Distribution by Scientific Domains
Distribution within Medical Sciences

Terms modified by Kruskal

  • kruskal Walli test

  • Selected Abstracts

    Regional variations in action potential alternans in isolated murine Scn5a+/, hearts during dynamic pacing

    ACTA PHYSIOLOGICA, Issue 2 2010
    G. D. K. Matthews
    Abstract Aim:, Clinical observations suggest that alternans in action potential (AP) characteristics presages breakdown of normal ordered cardiac electrical activity culminating in ventricular arrhythmogenesis. We compared such temporal nonuniformities in monophasic action potential (MAP) waveforms in left (LV) and right ventricular (RV) epicardia and endocardia of Langendorff-perfused murine wild-type (WT), and Scn5a+/, hearts modelling Brugada syndrome (BrS) for the first time. Methods:, A dynamic pacing protocol imposed successively incremented steady pacing rates between 5.5 and 33 Hz. A signal analysis algorithm detected sequences of >10 beats showing alternans. Results were compared before and following the introduction of flecainide (10 ,m) and quinidine (5 ,m) known to exert pro- and anti-arrhythmic effects in BrS. Results:, Sustained and transient amplitude and duration alternans were both frequently followed by ventricular ectopic beats and ventricular tachycardia or fibrillation. Diastolic intervals (DIs) that coincided with onsets of transient (tr) or sustained (ss) alternans in MAP duration (DI*) and amplitude (DI,) were determined. Kruskal,Wallis tests followed by Bonferroni-corrected Mann,Whitney U -tests were applied to these DI results sorted by recording site, pharmacological conditions or experimental populations. WT hearts showed no significant heterogeneities in any DI. Untreated Scn5a+/, hearts showed earlier onsets of transient but not sustained duration alternans in LV endocardium compared with RV endocardium or LV epicardium. Flecainide administration caused earlier onsets of both transient and sustained duration alternans selectively in the RV epicardium in the Scn5a+/, hearts. Conclusion:, These findings in a genetic model thus implicate RV epicardial changes in the arrhythmogenicity produced by flecainide challenge in previously asymptomatic clinical BrS. [source]

    Radiation-induced changes in oral carcinoma cells , a multiparametric evaluation

    CYTOPATHOLOGY, Issue 5 2003
    L. Bindu
    The aim of this study was to see whether serial cytological evaluation of various cellular abnormalities in tumours from patients receiving fractionated radiotherapy can predict radio-response in oral carcinoma. Cytological assessment was carried out in scrape smears collected prior to and during the course of radiotherapy in 68 patients with squamous cell carcinoma of the oral cavity planned for radical radiotherapy with accelerated fraction schedule. Smears were evaluated for a set of 15 radiation-induced cellular abnormalities. The relationship between the cellular alterations and the cumulative radiation dose was analysed by Kruskal,Wallis one-way anova. The results showed that among the various quantifiable changes that occur in irradiated cancer cells, karyolysis, karyorrhexis, pyknosis, cytolysis, multinucleation, micronucleation and nuclear budding show significant increase depending on the dose of radiation. The radio-resistant group of patients exhibited a lesser degree of change compared with the radio-sensitive group. This suggests that radio-resistance may be due to the defective induction of cell damage and that these cytological features may have potential use as predictive markers of radio-sensitivity in oral carcinoma. [source]

    Effect of temperature and storage media on human periodontal ligament fibroblast viability

    Beatriz Dulcineia Mendes Souza
    The purpose of this study was to compare the effectiveness of several storage media to preserve cultured periodontal ligament fibroblasts (PDLF) under different temperatures. The media tested were: sterile Hank's balanced salt solution (sHBSS), non-sterile HBSS (nHBSS), skimmed milk, Save-A-Tooth®, Minimum Essential Medium (MEM) and water (negative control). MEM at 37°C was used as positive control. PDLF were obtained from explants of extracted healthy human teeth. Plates containing confluent PDLF were soaked in the various media for 3, 6, 24, 48 and 72 h at 37°C and 20°C. After incubation, viability of the cells was determined using the tetrazolium salt-based colorimetric (MTT) assay and the Trypan Blue exclusion test after 6, 24, 48 and 72 h of incubation at 20°C. The results were analyzed statistically using Kruskal,Wallis, Scheffé and Mann,Whitney (, = 5%) tests. Results from the MTT assay at 37°C and 20°C showed that skimmed milk was the best storage medium for up to 24 and 48 h, respectively, followed by nHBSS and sHBSS. Results from the Trypan Blue exclusion test showed that the best storage media were milk, sHBSS and nHBSS, with no statistical differences, for any time period. The Save-A-Tooth® had a detrimental effect on cells after 24 h. The influence of temperature on the effectiveness of the storage media tested showed at 20°C a decreasing order of efficacy as follows: milk > sHBSS and nHBSS > MEM > Save-A-Tooth® > water while at 37°C it was: MEM > nHBSS > milk > sHBSS > Save-A-Tooth® > water. In conclusion, incubation temperature altered the effectiveness of the storage media and skimmed milk at 20°C was better than HBSS in maintaining PDLF viability. [source]

    Comparison of acidic fibroblast growth factor on collagen carrier with calcium hydroxide as pulp capping agents in monkeys

    Zhimei Li
    Abstract,,, Acidic fibroblast growth factor (aFGF) has been shown to facilitate wound healing by stimulating fibroblast proliferation and angiogenesis. It has also been reported to possess a powerful anti-apoptotic function This study compared the histological pulp responses to aFGF on collagen carrier and Ca(OH)2 placed on the mechanically exposed dental pulp in monkeys at two observation periods. Thirty-six teeth with pulp exposures were distributed into three groups according to the capping agents used prior to application of the coronal seal: collagen-based matrix carrier (group 1), aFGF on the collagen-based matrix carrier (group 2) and aqueous calcium hydroxide [Ca(OH)2] paste (group 3). Specimens were harvested at 6 and 13 weeks postoperatively and prepared for hematoxylin and eosin, and Gram staining. Histological qualitative evaluation of pulp responses were performed under the light microscope following criteria modified from Cox et al. (17) and Hu et al. (18). Semi-quantitative analysis was also carried out using Kruskal,Wallis and Mann,Whitney U -tests. There was neither negligible inflammatory infiltrates with no bacteria present in the three groups at both timings, nor was there any significant difference in the soft tissue organization among the three groups at or between the 6- and 13-week observation periods. At 6 weeks, the hard tissue barrier produced by Ca(OH)2 group (1.040 ± 0.089) was significantly more superior than aFGF/collagen carrier group (1.930 ± 0.825) (P = 0.030) as well as collagen carrier group (3.142 ± 1.069, P = 0.018). At 13 weeks, both aFGF/collagen carrier group (1.214 ± 0.485) and the collagen carrier group (1.457 ± 0.814) produced significantly better hard tissue barrier (P = 0.040 and P = 0.017, respectively) than earlier timing. However, these two groups did not induce significantly improved hard tissue barrier compared to that produced by aqueous Ca(OH)2 paste which stimulated matrix secretion in a polar tubular dentin-like pattern. [source]

    Emergency Department Treatment of Viral Gastritis Using Intravenous Ondansetron or Dexamethasone in Children

    Christine M. Stork PharmD
    Abstract Objectives To compare the efficacy of intravenous ondansetron or dexamethasone compared with intravenous fluid therapy alone in children presenting to the emergency department with refractory vomiting from viral gastritis who had failed attempts at oral hydration. Methods This double-blind, randomized, controlled trial was performed in a tertiary care pediatric emergency department. Children aged 6 months to 12 years presenting with more than three episodes of vomiting in the past 24 hours, mild/moderate dehydration, and failed oral hydration were included. Patients with other medical causes were excluded. Subjects were randomized to dexamethasone 1 mg/kg (15 mg maximum), ondansetron 0.15 mg/kg, or placebo (normal saline [NS], 10 mL). All subjects also received intravenous NS at 10,20 mL/kg/hr. Oral fluid tolerance was evaluated at two and four hours. Those not tolerating oral fluids at four hours were admitted. Discharged patients were evaluated at 24 and 72 hours for vomiting and repeat health care visits. The primary study outcome was hospitalization rates between the groups. Data were analyzed using chi-square test, Kruskal,Wallis test, Mantel,Haenszel test, and analysis of variance, with p < 0.05 considered significant. Results A total of 166 subjects were enrolled; data for analysis were available for 44 NS-treated patients, 46 ondansetron-treated patients, and 47 dexamethasone-treated patients. Hospital admission occurred in nine patients (20.5%) receiving placebo (NS alone), two patients (4.4%) receiving ondansetron, and seven patients (14.9%) receiving dexamethasone, with ondansetron significantly different from placebo (p = 0.02). Similarly, at two hours, more ondansetron-treated patients (39 [86.6%]) tolerated oral hydration than NS-treated patients (29 [67.4%]; relative risk, 1.28; 95% confidence interval = 1.02 to 1.68). There were no differences in number of mean episodes of vomiting or repeat visits to health care at 24 and 72 hours in the ondansetron, dexamethasone, or NS groups. Conclusions In children with dehydration secondary to vomiting from acute viral gastritis, ondansetron with intravenous rehydration improves tolerance of oral fluids after two hours and reduces the hospital admission rate when compared with intravenous rehydration with or without dexamethasone. [source]

    Geographical and individual variation in echolocation calls of the intermediate leaf-nosed bat, Hipposideros larvatus

    ETHOLOGY, Issue 8 2010
    Tinglei Jiang
    The cause and significance of variation in echolocation call frequency within hipposiderid bats is not well understood despite an increasing number of allopatric and sympatric examples being documented. We examined variation patterns in the resting frequency (RF) of echolocation calls emitted by the intermediate leaf-nosed bat, Hipposideros larvatus, on a broad geographical scale. Data mining technology and Kruskal,Wallis test both showed substantial variation with a longitudinal pattern in RF in H. larvatus among colonies, and this variation was associated with geographical distance and not body size. In addition, we found that a high degree of variability between individuals was hidden under the geographical variation. The results support an effect of random cultural drift, and challenge the prey detection hypothesis. Moreover, an acoustic difference among local island colonies may be indicative of a vocal dialect. We found that each colony of H. larvatus seems to maintain a ,private bandwidth', which could be used for colony identity and individual communication thus helping individuals and colonies to get a number of fitness benefits. [source]

    The impact of HLA-A and -DRB1 on age at onset, disease course and severity in Scandinavian multiple sclerosis patients

    C. Smestad
    The human leucocyte antigen (HLA) class II haplotype DRB1*15,DQB1*06 (DR15,DQ6) is associated with susceptibility to multiple sclerosis (MS), and HLA class I associations in MS have also been reported. However, the influence of HLA class I and II alleles on clinical phenotypes in MS has not yet been completely studied. This study aimed at evaluating the impact of HLA-A and -DRB1 alleles on clinical variables in Scandinavian MS patients. The correlation between HLA-A or -DRB1 alleles and age at onset, disease course and Multiple Sclerosis Severity Score (MSSS) were studied in 1457 Norwegian and Swedish MS patients by regression analyses and Kruskal,Wallis rank sum test. Presence of HLA-DRB1*15 was correlated with younger age at onset of disease (corrected P = 0.009). No correlation was found between HLA-A and the variables studied. This study analysed the effect of HLA-A on clinical variables in a large Scandinavian sample set, but could not identify any significant contribution from HLA-A on the clinical phenotype in MS. However, associations between HLA-DRB1*15 and age at onset of MS were reproduced in this extended Scandinavian MS cohort. [source]

    Genetic study of the myelin oligodendrocyte glycoprotein (MOG) gene in schizophrenia

    G. Zai
    Schizophrenia (SCZ) is a neuropsychiatric disorder that affects approximately 1% of the general population. The human leukocyte antigen (HLA) system has been implicated in several genetic studies of SCZ. The myelin oligodendrocyte glycoprotein (MOG) gene, which is located close to the HLA region, is considered a candidate for SCZ due to its association with white matter abnormalities and its importance in mediating the complement cascade. Four polymorphisms in the MOG gene (CA)n (TAAA)n, and two intronic polymorphisms, C1334T and C10991T, were investigated for the possibility of association with SCZ using 111 SCZ proband and their families. We examined the transmission of the alleles of each of these polymorphisms with the transmission disequilibrium test. We did not observe significant evidence for biased transmission of alleles at the (CA)n (,2 = 2.430, 6 df, P = 0.876) (TAAA)n (,2 = 3.550, 5 df, P = 0.616), C1334T (,2 = 0.040, 1 df, P = 0.841) and C10991T (,2 = 0.154, 1 df, P = 0.695) polymorphisms. Overall haplotype analysis using the TRANSMIT program was also not significant (,2 = 7.954, 9 df, P = 0.539). Furthermore, our results comparing mean age at onset in the genotype groups using the Kruskal,Wallis Test were not significant. Our case-control analyses (182 cases age-, sex- and ethnicity-matched with healthy controls) and combined z -score [(CA)n: z -score =,1.126, P = 0.130; (TAAA)n: z -score = ,0.233, P = 0.408; C1334T: z -score = 0.703, P = 0.241; C10991T: z -score = 0.551, P = 0.291] were also not significant. Although our data are negative, the intriguing hypothesis for MOG in SCZ may warrant further investigation of this gene. [source]

    The occurrence of porosity in reline acrylic resins.

    GERODONTOLOGY, Issue 1 2009
    Effect of microwave disinfection
    Background:, Microwave energy has proved to be an effective method for disinfecting acrylic dentures. However, the effect of microwave heating on the porosity of autopolymerising denture reline resins has not been investigated. Objective:, The purpose of the study was to determine the effect of microwave disinfection on the porosity of autopolymerised denture reline materials (Kooliner-K, New Truliner-NT, Tokuso Rebase Fast-TR and Ufi Gel Hard-UGH) and a conventional heat-polymerised denture base resin (Lucitone 550-L). Material and methods:, Specimens (10 mm × 20 mm × 1 mm) were obtained from the impression surface of the palatal mucosa in a single person and divided into four groups (n = 5). The porosity was evaluated after polymerisation (C1), after two cycles of microwave disinfection (MW2), after seven cycles of microwave disinfection (MW7) and after 7 days storage in water at 37°C (C2). Specimens from group MW7 were exposed to microwave disinfection daily being stored in water at 37°C between exposures. All the replicas were sputter coated with gold and micrographs/digital images were taken of each replica using scanning electron microscopy at magnification × 100. The SEM micrographs were then examined using an image analyser to determine the number of pores. Comparison between materials and groups were made using Kruskal,Wallis tests. Results:, MW7 resulted in a significant increase in the number from the pores of material K, but decreased in number in reline material TR and UGH reline resin. The number of pores in materials NT and L remained unaffected following microwave disinfection. Conclusion:, Differences in the porosity amongst the materials and for different experimental conditions were observed following microwave disinfection. [source]

    HFE C282Y gene variant is a risk factor for the progression to decompensated liver disease in chronic viral hepatitis C subjects in the Czech population

    Aim:, To determine the prevalence of selected HFE polymorphisms (C282Y, H63D and S65C) among patients with chronic viral hepatitis B and C and to investigate their role in the progression of liver disease. Methods:, A total of 207 subjects with chronic B or C viral hepatitis and 243 healthy controls were enrolled in the case,control study. Cases were further classified into three groups according to the clinical stage of liver disease: (A) virus carriers; (B) compensated liver disease; and (C) decompensated liver disease. HFE polymorphisms were detected by polymerase chain reaction-based methodology. Fisher's exact test, ,2 and Kruskal,Wallis tests were used to test for differences in variables studied between groups. Haplotypes were inferred in silico and their distribution compared by permutation test. Modified survival (time-to-event) analysis was used to test for the differences in the progression to the decompensated liver disease in carriers of C282Y wild-type versus mutated genotypes. Results:, The frequency of HFE genotypes, alleles and haplotypes differed neither between HBV nor HCV patients versus controls. In HCV subjects: (i) the frequency of the 282Y allele was significantly higher in the (C) group compared to (B) group (12.5 vs 2.2%, respectively, P = 0.002, Fisher's exact test); and (ii) carriers of the 282Y mutation exhibited significantly faster progression to decompensated liver disease than wild-type carriers (P = 0.044, log,rank test). Conclusion:, Carriage of the minor HFE C282Y polymorphism is associated with decompensated liver disease and its earlier onset in the subjects with chronic viral hepatitis C in the Czech population. [source]

    SEM evaluation of root canal debridement with Sonicare CanalBrush irrigation

    M. I. Salman
    Salman MI, Baumann MA, Hellmich M, Roggendorf MJ, Termaat S. SEM evaluation of root canal debridement with Sonicare CanalBrush irrigation. International Endodontic Journal, 43, 363,369, 2010. Abstract Aim, To determine the efficacy of Sonicare CanalBrush irrigation for root canal cleaning. Methodology, Fifty human molar root canals were shaped with sequential NiTi rotary instruments up to size F3 (size 30, 0.09 taper; ProTaper system) and then enlarged apically with a Profile size 40, 0.04 taper. Five different irrigation protocols were tested (n = 10 canals per group) with 2 mL of distilled water (control, group I) or 2.5% NaOCl (control group II and test groups III, IV and V) between instrument size changes. Group III,IV received a final rinse with 17% EDTA for one min. This was extended by 30 s in group IV, whereas group V received this additional 30 s of 17% EDTA sonically dispersed with a Sonicare CanalBrush. For cleanliness evaluations, roots were split longitudinally, examined with scanning electron microscopy and scored according to Hülsmann et al. (1997) for debris and smear layer on the surface of the root canal wall. Walls were assessed at the coronal, middle and apical thirds. Data were analysed with the Kruskal,Wallis and Mann,Whitney tests. Results, Irrigation with 17% EDTA significantly reduced debris and smear layer scores (P < 0.05) compared to controls. The coronal and middle thirds had lower debris and smear layer scores than the apical third (P < 0.05). In all thirds, sonic agitation of the irrigant with a CanalBrush (group V) resulted in significantly cleaner canal walls compared to all other groups (P < 0.05). Conclusions, Irrigation by agitation with the Sonicare CanalBrush improved root canal debridement in the coronal, middle and particularly the apical thirds of the root canal. [source]

    Analysis of the gutta-percha filled area in C-shaped mandibular molars obturated with a modified MicroSeal technique

    R. Ordinola-Zapata
    Abstract Aim, To analyse the gutta-percha filled area of C-shaped molar teeth root filled with the modified MicroSeal technique with reference to the radiographic features and the C-shaped canal configuration. Methodology, Twenty-three mandibular second molar teeth with C-shaped roots were classified according to their radiographic features as: type I , merging, type II , symmetrical and type III , asymmetrical. The canals were root filled using a modified technique of the MicroSeal system. Horizontal sections at intervals of 600 ,m were made 1 mm from the apex to the subpulpal floor level. The percentage of gutta-percha area from the apical, middle and coronal levels of the radiographic types was analysed using the Kruskal,Wallis test. Complementary analysis of the C-shaped canal configurations (C1, C2 and C3) determined from cross-sections from the apical third was performed in a similar way. Results, No significant differences were found between the radiographic types in terms of the percentage of gutta-percha area at any level (P > 0.05): apical third, type I: 77.04%, II: 70.48% and III: 77.13%, middle third, type I: 95.72%, II: 93.17%, III: 91.13% and coronal level, type I: 98.30%, II: 98.25%, III: 97.14%. Overall, the percentage of the filling material was lower in the apical third (P < 0.05). No significant differences were found between the C-shaped canal configurations apically; C1: 72.64%, C2: 79.62%, C3: 73.51% (P > 0.05). Conclusions, The percentage of area filled with gutta-percha was similar in the three radiographic types and canal configuration categories of C-shaped molars. These results show the difficulty of achieving predictable filling of the root canal system when this anatomical variation exists. In general, the apical third was less completely filled. [source]

    Radicular peroxide penetration from carbamide peroxide gels during intracoronal bleaching

    O. Gökay
    Abstract Aim, To evaluate and compare radicular peroxide diffusion from different concentrations of carbamide peroxide bleaching gels. Methodology, Fifty maxillary premolar teeth were separated into five groups (n = 10). Standardized endodontic access cavities were prepared in the occlusal surfaces, and the root canals were prepared using a step back technique and filled using the lateral compaction technique. The gutta-percha filling was removed 4 mm short of the cemento-enamel junction (CEJ) and a 2-mm-thick glass,ionomer cement base was placed. Outer root surfaces were sealed with wax and nail polish, leaving the coronal third of the tooth and the CEJ exposed. All teeth were immersed in a plastic tube containing 2 mL of distilled water, and the experimental groups were treated with a bleaching agent of either 10%, 17% or 37% carbamide peroxide (CP) or a mixture of 30% hydrogen peroxide (HP) and sodium perborate (SP) placed into the coronal pulp chamber of teeth and left for 24 h. Peroxide penetration was measured using the ferrothiocyanate method. Statistical analysis of data was conducted by using the Kruskal,Wallis Analysis of Variance and Mann,Whitney U test. Results, Higher peroxide penetration occurred with the 30% HP-SP mixture than with the CP bleaching gels, and the 37% CP group also promoted greater peroxide penetration than the other CP groups (P < 0.05). There was no statistically significant difference between 10% and 17% CP groups (P > 0.05). Conclusion, Peroxide penetration of CP gels was significantly lower than that of a HP-SP mixture. [source]

    Efficacy of three rotary NiTi instruments in removing gutta-percha from root canals

    T. Ta, demir
    Abstract Aim, To investigate the ability of three rotary nickel,titanium instruments and hand instrumentation to remove gutta-percha and sealer. Methodology, Sixty freshly extracted human single-rooted teeth, each with one root canal, were instrumented with K-files and filled using cold lateral compaction of gutta-percha and AH Plus (Dentsply Detrey, Konstanz, Germany) sealer. The teeth were randomly divided into four groups of 15 specimens each. Removal of gutta-percha was performed with the following devices and techniques: ProTaper, R-Endo, Mtwo and Hedström files. The specimens were rendered transparent and the area of remaining filling material on the root canal wall was measured using a computer image analysis program. Statistical analysis was accomplished by Kruskal,Wallis and Mann,Whitney U -tests with Bonferroni correction for the analysis of residual root filling material and working time. Results, The ProTaper group had less filling material inside the root canals than the other groups, but a significant difference was found between only the ProTaper and Mtwo groups (P < 0.05). The retreatment time for Mtwo and ProTaper was significantly shorter compared with R-Endo and manual instrumentation with Hedström files (P < 0.001). R-Endo was significantly faster than manual instrumentation (P < 0.001). Conclusions, Under the experimental conditions, ProTaper left significantly less gutta-percha and sealer than Mtwo instruments. Complete removal of materials did not occur with any of the instrument systems investigated. [source]

    Fracture strength of bovine incisors after intra-radicular treatment with MTA in an experimental immature tooth model

    E. A. Bortoluzzi
    Abstract Aim, To evaluate, using an experimental immature tooth model, the fracture resistance of bovine incisors submitted to different reinforcement treatments with mineral trioxide aggregate (MTA). Methodology, An immature tooth model was created by sectioning the coronal and apical portions of 40 bovine incisors 8 mm above and 12 mm below the cementoenamel junction. The root canals were irrigated with 1.0% sodium hypochlorite. They were enlarged both coronally and apically using number 703 carbide burs (ISO: 500,104-168-007-021) and their internal diameter was standardized to 2.1 mm. The specimens were assigned to four groups (n = 10): GI-control (without filling); GII-apical MTA plug + filling with gutta-percha and endodontic sealer; GIII-filling with MTA; GIV-apical MTA plug + filling with MTA + metallic post (Reforpost I). A polyether impression material was used to simulate the periodontal ligament. The specimens were submitted to a compressive load at a crosshead speed of 0.5 mm min,1 in a servo-hydraulic universal testing machine (MTS 810) applied at 45° to the long axis of the tooth until failure. Data were submitted to statistical analysis by the Kruskal,Wallis test at 5% significance level. Results, GIV presented the highest fracture resistance (32.7N) and differed significantly from the other groups (P < 0.05). No statistically difference was found between GII (16.6N) and GIII (23.4N) (P > 0.05). GIII had a significantly higher fracture resistance than GI (P < 0.05). Conclusions, The use of MTA + metallic post as an intra-radicular reinforcement treatment increased the resistance to fracture of weakened bovine teeth in an experimental immature tooth model. [source]

    Recovery of Enterococcus faecalis after single- or multiple-visit root canal treatments carried out in infected teeth ex vivo

    N. Vivacqua-Gomes
    Abstract Aim, To assess the presence of Enterococcus faecalis after root canal treatment in single or multiple visits in an ex vivo model. Methodology, Forty-five premolar teeth were infected ex vivo with E. faecalis for 60 days. The canals were then prepared using a crowndown technique with System GT and Gates,Glidden burs and irrigated with 2% chlorhexidine gel. The specimens were divided into five groups (G1, G2, G3, G4 and G5) according to the time elapsed between chemical,mechanical preparation and root canal filling, the irrigant solution used and the use or nonuse of a calcium hydroxide intra-canal medicament. The teeth were then root-filled and incubated for 60 days at 37 °C. Dentine chips were removed from the canal walls with sequential sterile round burs at low speed. The samples obtained with each bur were immediately collected in separate test tubes containing Brain,Heart Infusion broth. These samples were placed onto agar plates and colony forming units were counted after 24 h at 37 °C. Data were ranked and analysed using the Kruskal,Wallis statistical test. Results,Enterococcus faecalis was recovered from 20% (three of 15 specimens) of G1 (chlorhexidine irrigation and immediate root filling in a single visit), 25% (four of 15 specimens) of G2 (chlorhexidine irrigation and filling after 14 days use of a calcium hydroxide dressing in multiple visits), 40% (two of five specimens) of G3 (chlorhexidine irrigation and filling after 7 days), 60% (three of five specimens) of G4 (saline irrigation and filling after 7 days) and from 100% (five of five specimens) of G5 (saline irrigation and immediate filling without sealer). Conclusions, Neither single- nor multiple-visit root canal treatment ex vivo, eliminated E. faecalis completely from dentinal tubules. Up to 60 days after root filling, E. faecalis remained viable inside dentinal tubules. When no sealer was used, E. faecalis presented a higher growth rate. [source]

    The effect of the renewal of calcium hydroxide paste on the apexification and periapical healing of teeth with incomplete root formation

    M. C. S. Felippe
    Abstract Aim, To evaluate the influence of renewing calcium hydroxide paste on apexification and periapical healing of teeth in dogs with incomplete root formation and previously contaminated canals. Methodology, Forty premolars from four 6-month-old dogs were used. After access to the root canals and complete removal of the pulp, the canal systems remained exposed to the oral environment for 2 weeks. Canal preparation was then carried out using Hedströem files, under irrigation with 1% sodium hypochlorite, 1 mm short of the radiographic apex. After drying, the canals of one premolar in each dog were left empty (group 4-control), and those of the other nine teeth in each animal were filled with a calcium hydroxide-propylene glycol paste. All teeth were restored with reinforced zinc oxide cement (IRM) or IRM and amalgam (group 4). The paste was renewed and the teeth restored again 1 week later. Then, the nine teeth in each animal were divided into three experimental groups: group 1 , paste not changed; group 2 , paste renewed every 4 weeks for 5 months; and group 3 , paste renewed after 3 months had elapsed. The teeth were restored with IRM and amalgam (groups 1 and 3) or IRM (group 2). The animals were killed 5 months later, and blocks of the teeth and surrounding tissues were submitted to histological processing. The sections were studied to evaluate six parameters: apical calcified tissue barrier, inflammatory reaction, bone and root resorption, paste extrusion and microorganisms. Results of experimental groups were analysed by Kruskal,Wallis nonparametric tests and by the test of proportions. The critical value of statistical significance was 5%. Results, Significant differences (P < 0.05) were found in relation to the presence of bone resorption and paste in the periradicular area, the formation of a calcified tissue barrier at the apex, and the intensity of the apical inflammatory reaction. Bone resorption was more evident in group 1 (medicament not changed), and the presence of paste in the periodontal tissues was more common in groups 2 and 3. Renewal of the paste reduced the intensity of the inflammatory reaction (groups 2 and 3), but the formation of apical calcified tissue was more noticeable in the teeth where the paste had not been renewed. Conclusions, Replacement of calcium hydroxide paste was not necessary for apexification to occur, however, it did reduce significantly the intensity of the inflammatory process. Monthly renewal of calcium hydroxide paste reduced significantly the occurrence of apexification. [source]

    Effectiveness in cleaning oval-shaped root canals using Anatomic Endodontic Technology, ProFile and manual instrumentation: a scanning electron microscopic study

    O. Zmener
    Abstract Aim, To compare in vitro the cleanliness of root canal walls in oval-shaped root canals following automated or manual instrumentation. Methodology, Forty-five oval-shaped single-rooted maxillary and mandibular premolars with straight canals were divided into three groups of 15. Automated canal preparation was performed using Anatomic Endodontic Technology (AET, group 1) and the ProFile system (group 2). Manual instrumentation (group 3) was performed with K-Flexofiles. Irrigation was performed using alternately 5.25% NaOCl and 17% EDTA, followed by rinsing with saline. The roots were split longitudinally into halves and the canals examined at ×200 and ×400 in a scanning electron microscope. The presence of debris and smear layer was recorded at distances of 1, 5 and 10 mm from the working length using a three-step scoring scale and a 300 ,m square grid. Mean scores for debris and smear layer were calculated and statistically analysed for significance (P < 0.05) between and within groups, using the Kruskal,Wallis nonparametric anova and Dunn's tests. Results, At 1, 5 and 10-mm levels the root canals prepared with AET had significantly less surface debris and smear layer on the canal walls compared with canals prepared with ProFile or manual instrumentation. For all three groups significantly lower mean smear layer scores (P < 0.05) were recorded at 5 and 10-mm levels compared with the 1 mm level. Significantly lower mean debris scores (P < 0.05) were also recorded at 5 and 10-mm levels for the AET group whereas no significant differences were found between the three levels for the ProFile and manual instrumentation groups. Conclusions, Although better instrumentation scores were obtained in canals prepared with AET, complete cleanliness was not achieved by any of the techniques and instruments investigated. [source]

    The effect of application time of EDTA and NaOCl on intracanal smear layer removal: an SEM analysis

    C. S. Teixeira
    Abstract Aim, To verify, under the scanning electron microscope (SEM), the influence of irrigation time with ethylenediaminetetraacetic acid (EDTA) and sodium hypochlorite (NaOCl) on intracanal smear layer removal. Methodology, Twenty-one extracted human permanent teeth with single straight root canals were included. The root canals of the teeth were instrumented and, at the end of preparation, were irrigated with 3 mL of 15% EDTA, followed by 3 mL of 1% NaOCl for 1 min (group 1), for 3 min (group 2), and for 5 min (group 3). The canals of teeth in group 4 (control) did not receive the final irrigation. The teeth were sectioned longitudinally and prepared for an SEM. The dentinal wall of cervical, middle and apical thirds was graded according to the amount of debris and smear layer remaining on the walls. The results were analysed using the Kruskal,Wallis and Conover,Inman tests. Results, In all the canals of experimental groups irrigation with EDTA and NaOCl completely removed the smear layer from the cervical and middle thirds. In the apical third, the dentine surface were partially covered, particularly in the teeth of group 1, where there was significantly more smear layer when compared with the other thirds in the same group (P < 0.007). However, the Kruskal,Wallis test showed overall that there were no significant differences between groups 1, 2 and 3 (P > 0.05). Conclusion, In this limited laboratory study, canal irrigation with EDTA and NaOCl for 1, 3 and 5 min were equally effective in removing the smear layer from the canal walls of straight roots. [source]

    Decalcification of root canal dentine by citric acid, EDTA and sodium citrate

    L. F. Machado-Silveiro
    Abstract Aim, To measure the demineralization capability of 1 and 10% citric acid, 10% sodium citrate and 17% EDTA during immersions of 5, 10 and 15 min on root canal dentine. Methodology, Crowns were sectioned from eight maxillary canines. The cementum was removed from the cervical third of the roots to expose the dentine. Canals were prepared using a handpiece-mounted Largo Peeso reamer. A 3-mm thick cross-sectional slice was obtained from the cervical third of each root. Each slice was sectioned into four equal parts. These specimens were assigned to one of four groups (n = 8) for the application of 1% citric acid, 10% citric acid, 10% sodium citrate or 17% EDTA. Each specimen underwent three successive 5-min immersions in each solution at room temperature. The solutions were not renewed between immersions. Two millimetres of solution were collected from the extracts and lanthanum oxide was added for the calcium reading by spectrophotometry. To compare the amounts of calcium removed by each solution, the Friedman test was used for the global comparison and the Wilcoxon test for paired comparisons. Differences between groups were evaluated using the Kruskal,Wallis test for the global comparison and Mann,Whitney test for paired comparisons. Results, Overall, 1 and 10% citric acid were more effective than EDTA or sodium citrate at the three immersion times (P < 0.001); 10% citric acid was more effective than 1% citric acid (P < 0.001). EDTA and 1 and 10% citric acid showed decreasing effectiveness with time, and the decrease was significant for citric acid at both concentrations (P < 0.001). Although sodium citrate removed little calcium during the three time periods, the small increase recorded was significant (P < 0.01). Conclusions, Citric acid at 10% was the most effective decalcifying agent, followed by 1% citric acid, 17% EDTA and 10% sodium citrate. [source]

    An in vitro comparison of adhesive systems to seal pulp chamber walls

    B. Ozturk
    Abstract Aim, To compare in vitro the sealing properties of five different dentine adhesive materials (Prime&Bond NT (PBNT); Prompt L-Pop (PLP); Clearfil SE Bond (CSEB); Scotchbond Multi Purpose Plus (SMPP); EBS-Multi (EBSM)) inside the pulp chamber. Methodology, Seventy-five recently extracted human molar teeth were used. The roof of the pulp chambers and roots were removed under water cooling. Pulp tissue was removed, and the canal orifices were sealed. The pulp chambers were then treated with 5% sodium hypochlorite (NaOCl) for 1 min. The teeth were randomly divided into five groups of 15 teeth each. Adhesive systems were applied to the pulp chamber walls according to the manufacturers' instructions. The samples were connected to Plexiglass plates, and a fluid filtration method was used for quantitative evaluation of leakage. Measurements of fluid movement were made at 2-min intervals for 8 min. The quality of seal of each specimen was measured immediately, after 24 h, 1 week and 1 month. The data were statistically analysed by repeated-measurements multivariate anova, Friedman test, Wilcoxon signed rank test, Kruskal,Wallis of one-way anova and Mann,Whitney U -tests. The pulp chamber wall with and without NaOCl and resin,dentine interfaces of specimens were observed under a scanning electron microscope (SEM). Results, The leakage values of the materials were significantly different at different measurement periods. In all groups, leakage values decreased with time (P < 0.05). PBNT and PLP had the least leakage during immediate measurements (P < 0.05). After 1 month, leakage of all adhesive systems was not significantly different (P < 0.05). SEM observation of pulp chamber walls demonstrated that the irregular dentine surface without smear layer was present in the nontreated group. However, NaOCl application removed the collagen fibrils leaving the dentine surface smooth. At resin,dentine interfaces of specimens, no hybridization zone was observed. Conclusions, None of the materials had created a perfect seal to the pulp chamber walls. PBNT and PLP had better sealing over the short term, but over the long term, there were no differences between the materials. [source]

    Effect of different irrigation solutions and calcium hydroxide on bacterial LPS

    J. M. G. Tanomaru
    Abstract Aim, To evaluate the effect of biomechanical preparation with different irrigating solutions and calcium hydroxide dressing in dog root canals containing bacterial endotoxin (lipopolysaccharides; LPS). Methodology, One hundred and forty premolar roots from seven dogs were filled with Escherichia coli LPS for 10 days (three roots were lost during histological processing). The following irrigating solutions were used for biomechanical preparation: 1% (group I, n = 20), 2.5% (group II, n = 19) and 5% sodium hypochlorite (group III, n = 19), 2% chlorhexidine digluconate (group IV, n = 20) and physiological saline solution (group V, n = 19). In group VI (n = 20), the LPS solution was maintained in the root canal during the entire experiment and in group VII (n = 20), after biomechanical preparation with saline solution, the root canals were filled with a calcium hydroxide dressing (Calen; control). After 60 days, the animals were sacrificed and the following parameters of periapical disease were evaluated: (a) inflammatory infiltrate, (b) periodontal ligament thickness, (c) cementum resorption and (d) bone resorption. Scores were given and data were analysed statistically with the Kruskal,Wallis and Dunn tests (P < 0.05). Results, Histopathological evaluation showed that groups I,VI had more inflammatory infiltrate, greater periodontal ligament thickening and greater cementum and bone resorption (P < 0.05) compared to group VII, which received the calcium hydroxide intracanal dressing. Conclusions, Biomechanical preparation with the irrigating solutions did not inactivate the effects of the endotoxin but the calcium hydroxide intracanal dressing did appear to inactivate the effects induced by the endotoxin in vivo. [source]

    Effects of rotary instruments and ultrasonic irrigation on debris and smear layer scores: a scanning electron microscopic study

    B. E. Mayer
    Abstract Aim This study evaluated debris and smear layer scores after two types of instruments manufactured from different alloys were used to ultrasonically activate irrigants during canal preparation. The influence of two rotary preparation techniques on cleanliness of the shaped canals was also studied. Methodology Apical stops were prepared to size 45 in 42 single-canalled extracted premolars and canines, which were divided into six equal groups. Groups 1, 2 and 3 were prepared by ProFile .04 (PF) while groups 4, 5 and 6 were prepared by Lightspeed (LS). All groups were irrigated using 5.25% NaOCl and 17% EDTA. Irrigants in groups 2 and 5 were ultrasonically activated using a size 15 steel K-file and by a blunt flexible nickel,titanium wire in groups 3 and 6. Groups 1 and 4 served as negative controls. Roots were split and canal walls examined at 15×, 200× and 400× magnification in an SEM. Smear layer and debris scores were recorded at 3, 6 and 9 mm levels using a 5-step scoring scale and a 200-µm grid. Means were tested for significance using nonparametric Mann,Whitney U and Kruskal,Wallis tests. Results Debris and smear layer scores for the six groups varied from 1.98 ± 1.04 to 3.47 ± 0.97 and from 1.37 ± 0.4 to 2.36 ± 0.99, respectively. Although all groups had significantly higher smear layer and debris scores at the 3 mm levels compared to the 9 mm levels (P < 0.05), no significant differences were recorded due to the ultrasonic energy transmitted by the two alloys. Conclusion Ultrasonically activated irrigants did not reduce debris or smear layer scores. This finding was not influenced by the material nor by the design of the instrument used to transmit ultrasonic activation. [source]

    In vitro antimicrobial activity of several concentrations of sodium hypochlorite and chlorhexidine gluconate in the elimination of Enterococcus faecalis

    B. P. F. A. Gomes
    Abstract Aim The aim of this study was to assess, in vitro, the effectiveness of several concentrations of NaOCl (0.5%, 1%, 2.5%, 4% and 5.25%) and two forms of chlorhexidine gluconate (gel and liquid) in three concentrations (0.2%, 1% and 2%) in the elimination of E. faecalis. Methodology A broth dilution test using 24-well cell culture plates was performed and the time taken for the irrigants to kill bacterial cells was recorded. Isolated 24 h colonies of pure cultures of E. faecalis grown on 10% sheep blood plus Brain Heart Infusion (BHI) agar plates were suspended in sterile 0.85% NaCl solution. The cell suspension was adjusted spectrophotometrically to match the turbidity of a McFarland 0.5 scale. One mL of each tested substance was placed on the bottom of wells of 24-well cell culture plates (Corning, NY), including the control group (sterile saline). Six wells were used for each time period and irrigant concentration. Two mL of the bacterial suspension were ultrasonically mixed for 10 s with the irrigants and placed in contact with them for 10, 30, and 45 s; 1, 3, 5, 10, 20, and 30 min; and 1 and 2 h. After each period of time, 1 mL from each well was transferred to tubes containing 2 mL of freshly prepared BHI + neutralizers in order to prevent a residual action of the irrigants. All tubes were incubated at 37°C for 7 days. The tubes considered to have positive growth were those which presented medium turbidity during the incubation period. Data were analysed statistically by the Kruskal,Wallis test, with the level of significance set at P < 0.05. Results All irrigants were effective in killing E. faecalis, but at different times. Chlorhexidine in the liquid form at all concentrations tested (0.2%, 1% and 2%) and NaOCl (5.25%) were the most effective irrigants. However, the time required by 0.2% chlorhexidine liquid and 2% chlorhexidine gel to promote negative cultures was only 30 s and 1 min, respectively. Conclusions Even though all tested irrigants possessed antibacterial activity, the time required to eliminate E. faecalis depended on the concentration and type of irrigant used. [source]

    A novel approach to controlling bacterial contamination on toothbrushes: chlorhexidine coating

    LA Turner
    Abstract:, Purpose:, This project was conducted to determine the effectiveness of chlorhexidine-coated toothbrush filaments in reducing quantities of bacteria. Materials and methods:, An Institutional Review Board (IRB)-approved, two-group, double-blind, randomized, post-test only study was conducted. Sixty-four individuals utilized control and experimental toothbrushes, for 30 days. At the end of the study toothbrushes were returned and transported to the laboratory for analysis. Microorganisms were detached from the filaments by sonification and vortexing then plated on Mitis Salivarius (MS) (selective) and trypticase soy agar (TSA) 5% Sheep Blood (non-selective) media. Inoculated plates were incubated aerobically for 24 h at 37°C. After incubation, bacterial colony-forming units (CFU) were determined. Data were analysed using Wilcoxon and Kruskal,Wallis tests. Results:, Fifty-nine toothbrushes were returned for analysis; experimental (n = 31) and control (n = 28). Data from TSA media revealed a mean CFU for the control group of 5.41 × 105 compared with 6.28 × 105 for the experimental group. Data from MS agar resulted in a mean CFU for the control group of 4.32 × 105 compared with 4.20 × 105 for the experimental group. Conclusion:, Results revealed no statistically significant difference in the quantity of bacteria surviving on toothbrush filaments between control and experimental groups, on both selective and non-selective media, after 30 days. [source]

    Activated monocytes and platelet-monocyte aggregates in patients with sickle cell disease*

    Tumour necrosis factor-, (TNF-,) and interleukin-1, (IL-1,) increase endothelial surface receptors that mediate the adherence of sickle erythrocytes to the endothelium. Increased circulating levels of these cytokines have been found in patients with sickle cell disease (SCD). Monocytes are a source of both of these inflammatory mediators; we therefore determined whether circulating monocytes were activated in SCD, as defined by intracellular expression of these cytokines. Blood was also assayed for the presence of platelet,monocyte aggregates (PMAs), as platelet adherence is one possible mechanism for monocyte activation. The median percentages of monocytes expressing intracellular TNF-, and IL-1, in SCD patients were 6.8 (2.8,17.3) [median (range)] and 14.1 (1.3,44.8), respectively. In African-American controls the corresponding percentages were 0.3 (0.1,0.5) and 0.4 (0.1,3.0), and in Caucasians 0.2 (0.1,0.5) and 0.8 (0.8,1.9) (P < 0.001, Kruskal,Wallis). The mean percentage (± SD) of PMA was 14.0 ± 8.3 for Caucasian controls, 25.7 ± 7.3 for African-American controls, and 45.7 ± 21.6 for patients with SCD (P < 0.001, RM ANOVA; P < 0.05, Newman,Keuls posthoc test). We conclude that there are increased circulating PMAs and monocyte activation in patients with SCD. [source]

    Growth of functional cranial components in rats submitted to intergenerational undernutrition

    JOURNAL OF ANATOMY, Issue 2 2006
    María F. Cesani
    Abstract The aim of the present study was to discover how intergenerational undernutrition affects the growth of major and minor functional cranial components in two generations of rats. Control animals constituted the parental generation (P). The undernourished generations (F1 and F2) were fed 75% of the control diet. Animals were X-rayed every 10 days from 20 to 100 days of age. The length, width and height of the major (neurocranium and splanchnocranium) and minor (anterior-neural, middle-neural, posterior-neural, otic, respiratory, masticatory and alveolar) cranial components were measured on each radiograph. Volumetric indices were calculated to estimate size variations of these components. Data were processed using the Kruskal,Wallis and Kolmogorov,Smirnov tests for two samples. Impairment in splanchnocranial and neurocranial growth was found, the latter being more affected than the former in F1. Comparison between F2 and F1 animals showed cumulative effects of undernutrition in both major and minor components (anterior-neural, respiratory, masticatory and alveolar in males, and middle-neural and respiratory in females). Such differential effects on minor components may reflect a residual mechanical strain resulting from the linkage between components. This phenomenon was clearly observed in the neurocranium and could be understood as an adaptive response to the demands of the associated functional matrices. [source]

    Feeding Practices of Dog and Cat Owners Reflect Attitudes Toward Pet Foods

    K. N. Willoughby
    The PET DINER study was a telephone survey conducted to better understand why pet owners make certain nutritional decisions for their pets. Both dog and cat owners were included, which allowed us to differentiate the way people feed pet cats vs. pet dogs and how that might reflect owners' attitudes about pet foods. Prospective survey respondents were selected from local telephone books using a randomized process. A total of 18,194 calls were made from the five study sites between May and August, 2004. 1074 people (6%) representing 619 dogs and 455 cats completed the survey. Detailed information about feeding practices was collected. Pet owners' perceptions were assessed based on agreement/disagreement with statements regarding pet foods and the pet food industry. The Mann,Whitney Rank Sum test was used to detect differences between dog and cat owners and the Kruskal,Wallis one-way analysis of variance on ranks was used to evaluate differences among pet owners based on both type of pet and feeding practices (,75% commercial vs. ,50% home-prepared diets). More cats than dogs ate commercial pet food as ,75% of their main diet (96% vs. 87%, respectively; p < 0.001), and more dogs than cats ate a home-prepared food as ,50% of their main diet (6% vs. 3%, respectively; p < 0.009). For five of the statements, a difference in the attitudes of cat vs. dog owners was detected (p < 0.05). In general, this reflected more positive attitudes regarding commercial foods and less positive attitudes regarding home-prepared foods on the part of cat vs. dog owners. Analysis based on both type of pet and feeding practices identified significant differences among groups for 18/26 statements. However, when the Dunn's Method for pairwise multiple comparisons was applied, significant differences were due to feeding practices rather than type of pet for 17/18 statements. Only differences in attitudes about the statement ,raw bones can be safely fed to pets' remained significant for cat vs. dog owners feeding commercial foods. In conclusion, more cat owners than dog owners feed ,75% commercial foods to their pets and this is reflected in different attitudes about the nutritional soundness of commercial pet foods. [source]

    Different apoptosis ratios and gene expressions in two human cell lines after sevoflurane anaesthesia

    Background: The aim of this study was to determine the effect of a single exposure of carcinoma cells (Caco-2 and HEp-2) to an anaesthetic gas mixture containing sevoflurane 3%, applied for a period of either 1 or 2 h, on the induction of apoptosis, propapototic gene expression and sphingomyelinase activity. Methods: Apoptosis was determined by flow cytometry. p53, caspase 3 and CYP2E1 gene expression was determined using reverse transcriptase polymerase chain reaction. Activities of acid (aSMase) and neutral sphingomyelinases (nSMase) were measured using methyl- 14C sphingomyeline, and for de novo ceramide and lipid synthesis [3H] palmitic acid was used. All results were compared with controls and analysed by Mann,Whitney and Kruskal,Wallis tests. Results: In the treated Caco-2 cells, the apoptotic ratio increased 24 h after anaesthesia (16.9%; P=0.04). The expression of both p53 and caspase-3 genes increased in Caco-2 and decreased in HEp-2 cells. The CYP2E1 gene expression was observed only in the Caco-2 cells. In control cells, the catalytic activity of aSMase was 2.3 times higher than that of nSMase activity. Decreased aSMase and nSMase activities were observed in Caco-2 cells 24 h after exposition. aSMase activity was halved (54.2%; P=0.06) in HEp-2 cells 24 h after anaesthesia. De novo ceramide synthesis correlated with SMase activity in Caco-2 cells. Conclusion: Sevoflurane anaesthesia induces late apoptosis in the colonic and laryngeal cancer cells investigated. Although the results obtained may indicate that an anaesthetic gas mixture containing sevoflurane induces p53-dependent apoptosis in the Caco-2 cells, the mechanism of apoptosis induction is unclear and remains to be elucidated. [source]

    Relationships between nurse care-giving behaviours and preterm infant responses during bathing: a preliminary study

    Jen-Jiuan Liaw
    Aims., The purpose of this study was to explore the relationships between specific nurse care-giving behaviours and preterm infant behavioural responses during bathing and to identify nurse behaviours associated with infant ,stress'. Background., Although recent advances in medical technology have improved neonatal intensive care, the high mortality and morbidity rates in preterm infants have not decreased proportionally. As caregivers strive to reduce infant mortality and morbidity, a factor for consideration is which caregiver behaviours are associated with preterm infant well-being. Design., A descriptive correlational design. Method., Convenience samples of 24 preterm infants and 12 nurses were recruited. A total of 120 baths were videotaped. Infant and nurse behaviours were measured using the coding schemes developed by the researchers. Pearson coefficient correlation, non-parametric Kruskal,Wallis test, t -test and generalised linear models were methods for data analysis. Results., As nurses provided more support, stress was reduced in the infants, and their self-regulation during the bath was enhanced especially by the use of ,containment' and ,positional support'. Conversely, non-therapeutic caregiver behaviours including ,rapid and rough handling' of the baby, ,chatting with other people' and ,inappropriate handling' increased infant ,stress' during the bath. Conclusion., The findings provide new information about the link between care-giving and infant responses and how caregivers can better interact with preterm infants during a very sensitive period of brain development. Relevance to clinical practice., How nurses take care of the preterm infants influences their responses to care-giving stimuli. To interact better with the infant during care-giving procedures, nurses need to provide more supportive care-giving behaviours especially ,position support' and ,containment' based on the infant's needs, and avoid care-giving that may be too rough and occur too quickly without attending the baby's stressful signals, positioning the baby in hyperextension posture, or chatting with other people during procedures. [source]