 °C) and high vacuum. These setups are of interest for the development and characterization of neutrino and dark matter detectors based on liquid argon, among others. Due to the high purity requirements, the sources have to withstand high vacuum and cryogenic temperatures for extended periods. The validation procedure has been applied to 241Am sources produced by electrodeposition.

Hemocyte cell types of the Cortes Geoduck, Panopea globosa (Dall 1898), from the Gulf of California, Mexico.

The geoduck Panopea globosa is an endemic and economic valuable species from the Mexican Northwest coast whose biology has been little studied. No information exists about their hemocytes to date, which is highly important to assess the welfare of wild and cultured organisms. In this study, hemocytes of adult P. globosa were characterized at the morphological, ultrastructural and functional level. The mean number of hemocytes in the hemolymph of P. globosa was 6 × 105 ± 2 × 105 cells mL-1. The cells were identified as granulocytes (Gr) and hyalinocytes (H). The former accounted for 28% of adhered cells in the hemolymph, measured 6-18 µm, showed numerous basophilic granules in the cytoplasm, with round and eccentric nuclei, and a nucleus:cytoplasm ratio of 0.44 ± 0.01. Hyalinocytes were the most abundant cells in the hemolymph of P. globosa (72% adhered cells) and were subdivided, according to their size, in small (Hs) 4-12 µm and large (HL) 6-18 µm. Hyalinocytes were eosinophilic round or ovoid cells with a central or eccentric nucleus, few or no granules in the cytoplasm and similar nucleus:cytoplasm ratio (Hs: 0.63 and HL: 061). Lysosomes and lipids were observed in Gr, while carbohydrates were the most abundant energy substrate in H. Both hemocytic cell types, mainly Gr, were capable to ingest particles and yield superoxide (P > 0.05). The present study shows for the first time the cell types, abundance and immune activities of hemocytes present in the hemolymph of P. globosa. This information provides a useful baseline to carry out further research on the cellular immune response of the clam to potential pathogens or changes in environmental factors.

Nano-odontology: nanostructured assemblies for endodontic regeneration.

The vitality of the pulp is so fundamental to the functional life of the tooth that new strategies are required to avoid the removal of the whole pulp following irreversible pulpitis and to regenerate the lost endodontic tissues. Nano-odontology would provide suitable solutions for pulp tissue conservative and regenerative approaches. In our group, we have shown that when covalently coupled to Poly-Glutamic Acid (PGA) the incorporation of an anti-inflammatory hormone (melanocortin, a-MSH) into the multilayered films Poly-L-Lysine (PLL)/PGA increases the anti-inflammatory reaction of pulp fibroblasts and macrophages stimulated by LPS (Lipo-Polysaccharides). Recently, usual linear PLL polymers have been chemically grafted for making new Dendrigraft polymers (DGLG4) whose higher branching ratios can give useful properties. The objective is to use nanostructured assemblies containing DGLG4 and PGA-alpha-MSH to design a new nanomaterial. These nanostructured assemblies (DGLG4-PGA-alpha-MSH)n constitute a thick reservoir of the anti-inflammatory peptide and promote adhesion and proliferation of pulp fibroblast on the biomaterial surface. These nanostructured films could be adapted for an endodontic regeneration application to target pulp connective tissue regeneration. Firstly, the crucial reduction of inflammation could be helpful by using PGA-alpha-MSH and secondly the initiation of the regeneration of the connective tissue will be promoted by the whole nanostructured film of which allows pulp cells colonisation.

Bone formation induced by growth factors embedded into the nanostructured particles.

Tissue engineering has merged with stem cell biotechnology with development of new sources of transplantable biomaterials for the treatment of bone tissue diseases. Bone defects are expected to benefit from this new biotechnology because of the low self-regenerating capacity of bone matrix secreting cells. The differentiation of stem cells to bone cells using bi-functionalized multilayered particles is presented. The functionalized particles are composed of poly-glutamic acid (PGA) and poly-L-lysine (PLL) with two bone growth factors (BMP-2 and TGFbeta1) embedded into the multilayered film. The induction of bone from these bioactive particles incubated with embryonic stem cells was demonstrated in vitro. We report the demonstration of a multilayered particle-based delivery system for inducing bone formation in vivo. This new strategy is an alternative approach for in vivo bone formation.

Protein-carbohydrate interactions between Lactobacillus salivarius and pig mucins.

Adherence to the gastrointestinal tract is a key element desirable for many of the proposed beneficial health effects of probiotic bacteria. The aims of this study were to determine the amounts of adhesion of 3 Lactobacillus salivarius strains (Lb6, Lb9, and Lb10) to porcine small intestinal mucins and to determine whether adhesion is a function of lectin-like activities. Dot and Western blot assays were performed to investigate bacterial adhesion. Several carbohydrates and glycoproteins were evaluated to determine whether they interfered with adhesion of the Lactobacillus strains to intestinal mucins and to determine whether they had lectin-like activities. The Lb9 and Lb10 strains had greater association with piglet mucins than did those from 22- to 24-wk-old finishing pigs (P = 0.021 and 0.037, respectively), whereas the Lb6 strain adhered to both (P = 0.138). Western blot assays showed that bacterial adhesion detected piglet mucosa from the duodenum, jejunum, and ileum. In finishing pigs, the adhesion was variable throughout the gastrointestinal tract. Galactose and mannose diminished the interaction of the Lb9 and Lb10 strains in intestinal mucosa (P = 0.028 and 0.026, respectively), whereas pig gastric mucin reduced the adhesion of the Lb6 strain (P = 0.013). Adhesion of the Lb9 and Lb10 strains to intestinal mucosa was less after protease treatment (P = 0.023 and 0.018, respectively), which indicates that proteins are needed for the Lb9 and Lb10 strains to recognize mucin. The Lb6 strain also demonstrated diminished adhesion after periodate treatment (P = 0.038). From these results, we suggest that the nature of the bacterial lectin-like substance is a surface protein that loosely binds to the bacterial cell surface. All the tested strains adhered to specific targets in the small intestinal mucosa of piglets, and the bacteria had lectin-like proteins involved in this adhesion.

Active multilayered capsules for in vivo bone formation.

Interest in the development of new sources of transplantable materials for the treatment of injury or disease has led to the convergence of tissue engineering with stem cell technology. Bone and joint disorders are expected to benefit from this new technology because of the low self-regenerating capacity of bone matrix secreting cells. Herein, the differentiation of stem cells to bone cells using active multilayered capsules is presented. The capsules are composed of poly-L-glutamic acid and poly-L-lysine with active growth factors embedded into the multilayered film. The bone induction from these active capsules incubated with embryonic stem cells was demonstrated in vitro. Herein, we report the unique demonstration of a multilayered capsule-based delivery system for inducing bone formation in vivo. This strategy is an alternative approach for in vivo bone formation. Strategies using simple chemistry to control complex biological processes would be particularly powerful, as they make production of therapeutic materials simpler and more easily controlled.

Unstimulated salivary flow rate, pH and buffer capacity of saliva in healthy volunteers.

OBJECTIVES: To assess the salivary flow rate, pH, and buffer capacity of healthy volunteers, and their relationships with age, gender, obesity, smoking, and alcohol consumption, and to establish the lower-end value of normal salivary flow (oligosialia). METHODS: A prospective study was conducted in 159 healthy volunteers (age > 18 years, absence of medical conditions that could decrease salivary flow). Unstimulated whole saliva was collected during ten minutes, and salivary flow rate (ml/min), pH, and bicarbonate concentration (mmol/l) were measured using a Radiometer ABL 520. The 5 percentile of salivary flow rate and bicarbonate concentration was considered the lower limit of normality. RESULTS: Median salivary flow rate was 0.48 ml/min (range: 0.1-2 ml/min). Age younger than 44 years was associated with higher flow rates (OR 2.10). Compared with women, men presented a higher flow rate (OR 3.19) and buffer capacity (OR 2.81). Bicarbonate concentration correlated with salivary flow rate. The lower-end values of normal flow rate and bicarbonate concentration were 0.15 ml/min and 1.800 mmol/l, respectively. The presence of obesity, smoking, and alcohol consumption did not influence salivary parameters. CONCLUSIONS: In healthy volunteers, salivary flow rate depends on age and gender, and correlates with buffer capacity. Obesity, smoking, and alcohol use do not influence salivary secretion.

Phenytoin serum concentration monitoring during pregnancy and puerperium in Mexican epileptic women.

Phenytoin serum concentrations were evaluated in 88 epileptic women at different stages of pregnancy and 40 women during postnatal periods. In addition, concentrations were determined from the umbilical cords of 27 neonates. On average, the dose of phenytoin was increased by 130 +/- 54 mg in 67% of the patients in order to control seizures. In 76% of the women during pregnancy and 95% in the postnatal periods, dose adjustment was achieved for the control of the seizures. Therapeutic clinical concentrations ( < 9.9 micrograms/ml) were found in 64% of the patients, with an average of 7.2 +/- 1.8 micrograms/ml during pregnancy and 6.2 +/- 2 micrograms/ml in 90% of the women during the postnatal period. The average phenytoin concentration reached with doses of 100, 200, 300, 400 and 500 mg were 3.3, 5.7, 8.4, 10.8, and 14.1 microliters/ml, respectively, without statistically significant differences among the pharmacokinetic parameters measured during pregnancy, between pregnancy and the postnatal period. The proportion between fetal and maternal phenytoin concentration was 0.37 +/- 0.28. Hydantoin fetal syndrome was seen in 8% of the neonates, without a statistically significant difference among patients with or without seizures. No relation was found between the concentration of phenytoin during pregnancy and the hydantoin fetal syndrome. The study shows that low concentrations of phenytoin can control seizures during pregnancy and the postnatal period and the need to relate serum phenytoin concentrations with the clinical state of pregnant women who suffer seizures.

[Nifedipine in gynecology and obstetrics]. / Nifedipina en ginecología y obstetricia.

Nifedipine has both vasodilator and relaxant actions in arterial smooth muscle and other tissues, like uterus. The goal of this review is describe the potential uses of this calcium antagonist in two clinical features in pregnancy. First, in premature labor, nifedipine is an appropriate alternative related with beta-mimetic or prostaglandin synthetase inhibitors agents, with good tocolytic properties and safe for both mother and baby. Second, in the treatment of hypertension in pregnancy or preeclampsia, where, according literature, nifedipine would be a valuable therapeutic gun. It is exposed the nifedipine advantages and disadvantages in pregnancy found by the authors from the reports reviewed here. It is analyzed the ethics of nifedipine use in pregnancy. Moreover, it is pointed out the nifedipine clinical usefulness in the treatment of primary dysmenorrhea and it is analyzed some nifedipine hemodynamic aspects on uterine blood flow.

[Post-dosage loading concentrations of theophylline and pharmacokinetic study after the fifth maintenance dosage in premature newborns with apnea]. / Concentraciones de teofilina postdosis de impregnación y estudio farmacocinético en la quinta dosis de mantenimiento en recién nacidos pretérmino con apneas.

From a group of 50 premature newborns with central and mixed apnea, 34 received a loading dose of 4.3 mg/kg intravenous theophylline (group I) and 16 received 6 mg/kg orally (group II); the maintenance dose was 0.86 and 1 mg/kg every eight hours, respectively. Mean maximum serum concentrations after the loading dose were 5.8 +/- 2.3 mcg/mL in 25 newborns from group I, and 6.6 +/- 1,3 mcg/mL in 8 newborns from group II (P less than 0.20). Mean maximum concentration after the fifth maintenance dose was 7.5 +/- 1.7 mcg/mL in 26 newborns from group I, and 5.8 +/- 1.4 mcg/mL in 16 newborns from group II (P = 0.001); mean minimum concentration was 5.3 +/- 1.6 mcg/mL and 4.5 +/- 1.4 mcg/mL, respectively (P greater than 0.10). Mean clearance was 30.21 +/- 11.03 and 27.1 +/- 7.7 mL/kg/h; mean apparent distribution volume was 0.5 +/- 0.25 and 0.76 +/- 0.32 L/kg; elimination rate constant was 0.049 +/- 0.04 and 0.040 +/- 0.03/h-1 for both groups respectively, with significant differences between groups only in the apparent distribution volume (P less than 0.001). Half-life time (T1/2) was from four to 118 hours. The study population was divided into three groups according to half-life time: those with a half-life time of lesser than 20 hours (47.6%); an intermediate half-life time of from 20 to 30 hours (23.8%); and a long half-life time of more than 31 hours (28.6%).(ABSTRACT TRUNCATED AT 250 WORDS)

[Relation between dose, plasma concentration and therapeutic effect of theophylline in children with sleep apnea]. / Relación entre la dosis, concentración plasmática y efecto terapéutico de teofilina en niños con apnea del sueño.

The plasma concentration of theophylline was determined in twelve children with infantile sleep apnea (average age 48.5 days). The purpose of the study was to correlate concentrations with the dosages given, the therapeutic response and any adverse effects which could arise. In addition, other pharmacokinetic values were found, half-life (t 1/2) and clearance concentrations (Clss). The oral maintenance dose used was 4 mg/kg/24 h. The serum concentration of theophylline was determined by a homogeneous immunoassay enzyme technique (EMIT). A bad correlation was found (r = 0.45) between the oral dosage given and the plasma concentrations found. This was probably due to variations in the clearance of the drug. Yet, plasma concentrations fell between 3.0 and 12.6 micrograms/mL, enough to satisfactorily control apneic episodes in all the children included in the study without undesirable side-effects. Only one patient had some trouble in falling asleep and showed signs of irritability. The half-life was 13.30 +/- 7.46 hours and Clss was 36.64 +/- 12.98 mL/h/kg. In general, our results correlate with those reported in the literature. The accuracy of the pharmacokinetic parameters with two samples is reliable, therefore avoiding the use of multiple sampling in this group of children.

[Indications and contraindications for analgesics and antibiotics in pediatric dentistry]. / Indicaciones y contraindicaciones de analgésicos y antibióticos en odontología pediátrica.

A general overview upon most used products in odontopediatrics is presented; the factors which influence the determination of the adequate doses in children and some useful recommendations in dental clinical practice are described. The most prescribed products in pediatric odontology are summarized into two groups: a) benzodiazepine, for anxiety and lidocaine, aspirin and acetaminophen, dipirone and naproxen, for pain; and b) penicillin, erythromycin, for treatment of infections. Doses, pharmacologic effects, clinical indications, side effects and contraindications of the chemicals mentioned are described. Also, the article presents some of the aspects which justify the use, in our country, of certain medicaments prescribed in other nations reporting, the recommendations in order to prevent the use of other chemicals because of their lack of therapeutical advantages over the ones of first choice.