Self-monitoring diabetes with multiple mobile health devices

OBJECTIVE

The purpose of this study was to examine the use of multiple mobile health technologies to generate and transmit data from diverse patients with type 2 diabetes mellitus (T2DM) in between clinic visits. We examined the data to identify patterns that describe characteristics of patients for clinical insights.

METHODS

We enrolled 60 adults with T2DM from a US healthcare system to participate in a 6-month longitudinal feasibility trial. Patient weight, physical activity, and blood glucose were self-monitored via devices provided at baseline. Patients also responded to biweekly medication adherence text message surveys. Data were aggregated in near real-time. Measures of feasibility assessing total engagement in device submissions and survey completion over the 6 months of observation were calculated.

RESULTS

It was feasible for participants from different socioeconomic, educational, and racial backgrounds to use and track relevant diabetes-related data from multiple mobile health devices for at least 6 months. Both the transmission and engagement of the data revealed notable patterns and varied by patient characteristics.

DISCUSSION

Using multiple mobile health tools allowed us to derive clinical insights from diverse patients with diabetes. The ubiquitous adoption of smartphones across racial, educational, and socioeconomic populations and the integration of data from mobile health devices into electronic health records present an opportunity to develop new models of care delivery for patients with T2DM that may promote equity as well.

Pilot-scale biofiltration at a materials recovery facility: The impact on bioaerosol control

This study investigated the performance of four pilot-scale biofilters for the removal of bioaerosols from waste airstreams in a materials recovery facility (MRF) based in Leeds, UK. A six-stage Andersen sampler was used to measure the concentrations of four groups of bioaerosols (Aspergillus fumigatus, total fungi, total mesophilic bacteria and Gram negative bacteria) in the airstream before and after passing through the biofilters over a period of 11 months. The biofilters achieved average removal efficiency (RE) of 70% (35 to 97%) for A. fumigatus, 71% (35 to 94%) for total fungi, 68% (47 to 86%) for total mesophilic bacteria and 50% (-4 to 85%) for Gram negative bacteria, provided that the inlet concentration was high (10³-10⁵ cfu m^-3), which is the case for most waste treatment facilities. The performance was highly variable at low inlet concentration with some cases showing an increase in outlet concentrations, suggesting that biofilters had the potential to be net emitters of bioaerosols. The gas phase residence time did not appear to have any statistically significant impact on bioaerosol removal efficiency. Particle size distribution varied between the inlet and outlet air, with the outlet having a greater proportion of smaller sized particles that represent a greater human health risk as they can penetrate deep into the respiratory system where gaseous exchange occurs. However, the outlet concentrations were low and would further be diluted by wind in full scale applications. In conclusion, this study shows that biofilters designed and operated for odour degradation can also achieve significant bioaerosol control in waste gas.

Oxidative Stress and Cardiovascular Risk in Type 1 Diabetes Mellitus: Insights From the DCCT/EDIC Study

Background

Hyperglycemia leading to increased oxidative stress is implicated in the increased risk for the development of macrovascular and microvascular complications in patients with type 1 diabetes mellitus.

Methods and Results

A random subcohort of 349 participants was selected from the DCCT / EDIC (Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications) cohort. This included 320 controls and 29 cardiovascular disease cases that were augmented with 98 additional known cases to yield a case cohort of 447 participants (320 controls, 127 cases). Biosamples from DCCT baseline, year 1, and closeout of DCCT , and 1 to 2 years post‐ DCCT ( EDIC years 1 and 2) were measured for markers of oxidative stress, including plasma myeloperoxidase, paraoxonase activity, urinary F 2α isoprostanes, and its metabolite, 2,3 dinor‐8 iso prostaglandin F 2α . Following adjustment for glycated hemoblobin and weighting the observations inversely proportional to the sampling selection probabilities, higher paraoxonase activity, reflective of antioxidant activity, and 2,3 dinor‐8 iso prostaglandin F 2α , an oxidative marker, were significantly associated with lower risk of cardiovascular disease (−4.5% risk for 10% higher paraoxonase, P <0.003; −5.3% risk for 10% higher 2,3 dinor‐8 iso prostaglandin F 2α , P =0.0092). In contrast, the oxidative markers myeloperoxidase and F 2α isoprostanes were not significantly associated with cardiovascular disease after adjustment for glycated hemoblobin. There were no significant differences between DCCT intensive and conventional treatment groups in the change in all biomarkers across time segments.

Conclusions

Heightened antioxidant activity (rather than diminished oxidative stress markers) is associated with lower cardiovascular disease risk in type 1 diabetes mellitus, but these biomarkers did not change over time with intensification of glycemic control.

Clinical Trial Registration

URL : https://www.clinicaltrials.gov . Unique identifiers: NCT 00360815 and NCT 00360893.

Characterization of non-dialyzable constituents from cranberry juice that inhibit adhesion, co-aggregation and biofilm formation by oral bacteria

An extract prepared from cranberry juice by dialysis known as nondialyzable material (NDM) has been shown previously to possess anti-adhesion activity toward microbial species including oral bacteria, uropathogenic Escherichia coli and Helicobacter pylori. Bioassay-guided fractionation of cranberry NDM was therefore undertaken to identify the anti-adhesive constituents. An aqueous acetone-soluble fraction (NDMac) obtained from Sephadex LH-20 inhibited adhesion-linked activities by oral bacteria, including co-aggregation of oral bacteria Fusobacterium nucleatum with Streptococcus sanguinis or Porphyromonas gingivalis, and biofilm formation by Streptococcus mutans. Analysis of NDMac and subsequent subfractions by MALDI-TOF MS and ¹H NMR revealed the presence of A-type proanthocyanidin oligomers (PACs) of 3-6 degrees of polymerization composed of (epi)catechin units, with some (epi)gallocatechin and anthocyanin units also present, as well as quercetin derivatives. Subfractions containing putative xyloglucans in addition to the mixed polyphenols also inhibit biofilm formation by S. mutans (MIC = 125-250 μg mL^-1). These studies suggest that the anti-adhesion activities of cranberry NDM on oral bacteria may arise from a combination of mixed polyphenol and non-polyphenol constituents.

Arthroscopic Electrothermal Collagen Shrinkage for Symptomatic Laxity of the Scapholunate Interosseous Ligament

The medical records, radiographs and operative reports of ten consecutive patients of average age 37 (range 19–67) years with wrist pain secondary to structural disruption of the scapholunate interosseous ligament (Geissler Type 2 injuries) who were treated with wrist arthroscopy and electrothermal collagen shrinkage of the scapholunate interosseous ligament were reviewed. Functional outcomes were assessed using the DASH scoring system at an average follow-up of 28 (range 12–44) months. At latest follow-up, nine patients (90%) were asymptomatic and had returned to their pre-injury functional level. The mean score on the DASH questionnaire was 20 (range 11–48). One patient developed wrist discomfort and mechanical symptoms 7 months postoperatively and required revision surgery. Our preliminary findings suggest that this may be a viable treatment option in the management of patients with symptomatic scapholunate interosseous ligament laxity without complete ligament disruption. Additional study is needed to better understand the role of this treatment modality.

Efficient graphene saturable absorbers on D-shaped optical fiber for ultrashort pulse generation

We demonstrated a method to construct high efficiency saturable absorbers based on the evanescent light field interaction of CVD monolayer graphene deposited on side-polished D-shaped optical fiber. A set of samples was fabricated with two different core-graphene distances (0 and 1 μm), covered with graphene ranging between 10 and 25 mm length. The mode-locking was achieved and the best pulse duration was 256 fs, the shortest pulse reported in the literature with CVD monolayer graphene in EDFL. As result, we find a criterion between the polarization relative extinction ratio in the samples and the pulse duration, which relates the better mode-locking performance with the higher polarization extinction ratio of the samples. This criterion also provides a better understanding of the graphene distributed saturable absorbers and their reproducible performance as optoelectronic devices for optical applications.

How do radiologists evaluate osteonecrosis?

OBJECTIVES

Management of patients with osteonecrosis of the hip remains controversial and challenging. Because the prognosis and treatment are determined in large part by the stage and extent of the disease, it is important to use a reliable and efficient method for evaluation and staging. The objective of this study was to determine how musculoskeletal (MSK) radiologists evaluate osteonecrosis and whether this evaluation is adequate.

MATERIALS AND METHODS

A 12-part questionnaire was designed to determine how MSK radiologists evaluate patients with osteonecrosis of the femoral head (ONFH). This was sent to 888 members of the Society of Skeletal Radiology.

RESULTS

One hundred and twenty-one members responded to essentially all questions. Patients were evaluated using plain radiographs and MRI. All agreed that it is clinically important to determine the extent of necrosis and joint involvement, and 115 (95 %) stated that this should be part of the radiologists' evaluation. However, only 55 (46 %) said that in practice they used a specific system of classification, and most of these used the Ficat and Arlet classification, which does not indicate the extent of involvement. One hundred and seven (88 %) respondents included a simple visual estimate of the extent of involvement, and a small number added a specific measurement of lesion size. The majority indicated that they were infrequently consulted about which imaging studies should be obtained.

CONCLUSIONS

Although radiologists recognize the clinical importance of determining the extent of necrosis and joint involvement in patients with ONFH, in practice the methods used to evaluate these patients often do not accomplish this satisfactorily. The use of an effective classification, which includes both stage and extent of involvement, should be stressed, as it will lead to improved treatment of patients with ON. Physicians who order imaging studies for patients with ON should be encouraged to consult routinely with their radiology colleagues regarding which studies to request, as well as on the interpretation of these studies.

200 MeV proton radiography studies with a hand phantom using a prototype proton CT scanner

Proton radiography has applications in patient alignment and verification procedures for proton beam radiation therapy. In this paper, we report an experiment which used 200 MeV protons to generate proton energy-loss and scattering radiographs of a hand phantom. The experiment used the first-generation proton computed tomography (CT) scanner prototype, which was installed on the research beam line of the clinical proton synchrotron at Loma Linda University Medical Center. It was found that while both radiographs displayed anatomical details of the hand phantom, the energy-loss radiograph had a noticeably higher resolution. Nonetheless, scattering radiography may yield more contrast between soft and bone tissue than energy-loss radiography, however, this requires further study. This study contributes to the optimization of the performance of the next-generation of clinical proton CT scanners. Furthermore, it demonstrates the potential of proton imaging (proton radiography and CT), which is now within reach of becoming available as a new, potentially low-dose medical imaging modality.

An in vivo method for measuring the adsorption of plasma proteins to titanium in humans

A novel method of collecting in vivo plasma proteins of humans from osteotomies prepared during insertion of an oral implant is described. A rod containing a collecting portion with a predetermined surface is introduced into the osteomy, removed, and transferred for enzyme-linked immunosorbent assay analysis. Two experiments were used to examine the feasibility of the method. In the first, titanium (Ti) rods with different roughness were exposed for 10 min to the blood. Blasted and acid-etched surfaces adsorbed four times more and acid-etched surfaces adosorbed two times more plasma proteins as compared to machined surfaces. In the second experiment, blasted and acid-etched rods were wetted for 10 s prior to the insertion. The adsorption for fibronectin, albumin, fibrinogen, and IgG was enhanced significantly compared with nonwetted rods. These results are discussed in the light of previous methods used in studies on adsorption. Thus, use of the collecting instrument enables aspects of human plasma-implant interface to be studied in a more realistic manner.

Development of a Head Scanner for Proton CT

We describe a new head scanner developed for Proton Computed Tomography (pCT) in support of proton therapy treatment planning, aiming at reconstructing an accurate map of the stopping power (S.P.) in a phantom and, in the future, in patients. The system consists of two silicon telescopes which track the proton before and after the phantom/patient, and an energy detector which measures the residual energy or range of the proton to reconstruct the Water Equivalent Path Length (WEPL) in the phantom. Based on the experience of the existing prototype and extensive Geant4 simulations and CT reconstructions, the new pCT scanner will support clinically useful proton fluxes.

Evaluation of plant and fungal extracts for their potential antigingivitis and anticaries activity

The link between diet and health has lead to the promotion of functional foods which can enhance health. In this study, the oral health benefits of a number of food homogenates and high molecular mass and low molecular mass fractions were investigated. A comprehensive range of assays were performed to assess the action of these foods on the development of gingivitis and caries using bacterial species associated with these diseases. Both antigingivitis and anticaries effects were investigated by assays examining the prevention of biofilm formation and coaggregation, disruption of preexisting biofilms, and the foods' antibacterial effects. Assays investigating interactions with gingival epithelial cells and cytokine production were carried out to assess the foods' anti- gingivitis properties. Anti-caries properties such as interactions with hydroxyapatite, disruption of signal transduction, and the inhibition of acid production were investigated. The mushroom and chicory homogenates and low molecular mass fractions show promise as anti-caries and anti-gingivitis agents, and further testing and clinical trials will need to be performed to evaluate their true effectiveness in humans.

[Influence of gender on the potency and course of action of rocuronium bromide]

OBJECTIVE

The correlation between gender and the potency of certain neuromuscular blockers, including rocuronium, has been investigated. However, the methods used have been inconsistent. This study aimed to look further at the role of gender in order to arrive at definitive conclusions.

PATIENTS AND METHODS

In a first and second phases of the study, rocuronium dose-response curves were constructed for patient groups as follows: 2 mixed-gender groups, 2 female groups, and 2 male groups. One group in each set received a single dose. In the other group the effect of the accumulated dose was measured after each of 3 fractions. The doses were transformed logarithmically. The effect was monitored by electromyography, and probit analysis was used to calculate the effective dose to induce 50%, 90% and 95% of the maximum effect (ED50, ED90 and ED95, respectively) in each patient. In the third phase, a bolus dose of 400 microg-Kg(-1) was administered to 3 additional groups. Onset time, maximum effect, speed of onset, duration of effect as the 10%-25% recovery index, and speed of recovery were recorded. In the fourth phase analysis was restricted to measurements during the period of onset.

RESULTS

No significant between-group differences in mean (SD) ED50, ED90, or ED95 values were observed after single doses (female group: 176 [68], 252 [97], and 285 [110] microg x Kg(-1), respectively; male group: 187 [69], 271 [100], and 307 [114] microg x Kg(-1); mixed group: 172 [73], 233 [98], and 258 [109] microg x Kg(-1)). Assessment of effect after cumulative fracional doses gave the following mean values for ED50, ED90, and ED95: 249 (63), 310 (79), and 334 (85) microg x Kg(-1) for the female group; 261 (60), 327 (75), and 354 (81) microg x Kg(-1) for the male group; and 242 (70), 305 (88), and 330 (95) microg x Kg(-1) for the mixed group. No significant differences in measures of effect were found after bolus administration in the third phase.

CONCLUSIONS

These results suggest that there is no significant effect of gender on potency or course of action of rocuronium bromide. Reports of such differences based on previous studies may be the result of problems in the methods applied.

A novel boundary issue: should a patient be an organ donor for their physician?

It is argued that organ donation from a patient to the patient's physician is ethically dubious because donation decisions will be inappropriately influenced and the negative public perceptions will result in more harm than good. It is suggested that to protect the perception of the physician-patient relationship, avoid cynicism about medicine's attitude to patient welfare and maintain trust in the medical profession, a new professional boundary should be established to prevent physicians from receiving organs for transplantation donated by their patients.

[Correlation between the molar potency of atracurium and its onset time and speed of action]

OBJECTIVE

To study the correlation between the subparalyzing dose of atracurium and its onset time and speed of action.

MATERIAL AND METHODS

Six groups of patients received 0.36, 0.68, 0.98, 1.44, 1.77, or 2.06 times the median effective dose of atracurium. The maximal effect, onset time, molar potency (microM kg(-1)) and speed of action (relationship between time in seconds and percentage of maximum effect and between percentage of maximum effect and time) of each dose were measured. The values were converted to logarithms and square roots to test for correlations. The regression line provided the equation, coefficient of determination (R2), and statistical significance.

RESULTS

The correlation between the logarithms of molar potency and onset time was poor and not statistically significant (R2 = 0.564, P = .138), whereas the correlations between the logarithms of molar potency and speed of action (seg/%) (s/maximum % effect, R2 = 0.952; and maximum % effect/s, R2 = 0.984) were strong and statistically significant (P < .0001) The regression formulas were able to predict the onset time. The results were similar when the values were converted to their square roots.

CONCLUSION

The onset time of a neuromuscular blocker is linked to its effect and its permeability is linked to the size of its molecules or the molar potency, which is dose-dependent. In the case of atracurium, this correlation was poor and not significant. This finding coincides with those of other authors, who found that atracurium was distant from the regression line for equipotent quantities of different neuromuscular blockers. Substituting onset time with speed of action, however, made it possible to establish a strong and significant correlation. Our results suggest that the speed of action of atracurium depends on the size of its molecule.

Acyl-substituted dermaseptin S4 derivatives with improved bactericidal properties, including on oral microflora

The 15-mer dermaseptin S4 derivative S4(1-15) was recently shown to exhibit potent activity against oral pathogens associated with caries and periodontitis. Here, we investigated possible modes for improving the peptide's properties through systematic replacement of an N-terminal amino acid(s) with various fatty acids that modulate the peptide's hydrophobicity and/or charge. Deletion of 1 to 3 residues led to progressive loss of potency as assessed by MIC experiments performed on four test bacteria. Replacing the deleted amino acids with fatty acids most often resulted in potency recovery or improvement, as evidenced by lower MICs and faster bactericidal kinetics in culture media. Best results were obtained after replacement of the N-terminal dipeptide alanine-leucine with heptanoic (C7) or aminododecanoic (NC12) acid. Circular dichroism analysis correlated antibacterial properties to the peptide's secondary structure. MIC experiments and confocal laser scanning microscopy results indicated that C7-S4(3-15) and NC12-S4(3-15) were bactericidal to various oral pathogens, including those which are immobilized in a biofilm. C7-S4(3-15) performed similarly to or better than (depending on growth medium) IB-367, a peptide assessed in clinical trials for treatment of oral mucositis, reducing CFU counts by >3 log units within 2 min of incubation. Collectively, the data indicate that substitution of fatty acids for amino acids may be a useful strategy in revealing improved derivatives of known antimicrobial peptides and suggest the suitability of such compounds for controlling pathogens associated with oral diseases.

In vitro assessment of antimicrobial peptides as potential agents against several oral bacteria

BACKGROUND

Antimicrobial peptides are components of the innate immunity that play an important role in systemic and oral health.

OBJECTIVES

The antibacterial activity of the amphibian-derived K4 -S4(1-15)a antimicrobial peptide was tested against oral pathogens associated with caries and periodontitis and compared with the activities of the human-derived antimicrobial peptides LL-37 and dhvar4a.

METHODS

Growth inhibition of planktonic bacteria was tested using standard microdilution assays. Live/Dead staining followed by confocal scanning laser microscopy (CSLM) was used to determine the bactericidal effect of K4 -S4(1-15)a on Streptococcus mutans attached to a glass surface or grown as biofilm.

RESULTS

The cariogenic species S. mutans, Streptococcus sobrinus, Lactobacillus paracasei and Actinomyces viscosus were resistant to LL-37 found in the oral cavity. Porphyromonas gingivalis was the species most resistant to the three tested peptides. K4 -S4(1-15)a demonstrated the highest activity against the tested planktonic bacteria. In addition, K4 -S4(1-15)a was bactericidal to surface-attached S. mutans as well as to S. mutans biofilms grown in vitro. However, surface attachment increased S. mutans resistance to the antimicrobial peptide.

CONCLUSIONS

Our results support growing evidence suggesting the use of antimicrobial peptides for prevention and treatment of oral disease.

The cytoskeletal network controls c-Jun translation in a UTR-dependent manner

The cytoskeleton is a dynamic network that undergoes restructuring during various cellular events, influencing cell proliferation, differentiation, and apoptosis. Here, we report that accumulation of c-Jun, a member of the AP1 family of transcription factors that play a key role in normal and aberrant cell growth, dramatically increases upon depolymerization of the cytoskeleton, and that, unexpectedly, this increase is controlled translationally. Depolymerization of the actin or microtubule network induces an increase in c-Jun accumulation with no corresponding increase in c-Jun mRNA or in the half-life of the c-Jun protein, but rather in the translatability of its transcript. This increase is mediated by the untranslated regions (UTRs) of c-Jun mRNA, and is not dependent on activated mitogen-activated protein kinase pathways. This novel mechanism of c-Jun regulation might be relevant to physiological conditions in which c-Jun plays a pivotal role.

In vitro binding interactions of oral bacteria with immobilized fructosyltransferase

AIMS

The objective of the present study was to explore the role of immobilized fructosyltransferase (FTF) in adhesion process.

METHODS AND RESULTS

We investigated real-time biospecific interactions between several types of oral bacteria and recombinant FTF immobilized on a biosensor chip, using surface plasmon resonance technology. Streptococcus mutans, Streptococcus sobrinus and Actinomyces viscosus demonstrated significant binding to FTF. Actinomyces viscosus had a greater binding to FTF, with 373 Resonance Units (RU), than the other tested bacteria. The binding level to FTF of Strep. sobrinus was 320 RU, whereas Strep. mutans and Streptococcus salivarious show binding of 296 and 245 RU, respectively. The binding sensograms displayed different profiles for the tested bacteria at various cell density, suggesting a different affinity to immobilized FTF.

CONCLUSIONS

The results from this study suggest that FTF may influence bacterial adherence and colonization of the dental biofilm.

SIGNIFICANCE AND IMPACT OF THE STUDY

The biomolecular interaction analysis enables real-time monitoring of the interaction between adhesions of intact bacteria and their ligands, which might be crucial in the initial phase of biofilm development in vivo.

[Interaction between mivacurium and succinylcholine from a different point of view]

OBJECTIVES

Succinylcholine (SCH) may first be used and continue with mivacurium (MIV). MIV has been suggested as a pretreatment. Conflicting results arises from studies on SCH-MIV interaction. The following trial revisits this interaction.

PATIENTS AND METHODS

The patients were intubated after randomized administration of 100 microg x Kg(-1) of mivacurium (group 1) or 1 mg x Kg(-1) of succinylcholine and, after 50% recovery, 100 microg x Kg(-1) of mivacurium (group 2). A third group received the same regimen as group 2, preceded by pretreatment with 10 microg x Kg(-1) of mivacurium. Maximum effect (MAX), onset time, the 10%-25% recovery index, and duration of effect of mivacurium were determined by electromyography. In groups 2 and 3, the corrected MAX was defined as the difference between the actual MAX effect and the residual block after administration of succinylcholine, and speed of action was defined as the ratio between MAX or corrected MAX and onset time. Data were subjected to analysis of variance and Student-Newman-Keuls and t tests for bivariate comparisons. A value of P less than 0.05 was considered significant.

RESULTS

Groups 2 and 3 had significantly greater MAX effects (97% and 98%, respectively) in comparison with group 1 (93%), shorter onset times (135 and 158 seconds in groups 2 and 3 vs 279 seconds in group 1), and greater speed of action without changes in duration of effect. MAX was halved when corrected (to 47% and 49% in groups 2 and 3, respectively), and speed of action was significantly reduced (from 1.34 and 1.62 seconds/% in groups 2 and 3 respectively, to 2.69 and 3.36 seconds/%). Mivacurium pretreatment did not produce relevant clinical changes.

CONCLUSIONS

When mivacurium is used before the effects of succinylcholine disappear, a residual effect is not usually taken into consideration. This study corrected MAX and calculated speed of action, demonstrating a reduction in net block and speed of action, consistent with an antagonistic action when the 2 blockers are administered sequentially.

The Jerusalem Balsam: from the Franciscan Monastery in the old city of Jerusalem to Martindale 33

The Jerusalem Balsam, a remedy based on an ethanolic extract of a herbal mixture, was formulated in 1719 in the pharmacy of the Saint Savior monastery in the old city of Jerusalem. Having gained fame, the Jerusalem Balsam was replicated and prepared in Europe. One can still find variations of the formula in current pharmacopoeias (B.P., 1998. The Stationary Office, London, p. 1510; Sweetman, S.C., Blake, P.S., McGlashan, J.M., Parsons, A.V., 2002. Martindale: The Extra Pharmacopeia, 33rd ed. Pharmaceutical Press, London, p. 1101). We report here, five different formulas, all referred to as "The Jerusalem Balsam". Three of those formulas were translated and two of these translations are presented in the text. A third one is available as Supplementary data online. As the formulas originate from different historical periods, the Jerusalem Balsam may be a good case study of the development of pharmaceutical formulations over a 250 years period. One of the formulas, found in a manuscript form in the archive of the monastery, contains four plants: olibanum (Boswellia spp.), myrrh (Commiphora spp.), aloe (Aloe sp.) and mastic (Pistacia lentiscus L.). We conducted pharmacological assays on this four-plant formula. It showed anti-inflammatory, as well as anti-oxidative, and anti-septic properties.

[Interaction between vecuronium and atracurium revisited by adapting an alternative method]

OBJECTIVES

Given that contradictory conclusions about the interaction between vecuronium and atracurium have been reached by previous investigators, the present study used an alternative method to analyze this interaction by way of the respective potencies of the two agents and the potency of their combination.

PATIENTS AND METHODS

Effective doses for each relaxant were first calculated by administering small amounts of the agents to 3 similar groups of patients anesthetized with intravenous drugs and ventilated with nitrous oxide. Depression of the first response to train-of-four stimulation was obtained during electromyographic monitoring. That information was used to estimate the mean potency for each individual by an alternative method based on prior knowledge of the slope of the dose-response curve. In another group of patients, fractions equipotent to the median effective dose (ED50) were administered and the same procedure was used to establish the theoretical and calculated potencies of fractionated doses. The algebraic sum of the ratios between the calculated and effective doses was used to define the type of interaction.

RESULTS

The ED50 and the doses giving 90% and 95% efficacy were 24, 38 and 45 microg x Kg(-1) for vecuronium and 144, 234 and 277 microg x Kg(-1) for atracurium. After combination, the new figures were 9, 14 and 17 microg x Kg(-1) for vecuronium and 57, 93 and 110 microg x Kg(-1) for atracurium. The algebraic sums of the ratios between calculated and effective doses were less than 1 for each level of effective dose (0.77, 0.76 and 0.77, respectively), denoting synergism.

CONCLUSIONS

The alternative method presented for analyzing the potency of the individual components of the vecuronium-atracurium interaction demonstrated that their effect is greater after combination and definitively synergistic.

Initial biofilm formation of Streptococcus sobrinus on various orthodontics appliances

Biofilms accumulate on hard and soft surface in the oral cavity. Accumulation of biofilms on orthodontic appliance bear scientific and clinical interest. The objection of this study was to examine the formation of dental biofilm by Streptococcus sobrinus on different types of orthodontics appliances, using a model consisting of host and bacterial constituents. The adsorption pattern of saliva to the orthodontics appliances was determined by means of gel electrophoresis coupled with computerized densitometry techniques. The amount of salivary proteins adsorbed onto the surfaces was measured using the Bradford method. Sucrose-dependent bacterial adhesion to the saliva-coated orthodontics appliances was tested by radioactive-labelled S. sobrinus. Our results show different adsorption patterns of salivary proteins to the various orthodontic appliances as modules, brackets, springs and intra oral elastics. Modules and brackets demonstrated the most affinity to salivary proteins. A surface dependent adhesion profile was recorded, showing a high affinity of albumin and amylase to modules. Bacterial accumulation was the highest on modules compared with springs which demonstrated the least bacterial adhesion. Our study demonstrates the specificity of biofilm formation on the different orthodontic appliances. Formation of a variety of dental biofilms has a significant impact on the progression of dental diseases associated with orthodontic treatment.

[Rocuronium: onset time or speed of action?]

OBJECTIVE

Rocuronium has been said to have an initially rapid onset of action followed by a slower final approach to maximum effect, the supporting data showing only that time to 75% of blockade is more rapid. Expressions of velocity are derived from basic measures such as length and time. The aim of our study was to confirm the onset characteristics of rocuronium by using appropriate expressions of velocity.

PATIENTS AND METHODS

After consenting, 25 adults scheduled for elective surgery were anesthetized, using a bolus dose of rocuronium of 400 microg Kg(-1) for relaxation. Electromyography was used to determine maximal effect, time to reach 80% of a full neuromuscular block, onset time, the time interval between these two points, and the differential blockade produced during each period. Velocity for each period was calculated as the ratio between the percentage of block produced per amount of time elapsed (%/s) during each respective period. The ratio between time and blockade (s/%) was also calculated.

RESULTS

More blockade was produced per second (velocity) during the initial period of activity (0.55%/s) than during the final period (0.109%/s). The average velocity during the onset period overall (0.33%/s) lay between those two figures. Rocuronium requires less time (acting fast) to achieve an initial effect (1.95 s/%) than it does to reach the final effect (10.8 s/%). The ratio of early to late speed of onset was 5.8 +/- 3.5.

CONCLUSION

Using appropriate expressions and calculations, we can unequivocally conclude that rocuronium has a biphasic onset that is initially rapid and then slower. The rate of action is nearly 6 times faster at the beginning.

Bacteriophage isolation from human saliva

AIMS

To detect bacteriophages for Gram-positive oral pathogens in human saliva.

METHODS AND RESULTS

Saliva samples from 31 donors were screened for the presence of bacteriophages for Streptococcus sobrinus, Streptococcus mutans, Streptococcus salivarius, Actinomyces viscosus and Enterococcus faecalis. Bacteriophages for Enterococcus faecalis were found in seven samples. Enterococcus faecalis phages were still present in saliva re-collected from one donor one month, and one year after initial saliva collection.

CONCLUSIONS

The presence and stability of the Enterococcus faecalis bacteriophages in human saliva suggests a possible role of these bacteriophages in the oral ecosystem.

SIGNIFICANCE AND IMPACT OF THE STUDY

Phage therapy as a way to control oral bacteria might be considered.

Formulation, development and characterization of sustained release varnishes containing amine and stannous fluorides

This study describes properties of potential sustained release varnishes (SRV) containing amine fluoride or amine fluoride with stannous fluoride. The release kinetics, antibacterial properties and antiadhesion properties of two potential varnishes were tested. The varnish of ethylcellulose matrix was found to release fluoride for 4 h in vitro, while the formulation based on hydroxypropylmethylcellulose acetate succinate had a rapid release rate. Hydroxyapatite tablets coated with ethylcellulose-based SRV increased adhesion of Streptococcus mutans, while tablets coated with hydroxypropylmethylcellulose acetate succinate-based SRV decreased bacterial adhesion. Both types of SRV demonstrated a strong antibacterial effect on bacteria in biofilm.

Immobilization of fructosyltransferase from Streptococcus mutans on hydroxyapatite surfaces induces the formation of multimeric complexes

AIMS

To investigate the formation of fructosyltransferase (FTF) complexes on hydroxyapatite (HA) surfaces.

METHODS AND RESULTS

Cell-free extracellular FTF from Streptococcus mutans, purified from hyperproducing strain V-1995, was adsorbed onto HA and then eluted from the surface by means of a concentration gradient of potassium phosphate buffer. The FTF monomers loaded onto HA formed, upon adsorption, various complexes ranging from 200 to 700 kDa as demonstrated using native PAGE. All these complexes exhibited enzymatic activity.

CONCLUSIONS

Adsorption of FTF onto HA induced the formation of stable and enzymatically-active complexes.

SIGNIFICANCE AND IMPACT OF THE STUDY

The formation of these complexes may explain the change of FTF catalytic properties after adsorption onto HA. This study is another step in determining the properties of a-cellular constituents of the oral biofilm.

Scavenger receptors, oxidized LDL, and atherosclerosis

Oxidized LDL (OxLDL) competes with oxidatively damaged and apoptotic cells for binding to mouse peritoneal macrophages, implying the presence of one or more common domains. However, the nature of the ligands involved has not been determined. Studies in this laboratory over the last several years provide evidence that oxidized phospholipids, present in OxLDL and also in the membrane of apoptotic cells, represent one such ligand. These oxidized phospholipids, either in the lipid phase of OxLDL or becoming attached covalently to apoprotein B during LDL oxidation, have been shown to play a major role in the binding of OxLDL to CD36 and to SR-B1 expressed in transfected cells. The lipid and protein moieties compete with each other to some extent, indicating that they are binding to at least one common site. A monoclonal antibody selected because of its reactivity with OxLDL proved to be an antibody against oxidized phospholipids (but not native phospholipids). This antibody (EO6) blocked the uptake of OxLDL by CD36 and by SR-B1 in transfected cells by as much as 80%; it also inhibited macrophage phagocytosis of apoptotic cells by about 40%. Thus, the persistence of receptors for OxLDL during evolution is probably accounted for by their role in recognition of ligands on the surfaces of oxidatively damaged or apoptotic cells. This has important implications in biology generally and specifically in atherogenesis, because apoptosis is a prominent feature of late lesions.

Effect of sodium hypochlorite and EDTA on mercury released from amalgam

OBJECTIVES

The effect of sodium hypochlorite (NaOCl) and EDTA on mercury released from dental amalgam was assessed in vitro.

STUDY DESIGN

Fifty-six samples of dental amalgam of similar size were prepared and exposed to a 10-mL solution of either 1% NaOCl, 3% NaOCl, 10% EDTA in 1% NaOCl, or 10% EDTA in 3% NaOCl for periods of 20, 40, and 60 minutes. Mercury concentrations in the solutions were measured by using a cold-vapor atomic absorption Mercury Analyzer System, and the differences between the groups were statistically analyzed.

RESULTS

All amalgam samples exposed to 1% NaOCl and 3% NaOCl-either alone or in combination with EDTA-released mercury into the solutions. Mercury release was significantly higher in the test groups than in the EDTA, distilled water, or phosphate buffer controls (P <.001). Increase in the mean concentration levels of mercury in solution was time-dependent and directly related to NaOCl concentration. The addition of EDTA caused a reduction in mercury levels detected in solution, which was more significant in amalgam samples exposed to 1% NaOCl combined with EDTA (P <.001).

CONCLUSIONS

NaOCl solutions commonly used for root canal cleaning and shaping cause mercury release from dental amalgam and may alter its chemo-physical properties as a sealant for root perforations.

[Effects of non-depolarizing muscle relaxants on the duration of mivacurium]

The interaction between Mivacurium and several muscle relaxants results in a slow recovery. We have previously described that small doses of d-tubocurarine prolong the duration of two successful administrations of Mivacurium. The present investigation was designed to uncover if such an effect could be observed after other neuro-muscular blocking drugs were administered, and if so, its consistency during the different methods of their use. Patients (n = 224) were anesthetized with Enflurane and randomly assigned to two control groups which received 100 micrograms/Kg-1 Mivacurium as a bolus or primed. Other groups received: Rocuronium (60 micrograms/Kg-1), Vecuronium (10 micrograms/Kg-1), Atracurium (60 micrograms/Kg-1), d-tubocurarine (50 micrograms/Kg-1) or Pancuronium (8 micrograms/Kg-1) before, after or as a mixture with 90 micrograms/Kg-1 of Mivacurium. The clinical effect was monitored by electromyography and the results show that all these agents prolong the duration of Mivacurium, the last three in a statistically significant fashion independently of the mode of administration. Current hypothesis are reviewed, but no definitive clues are obtained to explain the present results. Our conclusions must be considered as further research on the interaction between non-depolarizing muscle relaxants and a base for new theories on interactions.

Scavenger receptor class B type I as a receptor for oxidized low density lipoprotein

Scavenger receptor class B type I (SR-BI) has been established as the primary mediator of the selective transfer of lipids from HDL to mammalian cells. In addition to its role in cholesterol metabolism, SR-BI has been shown to bind apoptotic cells and thus could in theory also function as a scavenger receptor. We now show that SR-BI binds oxidized LDL (OxLDL) with high affinity (K(d) of 4.0 +/- 0.5 microg/ml) and mediates internalization and degradation to an extent comparable to that of other scavenger receptors, when normalized to binding activity. The best competitors for OxLDL binding to SR-BI were oxidized lipoproteins, whereas native or acetylated lipoproteins only competed for a small fraction of OxLDL binding. Both the isolated lipids and the isolated protein from OxLDL bound with high affinity to SR-BI and showed partial reciprocal competition. Monoclonal antibody EO6, an antibody against oxidized phospholipids, and 1-palmitoyl-2-(5-oxovaleroyl) phosphatidylcholine (POVPC) both competed effectively with intact OxLDL and with isolated lipids from OxLDL for SR-BI binding.Together, these results demonstrate a potential function of SR-BI, in addition to its role in selective uptake of lipids, to mediate internalization of OxLDL by macrophages and suggest a central role for oxidized phospholipids in this process.

Induction and 3D reconstruction of caries-like lesions in an experimental dental plaque biofilm model

The aim of this study was to examine an in vitro dental plaque model for volumetric assessment and 3D reconstruction of experimentally bacterial induced caries-like lesions. Twenty-three extracted, impacted human molars were coated with a varnish leaving a 3 x 3 mm window on the smooth surface. The teeth were coated with human saliva and Streptococcus sobrinus 6715 adhered onto the enamel via a sucrose dependent mechanism. The coated teeth were incubated for 1, 7, 14 and 28 days. At the end of each incubation period microhardness was measured on three sectioned teeth of each incubation period at the enamel surface and at 450 and 750 microm depth perpendicular to the enamel surface. The enamel surface was investigated by scanning electron microscopy (SEM) prior to embedding and serial sectioning of 12 other teeth. The serial sections were studied with polarization light microscopy to investigate subsurface demineralization. The outlines of the caries-like lesions were then traced consecutively on transparencies, digitized and three-dimensionally reconstructed to demonstrate the expansion of the lesion into enamel for volumetric assessment. Microhardness was significantly reduced on the enamel surface after 7, 14 and 28 days incubation. The SEM investigation showed a surface demineralization with dissolution of the prism cores after 28 days incubation. Polarization light microscopy demonstrated caries-like lesions with an irregular expansion into enamel. The results demonstrate that the described method produces caries-like lesions which can be used for further experimental studies regarding demineralization and remineralization processes.

Testing a degradable topical varnish of cetylpyridinium chloride in an experimental dental biofilm model

Dental biofilms are highly associated with the development of dental caries. Novel drug delivery systems are being developed in order to eliminate cariogenic bacteria from the dental biofilms. We formulated two degradable sustained release varnishes, based on acrylic resin, with cetylpyridinium chloride (CPC) as the active agent. These formulations were tested in a dental biofilm model. The retention of CPC in the biofilm was dependent upon the pharmaceutical additives of the varnish. Both varnishes decreased bacterial adhesion, while also demonstrating marked antibacterial properties against the bacteria in the biofilm.

The oxidative modification hypothesis of atherosclerosis: does it hold for humans?

This review suggests that oxidation of LDL is an important, if not obligatory, event in atherogenesis. The important clinical corollary is that inhibition of oxidation can inhibit atherosclerosis independent of lowering plasma cholesterol levels. This article surveys the extensive data supporting the presence of oxidized LDL in vivo in animal models; the many studies demonstrating that inhibition of oxidation by pharmacologic and/or genetic manipulations retards atherogenesis; the data in humans that supports a role for oxidation of LDL; and the results of intervention trials with antioxidant vitamins. Limitations of these trials that may have led to inconclusive results to date are discussed, and what this may mean for the oxidation hypothesis. The oxidation hypothesis is still viable, but a great deal needs to be learned in order to design the appropriate clinical trials to properly test the importance of oxidation in the pathogenesis of atherosclerosis in humans.