Observations on the use and clinical effectiveness of lacebacks.

J Orthod. 2005 Dec;32(4):294-5; author relpy 295-6

Authors: Bennett J

PMID: 16333051 [PubMed - indexed for MEDLINE]

A comparative study of dental arch widths: extraction and non-extraction treatment.

Eur J Orthod. 2005 Dec;27(6):585-9

Authors: Işik F, Sayinsu K, Nalbantgil D, Arun T

The aim of this study was to determine the pre- and post-treatment width changes in the canine, premolar and molar regions in subjects treated with extraction of four first premolars, non-extraction, and non-extraction with rapid maxillary expansion (RME). Pre- and post-treatment orthodontic study models of 60 females (13.83 +/- 2.77 years) and 24 males (14.33 +/- 2.67 years) who underwent comprehensive orthodontic therapy were evaluated. Forty-two were treated non-extraction with fixed appliance therapy, 15 non-extraction with RME, and 27 with extraction of the first premolars. In addition to standard descriptive statistical calculations, one way ANOVA was used for comparison of the groups, and the post hoc Tukey multiple comparison test for comparison of the subgroups. The results revealed that the distance between the upper canines was not affected by the treatment modality. Upper premolar and molar arch widths increased more in the non-extraction subjects when compared with those with extractions, with the greatest increase in patients with RME. In the lower canine area the extraction group showed the widest arch width at the end of treatment. There was also a 0.60 mm decrease in the lower canine width in the non-extraction group. A decrease was found in lower inter-premolar and molar distances due to consolidation of the extraction spaces. When making a decision between non-extraction with maxillary expansion and extraction treatment modalities in borderline cases where there is constriction in the upper inter-premolar distance, apart from taking profile values into consideration, it should be borne in mind that expansion treatment can be helpful in achieving a wider arch form.

PMID: 16257988 [PubMed - indexed for MEDLINE]

Third molar angulation during and after treatment of adolescent orthodontic patients.

Eur J Orthod. 2005 Dec;27(6):590-6

Authors: Artun J, Thalib L, Little RM

The purpose of this study was to analyse the effect of premolar extraction therapy on third molar angulation during active treatment, and to test the significance of such changes on subsequent impaction of the third molars. Lateral cephalograms made before (T1) and after (T2) treatment and at long-term follow-up (T3) of 157 patients treated non-extraction (non-ex) or with extraction of four premolars (ex), all accurately diagnosed for impaction versus eruption of at least one third molar at T3, were evaluated. Linear regression models demonstrated that the maxillary third molars uprighted more from T1 to T2 (P < 0.05) and were less distally angulated at T2 (P < 0.01) in the ex than in the non-ex patients. No such differences were detected in the mandible (P > 0.05). The regression models also showed similar uprighting of the maxillary and mandibular third molars from T1 to T2 and similar angulation of the maxillary third molars at T2 in those patients with subsequent eruption and impaction (P > 0.05), but more mesially angulated mandibular third molars at T2 in the impaction patients (P < 0.01). Chi square testing demonstrated a higher frequency of distal tipping of the maxillary third molars from T1 to T2 in the impaction patients (P < 0.01), while mesial tipping from T1 to T2 of the mandibular third molars occurred with similar frequency in the two patient groups (P > 0.05). Chi square analysis also showed a higher frequency of greater than 30 degree distal angulation as well as an amount mesial angulation of the maxillary third molars at T2 (P < 0.01), and a higher frequency of greater than 40 degree mesial angulation of the mandibular third molars at T2 (P < 0.01) in patients with impaction than in those with eruption.

PMID: 16009666 [PubMed - indexed for MEDLINE]

The effectiveness of laceback ligatures: a randomized controlled clinical trial.

J Orthod. 2004 Dec;31(4):303-11; discussion 300

Authors: Irvine R, Power S, McDonald F

OBJECTIVE: To evaluate the effects of laceback ligatures on the anteroposterior and vertical position of lower incisors and the mesial position of the lower first molars. DESIGN: Randomized controlled trial. SETTINGS: Patients under treatment in the Department of Orthodontics, Royal Bournemouth Hospital, Dorset, during a 6 month period from November 1999 to March 2000. SUBJECTS: Sixty-two adolescents (mean 13.7 years, range 11.2-16.8 years) with similar malocclusions, requiring extraction of all first premolars, were randomly assigned to experimental (laceback: 30; 12 male, 18 female) and control (non-laceback: 32; 14 male, 18 female) groups. INTERVENTIONS: Treatment using upper and lower fixed appliances following extraction of four premolars. One group had lacebacks placed, whilst the control group had no lacebacks. MAIN OUTCOME MEASURES: The participants were examined clinically and radiographically, and lateral cephalograms with radio-opaque tooth markers and lower study casts records were taken when lower fixed appliances were placed (T1) and following sufficient leveling with a 0.018 inch stainless steel round wire (T2). Linear measurements were recorded following digitization of the lateral cephalograms and using a vernier caliper on the study casts. A Student t-test was used to examine differences between the two groups following assessment for normality. RESULTS: In both groups the lower incisors retroclined during T1-T2; (Mean+/-SD: Experimental -0.53+/-1.9 mm, Control -0.44+/-1.29 mm). There was no statistical significance between the two groups (p = 0.84). The lower incisors extruded in both groups; 0.47+/-0.98 mm in the experimental group and 0.44+/-0.87 mm in the control group. There was no statistical difference between the groups (p = 0.9). The lower first molars showed 0.83 mm greater mesial movement in the experimental group, which was statistically significant (p < 0.05). Labial segment crowding decreased in both groups (experimental -3+/-1.6 mm, control -2.67+/-2.28 mm), the difference between the groups being non-significant (p = 0.51). Arch length decreased in both groups (experimental -2.08+/-2.82 mm , control -2.9+/-3.06 mm), but the difference between them was not significant (p = 0.28) CONCLUSIONS: In first premolar extraction cases, the lower labial segment does not procline during the leveling stage with the pre-adjusted edgewise appliance and the use of laceback ligatures conveys no difference in the anteroposterior or vertical position of the lower labial segment. Furthermore, the use of laceback ligatures creates a statistically and clinically significant increase in the loss of posterior anchorage.

PMID: 15608345 [PubMed - indexed for MEDLINE]

Clinical management in extraction cases using palatal implant for anchorage.

J Orthod. 2004 Dec;31(4):288-94

Authors: Giancotti A, Greco M, Mampieri G, Arcuri C

This case report presents a Class I extraction treatment in an adult patient with bimaxillary crowding using a palatal implant for anchorage control. The implant (pure titanium 6 mm SLA) is inserted in the middle of the palate, after a careful radiological assessment on a lateral cephalogram. At the end of the healing period (13 weeks), an anchorage device, such as a squared trans-palatal bar connecting the maxillary molars to the palatal implant, is projected and placed in order to obtain the posterior anchorage control. The orthodontic treatment was performed according to the bidimensional technique.

PMID: 15608343 [PubMed - indexed for MEDLINE]

Maurice Berman Prize 2003.

J Orthod. 2004 Dec;31(4):279-87

Authors: McKeown HF

A crowded, high angle Class II case is presented and illustrated with stage clinical photographs. It was successfully treated with modified Twin Blocks and high pull headgear, extraction of all four first premolars, and upper and lower pre-adjusted edgewise appliances.

PMID: 15608342 [PubMed - indexed for MEDLINE]

Axiographic findings in patients undergoing orthodontic treatment with and without premolar extractions.

Eur J Orthod. 2004 Aug;26(4):427-33

Authors: Heiser W, Stainer M, Reichegger H, Niederwanger A, Kulmer S

Mechanical axiography was performed on 49 (37 female, 12 male) patients prior to orthodontic treatment, after removal of the fixed appliance, and at the end of retention. Twenty-five subjects (mean age 12.8 years) underwent orthodontic treatment without premolar extractions (group 1) and 24 subjects (mean age 13.5 years) with premolar extractions (group 2). The axiographic tracings of the protrusive movements were analysed using a digitizer and specially designed software. A statistically significant increase (P < 0.05) in the values for horizontal condylar inclination (HCI) was found for both groups over the entire observation period. Group 1 showed a higher increase (P < 0.05) between the beginning of treatment and removal of the brackets, and group 2 between bracket removal and the end of retention. At the end of retention, a similar increase in HCI values was found for both groups. Over the observation period, the frequency of pathological axiographic findings decreased, which seems to be a positive effect of orthodontic treatment.

PMID: 15366388 [PubMed - indexed for MEDLINE]

Contemporary treatment of a crowded Class II division 1 case.

J Orthod. 2003 Jun;30(2):119-26

Authors: Lowe CI

A 12-year-old Caucasian male presented with a severe Class II division 1 incisor relationship on a mild Skeletal II base with an average maxillary-mandibular planes angle and average lower facial height. Crowding was severe in the upper arch and moderate in the lower arch. Treatment was commenced using Twin Block appliances, and followed by extractions in all four quadrants and fixed appliances. This case illustrates the versatility of the Twin Block appliance in the treatment of those cases exhibiting crowding.

PMID: 12835427 [PubMed - indexed for MEDLINE]

Forestadent Young Specialist Prize (1999).

J Orthod. 2003 Jun;30(2):101-18

Authors: Morris DO

This paper describes the clinical orthodontic treatment of the three cases that were awarded the 1999 Forestadent Young Specialist Prize. There are two Class II division 1 cases treated by different treatment modalities and a Class II division 2 case complicated by a palatally ectopic maxillary canine. These case reports demonstrate the three main treatment modalities available to the orthodontist for treating skeletally-based malocclusions, i.e. growth modification, orthodontic camouflage, and a combined surgical-orthodontic approach.

PMID: 12835426 [PubMed - indexed for MEDLINE]

The British Orthodontic Society medal of the Intercollegiate M.Orth. of the Royal College of Surgeons of London and Glasgow 2001 and the William Houston medal of the M.Orth. of the Royal College of Surgeons of Edinburgh 2001.

J Orthod. 2002 Jun;29(2):83-95

Authors: Scholey J

PMID: 12114456 [PubMed - indexed for MEDLINE]

Mandibular advancement using an intra-oral osteogenic distraction technique: a report of three clinical cases.

J Orthod. 2001 Jun;28(2):105-14

Authors: Mattick CR, Chadwick SM, Morton ME

Osteogenic distraction has been used for decades to lengthen limbs and now attention is focused upon its use within the craniofacial skeleton. This paper addresses distraction of the mandible. It is proposed that mandibular osteogenic distraction could be a possible adjunct to the orthodontic treatment of those adult patients with skeletal anomalies, who would benefit from combined orthodontic/orthognathic treatment. Three consecutive cases from one unit are presented, where adult patients with severe Class II division 1 malocclusions have undergone orthodontic treatment combined with mandibular osteogenic distraction, instead of conventional bilateral sagittal split osteotomies.

PMID: 11395524 [PubMed - indexed for MEDLINE]

A radiographic comparison of apical root resorption after orthodontic treatment with a standard edgewise and a straight-wire edgewise technique.

Eur J Orthod. 2000 Dec;22(6):665-74

Authors: Mavragani M, Vergari A, Selliseth NJ, B&#xF8;e OE, Wisth PL

The purpose of this study was to compare the severity of apical root resorption occurring in patients treated with a standard edgewise and a straight-wire edgewise technique, and to assess the influence of known risk factors on root resorption incident to orthodontic treatment. The sample consisted of 80 patients with Angle Class II division 1 malocclusions, treated with extraction of at least two maxillary first premolars. Variables recorded for each patient included gender, age, ANB angle, overjet, overbite, trauma, habits, invagination, agenesis, tooth shedding, treatment duration, use of Class II elastics, body-build, general factors, impacted canines, and root form deviation. Forty patients were treated with a standard edgewise and 40 with a straight-wire edgewise technique, both with 0.018-inch slot brackets. Crown and root lengths of the maxillary incisors were measured on pre- and post-treatment periapical radiographs corrected for image distortion. Percentage of root shortening and root length loss in millimetres were then calculated. There was significantly more apical root resorption (P < 0.05) of both central incisors in the standard than in the straight-wire edgewise group. No significant difference was found for the lateral incisors. Root shortening of the lateral incisors was significantly associated with age, agenesis, duration of contraction period (distalization of incisors), and invagination, while root shortening of the central incisors was related to treatment group and trauma.

PMID: 11212602 [PubMed - indexed for MEDLINE]

Optident-ormco 'A' company prize 1998.

Br J Orthod. 1999 Dec;26(4):261-8

Authors: O'Malley AM

PMID: 10592152 [PubMed - indexed for MEDLINE]

Evaluation of apical root resorption following extraction therapy in subjects with Class I and Class II malocclusions.

Eur J Orthod. 1999 Oct;21(5):491-6

Authors: Taner T, Ciğer S, Sençift Y

The purpose of this study was to determine the amount of root resorption during orthodontic treatment, and to examine the relationship between tooth movement and apical root resorption. Twenty-seven Class I and 27 Class II patients treated with edgewise mechanics following first premolar extractions were selected. The following measurements were made on the pre- and post-treatment cephalograms: upper central incisor to palatal plane distance, the inclination of upper central incisor to the FH and AP planes, the perpendicular distances from the incisor tip to the AP and PTV planes, and incisor apex to PTV. The amount of apical root resorption of the maxillary central incisors was determined for each patient by subtracting the post-treatment tooth length from the pre-treatment tooth length measured directly on cephalograms. Intra-group differences were evaluated by the Student's t-test and inter-group differences by the Mann-Whitney U-test. For correlations the Pearson correlation coefficient was used. The results show that there was a mean of approximately 1 mm (P < 0.01) of apical root shortening in Class I patients, but in Class II division I subjects the mean root resorption was more than 2 mm (P < 0.001). The inter-group differences were statistically significant. No significant correlations were found between the amount of apical root resorption and tooth inclination, or the duration of active treatment.

PMID: 10565089 [PubMed - indexed for MEDLINE]

Management of space problems in the primary and mixed dentitions.

J Am Dent Assoc. 1999 Sep;130(9):1330-9

Authors: Ngan P, Alkire RG, Fields H

BACKGROUND: According to the Third National Health and Nutrition Examination Survey, crowding and irregularity remain a consistent problem for children. Management of space problems continues to play an important role in a dental practice. It also represents an area of major interaction between the primary provider and the specialists. This article attempts to update clinicians on the current knowledge of space management. DESCRIPTION OF CONDITION: Proper management of space in the primary and mixed dentitions can prevent unnecessary loss in arch length. Diagnosing and treating space problems requires an understanding of the etiology of crowding and the development of the dentition to render treatment for the mild, moderate and severe crowding cases. Most crowding problems with less than 4.5 millimeters can be resolved through preservation of the leeway space, regaining space or limited expansion in the late mixed dentition. In cases with 5 to 9 mm of crowding, some can be approached with expansion after thorough diagnosis and treatment planning. Most of these cases will require extraction of permanent teeth to preserve facial esthetics and the integrity of the supporting soft tissue. Serial extraction or guidance of eruption is reserved for treatment of severe tooth-size/arch-size discrepancies. Due to variations in the timing and extraction sequence depending on the diagnosis, serial extraction should be reserved for those who can complete the treatment successfully. CLINICAL IMPLICATIONS: The recommended timing of referring patients with moderate crowding to specialists for treatment is in the late mixed-dentition stage of development. Patients with severe crowding will require earlier evaluation for serial extraction.

PMID: 10492540 [PubMed - indexed for MEDLINE]

The William Houston Gold Medal 1997.

Br J Orthod. 1999 Jun;26(2):81-8

Authors: Hickman J

PMID: 10420240 [PubMed - indexed for MEDLINE]

The validation of an orthodontic expert system rule-base for fixed appliance treatment planning.

Eur J Orthod. 1998 Oct;20(5):569-78

Authors: Stephens C, Mackin N

A peer review clinical trial was undertaken to assess the appropriateness of the advice produced by an expert system designed to plan orthodontic treatment in which the pre-adjusted bracket appliance was to be used. The results showed that the expert system's treatment plans were as reliable as those produced by a group of orthodontists. Two members of the panel actually ranked the expert system's plans more highly than their own.

PMID: 9825559 [PubMed - indexed for MEDLINE]

Forestadent Travel Award.

Br J Orthod. 1998 Aug;25(3):165-74

Authors: Moseley HC

PMID: 9800012 [PubMed - indexed for MEDLINE]

Late developing supernumerary teeth in the mandible.

Br J Orthod. 1997 Nov;24(4):293-6

Authors: Cochrane SM, Clark JR, Hunt NP

This paper presents two cases in which supplemental premolars were an incidental finding. Although anomalies of tooth number and form are quite common, both cases demonstrate late forming supernumeraries with one case illustrating their development in a more unusual site. It is not routine practice to screen for late development of teeth during orthodontic treatment. Therefore the possibility of their interference with occlusal development or orthodontic mechanics such as space closure, should always be kept in mind.

PMID: 9459027 [PubMed - indexed for MEDLINE]

The B.S.S.O. M. Orth. Prize of the Royal College of Surgeons of England 1996.

Br J Orthod. 1997 Nov;24(4):285-91

Authors: Spencer RJ

PMID: 9459026 [PubMed - indexed for MEDLINE]

Orthologic Travel Award 1996.

Br J Orthod. 1997 Aug;24(3):197-202

Authors: Thomas PW

PMID: 9313912 [PubMed - indexed for MEDLINE]

Evaluation of treatment and post-treatment changes by the PAR Index.

Eur J Orthod. 1997 Jun;19(3):279-88

Authors: Birkeland K, Furevik J, B&#xF8;e OE, Wisth PJ

To assess the outcome of orthodontic treatment, 224 cases treated in a postgraduate clinic were evaluated. Pre-treatment (T1), post-treatment (T2) and 5-year follow-up (T3) study casts were assessed by the Peer Assessment Rating (PAR) Index. The influence of various factors upon treatment and long-term outcome was analysed. According to the PAR Index, orthodontic treatment reduced the malocclusions on average by 76.7 per cent, and at follow-up the reduction was 63.8 per cent. Follow-up stability was good for 76.3 per cent of the cases. Some cases (4.0 per cent) even improved, while moderate to severe post-treatment relapse occurred in 19.7 per cent of the cases. Orthodontic treatment changed Angle Class I, II and III malocclusions to near ideal occlusion (PAR scores 4.4-6.8). No long-term interaction between the groups was discovered. Sex and extraction/non-extraction treatments did not significantly affect the results. The initial PAR score accounted for 77.8 per cent of the variation in treatment PAR score change (T1-T2), and for 61.8 per cent of the variation of long-term PAR score change (T1-T3). Age at treatment start accounted significantly for the variability of treatment changes (P < 0.001). The PAR score at the end of treatment had some explanatory importance (R2 = 0.099) for the long-term (T1-T3) result. However, PAR score changes in the follow-up period were difficult to predict.

PMID: 9239958 [PubMed - indexed for MEDLINE]

The drum spring (DS) retractor: constant and continuous force for canine retraction.

Eur J Orthod. 1997 Apr;19(2):115-30

Authors: Darendeliler MA, Darendeliler H, Uner O

Although much research has been undertaken on the rate of tooth movement, with different hypotheses having been put forward, the concepts of the threshold, light, heavy and optimal forces are not still clear. It has been stressed that an ideal orthodontic spring should have the ability to release a constant force throughout the entire range of its activation, but using traditional techniques applied initial force will decrease, depending on its deactivation due to the tooth movement and the physical properties of the force delivery system. The purpose of this study was to test the clinical use of a new and original spring, the drum spring (DS) retractor (developed in 1992), which applies a constant and continuous force without the need for reactivation, and to compare the effect of a constant and continuous force versus a continuous but diminishing force produced by a traditional pull coil (PC) retractor system on the rate of upper canine retraction. The clinical sample consisted of 15 patients with upper first premolar extractions. For each patient, the upper right canine was retracted by using a DS retractor applying a constant and continuous force of 50 g; the upper left canine was fitted with a conventional PC applying an initial force of 50 g, diminishing proportionally with the distal movement of the canine. In addition, each group was divided according to the age of each patient: eight patients (three males, five females) between 11.8 and 14.4 years of age (mean 13 +/- 1.2 years) represented the adolescent group, and seven patients (three males, four females) between 18.8 and 21.6 years of age (mean 18.2 +/- 1.9 years) representing the adult group. The experimental period started 1 week after the extraction of the first premolars. During this period no archwire was used, to avoid friction and force level changes, and the both springs were attached to a 6 mm hook fixed on the canine bracket to reduce tipping. The PC retractor was reactivated every 3 weeks whereas the DS retractor was left untouched over the entire experimental period. The study was continued until one of the two canines was completely retracted. The DS retractor was successful for space closure without any reactivation, and the continuous and constant force provided a more rapid canine movement than the continuous but diminishing force. Canine retraction occurred faster in adolescents than in adults. An entire field of clinical and research applications may be influenced by this new type of spring.

PMID: 9183061 [PubMed - indexed for MEDLINE]

Comparison of the changes in facial profile after orthodontic treatment, with and without extractions.

Br J Orthod. 1997 Feb;24(1):25-34

Authors: Bravo LA, Canut JA, Pascual A, Bravo B

A study was made of 31 patients with Angle Class II malocclusion. Fifteen patients did not undergo extraction of teeth (Group A), while 16 underwent extractions of four premolars (Group B). Data was obtained from the corresponding lateral radiographs of the head taken both before and after orthodontic treatment. The main aim of the study was to compare the response of the soft and hard tissues of the facial profile in Class II malocclusion treated with the extraction of four premolars and the response of borderline cases presenting with similar malocclusions, but not subjected to extraction. In this latter group reasonable doubt existed as to whether or not to remove teeth in order to solve the occlusal and aesthetic problems. It is concluded that significant hard tissue differences between the groups at the end of treatment were limited to a more retruded position of the incisors and a reduced overbite amongst those patients subjected to extraction. The main soft tissue differences between the groups at the end of treatment were a more retruded lower lip and a more pronounced lower labial sulcus in those patients subjected to extraction.

PMID: 9088600 [PubMed - indexed for MEDLINE]

The William Houston Gold Medal 1995.

Br J Orthod. 1997 Feb;24(1):1-11

Authors: Smith FE

PMID: 9088597 [PubMed - indexed for MEDLINE]

Mandibular incisor extraction: indications and long-term evaluation.

Eur J Orthod. 1996 Oct;18(5):485-9

Authors: Canut JA

The extraction of a lower incisor constitutes a therapeutic alternative limited to certain occlusal situations, i.e. supernumerary incisors, tooth size anomalies (peg-shaped upper laterals), ectopic eruption and anterior crossbites. The effect of the extraction of a single incisor on the out of retention alignment of lower anterior teeth was studied in 26 treated cases. Initial (T1), final (T2) and 5-8 years out of retention (T3) dental casts were measured. Mean crowding at the start of treatment (T1 = 3.86 mm) relapsed out of retention (T3 = 1.49 mm), with a net mean improvement of 2.37 mm. Little's irregularity index at the start of treatment (T1 = 6.44) relapsed out of retention (T3 = 2.53), with a net mean improvement of T1-T3 = 3.91. Alignment stability seems to be better than that achieved in cases subjected to premolar extraction.

PMID: 8942098 [PubMed - indexed for MEDLINE]

Consistency of orthodontic extraction decisions.

Eur J Orthod. 1996 Feb;18(1):77-80

Authors: Ribarevski R, Vig P, Vig KD, Weyant R, O'Brien K

Ten orthodontists having completed specialist training, examined on two occasions 1 month apart, the complete pre-treatment records of 60 Class II division 1 patients representing the full range of dental malocclusion severity. At each session the orthodontist recorded whether their proposed treatment involved extractions. The level of agreement both between and within the orthodontists was evaluated with the Kappa statistic. Data analysis revealed that the level of agreement within the examiners was good, however the between examiner agreement was poor. It appeared that the orthodontists were applying different criteria in terms of the extraction decision and this has implications for orthodontic patients.

PMID: 8746179 [PubMed - indexed for MEDLINE]

The use of tensor analysis to investigate facial changes in treated class II division 1 malocclusions.

Eur J Orthod. 1996 Feb;18(1):41-54

Authors: Battagel JM

This retrospective cephalometric study examined the facial changes brought about by treatment in 62 Class II division 1 children, using tensor analysis. Thirty-two children were treated with Fr&#xE4;nkel appliances, whilst the remaining thirty received premolar extractions, headgear, and conventional Edgewise mechanics. Each child was matched for age and sex with an untreated individual in whom the occlusion was deemed satisfactory and the treatment changes were compared with those expected during normal development. Results indicated that vertical facial development predominated in both treated groups: this exceeded the increase expected in an untreated population . The Fr&#xE4;nkel group exhibited the greater gain in lower face height, with changes confined almost entirely to the mandible. Effective mandibular position improved but there was no increase in body length. The incisors were more favourably positioned within the face with similar improvements in the soft tissues. Thus, although facial balance was better following a non-extraction Fränkel approach, control of the vertical dimension was inadequate. The fixed appliance group exhibited a smaller increase in lower facial height and no favourable mandibular development: maxillary retraction was the most striking skeletal alteration. By removing the traditional, fixed, superimpositional framework of the cranial base, tensor analysis highlights vertical and mandibular changes not easily detected by conventional cephalometry.

PMID: 8746176 [PubMed - indexed for MEDLINE]

Differentiation-dependent changes in the solubility of a 195-kD protein in human epidermal keratinocytes.

J Cell Biol. 1986 Jul;103(1):41-8

Authors: Ma AS, Sun TT

We have prepared a monoclonal antibody, AE11, that recognizes specifically a 195-kD protein (pI 5.4) of human keratinocytes. This antigen constitutes approximately 0.01-0.1% of total protein in keratinocytes of skin, esophagus, and cornea, and is readily detectable in these cells by immunofluorescent staining and immunoblotting. However, it is barely detectable in MCF mammary carcinoma cells and HeLa cells, and is undetectable in nonepithelial cell types. Results from serial extraction experiments have shown that this protein exists in two distinct pools: a Tris-soluble, and a Tris-insoluble but urea- or SDS-soluble one. The distribution of the 195-kD protein between these two pools appears to be differentiation-related, since relatively undifferentiated cells selected by a low-calcium medium contain primarily the soluble form, while highly differentiated cells contain mainly the insoluble form. Data from immunofluorescent staining and trypsin-sensitivity experiments suggest that the soluble form is cytoplasmic, whereas the insoluble form is submembranously located at the cell periphery of upper, differentiated cells. The insoluble, cell peripheral form of the 195-kD antigen increases progressively during epidermal differentiation; its insolubility appears to be related to the formation of disulfide-bond(s). These results indicate that the 195-kD protein, which has recently been suggested to be involved in cornified envelope formation (Simon, M., and H. Green, 1985, Cell, 36:827-834), undergoes significant changes in its solubility characteristics and intracellular location during keratinocyte maturation.

PMID: 3522606 [PubMed - indexed for MEDLINE]

Description and characterization of a surface lectin from Giardia lamblia.

Infect Immun. 1986 Feb;51(2):661-7

Authors: Farthing MJ, Pereira ME, Keusch GT

The mechanisms by which the human enteric pathogen Giardia lamblia colonizes the proximal small intestine are poorly understood. Although the parasite possesses an attachment organelle on its ventral surface, the "sucking" disk, we considered that like many bacteria and some protozoa, G. lamblia might also have a surface membrane-associated modality for adherence to its host. Using an erythrocyte mixed-agglutination model, we demonstrated a parasite surface lectin with specificities for D-glucosyl and D-mannosyl residues. This lectin is soluble in Triton X-100, is calcium dependent, and is maximally active at pH 5.5 to 6.0. Partial purification was achieved by serial extraction of parasites in Triton X-100 followed by Sephadex G-150 affinity chromatography. The lectin could not be surface radiolabeled with 125I-Bolton-Hunter reagent, but radiolabeling of the hapten eluate from an affinity column produced four bands of 57,000 to 78,000 Mr on sodium dodecyl sulfate-polyacrylamide gels under reducing conditions. The biological function of this lectin is unknown. The presence of mannosyl residues on the luminal surface of human small intestinal epithelial cells suggests that there are receptors for Giardia lectin at the site of colonization.

PMID: 3943906 [PubMed - indexed for MEDLINE]