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Representation of self and socioemotional competence in kindergartners: differential and combined effects of attachment to mother and to father.

In the present study, we examined the differential predictive power and the joint or compensatory effects of representations of child-mother and child-father attachment for children's representation of self and their socioemotional competence. The representations of attachment were assessed by an attachment story completion task, completed once for mother and once for father (in counterbalanced order). Eighty participants (40 boys and 40 girls), aged between 55 and 77 months (M = 5 years 3 months), took place in the study. The socioemotional competence (peer social competence, disruptive behavior, anxious/withdrawn behavior, and school adjustment) and behavioral manifestations of self-esteem were evaluated by the kindergarten teacher. The inner representation of self (positiveness of self, perceived competence, and social acceptance) was assessed in a subgroup of 50 children. Results showed that the relative predictive power of child-mother and child-father attachments differed according to the domain of child functioning that was assessed. More specifically, it was found that the child's positiveness of self was better predicted by the quality of the child-mother attachment representation than by the quality of the child-father attachment representation. In contrast, the child's anxious/withdrawn behavioral problems were better predicted by the quality of the child-father attachment representation than by the quality of the child-mother attachment representation. With regard to the joint effects of child-mother and child-father attachment, it was found that a secure attachment to one parent can compensate for or buffer against an insecure attachment to the other parent. However, the buffering effect was not complete.

Affect↗

Relationship of clinical parameters to attachment loss in subsets of subjects with destructive periodontal diseases.

23 subjects were followed prior to treatment for 5 to 12 months in an attempt to relate attachment loss during this period to attachment level, probing depth, gingival redness and bleeding on probing. The subjects were divided into 3 groups based on amount and distribution of prior attachment loss: minor periodontitis, predominantly molar periodontitis and generalized periodontitis. The % of sites that exhibited attachment loss during the study period in the minor periodontitis, predominantly molar periodontitis and generalized periodontitis groups, were 1.3, 8.1 and 5.4, respectively. Subjects with minor periodontitis and predominantly molar periodontitis exhibited attachment loss more frequently in molar sites, proximal sites and sites with attachment level greater than or equal to 4 mm. In subjects with generalized periodontitis, attachment loss was related to tooth surface and attachment level, but not to tooth type. The relationship between the clinical parameters and attachment loss was improved compared with previous studies by using more homogeneous subject groups, more sensitive methods of analyzing attachment change and multivariate data analysis. However, the clinical parameters could not be used as diagnostic tests to predict attachment loss at individual sites.

Adult↗

Relationship between CPITN and periodontal attachment loss findings in an adult population.

This study investigates the relationship between CPITN findings and the prevalence and severity of periodontal attachment loss in a rural Kenyan population comprising 1131 persons aged 15-65 years. All persons were examined for calculus, gingival bleeding, pocket depths and attachment loss levels on 4 sites of each tooth present. Recordings of bleeding, calculus and pocket depths were used to compute CPITN scores based on the 10 index teeth originally proposed, and these CPITN scores were subsequently related to the attachment loss findings derived from the full-mouth assessment. In most cases, persons with a CPITN score < or = 1 did not have attachment loss > or = 4 mm. However, among 40+ year-old persons with CPITN score 2 over 90% had attachment loss > or = 4 mm and over 50% of the 50+ year-olds with CPITN score 3 had attachment loss > or = 6 mm. Less than 20% of the 15-29 year-olds with CPITN score 3 had attachment loss > or = 6 mm, and usually the attachment loss levels ranged between 0 and 3 mm. Beyond the age of 35 years over 10% of the sextants with CPITN score 0 had attachment loss > or = 4 mm. Below the age of 35 years more than one third of all sextants with CPITN score 3 had attachment loss levels < or = 3 mm. Thus, the CPITN findings overestimate both prevalence and severity of periodontal attachment loss among the younger age groups and underestimate these parameters among elderly subject.

Adolescent↗

Characteristics of older adults experiencing periodontal attachment loss as gingival recession or probing depth.

While attachment loss currently is the best field examination indicator that periodontal disease has progressed, this measure is not disaggregated enough to differentiate between attachment loss that results in deeper pockets and attachment loss that results primarily in recession of the gingiva. If these two conditions have different etiologies, then efforts at predicting who will experience the condition from a single, general risk assessment model will be difficult. The purpose of this paper is to determine whether the characteristics of people who experience attachment loss primarily as increased probing depths are different from those people who experience attachment loss primarily as gingival recession. Baseline and 18-month follow-up periodontal measures were gathered on a representative sample of community-dwelling adults aged 65+. Based on measurement errors obtained one week apart on a reliability subsample, a threshold level of 3+mm was set to define attachment loss. Attachment loss was further characterized as resulting from mostly increased probing depth or from mostly increased gingival recession. In mesio-buccal sites, 58% of the people had attachment loss mostly due to increased probing depth with 42% having attachment loss mostly due to gingival recession. For buccal sites, the figures were 24% and 76% respectively. The logistic regression models for both sites indicated that people who had their attachment loss in the form of increased probing depths had different characteristics than people who had most of their attachment loss in the form of gingival recession.(ABSTRACT TRUNCATED AT 250 WORDS)

Black or African American↗

Attachment representations and representations of the self in relation to others: a study of preschool children in inner-city London.

The study examined the relationship between attachment representations and representations of the self in relation to others in a sample of 42 children aged between 4 and 5.9 years. The relationship between children's attachment representations and parents' style of regulating negative affect was also explored. The families were using local authority day-care facilities in a deprived inner-city area of London. The quality of attachment representations was assessed using a modified version of the Separation Anxiety Test. Assessments of the representation of the self in relation to others consisted of (a) assessment of the child's view of self within the relationship with the attachment figure, using an incomplete doll story procedure; and (b) assessment of the child's perceptions of the way others view them using a puppet interview. Significant connections between attachment representations, representations of self in relation to others, and parents' negative affect regulation were found. Children with secure attachment representations had a significantly more positive view of the self in the relationship with the attachment figure than children with disorganized attachment representations, and a significantly more positive perception of the way others view them than children with avoidant attachment representations. Children with secure attachment representations had parents with more adaptive ways of regulating their own negative affect than children with ambivalent or disorganized attachment representations.

Child Day Care Centers↗

Rethinking adult attachment: a study of expert consensus.

Self-report questionnaires designed to assess attachment in adulthood potentially confound global valence of relationships (e.g., liking and disliking) with attachment. The authors surveyed an international panel of experts to develop items for a new measure of attachment that systematically distinguishes between attachment and non-attachment aspects of relationships. The survey yielded a large set of items on which there is consensus in five domains: secure attachment, dismissing attachment, preoccupied attachment, positive non-attachment, and negative non-attachment. This report presents a content analysis of the core themes in each of these five domains and discusses implications of these results for conceptualizing and researching adult attachment.

Adult↗

Stability and change of attachment at 14, 24, and 58 months of age: behavior, representation, and life events.

Stability and change of attachment was examined longitudinally in a group of 48 children at 14, 24, and 58 months of age. Whereas attachment classifications showed stability between 14 and 24 months, lack of stability was the case between either 14 or 24 months and 58 months. Mothers of children who did not exhibit stability of attachment reported more negative and less positive life events. No correspondence was found between attachment classification at 14 or 24 months and mental representations at 58 months. However there was agreement between representational and behavioral measures of attachment at 58 months, where mental representations of attachment appeared to mirror and complement behavioral classification of the attachment relationship with the mother. Evidence for continuity of attachment from infancy to childhood internal representations was found only in a subgroup of children who showed stability of secure attachment between infancy and 58 months of age. These children exhibited greater Emotional Openness in the SAT at 4.5 years. Findings are discussed in terms of different positions in attachment theory and research regarding the stability and change of attachment relationships.

Anxiety, Separation↗

What do we know about maternal-fetal attachment?

A review of the literature suggests that there are three critical attributes related to the concept of maternal-fetal attachment, including cognitive, affective, and altruistic attachment. Cognitive attachment is the desire to know the baby. Affective attachment is the pleasure associated with thoughts of or interaction with the fetus. Altruistic attachment refers to a desire to protect the unborn child. Existing measurements on maternal-fetal attachment are developed based on low-risk and white pregnant women and previous research has not yet resulted in a consistent theoretical model. Future research should focus on development of culturally sensitive instruments and combining qualitative and quantitative measures to broaden theoretical understanding of the concept. Nursing assessment of maternal-fetal attachment is an on-going process. The nurse's role is to reassure those who have developed attachment to their fetuses and to motivate those who are unaware of or unconcerned about their attachment to their fetuses. Collecting data from different attributes of attachment helps nurses identify each woman's attachment patterns and areas of concern.

Affect↗

Maximum dislodging forces of implant overdenture stud attachments.

PURPOSE: The aim of this study was to compare the retention and stability of the Nobel Biocare standard ball (NBS), Nobel Biocare 2.25-mm-diameter ball (NB2), Zest Anchor (ZA), Zest Anchor Advanced Generation (ZAAG), Sterngold ERA orange (SEO), and Sterngold ERA white (SEW) attachments on an implant-retained overdenture model. MATERIALS AND METHODS: The attachments were tested using 2 permanently placed Brånemark System implants on a test model that was attached to an Instron machine (crosshead speed 50.8 mm/minute). Each attachment had one part embedded in a denture-like housing and the other part screwed into the implants. Dislodging tensile forces were applied to the housings in 3 directions simulating function: vertical, oblique, and anterior-posterior. Eight tests were done in 3 directions with 6 samples of each attachment. The dislodging forces generated measurements of the peak load (maximum dislodging force). A 1-way analysis of variance followed by the Tukey studentized range test was used to determine groups that were significantly different. All tests for significance were carried out at the .05 level of significance. RESULTS: Results showed the ZAAG attachment to be the most retentive for the peak load measurement when subjected to vertically directed forces, with mean values and standard deviations of 37.2 +/- 5.5 N. The next most retentive attachment was the NBS, followed by the SEO, NB2, SEW, and ZA. For obliquely directed forces, the ZAAG attachment was the most retentive, with mean values and standard deviations of 27.2 +/- 4.2 N. The next most retentive was the NBS, followed by the NB2, SEO, ZA, and SEW. For anterior-posteriorly directed forces, results showed the NBS had the highest measured retentive force, with mean values and standard deviations of 34.6 +/- 18.8 N, but this was not statistically different from the NB2 and ZAAG; this was followed by the SEO, SEW, and ZA. DISCUSSION: There has been a marked resurgence in the treatment of patients with overdentures using implant attachments as retentive devices. The maximum force developed (a measure of retention) as the implant stud attachments were resisting removal from the implant abutments was determined. CONCLUSIONS: Based on the present study, the clinician may be able to make empirical decisions on attachment selection, depending on the amount of retention desired and the specific clinical situation.

Analysis of Variance↗

[Study on abutment movement of distal removable dentures retained by attachments].

PURPOSE: To study the influence on the abutment movement with three kinds of precision attachments designed for distal-extension removable partial dentures (RPDs). METHODS: Snap attachment, Ceka attachment, Mini-SG attachment were used to retain RPDs. Then food chip was masticated between the upper and lower dentitions on the attachments side. Placement of abutment was measured by LB-72 high-sensitive-laser-traneferring-detector and the data were statistically analyzed for random block analysis of variance. RESULTS: The displacement, inclination, and torsion of the abutment movements in the mesial-distal, bucco-lingual and occluso-gingival directions all had statistical significance (P<0.05). The largest mesial-distal inclination occurred with the Mini-SG attachment. The Ceka attachment produced more abutment displacement in mesial distal and apical directions. Occlusal displacement and anti-clockwise rotation were the least with the Snap attachment. CONCLUSION: The most equitable distribution of stresses on the supporting structures was achieved by Snap attachment with its resilent assemble, Ceka attachment transfers most of the loading forces to the abutments, Mini-SG attachment can not reduce the excessive torque applied to the abutments effectively.

Dental Abutments↗

Emotion regulation: influences of attachment relationships.

Emotion regulation and quality of attachment are closely linked. It has been proposed here that one influence on individual differences in emotion regulation may be a child's attachment history. Individuals characterized by the flexible ability to accept and integrate both positive and negative emotions are generally securely attached; on the other hand, individuals characterized by either limited or heightened negative affect are more likely to be insecurely attached. While acknowledging the role of infant temperament, I have focused on the role of social factors in examining the link between emotion regulation and attachment. The approach to emotion regulation taken here--that emotion regulation is adaptive in helping a child attain her goals--is esentially a functionalist approach (Bretherton et al., 1986; Campos et al., 1983), consistent with earlier views of emotions as important regulators of interpersonal relationships (Charlesworth, 1982; Izard, 1977). It has been proposed that patterns of emotion regulation serve an important function for the infant: the function of maintaining the relationship with the attachment figure. Emotion regulation has been described as serving this function in two ways. First, the function of maintaining the relationship is thought to be served when infant emotion regulation contributes to the infant's more generalized regulation of the attachment system in response to experiences with the caregiver. Infants who have experienced rejection (insecure/avoidant infants) are thought to minimize negative affect in order to avoid the risk of further rejection. Infants whose mothers have been relatively unavailable or inconsistently available (insecure/ambivalent infants) are thought to maximize negative affect in order to increase the likelihood of gaining the attention of a frequently unavailable caregiver. Both these patterns of emotion regulation help ensure that the child will remain close to the parent and thereby be protected. Second, the function of maintaining the attachment relationship is thought to be served when the infant signals to the parent that she will cooperate in helping maintain the parent's own state of mind in relation to attachment. The minimizing of negative affect of the avoidant infant signals that the infant will not seek caregiving that would interfere with the parent's dismissal of attachment. The heightened negative emotionality of the ambivalent infant signals to the parent that the infant needs her and thus helps maintain a state of mind in which attachment is emphasized. The approach to emotion regulation presented here is congruent with much work examining the socialization of emotions (Lewis & Saarni, 1985; Thompson, 1990).

Affect↗

Split-thickness skin graft attachment to bone lacking periosteum.

OBJECTIVES: To develop an animal model to investigate the survival of split-thickness skin grafts (STSGs) on bone without periosteum, to compare STSG attachment to bone with and without periosteum, and to determine the effect of fibrin glue on STSG attachment to bone. DESIGN: Prospective laboratory study. SETTING: University laboratory. SUBJECTS: Sprague-Dawley rats. MAIN OUTCOME MEASURE: Percentage of survival of the STSGs at 2 weeks determined independently by the authors and a third, blinded head and neck surgeon. RESULTS: In experiment 1, which included 40 rats, the sutured STSGs showed an average survival rate of 38% when attached to bone with periosteum, 6% when attached to bare bone, and 10% when attached to bare bone using fibrin glue. The poor survival rate was thought to be attributable to the animals scratching at their bolster dressings. In experiment 2, 18 animals underwent a posteriorly based U-shaped flap of skin and subcutaneous tissue. The grafts were placed and isolated from the overlying flap with a biosynthetic wound dressing. The sutured STSG survival rates were as follows: 87% when attached to bone with periosteum, 94% when attached to bare bone, and 74% when attached to bare bone using fibrin glue. CONCLUSIONS: The survival of STSGs attached to bare bone was comparable to that of STSGs attached to bone with periosteum when grafts were protected with the skin-subcutaneous flap. The STSGs that were fixed with 0.1 cc of fibrin glue demonstrated poorer survival rates than those attached with sutures and were associated with more seromas.

Animals↗

Attachment of cultured human bone cells to novel polymers.

The initial attachment of human bone-derived cells (HBDC) to several polymer systems has been studied in vitro. A novel polymer system based on poly(ethyl methacrylate) polymer and tetrahydrofurfuryl methacrylate monomer (PEMA/THFMA) was compared with a variant in which THFMA was replaced by 2-hydroxyethyl methacrylate (PEMA/HEMA). Tissue culture polystyrene (TCPS) and polystyrene (PS) were used as reference materials. The ability of the substrates to adsorb the attachment glycoproteins fibronectin (Fn) and vitronectin (Vn) from serum and the subsequent effect on radiolabeled HBDC attachment were examined. Initial cell attachment from the medium containing 10% (v/v) serum was highest on TCPS; on PEMA/THFMA and PEMA/HEMA substrates it was about 25% of this level, and on PS it was only 10% of that on TCPS. Attachment of HBDC to all substrates was dependent on the presence of Vn, which, unlike Fn, was able to adsorb in the face of competition from other serum components. Both Vn and Fn were able to support cell attachment when precoated onto all substrates. In comparison to TCPS, PEMA/THFMA did not show enhanced adsorption of either Fn or Vn from serum, and this was reflected in the level of cell attachment. Interestingly, the potency of preadsorbed Fn for cell attachment was much higher on this substrate than on any other: 45 ng/cm2 Fn when adsorbed to PEMA/THFMA gave a level of cell attachment 1.6-fold higher than the same density of Fn on PS or TCPS. The maximum Fn surface density achieved on HEMA/PEMA was 16 ng/cm2. Cells on PEMA/THFMA showed typical clustering of the alpha5 beta1 Fn receptor, but this was not evident in cells attached to PEMA/HEMA even when precoated with Fn. This study indicates that the initial attachment of HBDC to all substrates was Vn dependent. It also indicates that on PEMA/THFMA the favorable presentation of subsequently adsorbed Fn may assist matrix assembly.

Biocompatible Materials↗

Tendons attached to prostheses by tendon-bone block fixation: an experimental study in dogs.

To develop a method of tendon attachment to a metallic endoprosthesis, we evaluated fixation strength, clinical function of the tendon, and morphological changes in an experimental model. The canine supraspinatus tendon was removed from the greater tubercle of the humerus and attached to a titanium prosthesis. In 12 animals, the bone block underlying the tendon insertion was preserved and attached in one limb; the soft part of the tendon was attached directly to the prosthesis in the contralateral limb. Fixation strength was evaluated after 16 weeks of in vivo implantation (12 specimens) and compared with the in vitro fixation strength (12 specimens) and with intact normal controls (six specimens from cadavera). Function of the tendon in vivo was evaluated by force-plate analysis (at 3-week intervals). All specimens were evaluated histologically. Sixteen weeks after surgery, the tendon-bone block attachment was significantly stronger (mean, 16%) than the direct tendon attachment and not significantly different from the normal control, and the direct tendon attachment was significantly weaker (mean, 68%) than the normal control. There was significantly more weight-bearing on the limbs with a tendon-bone block attachment than on the limbs with a direct tendon attachment at both 3 and 6 weeks postoperatively. Both front legs showed increased weight-bearing with time, but the differences were not statistically significant. Anchorage by tissue ingrowth to the titanium prosthesis was found consistently--there was bone ingrowth in the tendon-bone block attachments and fibrous tissue ingrowth in the direct tendon attachments. When a bone block was preserved, the strength and stiffness were comparable with those of a normal tendon insertion.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Development of the indirect flight muscle attachment sites in Drosophila: role of the PS integrins and the stripe gene.

Using markers that are expressed at muscle attachment sites, we have examined the early pupal development (first 36 hr) of Indirect Flight Muscle (IFM) attachments in the fruit fly Drosophila melanogaster. Expression of the Drosophila homologs of vertebrate integrins, the Position-Specific (PS) antigens, is known to differentially mark epidermal (PS1alpha) and muscle (PS2alpha) components of the developing IFM attachment sites. During myogenesis, PS2alpha is detected transiently in imaginal myoblasts that fuse with persistent larval muscles to give rise to the Dorsal Longitudinal Muscles (DLMs), but not in myoblasts that fuse de novo to give rise to the Dorso Ventral Muscles. The integrins are not expressed at attachment sites when the muscle fibers first make their appearance (12-20 hr). Following muscle-epidermal contact, PS1 and PS2 are detected at muscle attachment sites. PS1 expression is at the muscle ends and also in the long epidermal processes that connect the developing muscle fibers to their sites of attachment in the epidermis, while PS2 expression is restricted to the muscle ends. Epidermal cells that will contribute to the adult attachment sites are defined as early as the third larval instar. Both anterior and posterior sites of attachment of the IFMs are marked by the expression of reporter beta-galactosidase activity in a P-element line B14.0, which is an insertion at the stripe locus. B14.0 (stripe) is seen in distinct domains in the wing and leg imaginal discs which give rise to the thoracic cuticle. The expression is maintained during pupal development. The B14.0 (stripe) expressing epidermal cells contact the developing muscle fibers, leading to the formation of the myotendon junction. We show that the dorsal and ventral attachment sites of one group of IFMs, the DVMs arise from two different imaginal discs (wing and leg, respectively), which may explain the differential effect of mutations such as bendless on these muscles. Attachment sites for the other group of IFMs, the DLMs, on the other hand, arise from one imaginal disc (wing). B14.0 (stripe) expression defines epidermal cells of the adult attachment sites and is likely to function during early events leading to the formation of muscle-epithelial contacts. The PS integrins are detected at later stages, suggesting a role in the stabilization and maturation of the muscle-epidermal contacts into myotendon junctions.

Animals↗

Spatial control of neuronal cell attachment and differentiation on covalently patterned laminin oligopeptide substrates.

The spatial control of neuronal cell attachment and differentiation via specific receptor mediated interactions, may provide an effective means for the in vitro reconstruction of neuronal cell architecture. In this study, receptor-specific oligopeptide sequences derived from the extracellular matrix (ECM) molecule laminin, a potent neural cell attachment and differentiation promoter were covalently bound on fluorinated ethylene propylene (FEP) films. The degree of receptor-specific cell attachment and the ability to spatially control neurite outgrowth by covalently patterning the oligopeptide sequences on the FEP film surface were assessed. FEP films were first chemically activated with a Radio Frequency Glow Discharge (RFGD) process that covalently replaces the surface fluorine atoms with reactive hydroxyl groups. Oligopeptides containing the YIGSR sequence from the B1 chain of laminin and the water soluble oligopeptide containing the IKVAV sequence (CSRARKQAASIKVAVSADR) from the A chain were covalently bound to the hydroxylated FEP films. Electron Spectroscopy for Chemical Analysis (ESCA) verified the covalent attachment of the oligopeptides to the material surface. The degree of receptor mediated NG108-15 cell attachment on immobilized CDPGYIGSR films was determined using competitive binding media. A 78% reduction in cell attachment was observed on films containing CDPGYIGSR in the cell plating medium. Only a 23% reduction in cell attachment was noted on films plated in medium containing a mock CDPGYIGSK sequence. FEP films immobilized with the IKVAV oligopeptide sequence were shown to mediate PC12 cell attachment and a competitive binding medium also significantly attenuated cell attachment on the immobilized films. The spatial patterning of these oligopeptide sequences to the FEP surface was shown to localize cell attachment and neurite extension on the patterned pathways. The surrounding unmodified FEP surface was inhibitory in serum containing medium and prevented cellular interactions outside the oligopeptide modifications. The spatial immobilization of laminin oligopeptides on FEP films provides a means to organize the attachment and differentiation of neuronal cells in a receptor-specific manner.

Animals↗

Attachment of Shiga toxigenic Escherichia coli to stainless steel.

Shiga toxigenic Escherichia coli (STEC) are important foodborne pathogens causing gastrointestinal disease worldwide. Bacterial attachment to food surfaces, such as stainless steel may lead to cross contamination of foods and subsequent foodborne disease. A variety of STEC isolates, including E. coli O157:H7/H- strains, were grown in planktonic (broth) and sessile (agar) culture, following which initial attachment to stainless steel was determined using epifluorescence microscopy. Experiments were performed to determine whether the number of bacteria attached to stainless steel differed between STEC strains and between the two modes of growth. No relationship was found between STEC strains and the number of bacteria attached to stainless steel. Five STEC strains, including one non-toxigenic O157 isolate, attached in significantly greater (p<0.05) numbers to stainless steel following growth in planktonic culture compared to sessile culture. In contrast, two clinical strains of O157:H7 attached in significantly greater (p<0.05) numbers following growth in sessile culture compared to planktonic culture. Thirteen out of twenty E. coli strains showed no significant difference (p>0.05) in attachment when grown in planktonic or sessile culture. The change of interfacial free energy between the bacterial strains and stainless steel was calculated and the influence of free energy in attachment was determined. Although a significant variation (p<0.05) in free energy values was found between STEC strains, no correlation was found between free energy values and bacterial counts on stainless steel. In addition, no correlation was also found between bacterial hydrophobicity and surface charge values or production of surface structures (type I fimbriae or flagella) (previously determined) with the number of bacteria attached to stainless steel. The results of this study suggest that different growth conditions (planktonic and sessile) can influence the attachment of STEC to stainless steel. Factors other than bacterial physicochemical properties and these surface structures may also influence STEC attachment to stainless steel.

Bacterial Adhesion↗

Attachment of Acanthamoeba to first- and second-generation silicone hydrogel contact lenses.

PURPOSE: To investigate the attachment of Acanthamoeba to first- and second-generation silicone hydrogel contact lenses, and to determine if patient wear or the presence of a bacterial biofilm coating affects attachment characteristics. DESIGN: Experimental study. PARTICIPANTS AND CONTROLS: Attachment to the silicone hydrogel lenses was compared with that to a conventional hydrogel control lens. Sixteen replicates (n = 16) were carried out for unworn, worn, and biofilm-coated lenses of each type. METHODS: Unworn, worn, and Pseudomonas aeruginosa biofilm-coated first-generation (lotrafilcon A) and second-generation (galyfilcon A) silicone hydrogel and conventional hydrogel (etafilcon A) lens quarters were incubated for 90 minutes in suspensions of plate-cultured Acanthamoeba castellanii trophozoites. MAIN OUTCOME MEASURES: Trophozoites attached to one surface of each lens quarter were counted by direct light microscopy. Logarithmic transformation of data allowed the use of parametric analysis of variance for statistical analysis. RESULTS: Attachment of Acanthamoeba was affected significantly by lens material type (P<0.001), with higher numbers of trophozoites attaching to the first-generation lotrafilcon A silicone hydrogel lens, compared with the second-generation galyfilcon A lens and the conventional hydrogel lens. Attachments to the latter 2 lenses did not differ significantly from each other (P = 0.126). Patient wear and the presence of a bacterial biofilm had no significant effect on attachment to the lotrafilcon A lens (P = 0.426) but did significantly increase attachment to the galyfilcon A (P<0.001) and the etafilcon A (P = 0.009) lenses; attachment to the latter 2 lenses was still significantly less than that found with the first-generation silicone hydrogel (P<0.001). CONCLUSIONS: Acanthamoeba demonstrated a significantly greater affinity for the first-generation silicone hydrogel lens as compared with the second-generation silicone hydrogel and the conventional hydrogel. If exposed to Acanthamoeba (e.g., when showering or swimming, through noncontinuous wear and ineffective lens care regimes), first-generation silicone hydrogel lenses may promote a greater risk of Acanthamoeba infection due to the enhanced attachment characteristics of this lens material. However, prospective studies in patients are required to determine if these experimental results are clinically significant.

Acanthamoeba castellanii↗