[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.

The LDL modification hypothesis of atherogenesis: an update

The accumulated evidence that oxidative modification of LDL plays an important role in the pathogenesis of atherosclerosis in animal models is very strong. The negative results in recent clinical studies have caused many to conclude that LDL oxidation may not be relevant in the human disease. Yet many of the lines of evidence that support the hypothesis have been demonstrated to apply also in humans. In this review, we briefly summarize the lines of evidence on which the hypothesis rests, its strengths, and its weaknesses.

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.

A diet-induced hypercholesterolemic murine model to study atherogenesis without obesity and metabolic syndrome

OBJECTIVE

Western-type high-fat/high-cholesterol diets used to induce atherogenesis in low-density lipoprotein (LDL) receptor-deficient mice also lead to obesity with concomitant metabolic complications, eg, hypertriglyceridemia, hyperinsulinemia, and insulin resistance. Our aim was to design a diet inducing atherosclerosis through moderate hypercholesterolemia without associated parameters of the metabolic syndrome.

METHODS AND RESULTS

Male LDL receptor-deficient mice were fed regular chow (RC; 0.01% cholesterol/4.4% fat), cholesterol-enriched regular chow (HC; 1% cholesterol/4.4% fat), or Western diet (WD 0.06% cholesterol/21% milk fat) for 28 weeks. HC-feeding led to elevated plasma (approximately 20.7 mmol/L [800 mg/dL]) and LDL cholesterol and accelerated atherosclerosis. Plasma triglycerides were unaffected. Compared with RC-fed controls, HC-fed mice had normal body weight gain and normal fasting levels of glucose, free fatty acids, and insulin. In contrast, WD-fed mice were extremely hypercholesterolemic (>41.4 mmol/L), obese, hypertriglyceridemic, hyperinsulinemic, insulin resistant, and showed adverse health such as skin/fur abnormalities and hepatic steatosis. Although atherosclerotic surface areas in the entire aorta were similar in HC-fed and WD-fed mice, lesions in aortic origin cross sections were significantly larger in WD-fed mice. However, morphology was similar in lesions of equal size.

CONCLUSIONS

The HC diet induced moderate hypercholesterolemia and extensive atherosclerosis and should be useful to study specific aspects of atherogenesis in the absence of confounding effects of the metabolic syndrome.

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.

Thematic review series: the pathogenesis of atherosclerosis. An interpretive history of the cholesterol controversy, part V: the discovery of the statins and the end of the controversy

The first four reviews in this series (Steinberg, D. 2004. J. Lipid Res. 45: 1583-1593; Steinberg, D. 2005. J. Lipid Res. 46: 179-190; Steinberg, D. 2005. J. Lipid Res. 46: 2037-2051; Steinberg, D. 2006. J. Lipid Res. 47: 1-14) traced the gradual accumulation of evidence, evidence of several different kinds, supporting the lipid hypothesis. They tracked the history from Anitschkow's 1913 classic work on the cholesterol-fed rabbit model to the breakthrough 1984 Coronary Primary Prevention Trial, the first large, randomized, double-blind primary intervention trial showing that decreasing blood cholesterol (using cholestyramine) significantly reduces coronary heart disease events. At that point, for the first time, decreasing blood cholesterol levels became an official national public health goal. Still, only a small fraction of patients at high risk were getting appropriate cholesterol-lowering treatment, and a number of important clinical questions remained unanswered. This final review in the series traces the early studies that led to the discovery of the statins and briefly reviews the now familiar large-scale clinical trials demonstrating their safety and their remarkable effectiveness in reducing coronary heart disease morbidity and mortality.

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.

Thematic review series: The Pathogenesis of Atherosclerosis. An interpretive history of the cholesterol controversy, part IV: The 1984 Coronary Primary Prevention Trial ends it—almost

As of the early 1980s, despite the wealth of evidence from experimental animal models, the extensive epidemiologic evidence, the powerful genetic evidence, and the strongly suggestive clinical intervention trial results, most clinicians still remained unpersuaded regarding the relevance of the lipid hypothesis. What was needed was a well-designed, large-scale, long-term, double-blind study demonstrating a statistically significant impact of treatment on coronary heart disease events. The National Institutes of Health (NIH) had laid the groundwork for such a study as early as 1970, but the study was not completed and the results published until 1984. This study, the Coronary Primary Prevention Trial, showed that treatment with a bile acid binding resin reduced major coronary events in hypercholesterolemic men by 19%, with a P value of 0.05. The NIH followed this up with a national Consensus Development Conference on Lowering Blood Cholesterol to Prevent Heart Disease. For the first time, the NIH now went on record advocating screening for hypercholesterolemia and urging aggressive treatment for those at high risk. The Institute initiated a national cooperative program to that end, the National Cholesterol Education Program. For the first time, preventing coronary heart disease became a national public health goal.

Hypercholesterolemia and inflammation in atherogenesis: Two sides of the same coin

An abundance of experimental, clinical, and epidemiologic data capped by stunning interventional results with the statins has established hypercholesterolemia as a major causative factor in atherogenesis. In familial hypercholesterolemia and in animal models it is a sufficient cause. Some degree of hypercholesterolemia, perhaps 30-50 mg/dL, may even be a necessary cause. It is equally clear that from the very beginning atherogenesis has a strong inflammatory component, i. e., it is characterized by penetration of monocytes and of T-cells into the developing lesion. These cells, through the secretion of cytokines and growth factors, through immune responses, and through complex cross-talk with elements of the artery wall modulate the growth of the lesion and affect its stability. But inflammation has to occur in response to something. What is that something? What is the "injury" in "response-to-injury"? The case will be made that oxidized lipids in oxidized LDL or generated in response to prooxidative changes in the cells of the artery wall should be considered a plausible candidate. There is no need to consider hypercholesterolemia and inflammation as alternative hypotheses. Both are very much involved. Optimal intervention and prevention will probably require attention to both.

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.

Thematic review series: The Pathogenesis of Atherosclerosis. An interpretive history of the cholesterol controversy, part III: mechanistically defining the role of hyperlipidemia

In this third installment of the series, we point out that the absence of an explicit, detailed and plausible hypothesis linking hypercholesterolemia to the events in the artery wall was probably an important reason for continuing skepticism and for failure to treat elevated blood cholesterol levels. The rapid advances in understanding of lipoprotein metabolism in the 1950s and 1960s and the application of modern cellular biology in the 1970s provided the context for a modern consensus on pathogenetic mechanisms of atherogenesis.

Phosphocholine as a pattern recognition ligand for CD36

We have previously shown that CD36 recognizes oxidation products of phospholipids on oxidized LDL (OxLDL) such as 1-palmitoyl-2-(5'-oxovaleroyl)-sn-glycero-3-phosphocholine (POVPC). The current study was designed to examine whether the phosphocholine (PC) headgroup in POVPC constitutes an obligatory binding target for CD36. To examine the contribution of PC in the binding of POVPC to CD36, we used well-defined synthetic oxidized phospholipids (OxPLs) cross-linked to BSA or to a hexapeptide. The OxPL adducts were then tested for their ability to bind to CD36-transfected cells and for their ability to inhibit OxLDL binding to CD36. Both POVPC-BSA and POVPC-peptide adducts were high-affinity ligands for CD36 and potent inhibitors of OxLDL binding. Enzymatic removal of the entire PC moiety of the POVPC-peptide, or of the choline headgroup alone, as well as substitution of the choline headgroup by ethanolamine abrogated the inhibitory activity of POVPC. Interestingly, PC by itself or cross-linked to BSA did not show any intrinsic competition activity. In conclusion, our data demonstrate that the PC headgroup of OxPL alone is sufficient for binding to CD36, but only if presented in the correct conformation as in OxPL of OxLDL or as in POVPC-peptide adducts.