The same pattern was found for brown vs white standardized packa

The same pattern was found for brown vs. white standardized packages, with the exception of attractiveness and initiation. Compared with the regular Silk Cut pack, the ‘Superslims’ Silk Cut pack was perceived as significantly more favourable on all six outcomes. buy MK-4827 Finally, among respondents who selected a pack in the pack selection task, 95.1% selected a branded pack vs. 4.9% who selected a standardized pack. Conclusions: Increasing the size of pictorial health warnings and standardizing the appearance and shape of packages may discourage smoking initiation among young people.”

lower rectal cancer, postoperative outcome is still subject of controversy between the advocates of abdominoperineal resection (APR) and low anterior resection (LAR). Reports suggest that low anterior resection may be oncologically superior to abdominoperineal excision, although no good evidence exists to support this. Publications were identified which assessed the differences comparing 5-year survival, local recurrence, circumferential resection SBE-β-CD margin rate, complications and so on. A meta-analysis was performed to clarify the safety and feasibility of the two procedures with several

types of outcome measures. A total of 13 studies met the inclusion criteria, and comprised 6,850 cases. Analysis of these data showed that LAR group was highly correlated with 5-year survival (pooled

OR = 1.73, 95%CI: 1.30-2.29, P = 0.0002 random-effect). And local recurrence rate of APR group was significantly higher than that in LAR group (pooled OR = 0.63, 95%CI: 0.53-0.75, P smaller Z-DEVD-FMK than 0.00001 fixed-effect). Also, the circumferential resection margin (CRM) were high involved in APR group than in LAR group. (5 trials reported the data, pooled OR = 0.43, 95%CI: 0.36-0.52, P smaller than 0.00001 fixed-effect). Besides, the incidents of overall complications of APR group was higher compared with LAR group (pooled OR = 0.52, 95%CI: 0.29-0.92, P = 0.03 random-effect). Patients treated by APR have a higher rate of CRM involvement, a higher local recurrence, and poorer prognosis than LAR. And there is evidence that in selected low rectal cancer patients, LAR can be used safely with a better oncological outcome than APR. due to the inherent limitations of the present study, for example, the trails available for this systematic review are limited and the finite retrospective data, future prospective randomized controlled trials will be useful to fully investigate these outcome measures and to confirm this conclusion.

Main resultsSixteen trials (1748 participants), spanning

\n\nMain results\n\nSixteen trials (1748 participants), spanning four decades and with differing sensitivity to Shigella isolates, met the inclusion criteria. Seven were judged to be at risk of bias due to inadequate allocation concealment or blinding, and 12 due to incomplete reporting of outcome data. Limited data from one three-armed trial of people with moderately severe illness suggest that antibiotics reduce the episodes of diarrhoea at

follow-up (furazolidone versus no drug RR 0.21, 95% CI 0.09 to 0.48, 73 participants; cotrimoxazole versus no drug RR 0.30, 95% CI 0.15 to 0.59, 76 participants).\n\nThere was insufficient evidence to consider any class of antibiotic superior find protocol in efficacy in treating Shigella dysentery, but heterogeneity for some comparisons

limits confidence in the results. All the antibiotics studied were safe. There was inadequate evidence regarding the role of antibiotics in preventing AZD1152 relapses.\n\nAuthors’ conclusions\n\nAntibiotics reduce the duration of Shigella dysentery.\n\nRegularly updated local or regional antibiotic sensitivity patterns to different species and strains of Shigella are required to guide empiric therapy. More trials adhering to standard guidelines are required to evaluate the role of antibiotics in the treatment of severe forms of Shigella dysentery and in groups who are at high risk of complications.”
“Surface-initiated atom transfer radical polymerizations (ATRP) from narrowly size-distributed silica nanoparticles (SiNPs) of diameters less than 100 nm were investigated. Two methods were used for the preparation

of the SiNP cores: one was the reverse-micelle technique, which gave monodisperse SiNPs of average diameter 55 nm, and the other was the lysine-addition technique, which gave nearly monodisperse SiNPs of average diameter 15 nm. These nanoparticles were surface-modified with a triethoxysilane derivative containing an ATRP-initiating group. The surface-initiated ATRP of methyl methacrylate (MMA) mediated by a copper complex was carried out with the initiator-Fixed SiNPs in the presence of a “sacrificial” free initiator. Well-defined poly ethyl methacrylate) (PMMA) brushes of a target molecular weight were successfully grafted with a surface density as high as 0.4-0.8 chains/nm(2). These core-shell hybrid particles were highly dispersible, without any aggregation, in various solvents for PMMA. Because of the exceptionally high uniformity and perfect dispersibility, these hybrid particles formed two- and three-dimensional ordered arrays at the air-water interface and in suspension, respectively.”
“Three allelic short root mutants were identified by screening mutants with defective root elongation of the rice japonica cultivar Nipponbare mutant library generated via (60)Co gamma-ray irradiation mutagenesis.

Driving glucose to its complete oxidation inside the mitochondria

Driving glucose to its complete oxidation inside the mitochondria has potential in cancer therapy to reconstitute

apoptotic Competence in tumor cells and, in mitochondrial disease, to treat lactic acidosis. This minireview investigates AZD1480 research buy the development of small molecule agents for suppressing the Warburg effect in cancer therapy and lactic acidosis in mitochondrial disease. Drug Dev Res 70: 499-511, 2009. (C) 2009 Wiley-Liss, Inc.”
“Ubiquitin thioester is a key intermediate in the ubiquitylation of proteins and is formed enzymatically through the activation of alpha-COOH of ubiquitin in an ATP dependent manner using the E1 enzyme. The current methods used for the preparation of ubiquitin thioester rely on either the enzymatic machinery or on expressed protein ligation technology. In this article, we report a new chemical strategy, combining native chemical ligation and N-methylcysteine containing peptides, to chemically prepare ubiquitin thioester for the first time. The N-methylcysteine is utilized as an N -> S acyl transfer device, and in its protected form serves as a latent thioester functionality. This enabled us to trigger the formation of ubiquitin

thioester subsequent to the assembly of the ubiquitin polypeptide via native chemical SB202190 MAPK inhibitor ligation. The synthetic ubiquitin thioester showed a similar behavior in peptide ubiquitylation to the one obtained via expression. This approach should allow for higher flexibility in the chemical manipulation of ubiquitin thioester in a wide variety of ubiquitylated peptides and proteins for structural and biochemical analysis and for the synthesis of ubiquitin chains.”
“Study objective:

This study sought to determine and compare the utility of the Airway scope (AWS; Pentax Corporation, Tokyo, Japan) and the conventional Macintosh laryngoscope (MLS) for intubation in the prehospital setting.\n\nMethods: In this randomized controlled trial in the prehospital setting, the primary outcome was time required for intubation, and the secondary outcomes were ultimate success, first attempt success, and difficulty of intubation. The intent-to-treat principle was used to analyze time to intubation. Ultimate success was defined as intubation Selleck AG-14699 completed within 600 s regardless of the device ultimately used.\n\nResults: A total of 109 patients, primarily with cardiac arrest, were randomly assigned to the AWS or MLS arms. Median time (interquartile range) to intubation was 155 (71-216) s with the AWS versus 120 (60-170) s with the MLS (P=.095). Ultimate success rate was slightly lower with the AWS (96.4%) than with the MLS (100%) (P=.496), while the first attempt success rate was significantly lower (46% and 75%, respectively; P=.002). There was no significant difference in difficulty of intubation (P=.066).

However although EVAR offers immediate advantages over open surgi

However although EVAR offers immediate advantages over open surgical repair, it carries the need of close lifelong AZD1208 surveillance due to specific possible complications including rupture, endoleaks, graft migration and enlargement of aneurysm sac size. Contrast Enhanced Computed Tomography [CTA] is actually considered the standard reference in EVAR follow-up. However CTA carries high costs, radiation exposure and potential renal impairment. In the last five years several studies have been published on the role of Contrast Enhanced UltraSound [CEUS] in EVAR follow-up asserting

high accuracy of this evaluation technique with absence of renal impairment, without radiation risk and at low costs. Especially since introduction of second generation Contrast Agents this evaluation technique is gaining popularity in EVAR follow-up surveillance. The diffusion of CEUS investigations by using new generation of contrast medium with appropriate software represents without any doubt an important step in the EVAR surveillance and could open up new strategies in the evaluation of endovascular aortic procedures gaining a fundamental role in EVAR follow-up.”
“Amyloid-beta and tau are the two hallmark proteins in Alzheimer’s disease. Although both amyloid-beta and tau have been extensively

studied individually with regard to their separate modes of toxicity, more recently new light has been shed on their possible interactions and synergistic effects in Alzheimer’s disease. Here, we review novel

findings that have shifted our understanding of the role of tau in the pathogenesis of Alzheimer’s disease GSK2126458 towards being a crucial partner of amyloid-beta. As we gain a deeper understanding of the different cellular functions of tau, the focus shifts from the axon, where tau has a principal role as a microtubule-associated protein, to the dendrite, where it mediates amyloid-beta toxicity.”
“An increasing amount of data provides support for the hypothesis that periventricular leukomalacia (PVL) results from pre-or perinatal hypoxia occurring and is a major cause of cerebral palsy. In this work, anoxic and hypoxic-ischemic brain injuries were observed by us, after injection of neurotoxin 3-nitropropionic acid (3-NP) in a neonatal rat model on postnatal day 5 (P5). 3-NP-induced brain injury was examined in fixed brain sections at 24 h (P6), 48 h (P7), 72 h (P8), and 9 days (P74) after 3-NP injection, respectively. Injection with 3-NP results in pathological injuries including white matter lesions, cerebral cortex destruction, callose thinness, and cerebral ventricle expansion. Numbers of immature oligodendrocytes turned to less in the model of 3-NP. Furthermore myeline basic protein expression became significantly lower after 3-NP was injected. Pathological changes after injection of 3-NP appeared also significantly among rats of postnatal day 5.

Human herpesvirus 8 (HHV-8) appears to be the causative factor fo

Human herpesvirus 8 (HHV-8) appears to be the causative factor for the development of this neoplasm. Transplant programs are concerned about the frequencies of HHV-8 infection either in general population or transplant patients.\n\nMethods: The current study was conducted in two phases. Firstly, we detected antibodies against HHV-8 in 790 otherwise healthy blood donors. Secondly, a total of 125 kidney allograft recipients evaluated as being seropositive for HHV-8. We utilized enzyme immunoassay (EIA) for serologic studies.\n\nResults: Among blood donors, the male to female ratio was 1.05 (405 vs.

385) while the mean age was 38.9 +/- 11.7 years. The serostatus of none of these blood donors INCB024360 were positive for HHV-8. Among kidney recipients, the male to female ratio was 1.9 (82 vs. 43). The mean age was 39.01 +/- 14.77 years. Two (1.6%) patients were seropositive for HHV-8.\n\nConclusion: The prevalence of HHV-8 infection

among Iranians is likely to be low. Yet, owing to the evidence of this infection among kidney allograft recipients and its probable role in developing post-transplantation KS (PT-KS), further studies appear to be required to keep the various aspects of this infection under close surveillance.”
“Swine skin is one of the best structural models for human Savolitinib manufacturer skin, widely used to probe drug transcutaneous passage and to test new skin vaccination devices. However, little is known about its composition in immune cells, and among them dendritic BKM120 nmr cells (DC), that are essential in the initiation of the immune response. After a first seminal work describing four different DC subpopulations in

pig skin, we hereafter deepen the characterization of these cells, showing the similarities between swine DC subsets and their human counterparts. Using comparative transcriptomic study, classical phenotyping as well as in vivo and in vitro functional studies, we show that swine CD163(pos) dermal DC (DDC) are transcriptomically similar to the human CD14(pos) DDC. CD163(pos) DDC are recruited in inflamed skin, they migrate in inflamed lymph but they are not attracted toward CCL21, and they modestly activate allogeneic CD8 T cells. We also show that CD163(low) DDC are transcriptomically similar to the human CD1a(pos) DDC. CD163(low) DDC migrate toward CCL21, they activate allogeneic CD8 and CD4 T cells and, like their potential human lung counterpart, they skew CD4 T cells toward a Th17 profile. We thus conclude that swine skin is a relevant model for human skin vaccination.”
“We investigated the hypoglycemic and hypolipidemic effects of two hesperertin glycosides, namely, hesperidin and cyclodextrin (CD)-clathrated hesperetin, in Goto-Kakizaki (GK) weanling rats with type 2 diabetes.

3% in intrinsic apoptosis of lymphocytes was found in the supplem

3% in intrinsic apoptosis of lymphocytes was found in the supplemented groups of young and elderly people compared with their control groups (all p values <0.001), but no significant decrease in children.

Moreover, percentages UV-induced apoptosis significantly decreased by 1.4%, 1.9% and 3.1% in children, young and elderly people, respectively, compared with control groups after the trial. There were considerable increments in concentrations of plasma beta-carotene, retinol, tocopherol, VS-6063 ascorbic acid and selenium in all three treated groups after the supplementation. Conclusions: Young and elderly people have a higher intrinsic apoptosis than children, which was improved by antioxidant supplementation. UV-induced damage was attenuated by the supplementation in all three age groups.”
“It is necessary to form fine holes and grooves by machining in the

manufacture of equipment in the medical or information field and the establishment of such a machining technology is required. In micromachining, the use of the ultrasonic vibration cutting method is expected and examined. In this study, I experimentally form microgrooves in stainless steel SUS304 by the ultrasonic vibration cutting method and examine the effects of the shape and material of the tool on the machining accuracy. As a result, the following are clarified. The evaluation of the machining accuracy of the straightness of the finished surface Selleck Tariquidar revealed that there is an optimal rake angle of the tools related to the increase in cutting resistance as a result of increases in work hardening and the cutting area. The straightness this website is improved by using a tool with low flexural rigidity. In particular, Young’s modulus more significantly affects the cutting accuracy than the shape of the tool. (C) 2010 The Japan Society of Applied Physics”
“Genetic polymorphisms in the RAD51 gene may be associated with increased cancer risk. The aim of the present study was to evaluate associations between the risk of ovarian cancer and 135G bigger than C (rs1801320) and 172G bigger than T (rs1801321) polymorphisms in the RAD51 gene. We analysed

the distribution of genotypes and frequency of alleles of the RAD51 polyrnorphisms in 210 women with ovarian cancer and 210 healthy controls. Both polymorphisms were genotyped by restriction fragment length polymorphism-polymerase chain reaction (PCR-RFLP). In the present study only 135G bigger than C polymorphism of the RAD51 gene was associated with ovarian cancer risk. The distribution of genotypes for 135G bigger than C in ovarian cancer patients vs. controls was: 20% vs. 30% for G/G, 22% vs. 47% for G/C, and 58% vs. 23% for C/C genotype, respectively. We found evidence of an increased ovarian cancer risk in C/C homozygotes but not in heterozygotes. The 135C allele of RAD51 increased cancer risk. In the present work we demonstrated a significant positive association between the RAD51 135G bigger than C polymorphism and ovarian carcinoma in Poland.

GST expression data were compared to those for metallothionein (M

GST expression data were compared to those for metallothionein (MT), a prototypical biomarker of metal exposure. Data mining of genomic databases find more led to the development of quantitative real-time PCR (qPCR) assays for salmon GST isoforms encompassing 9 subfamilies, including alpha, mu, pi, theta,

omega, kappa, rho, zeta and microsomal GST. In vivo acute (8-48 h) exposures to low (3.7 ppb) and high (347 ppb) levels of Cd relevant to environmental scenarios elicited a variety of transient, albeit minor changes (<2.5-fold) in tissue GST profiles, including some reductions in GST mRNA expression. In general, olfactory GSTs were the earliest to respond to cadmium, whereas, more pronounced effects in olfactory and gill GST expression were observed at 48 h relative to earlier time points. Although evaluation of GSTs reflected a cadmium-associated oxidative stress response, there was no clear GST isoform in any tissue that could serve as a reliable biomarker of acute cadmium exposure. By contrast, metallothionein (MT) mRNA was consistently and markedly induced in all three tissues by cadmium, and among the tissues examined, olfactory MT was the

most sensitive marker of cadmium exposures. In summary, coho salmon exhibit a complex GST tissue profile consisting of at least 9 isoforms, all of which are present in the peripheral olfactory system. Short-term exposure to environmental levels of Cd causes transient changes in salmon GST consistent with oxidative stress, and in some cases, includes a loss of GST. In a biomarker context, however, monitoring of tissue Rabusertib purchase MT mRNA expression, especially in the peripheral Panobinostat clinical trial olfactory system, may be of greater utility for assessing short-term environmental exposures to

cadmium. (C) 2011 Elsevier B.V. All rights reserved.”
“Hepatitis C virus (HCV) infection is probably the most common chronic viral infection and affects an estimated 180 million people worldwide, accounting for 3% of the global population. Although the liver is considered to be the primary target, extrahepatic manifestations are well recognized among patients with chronic HCV infection. Epidemiological studies have clearly demonstrated a correlation between chronic HCV infection and occurrence of B-cell non-Hodgkin’s lymphomas (B-NHL). The clinical evidence that antiviral therapy has a significant role in the treatment at least of some HCV-associated lymphoproliferative disorders, especially indolent B-NHL, further supports the existence of an etiopathogenetic link. However, the mechanisms exploited by HCV to induce B-cell lymphoproliferation have so far not completely clarified. It is conceivable that different biological mechanisms, namely, chronic antigen stimulation, high-affinity interaction between HCV-E2 protein and its cellular receptors, direct HCV infection of B-cells, and “hit and run” transforming events, may be combined themselves and cooperate in a multifactorial model of HCV-associated lymphomagenesis.

The calculation of prognostic indices did not provide additional

The calculation of prognostic indices did not provide additional discriminative power. Copyright (C) 2012 S. Karger AG, Basel”
“Objective: The purpose of this study was to determine the frequency of chromosomal anomalies among the fetuses with isolated and non-isolated aberrant right subclavian artery (ARSA), and to evaluate the sonographic findings associated with ARSA. Methods: This is a retrospective study conducted during the period between January 2008 and December 2012 at the maternal fetal medicine units of three different referral centers. Results: Among

the 148 cases of ARSA, 98 were isolated and 50 were associated with cardiac anomalies, extracardiac malformations or soft markers. Trisomy 21 was the only chromosomal anomaly EX 527 mouse with a prevalence of 6.8% (10/148). The corresponding rate was 6.1% (6/98) and 8% (4/50) for isolated and non-isolated ARSA, respectively. Cardiac anomalies, extracardiac findings and soft markers were detected in 5.4% (8), 10.8% (16) and 24.3%

(36) of cases, respectively. Among the 10 fetuses with trisonny 21, 6 were find more isolated, 4 were associated with soft markers, 2 were associated with fetal growth restriction and 1 was associated with hydrops fetalis. Cardiac anomalies were not observed in any of these fetuses. Conclusion: The prenatal diagnosis of ARSA should prompt meticulous anatomic survey, and karyotype analysis might be offered even in the absence of associated findings. Copyright (C) 2013 S. Karger AG, Basel”
“Background: Cytomegalovirus (CMV) infection is now the commonest congenital form of infective neurological handicap, recognized by the Institute of Medicine as the leading priority for the developed world in congenital infection. In the absence of an effective vaccine, universal screening for CMV in pregnancy has been proposed, in order that primary infection could be diagnosed and-potentially-the burden of disability due to congenital CMV prevented.\n\nDiscussion: Universal screening for CMV to identify seronegative JIB-04 manufacturer women at the beginning of pregnancy

could potentially reduce the burden of congenital CMV in one of three ways. The risk of acquiring the infection during pregnancy has been shown to be reduced by institution of simple hygiene measures (primary prevention). Among women who seroconvert during pregnancy, CMV hyperimmune globulin (CMV HIG) shows promise in reducing the risk of perinatal transmission (secondary prevention), and CMV HIG and/or antivirals may be effective in reducing the risk of clinical sequelae among those known to be infected (tertiary prevention). The reports from these studies have re-ignited interest in universal screening for CMV, but against the potential benefit of these exciting therapies needs to be weighed the challenges associated with the implementation of any universal screening in pregnancy.

This article reports a new case of this unusual neoplasm in a

\n\nThis article reports a new case of this unusual neoplasm in a 66 year-old woman in which the main complaint was an asymptomatic swelling located in the right body of mandible. Histopathological findings were similar to the two previously reported cases DZNeP Epigenetics inhibitor of this tumor. Positive immunohistochemical stain for laminin V and type IV collagen suggests an inductive effect of the epithelium over the stroma while the low index of p53 protein and Ki-67 expression in epithelium and stromal cells, as well as CD138 uniform positive-stain in epithelial cells, support the benign biological behavior of this lesion. Including

this new case, currently there are only three reports of this rare neoplasm. Reports of new cases of peripheral desmoplastic ameloblastoma are necessary

for a better understanding of the origin and behavior of this particular subtype of ameloblastoma.”
“Root border cells are a population of rhizosphere cells surrounding the root tips but separated from them. The root tip is a major target of Fe2+ toxicity; thus, it was hypothesized that the border cells might protect or exacerbate Fe2+ toxicity. To explore the effects of excess Fe2+ on the border cells in rice (Oryza sativa L.), experiments were carried out using the border cells in vitro (Shanyou No. 10). The border cells were precultured under “hanging in the air” and detached from the root tips. The shape, numbers, and viability

Selleckchem CT99021 of border cells were examined during exposure Bindarit in vitro to toxic levels of Fe2+. When the root was 1 mm long, there were 205 border cells on average. With the growth of the root, more border cells were observed. When the root grew to 25 mm long, the total number of border cells reached a maximum, while the maximum activity of border cells appeared when the root was 20 mm long. The pectin methyl esterase (PME) activity of the root cap peaked at a root length of 2 mm. Border cell development was related to PME activity in rice. Excessive Fe2+ was toxic to detached border cells. After treatment with 200 mu M Fe2+ solution for 48 h, cell viability decreased by 72.70%. However, when treated with 400 mu M Fe2+ solution, the number of viable cells was actually higher, suggesting the induction of a cellular self-protection response. The activity of PME first increased under high concentrations of Fe2+ and then decreased. These results indicate that toxic levels of Fe2+ modulate PME activity and border cell survival.”
“Oropharyngeal candidiasis is a common opportunistic infection of the oral cavity caused by an overgrowth of candida species, the commonest being Candida albicans. The prevalence in the hospital or institution varies from 13 to 47% of elderly persons. The main clinical types are denture stomatitis, acute atrophic glossitis, thrush and angular cheilitis. Diagnosis is usually made on clinical ground.

In addition, we correlated the mutational data with p53 immunosta

In addition, we correlated the mutational data with p53 immunostaining to determine the role of p53 immunoreactivity as a surrogate for TP53 mutations in histological diagnosis. Somatic TP53 mutations were detected in all 29 HGSCs analysed and the identical mutations were detected in 27 of 29 pairs of STICs and concurrent

HGSCs. Missense mutations were observed in 61% of STICs and frameshift/splicing junction/nonsense mutations in 39%. Interestingly, there were two HGSCs with two distinctly different TP53 mutations each, but only one of the mutations was detected in the concurrent STICs. Missense mutations were associated with intense and diffuse (= 60%) p53 nuclear immunoreactivity, while most of the null mutations were associated with complete loss of p53 staining (p < 0.0001). Overall, this p53 staining Akt inhibitor pattern yielded a sensitivity of 87% and a specificity of 100% in detecting TP53 missense mutations. In conclusion, the above findings support the clonal relationship of STIC and pelvic HGSC and demonstrate the utility of p53 immunostaining as a surrogate for TP53 mutation in the histological diagnosis of STIC. In this regard, it is important to appreciate the significance of different

staining patterns. Specifically, strong diffuse staining correlates with a missense mutation, whereas complete absence of staining correlates with null mutations. Copyright (C) 2012 Pathological Society of Great Britain and Ireland. Published by John see more Wiley & Sons, Ltd.”
“Kawasaki disease (KD) is an acute vasculitis of childhood that predominantly

affects the coronary arteries. We investigated single nucleotide polymorphisms (SNPs) of the tryptophan hydroxylase 2 (TPH2) gene as risk factors for KD with coronary artery lesions (CALs) in Korean children. We genotyped two SNPs [rs7305115 (exon 7) and rs4290270 (exon 9)] using direct sequencing in 101 KD and 256 control subjects. To analyze the genetic data, SNPStats, SNPAnalyzer, and Helixtree programs were used. The genotype analysis of rs7305115 and rs4290270 showed no significant differences between KD and control groups. However, we found a statistically significant association between the two SNPs and the development of CALs in KD (p < 0.05). The minor homozygous genotype (rs7305115, AA genotype and rs42901270, AA genotype) of each SNP showed increased susceptibility to risk of CALs in KD patients. These results suggest that TPH2 may be associated with the development of KD with CALs in Korean children.”
“Introduction: The center of resistance is considered the most important reference point for tooth movement. It is often stated that forces through this point will result in tooth translation. The purpose of this article is to report the results of numeric experiments testing the hypothesis that centers of resistance do not exist in space as 3-dimensional points, primarily because of the geometric asymmetry of the periodontal ligament.