Photobiomodulation and salivary glands: a systematic review.

To date, there is no compilation of evidence-based information associating photobiomodulation effect and salivary glands. This systematic review aims to assess photobiomodulation effect of low intensity laser on salivary glands in the presence of systemic diseases. MEDLINE databases were searched in duplicate through December 2018. In vivo studies and clinical trials were included if photobiomodulation was performed in salivary glands of animal (rat or mice) or human in the presence of systemic disease. The methodological quality was assessed in duplicate using the modified Newcastle-Ottawa scale (NOS). Search strategy identified 483 potentially eligible articles, and 449 were included. The Boolean search naturally leads to a high amount of works the majority of which were excluded because the analysis of the title and abstract demonstrated it was not focusing on PBM. Only 34 studies were selected for the full-text analysis, of which 5 were excluded due to non-use of photobiomodulation, 4 due to lack of control group, 2 because they were studies of cell cultures and 1 because they did not have the total of animals used. Thus, 21 papers were included for the critical evaluation of the impact of photobiomodulation on the major salivary glands; the studies used rats (n = 10) and humans (n = 11). Although studies reported an increase in the salivary rate, decrease in pain, and increase in quality of life after the PBM, the lack of standards for the application of light and reporting of the parameters, make it hard to reproduce the results. This topic is still in need for further research.

Genomic insights into the expansion of carbapenem-resistant Klebsiella pneumoniae within Portuguese hospitals.

Carbapenem-resistant Klebsiella pneumoniae (CR-KP) are a public health concern, causing infections with a high mortality rate, limited therapeutic options and challenging infection control strategies. In Portugal, the CR-KP rate has increased sharply, but the factors associated with this increase are poorly explored. In order to address this question, phylogenetic and resistome analysis were used to compare the draft genomes of 200 CR-KP isolates collected in 2017-2019 from five hospitals in the Lisbon region, Portugal. Most CR-KP belonged to sequence type (ST) 13 (29%), ST17 (15%), ST348 (13%), ST231 (12%) and ST147 (7%). Carbapenem resistance was conferred mostly by the presence of KPC-3 (74%) or OXA-181 (18%), which were associated with IncF/IncN and IncX plasmids, respectively. Almost all isolates were multi-drug resistant, harbouring resistance determinants to aminoglycosides, beta-lactams, trimethoprim, fosfomycin, quinolones and sulphonamides. In addition, 11% of isolates were resistant to colistin. Colonizing and infecting isolates were highly related, and most colonized patients (89%) reported a previous hospitalization. Moreover, among the 171 events of cross-dissemination identified by core genome multi-locus sequence typing data analysis (fewer than five allelic differences), 41 occurred between different hospitals and 130 occurred within the same hospital. The results suggest that CR-KP dissemination in the Lisbon region results from acquisition of carbapenemases in mobile genetic elements, influx of CR-KP into the hospitals by colonized ambulatory patients, and transmission of CR-KP within and between hospitals. Prudent use of carbapenems, patient screening at hospital entry, and improvement of infection control are needed to decrease the burden of CR-KP infection in Portugal.

Electrochemical methods for speciation of trace elements in marine waters. Dynamic aspects.

The contribution of electrochemical methods to the knowledge of dynamic speciation of toxic trace elements in marine waters is critically reviewed. Due to the importance of dynamic considerations in the interpretation of the electrochemical signal, the principles and recent developments of kinetic features in the interconversion of metal complex species will be presented. As dynamic electrochemical methods, only stripping techniques (anodic stripping voltammetry and stripping chronopotentiometry) will be used because they are the most important for the determination of trace elements. Competitive ligand exchange-adsorptive cathodic stripping voltammetry, which should be considered an equilibrium technique rather than a dynamic method, will be also discussed because the complexing parameters may be affected by some kinetic limitations if equilibrium before analysis is not attained and/or the flux of the adsorbed complex is influenced by the lability of the natural complexes in the water sample. For a correct data interpretation and system characterization the comparison of results obtained from different techniques seems essential in the articulation of a serious discussion of their meaning.

Analysis of the activation mechanism of Pseudomonas stutzeri cytochrome c peroxidase through an electron transfer chain.

The activation mechanism of Pseudomonas stutzeri cytochrome c peroxidase (CCP) was probed through the mediated electrochemical catalysis by its physiological electron donor, P. stutzeri cytochrome c-551. A comparative study was carried out, by performing assays with the enzyme in the resting oxidized state as well as in the mixed-valence activated form, using cyclic voltammetry and a pyrolytic graphite membrane electrode. In the presence of both the enzyme and hydrogen peroxide, the peak-like signal of cytochrome c-551 is converted into a sigmoidal wave form characteristic of an E(r)C'(i) catalytic mechanism. An intermolecular electron transfer rate constant of (4 ± 1) × 10(5) M(-1) s(-1) was estimated for both forms of the enzyme, as well as a similar Michaelis-Menten constant. These results show that neither the intermolecular electron transfer nor the catalytic activity is kinetically controlled by the activation mechanism of CCP in the case of the P. stutzeri enzyme. Direct enzyme catalysis using protein film voltammetry was unsuccessful for the analysis of the activation mechanism, since P. stutzeri CCP undergoes an undesirable interaction with the pyrolytic graphite surface. This interaction, previously reported for the Paracoccus pantotrophus CCP, induces the formation of a non-native conformation state of the electron-transferring haem, which has a redox potential 200 mV lower than that of the native state and maintains peroxidatic activity.

Redox chemistry of low-pH forms of tetrahemic cytochrome c3.

Desulfovibrio vulgaris Hildenborough cytochrome c(3) contains four hemes in a low-spin state with bis-histidinyl coordination. High-spin forms of cytochrome c(3) can be generated by protonation of the axial ligands in order to probe spin equilibrium (low-spin/high-spin). The spin alterations occurring at acid pH, the associated changes in redox potentials, as well as the reactivity towards external ligands were followed by the conjunction of square wave voltammetry and UV-visible, CD, NMR and EPR spectroscopies. These processes may be used for modelling the action of enzymes that use spin equilibrium to promote enzyme activity and reactivity towards small molecules.

Influence of UV-B radiation on lead speciation in the presence of natural particles of estuarine waters.

The influence of UV-B irradiation on filtered and non-filtered water samples collected in a non-polluted area of Tagus estuary was evaluated in this study. In the laboratory, both samples were titrated with lead (Pb(+2)) followed by differential pulse anodic stripping voltammetry (DPASV), before and after 1 and 10 days under UV-B irradiation. Metal-ligand complexing parameters were obtained based on a macromolecular heterogeneous ligand described by two distinct sites with a labile behavior, and a third small homogeneous weaker group, which concentration was determined from a potentiometric titration. Under UV-B radiation, the complexing strength decreased with time in both (filtered and non-filtered) irradiated samples, but this effect was more pronounced in the non-filtered water, which might be due to some adsorption of dissolved macromolecular ligands on the particles and/or to further degradation of dissolved organic matter (DOM). Furthermore, the presence of particles favored the break-down of the macromolecular ligand under long UV-B exposure time. These results present ecological implications for the estuarine ecosystems such as bioavailability and toxicity.

Influence of the sediment on lead speciation in the Tagus estuary.

The aim of this work is to study the influence of the Tagus estuarine sediment on lead speciation in the overlying natural water. The water sample in the presence of the sediment was contaminated three times with Pb(II) in a laboratory experiment. In different periods of time, at 1-7 days after each contamination, small volumes of water were titrated with lead. The titration was followed by anodic stripping voltammetry in differential pulse mode. Before and after contamination systematic analysis of the voltammetric parameters (peak current, peak potential and peak width) were carried out to get a clear picture of Pb(II) complexation in the soluble fraction in contact with the sediment. Two main types of organic ligands, macromolecular ligands and small compounds, were detected before contamination. Both of them form labile complexes (degree of lability within the timescale of some milliseconds). The small compounds, with a diffusion coefficient similar to that of the free metal ion, present a homogeneous behaviour in terms of Pb complexation. On the other hand macromolecular ligands, with a diffusion coefficient of 1.2 x 10(-6) cm2s(-1), can be described by two different binding groups, which might be of phenolic and carboxylic type as presented by humic matter. The sediment eliminated lead contamination (10(-6) moldm(-3) was the maximum concentration added) from 12 dm3 of water (surface of 8 dm2) within 2 days. It was also found that the sediment released organic ligands responsible for both labile and inert Pb complexes "seen" by voltammetry. The release of organic ligands that decreases the bioavailability of Pb(II) was clearly detected 1 week after contamination. Therefore, the sediment acts as a buffer for lead through two mechanisms against lead contamination: removing lead ions from the solution and releasing organic ligands to the water column. In a short period of time the sediment responds as a self-cleaning system for Pb(II) contamination in the estuarine water, which may have a very important influence in environmental pollution.

The finding of Echinostoma (Trematoda: Digenea) and hookworm eggs in coprolites collected from a Brazilian mummified body dated 600-1,200 years before present.

The identification of parasites from ancient cultures expands our list of parasites infective to extant humans. A partially mummified human body from the archeological site of Lapa do Boquete, Minas Gerais State, Brazil, was recently discovered. It was interred between 600 and 1,200 yr ago. Dietary analysis showed that the mummified body was from a society that had a mixed subsistence of agriculture and gathering of wild foods. Coprolites from the body contained numerous helminth eggs. The eggs were identified as those of Echinostoma sp. and hookworm. Hookworm infection in pre-Columbian populations is already established, but this is the first evidence of Echinostoma sp. eggs found in human coprolites. The diagnosis of a true infection, as opposed to false parasitism, is discussed. The possibility of Echinostoma ilocanum infection is discussed, as this is a common species found in humans in the Asiatic region, which could have been introduced in South America in the pre-Columbian period. Alternative possibilities are also considered, including indigenous Brazilian Echinostoma species.

Influence of serum proteins on erythrocyte uptake of digoxin and digitoxin.

My purpose was to find out whether changes in serum protein content (albumin and gamma globulin) influenced erythrocyte uptake of glycosides and the capacity of erythrocytes to equilibrate glycoside levels when there are changes in protein binding. Heparinized human blood was incubated with 3H-digoxin, 6 ng/ml, and 3H-digitoxin, 44 ng/ml for 15 min. After centrifugation, distribution between plasma and erythrocytes was determined by liquid scintillation. Ratios between erythrocyte and plasma concentrations were 0.84 and 0.11 for digoxin and digitoxin. Replacing plasma by a protein-free isotonic solution led to increased erythrocyte uptake by 15% and 540% for digoxin and digitoxin. Erythrocyte uptake for both drugs was also determined in varying amounts of albumin (0 to 120 gm/l) and gamma globulin (0 to 25 gm/l). Only albumin influenced the erythrocyte uptake of these drugs. Calculations of free and bound plasma levels for both drugs showed that free digitoxin increased when albumin concentrations were equal to or less than 10 gm/l and remained constant (3%) for albumin concentrations between 15 and 120 gm/l. Free digoxin plasma levels rise when the albumin concentration is equal to or less than 15 gm/l and do not change at albumin levels between 30 and 120 gm/l. These data indicate that blood components play an important role in equilibrating changes in free digoxin and digitoxin levels.

Adenosine A2 receptor activation facilitates 45Ca2+ uptake by rat brain synaptosomes.

Adenosine has been shown to increase the release of neurotransmitters by stimulation of adenosine A2 receptors. This effect probably depends on Ca2+ entry into presynaptic nerve terminals. In the present work the ability of the mixed adenosine A1/A2 agonist, 2-chloroadenosine, to stimulate Ca2+ uptake into rat brain synaptosomes was investigated. 45Ca2+ uptake was induced by 20 microM veratridine. In the absence of other drugs, 2-chloroadenosine (1 microM) decreased 45Ca2+ uptake into synaptosomes. Blocking the adenosine A1 receptor with 100 nM of 1,3-dipropyl-8-cyclopentylxanthine (DPCPX), 2-chloroadenosine (1 microM) increased rather than decreased the uptake of 45Ca2+ into synaptosomes. The excitatory effect of 2-chloroadenosine observed in the presence of DPCPX was reversed by 200 nM of omega-agatoxin-IVA, a specific P-type Ca2+ channel antagonist, but not by L-type (nifedipine, 100 nM to 1 microM; methoxyverapamil 1-10 microM) or N-type (omega-conotoxin GVIA, 500 nM) Ca2+ channel antagonists. The adenosine A2A selective agonist 2-p-(2-carboxyethyl)-phenethylamino-5'-N-ethyl-carboxamido-adenosi ne (CGS 21680), did not significantly modify Ca2+ uptake induced by veratridine. In contrast, the selective adenosine A2 receptor agonist, N6-(2-(3,5-dimethoxyphenyl)-2-(2-methylphenyl)ethyl)-adenosine (DPMA), in concentrations ranging from 10 nM to 1 microM increased Ca2+ uptake induced by veratridine. The selective adenosine A2 receptor antagonist 3,7-dimethyl-1-propargylxanthine (DMPX) at a concentration of 10 microM antagonized the stimulatory effect of DPMA (0.1 microM) on 45Ca2+ uptake. In conclusion, activation of adenosine A2 receptors increases Ca2+ uptake by synaptosomes depolarized by veratridine, which could explain the increase of neurotransmitter release observed when A2 receptors are activated.

Adenosine A2A receptors facilitate 45Ca2+ uptake through class A calcium channels in rat hippocampal CA3 but not CA1 synaptosomes.

In the hippocampus, the neuromodulatory role of adenosine depends on a balance between inhibitory A1 responses and facilitatory A2A responses. Since the presynaptic effects of hippocampal inhibitory A1 adenosine receptors are mostly mediated by inhibition of Ca2+ channels, we now investigated whether presynaptic facilitatory A2A adenosine receptors would modulate calcium influx in the hippocampus. The mixed A1/A2 agonist, 2-chloroadenosine (CADO; 1 microM) inhibited veratridine (20 microM)-evoked 45Ca2+ influx into hippocampal synaptosomes of the CA1 or CA3 areas by 24.2 +/- 4.5% and 17.2 +/- 5.8%, respectively. In the presence of the A, antagonist, 1,3-dipropyl-8-cyclopentylxanthine (DPCPX; 100 nM), the inhibitory effect of CADO (1 microM) on 45Ca2+ influx was prevented in CA1 synaptosomes, but was converted into a facilitatory effect (14.2 +/- 6.7%) in CA3 synaptosomes. The A2A agonist, CGS 21680 (3-30 nM) facilitated 45Ca2+ influx in CA3 synaptosomes, with a maximum increase of 22.9 +/- 3.9% at 10 nM, and was virtually devoid of effect in CA1 synaptosomes. This facilitatory effect of CGS 21680 (10 nM) in CA3 synaptosomes was prevented by the A2A antagonist 8-(3-chlorostyryl)caffeine (CSC; 200 nM), but not by the A1 antagonist, DPCPX (20 or 100 nM). The facilitatory effect of CGS 21680 on 45Ca2+ uptake by CA3 synaptosomes was prevented by the class A calcium channel blocker, omega-agatoxin-IVA (200 nM). These results indicate that presynaptic adenosine A2A receptors facilitate calcium influx in the CA3 but not the CA1 area of the rat hippocampus through activation of class A calcium channels.

Effects of purines and forskolin on haemolysis.

Effects of adenosine triphosphate (ATP), adenosine diphosphate (ADP), adenosine monophosphate (AMP), and adenosine on the antihaemolytic action of procaine, and the effect of ATP on the antihaemolytic actions of lidocaine, dibucaine, tetracaine, pentobarbitone, and chlorpromazine were investigated in rat erythrocytes. The effects of adenosine and its analogues D-N6-phenylisopropyladenosine (D-PIA), L-N6-phenylisopropyladenosine (L-PIA), N6-cyclohexyladenosine (CHA), 2-chloroadenosine, and N6-methyladenosine, as well as the effects of cyclic-AMP (cAMP), dibutyryl cAMP, and forskolin on haemolysis were also investigated in rat erythrocytes. ATP, ADP, and AMP, but not adenosine, antagonized in a concentration-dependent manner the antihaemolytic action of procaine, and ATP was ineffective against the antihaemolytic actions of lidocaine, dibucaine, tetracaine, pentobarbitone, and chlorpromazine. Adenosine and its analogues, but not N6-methyladenosine, protected erythrocytes against hypotonic haemolysis in a concentration-dependent manner. The order of potencies was: D-PIA greater than CHA greater than L-PIA greater than adenosine greater than 2-chloroadenosine. The effect of adenosine on haemolysis was not prevented by theophylline, 8-phenyltheophylline, or 8-sulfophenyltheophylline. Dibutyryl cAMP, a stable analogue of cAMP, and forskolin, a specific activator of adenylate cyclase, mimicked the antihaemolytic action of adenosine. cAMP was less efficient than adenosine. Adenine nucleotides antagonized the antihaemolytic action of procaine, probably due to calcium-chelating properties. In contrast, adenine nucleosides have antihaemolytic properties. The possibility that the antihaemolytic effects of these substances relate to cAMP and/or to lipophilicity is discussed.

Complexes of vanadyl and uranyl ions with the chelating groups of humic matter.

The uranyl and vanadyl complexes formed with salicylic, phthalic and 3,4-dihydroxybenzoic acids have been studied by potentiometry in order to determine the stability constants of the M(m)L(n) species formed in solution, and the constants for the hydrolysis and polymeric complexes, at 25.0 degrees , in 0.10, 0.40 and 0.70M sodium perchlorate. MINIQUAD was used to process the data to find the best models for the species in solution, and calculate the formation constants. The uranyl-salicylic acid system was also studied by spectrophotometry and the program SQUAD used to process the data obtained. The best models for these systems show that co-ordination of the uranyl ion by carboxylate groups is easier than for the vanadyl ion, whereas the vanadyl ion seems to form more stable complexes with phenolate groups. Both oxo-cations seem to tend to hydrolyse rather than form complexes when the L:M ratios are greater than unity. Although the change in the constants with ionic strength is small, the activity coefficients of the salicylate and phthalate species have been calculated at ionic strengths 0.40 and 0.70M, along with the interaction parameters with Na(+), from the stability constants found for the species ML and H(2)L, according to the Brønsted-Guggenheim expression.

Uranyl complexes of n-alkanediaminotetra-acetic acids.

The uranyl complexes of n-propanediaminetetra-acetic acid, n-butanediaminetetra-acetic acid and n-hexanediaminetetra-acetic acid have been studied by potentiometry, with computer evaluation of the titration data by the MINIQUAD program. Stability constants of the 1:1 and 2:1 metal:ligand chelates have been determined as well as the respective hydrolysis and polymerization constants at 25 degrees in 0.10M and 1.00M KNO(3). The influence of the length of the alkane chain of the ligands on the complexes formed is discussed.

Uptake of lead and its influence in the alga Selenastrum capricornutum printz.

The influence of nutrient level, hours of fight and the flux of air by volume of solution on uptake of lead has been examined from batch growth experiments carried out with the alga Selenastrum capricornutum Printz. The organic matter released by the alga has been characterized in terms of absorbance at 285 nm, dissolved organic carbon and maximum intensity of fluorescence at the excitation peak. The lability of lead complexes formed with the alga exudates has been investigated in terms of differential pulse anodic stripping voltammetry (DPASV). It has been noticed that lead inhibits the division of the cells which become bigger in size but with less pigment per cell.

Flow amperometric determination of pharmaceuticals with on-line electrode surface renewal.

In this article, a flow system developed for the amperometric determination of a great variety of pharmaceuticals that are known to lead the rapid poisoning of the working electrode surface is described. The referred system was made up of two parallel flow channels that shared the voltammetric detector of tubular configuration, whose movement in the manifold followed the concept of multi-site location of detector. In this way, after each measurement, the conditioning of the working electrode was possible through the passage by its surface of a regeneration solution without implying the alteration of the carrier that flowed in the analytical channel of the manifold. The methodology proposed was evaluated through the determination of two drugs belonging to two distinct therapeutic groups: an antihypertensive (diltiazem) and a non-steroid anti-inflammatory (nimesulide). The results obtained after evaluation of various pharmaceutical formulations on the Portuguese market were in the case of diltiazem compared with those supplied by the reference US Pharmacopoeia XXIV method, with no statistically significant differences having been observed for a confidence interval of 95%. In the case of nimesulide, since no official reference method exists, a series of recovery experiments were proceeded with and a mean value of 101.1% with a R.S.D. of 0.7% was obtained.

Interactions of heavy metals with organisms and proteins.

Voltammetric techniques [differential pulse polarography (DPP) and differential pulse anodic stripping voltammetry (DPASV)] have been used to determine, at various pH, conditional differential functions and average equilibrium constants of copper, zinc and lead with the bacteria Klebsiella pneumoniae and Methanosarcine, the alga Selenastrum capricornutum Printz and the proteins horse-heart cytochrome C and the soluble extract of sulphate-reducing bacteria. The buffer intensity in terms of metal ion and complexing capacity has also been determined. From a comparison of the results a better insight into the groups involved has been obtained.

Metal ion binding by biological surfaces: voltammetric assessment in the presence of bacteria.

Voltammetric techniques (differential pulse polarography (DPP) and differential pulse anodic stripping voltammetry (DPASV)) were evaluated for their capability to distinguish, without prior separation of the solid phase (e.g. filtration, centrifugation), between dissolved and particulate concentrations of Zn(II), Pb(II) and Cu(II), and to measure the extent of binding of these metals to the surface of a bacterium (Klebsiella pneumonia, formaldehyde treated). From titration curves of bacterial cell suspensions with metals the specific adsorption of metals was determined and quantified in terms of average surface complex formation constants and differential equilibrium functions. The following stability sequence for surface complexes was found: Cu2+ greater than Pb2+ greater than Zn2+ much greater than Ca2+. Simultaneous analytical determination permitted the measurement of both the binding of Cu(II) to the cell surface, and the binding to the solute exudate ligands. The affinity of the metal ions for the functional groups of the cell surface is strongly pH-dependent, and, at a given pH, decreases with increasing metal loading of the bacterial surfaces. This indicates that metal ions bind first to the highest affinity surface ligands and subsequently to those of lesser activity. Copper(II) appears to form stronger surface complexes with the high affinity ligands of the bacterial surface than with the functional groups of hydrous oxides.

[Subdural empyema secondary to sinusitis: four pediatric cases]. / Empiema subdural secundario a sinusitis: cuatro casos pediátricos.

INTRODUCTION: Perinasal sinus infections is a common and benign condition in most pediatric cases. Because of the widespread use of antibiotics, intracranial extension of sinusitis is rarely seen today. Nevertheless, the clinician must be aware of the gravity of this condition, because late recognition and delay in treatment can increase mortality and morbidity. The authors made a retrospective study of pediatric patients admitted to Garcia de Orta Hospital between 1996 and 2001 with the diagnosis of subdural empyema and sinusitis. CASE REPORTS: Four patients were identified, with ages between 9 and 13 years. Prodromal manifestations of sinusitis were present in all, followed several days later by headaches, fever, vomiting and neurological abnormalities. Two patients presented in the emergency department with an acute confusional state and a non convulsive status epilepticus. The other two patients had a longer duration of disease, severe deterioration of consciousness and focal neurologic signs. Medical treatment was started in all cases at admission, but none improved significantly before being submitted to surgical intervention, which was repeated several times in two patients. Streptococcus milleri and anaerobic organisms were isolated. There was no mortality and global evolution was favorable, with a median follow up of 32 months. CONCLUSIONS: Clinical presentation of subdural empyema can be relatively inespecific, requiring a high degree of suspicion. Facing a young adolescent with fever of unknown origin associated with any neurological abnormality and previous history of sinusitis, neuroradiological investigation shoul be asked. Early diagnosis and treatment are the mainstays of successful outcome.