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PubMed2001

Fractional occurrence of defects in membranes and mechanically driven interleaflet phospholipid transport.

The picture of biological membranes as uniform, homogeneous bileaflet structures has been revised in recent times due to the growing recognition that these structures can undergo significant fluctuations both in local curvature and in thickness. In particular, evidence has been obtained that a temporary, localized disordering of the lipid bilayer structure (defects) may serve as a principal pathway for movement of lipid molecules from one leaflet of the membrane to the other. How frequently these defects occur and how long they remain open are important unresolved questions. In this report, we calculate the rate of molecular transport through a transient defect in the membrane and compare this result to measurements of the net transbilayer flux of lipid molecules measured in an experiment in which the lipid flux is driven by differences between the mechanical stress in the two leaflets of the membrane bilayer. Based on this comparison, we estimate the frequency of defect occurrence in the membrane. The occurrence of defects is rare: the probability of finding a defect in 1.0 microm2 of a lecithin membrane is estimated to be approximately 6.0x10(-6). Based on this fractional occurrence of defects, the free energy of defect formation is estimated to be approximately 1.0x10(-19) J. The calculations provide support for a model in which interleaflet transport in membranes is accelerated by mechanically driven lipid flow.

Biological Transport, Active↗
PubMed2005

Trapping Bragg solitons by a pair of defects.

We study collisions of moving solitons in a fiber Bragg grating with a structure composed of two local defects of the grating, attractive or repulsive. Results are summarized in the form of diagrams showing the share of the trapped energy as a function of the soliton's velocity and defects' strength. The moving soliton can be trapped by a cavity bounded by repulsive defects; a well-defined region of the most efficient trapping is identified. The trapped soliton performs persistent oscillations in the cavity, with the frequency in the GHz range. For attractive defects, essential differences are found from the earlier studied case of the collision of a soliton with a single defect: in this case, too, there appears a well-defined region of the most efficient trapping, and the largest velocity, up to which the soliton can be captured, increases. The findings may be significant for experiments aimed at the creation of "standing-light" pulses in the fiber gratings and for related applications. Collisions between identical solitons moving across the two-defect structure are also studied. On the attractive set, soliton-soliton collisions may give rise to symmetric capture of the solitons by both defects or merger into a single pulse trapped at one defect.

Journal Article↗
PubMed1981

Enzyme defects in the porphyrias and their relevance to the biochemical abnormalities in these disorders.

Defects in enzymes of the heme biosynthesis pathway underlie the biochemical abnormalities which occur in the porphyrias. Porphyrins and porphyrin precursors are accumulated and excreted in excessive amounts because of the enzyme defects. This is illustrated by studies in protoporphyria and variegate porphyria, disorders in which the biochemical abnormalities indicate a defect(s) in the terminal part of the heme biosynthesis pathway. The activity of heme synthease (ferrochelatase), which catalyzes the chelation of ferrous iron to protoporphyrin, is deficient in tissues of patients with protoporphyria. This causes protoporphyrin to be accumulated and excreted excessively. In variegate porphyria protoporphyrinogen oxidase, which catalyzes the oxidation of protoporphyrinogen to protoporphyrin, appears to be defective. As a result, protoporphyrinogen may be excreted in increased amounts in bile, where it is subsequently auto-oxidized to protoporphyrin. The following questions have arisen as a result of the demonstrations of enzyme defects in tissues of patients with porphyria: (1) Will different defects in the same enzyme be found among patients who fulfill the clinical and biochemical criteria for diagnosis of a specific porphyria? That is, does genetic heterogeneity exist in each of the porphyrias? (2) Why do some patients with an enzyme defect not have biochemical abnormalities? (3) Why is one type of tissue, usually the liver, the major site of expression of the biochemical abnormality, when the enzyme defect can be demonstrated in all tissues?

Fibroblasts↗
PubMedDate not supplied

Pig chondrocyte xenoimplants for human chondral defect repair: an in vitro model.

The objective of this study was to evaluate the use of cultured porcine chondrocyte xenotransplantation for the repair of human chondral defects. Two-millimeter-diameter defects were drilled into explants of femoral cartilage from healthy adult donors. No cells were implanted in the chondral defects of the control group, while pig chondrocytes from normal femoral cartilage were deposited into the treated chondral defects. Cartilage explants were cultured for 4, 8, and 12 weeks. Tissue sections were processed for standard histologic staining and immunostaining with monoclonal antibodies against types I and II collagen, chondroitin-4-sulfate, chondroitin-6-sulfate, keratan sulfate, and integrin subunit beta1. The porcine origin of chondrocytes was confirmed using a specific pig monoclonal anti-CD46. Repair was only observed in the cell-treated defects. Mono- or bilayers of cells were detected after 4 culture weeks on the bottom of the defects, while after 8-12 weeks a repair tissue filled near 30-40 percent of the defect. At 8 weeks, the newly synthesized tissue was composed of a fibrous mesh including some cells. However, at 12 weeks it showed a hypercellular hyaline-like region. This hypercellular region showed excellent bonding with the native cartilage, cells were located in numerous lacunae, and a high content of proteoglycans as indicated by an intense toluidine blue stain was observed. The repaired tissue showed positive immunostaining for both type I and II collagen, as well as chondroitin-4-sulfate, chondroitin-6-sulfate, keratan sulfate, and integrin subunit beta1. Positive staining for porcine anti-CD46 was localized exclusively in the neo-synthesized tissue. We conclude that xenotransplantation of pig chondrocytes can repair, in an in vitro model, defects in human articular cartilage.

Aged↗
PubMed1988

Heterogeneous defects of platelet secretion and responses to weak agonists in patients with bleeding disorders.

Eleven patients with mild bleeding disorders had as a common abnormality, impaired platelet aggregation and secretion with low concentrations (0.5-1.0 micrograms/ml) of collagen and, in most cases, an absence of second phase aggregation with epinephrine. Platelet granule contents were normal, ruling out storage pool deficiency. To characterize further the platelet abnormalities, we measured aggregation, 14C-5HT secretion, and TxB2 formation induced by a variety of platelet agonists. In eight of the 11 patients we observed decreased initial rates as well as extents of aggregation with one or more weak agonists (ADP, epinephrine, thromboxane A2 and the endoperoxide analogue U44069), i.e. agonists which induced secretion only as a result of aggregation, but normal responses to strong agonists such as arachidonate and high (10 micrograms/ml) concentrations of collagen, which can induce secretion in the presence or absence of aggregation. In all of these patients, TxB2 formation with arachidonate and all concentrations of collagen was normal. The platelet defects in these eight patients have been designated as weak agonist response defects (WARDs). In contrast, the initial aggregation responses to all weak agonists were normal in the three other patients, while secretion and TxB2 formation induced by strong agonists were impaired. Thus, in contrast to the eight patients above, the platelet defects in these three patients were characteristic of defects in the secretion response per se. The results obtained in the 11 patients studied indicate that these types of platelet disorders, previously referred to as primary secretion defects, include defects in the initial platelet responses which precede secretion (WARD) as well as defects in the secretory mechanism per se. Both groups of defects appear to be heterogeneous in nature.

Adult↗
PubMed1986

Direct demonstration of immunoregulatory T-cell defects in patients with systemic lupus erythematosus.

The present study was undertaken to determine directly whether immunoregulatory T cells have a defective suppressor function in patients with systemic lupus erythematosus (SLE), and whether anti-T-cell antibodies are essential for immunoregulatory T-cell defects. Peripheral blood T cells and T-cell subsets were determined in 52 SLE patients. The ratio of T4 to T8 cells was distributed over a wider range in patients with SLE than in the controls. Patients with SLE were divided into three groups (low, normal and high) by the T4/T8 ratio. Lymphocytes from 12 SLE patients (7 with low and 5 with high T4/T8 ratios) were studied extensively. Their disease was inactive or in remission. Anti-T-cell antibodies were not detected, and yet the patients had immunological abnormalities characterized by the presence of antinuclear antibodies and hypergammaglobulinaemia. The SLE patients with high T4/T8 ratios had a decreased number of T8 cells, and defective suppressor-effector cells. In contrast, patients with low T4/T8 ratios had decreased T4 cells and/or increased T8 cells, and defective suppressor-inducer cells. Two patients with low T4/T8 ratios had both suppressor-effector and suppressor-inducer cell defects. These results indicate that immunoregulatory circuits in SLE patients are heterogeneous and that immunoregulatory defects exist even when the disease is inactive or in remission. Anti-T-cell antibodies were not essential for such immunoregulatory defects. Thus, immunoregulatory T-cell defects and the development of SLE may be independent conditions due to other unknown causes.

Adult↗
PubMed2006

Sperm morphology and aneuploidies: defects of supposed genetic origin.

As individuals with genetic sperm defects are intracytoplasmic sperm injection candidates, the study of the chromosomal constitution of their spermatozoa is of great interest. This study is a review of the current literature concerning fluorescence in situ hybridisation studies in spermatozoa with genetic sperm defect as 'round head', 'dysplasia of fibrous sheath' (DFS), 'primary ciliary dyskinesia' (PCD), the 'detached tail' and the 'absence of fibrous sheath'. Regarding sperm head defects, elevated XY disomy and diplodies were detected. Genetic defects affecting the sperm tail seemed to have a different correlation with chromosome meiotic segregation. Only chromosome 18, among the autosomes, was studied and the percentage of frequency of disomy was generally within the normal range. In the more frequently studied defect, DFS, the alterations in gonosome disomy and diploidy were recorded by different groups. Regarding PCD defects, elevated frequencies of disomy of sex chromosomes and diploidy were observed, whereas the absence of the fibrous sheath and the detached tail did not show any meiotic disturbance. The problem of genetic sperm defects should be seriously considered when these sperm are used for assisted reproduction, owing to the high risk of transmission of chromosomal imbalance and of mutations that could cause genetic sperm defects in offspring.

Aneuploidy↗
PubMed1995

Limb reduction defects in South America.

OBJECTIVE: Limb reduction defects were considered as possible indicators of environmental teratogenesis; it was suggested that also invasive prenatal procedures could increase the risk for limb reduction defects. The purpose of this work is to give a baseline frequency for limb reduction defects, using data from a population not exposed to prenatal diagnosis procedures. DESIGN: Using data collected in the period 1967 to 1992 within the frame of the Latin American Collaborative Study of Congenital Malformations which clinically examined 2,917,074 newborn infants, a total of 1715 with limb reduction defects were found. All cases were classified and analysed in 25 categories. Geographic differences in recorded rates were tested by chi 2 for homogeneity. Secular trends were analysed using chi 2 test for linear trends. RESULTS: The overall birth prevalence rate of limb reduction defects among liveborn infants was 4.91(per 10,000 births) (3.05 for isolated and 1.85 for associated cases). For stillbirths, the total prevalence was 26.73/10,000 (5.53 for isolated and 21.20 for associated cases). The inclusion of the brachydactylies increased those figures to 5.55/10,000 (3.39 for isolated and 2.16 for associated cases), and 27.42, respectively, (5.53 for isolated and 21.89 for associated cases). When isolated and associated cases were considered together, a geographic heterogeneity was found in pre-axial limb reduction defects; there was also some heterogeneity for amputations. A maternal age effect was found for the isolated hypoplasias. Standardising by maternal age, the overall prevalence of limb reduction in liveborn infants was 5.66 per 10,000 (95% CI = 5.38-5.93). An increasing trend was suggested by the isolated form of distal amputations which involved hands, feet, or digits. CONCLUSIONS: Our data suggest that clustering limb reduction defects in wide groups as transverse and longitudinal may lead to heterogeneous entities. When a possible association is suspected, it would be preferable to present and analyse data in the most discriminant form available. Due to the maternal age effect, it would be advisable to standardise the rates of transversal limb reduction defects by this variable.

Chi-Square Distribution↗
PubMed1997

Exoanal ultrasound of the anal sphincter: normal anatomy and sphincter defects.

OBJECTIVE: To describe the sonographic appearance of normal anal sphincter anatomy and sphincter defects evaluated with a conventional 5 MHz convex transducer placed on the perineum. DESIGN: Prospective, single-blind study. SETTING: Department of Obstetrics and Gynecology, University of Michigan Medical Center, USA. POPULATION: Twenty-five women with symptoms of faecal incontinence, 11 asymptomatic nulliparous women, and 32 asymptomatic parous women. METHODS: A convex scanner was placed on the perineum with the woman in lithotomy position. Images were taken at three levels of the sphincter canal. Pictures were evaluated by two examiners who were blinded to the case history of the women and to the results of each other for the presence or absence of sphincter defects. MAIN OUTCOME MEASURES: Description of anal sphincter appearance on endoanal ultrasound. Reproducibility of the evaluation of sphincter defects. RESULTS: The internal anal sphincter is visible as a hypoechoic circle; the external anal sphincter shows a hyperechoic pattern. Proximally the sling of the puborectalis muscle is visible. Sphincter defects were detected in 20 women. In all five women who subsequently underwent surgery, the presence and location of the defect was confirmed at the time of surgery. Examiners were in agreement 100% of the time on the presence or absence of internal defects. They disagreed in one patient on the presence of an external defect. CONCLUSION: Exoanal ultrasound provides information on normal anatomy and on defects of the anal sphincter.

Adult↗
PubMed2005

Paravaginal defects: a comparison of clinical examination and 2D/3D ultrasound imaging.

BACKGROUND: Paravaginal defects are often assumed to be the underlying anatomical abnormality in anterior compartment descent. Neither clinical examination nor ultrasound assessment are generally accepted diagnostic modalities. AIMS: To compare clinical examination and translabial 3D ultrasound in the detection of such defects. METHODS: Fifty-nine women without previous prolapse or incontinence surgery were seen prospectively. Clinical and ultrasound assessments were carried out in blinded fashion. 3D translabial ultrasound was undertaken after voiding and supine. Volumes were acquired at rest, on Valsalva and on levator contraction. Loss of paravaginal support ('tenting') in the axial plane was taken to signify paravaginal defects. RESULTS: Paravaginal defects were reported clinically in 14 cases on the left (24%), 19 times on the right (32%). Two 3D ultrasound examinations did not yield satisfactory volumes, leaving 57 for analysis. Neither midsagittal nor coronal views yielded data that correlated with clinical assessments. In the axial plane there was absence of tenting at rest in 32/57 (57%) patients, but this did not correlate with clinical findings. Loss of tenting on Valsalva was observed less often (21/57, 37%) and was weakly associated with clinically observed lateral defects (P = 0.036). CONCLUSIONS: Pelvic floor ultrasound in midsagittal, axial or coronal planes does not correlate well with clinical assessment for paravaginal defects. This could be due to poor clinical assessment technique or limitations of the ultrasound method. On the other hand, paravaginal defects may be uncommon or clinically irrelevant. On present knowledge, the paravaginal defect has to be regarded as an unproven concept.

Adult↗
PubMed1995

Freehand technique to harvest partial-thickness skin to repair superficial facial defects.

BACKGROUND: The freehand-scalpel technique to harvest skin for grafting is a forgotten surgical art. Modern facial surgeons prefer to use local skin flaps or Wolfe-type full grafts to repair facial defects. OBJECTIVE: To determine the relative merits and cosmetic results of freehand skin grafts to cover facial defects following Mohs surgery. METHODS: We used the freehand-scalpel technique to harvest skin from the periauricular region of the neck and cheek, and other sites. After a local anesthetic is injected the number 15 or 10 blade is used to harvest skin by sequential tangential incisions. The average dermal thickness was about 1.0 mm. To improve cosmetic appearance, the overall shape and thickness of the graft was contoured during harvesting to fit cosmetic unit or facial line. RESULTS: For more than 5 years we have used the freehand technique to repair superficial facial defects of the nose, ear, scalp, temple, forehead, and other nonhead sites. A total of 65 freehand procedures were performed to repair facial defects. The distribution of the anatomic sites and sizes are presented. The size ranged from less than 1 cm to greater than 5 cm in diameter. Three typical cases are presented to illustrate the gratifying results that can be obtained with this technique. CONCLUSIONS: In selected sites and patients, the freehand graft is a rapid and convenient method of harvesting skin. When harvested from the preauricular cheek and subauricular neck, the graft is a good match to cover sun-exposed defects of the nose and ear. The major advantages of the freehand technique are that: 1) it expands the number of potential donor sites from which to select the most compatible skin to cover facial defects; 2) it allows the surgeon to efficiently configure the graft to the desired shape and depth to conform to the cosmetic unit or defect that is being reconstructed; 3) it does not require a dermatome or other specialized instrument to perform; and 4) it achieves wound repair with good appearance and function. The freehand partial-thickness skin graft has become our preferred method of grafting superficial facial defects.

Ear↗
PubMed2004

Trilobed skin flap on the face: for reconstruction of full-thickness or commissural defects.

BACKGROUND: Although many local skin flaps have been described for reconstruction of defects on the face, there are still some difficulties in reconstruction of full-thickness defects of alar and ear region and commissural defects in periorbital and perioral region. OBJECTIVE: A trilobed skin flap can offer single-stage reconstruction of difficult full-thickness or commissural defects. We performed trilobed skin flaps in reconstruction of the defects on the face. The design of the flap and outcomes of the procedures are presented. METHODS: Twelve patients with skin cancer on the face were operated under general or local anesthesia. After tumor resection, defects were closed with a trilobed skin flap. Patients were followed-up for a minimum 6 months. RESULTS: There was no early or late complication in all patients. Oral competence was achieved in reconstruction of the oral commissure. A new lateral canthus with angles as in the original one was created. Alar and ear reconstructions were performed at one session using the same flap without a graft. The outcome was satisfactory. CONCLUSION: Because it is easy to obtain a trilobed skin flap, it can be used for reconstruction of canthal, oral, and commissural defects, and the new canthus, mouth, and commissures with angles as in the original ones can be created. In addition, the flap can be used for reconstruction of full-thickness defects in the alar region and the ear.

Aged↗
PubMed2006

Reducing opposed multilobed flaps results in fewer complications than traditional repair techniques when closing medium-sized defects on the leg after excision of skin tumor.

BACKGROUND: The reducing opposed multilobed (ROM) flap involves a series of transpositions effected cephalic and caudal to the primary defect, sequentially mobilized toward and then into the primary defect. OBJECTIVE: To compare the ROM flap with other techniques to close defects below the knee after excision of skin tumor. METHOD: This retrospective study compares 140 defects closed with a ROM flap with 85 defects closed with traditional techniques. RESULTS: A total of 225 defects between 11 and 44 mm in diameter were excised over 3 years from July 1, 2002. There were 140 defects closed by ROM flap and 85 non-ROM closures including 29 "O-to-Z" flaps and 12 bilateral transposition flaps. A total of 111 squamous cell carcinomas, 64 basal cell carcinomas, and 11 melanoma were excised. ROM flap closures developed 20 complications (14.3%): 13 infections, 5 partial dehiscence, and 2 partial end flap necrosis. Non-ROM closures developed 27 complications (31.8%): 13 infections, 6 partial end flap necrosis, 4 partial dehiscence, 2 wound depression, 1 hemorrhage, and 1 persisting pain. Three ROM and 7 non-ROM cases suffered two complications. The total complication rate was significantly lower with ROM flaps (p=.003), including lower end flap necrosis incidence (p=.027). CONCLUSION: The ROM flap results in fewer complications than traditional techniques when closing defects 11 to 45 mm in size on the leg and foot. In particular, end flap necrosis incidence is lower with ROM flap closure.

Basal Cell Carcinoma↗
PubMedDate not supplied

The effects of beveling the margins of articular cartilage defects in immature dogs.

Eight 4 month old crossbred puppies underwent surgery simulating treatment of osteochondritis dissecans. Both humeral heads were exposed by a caudal approach to the shoulder joint. In one, an 8 mm circular, full-thickness cartilage defect was created so that the remnant cartilage margin was perpendicular to the joint surface. In the other, a similar 8 mm defect was created with the chondral margins beveled at approximately 45 degrees. There was no clinical lameness in any of the dogs. At necropsy after 16 weeks, the cartilage defects with beveled edges were significantly larger (11.0 +/- 0.6 mm SD) than those with perpendicular edges (8.0 +/- 0.1 mm SD), because of the beveling (p = 0.0039). Fibrocartilage was present but did not always completely fill the defects. Articular surfaces of the glenoid cavities suffered erosion and fibrillation more frequently opposite beveled defects than opposite defects with vertical walls (p = 0.0312). This was presumably due to the larger apposing defect. It was concluded that the cartilage margins surrounding a chondral defect should not be beveled.

Animals↗
PubMed2006

Induction of a barrier membrane to facilitate reconstruction of massive segmental diaphyseal bone defects: an ovine model.

OBJECTIVES: To report an ovine model that can be used to evaluate the efficacy of bone substitutes for repair of segmental diaphyseal bone defects. STUDY DESIGN: Experimental study. ANIMALS: Eleven 2-year-old Pré-Alpes Sheep. METHODS: Mid-diaphyseal metatarsal bone defects (25 mm long) were stabilized by a dynamic compression plate over a polymethylmethacrylate (PMMA) cement spacer, and by external coaptation. The PMMA spacer was removed at 6 weeks by incising the encapsulating membrane. The defect remained unfilled (Group 1; n=5) or was filled with morselized autologous corticocancellous graft (Group 2; n=6), the membrane sutured closed, and external coaptation applied for 6 months, when healing was evaluated. RESULTS: Radiographic, computed tomographic, and histologic examinations at 6 months after the 2nd surgery revealed non-union in ungrafted defects whereas grafted defects showed bone healing. The induced membrane had blood vessels, CBFA1+ cells, and very few macrophages entrapped in a collagenous tissue positive for type I collagen. CONCLUSION: This ovine metatarsal defect model resulted in a critical-size defect (non-union) that healed when grafted. The PMMA-induced membrane constrained the graft, was well vascularized, and may have osteogenic properties. CLINICAL RELEVANCE: This model may be useful to evaluate new strategies in bone tissue engineering because the PMMA-induced membrane may help confine bone morphogenetic proteins, skeletal stem cells, or other agents to the defect cavity where they could be useful to enhance bone formation.

Animals↗
PubMed1980

Interproximal periodontal intrabony defects. Prevalence, localization and etiological factors.

The purpose of the present investigation was to study the distribution of interproximal periodontal intrabony defects as related to age, sex and localization, and to examine the relationship between some possible etiological factors and the occurrence of intrabony defects. A total of 209 adult patients presenting for dental treatment at the Royal Dental College in Arhus participated in this study. The patients were subjected to a questionnaire and were examined clinically and radiographically. All osseous defects in the radiographs were recorded but only those with a depth and width of a least 2 mm were considered periodontal intrabony defects. Only 18% of the participants had one or more periodontal intrabony defects but the prevalence was higher in older than in younger age groups. While periodontal intrabony defects occurred with the same frequency on the various tooth types, more defects were found on distal than on mesial surfaces. The presence of periodontal intrabony defects correlated with loss of attachment, increased tooth mobility, a wide interproximal space and open mesio-distal contact relationships between the teeth.

Adolescent↗
PubMed1998

GTR therapy of intrabony defects using 2 different bioresorbable membranes: 12-month results.

This prospective split-mouth study was designed to compare the clinical and radiographic healing results in intrabony periodontal defects 12 months after GTR therapy with 2 different bioresorbable barriers. The study comprised 25 healthy patients with one pair of contralaterally located intrabony defects with a probing pocket depth of > or = 6 mm and radiographic evidence of angular bone loss of > or = 4 mm. The 2 defects of each patient were randomized for treatment either with polylactic acid (PLA) membranes or with polyglactin-910 (PG-910) membranes. The patients received systemic doxycycline (100 mg/d) for 11 days postoperatively. One blinded examiner recorded the following clinical parameters using a pressure calibrated probe at baseline and after 12 months: papillary bleeding index (PBI), gingival recession (REC), probing pocket depth (PPD), and probing attachment level (PAL). The vertical relative attachment gain (V-rAG) was calculated as a % of the PAL gain related to the maximum possible attachment gain (expressed by the intraoperatively measured depth of the osseous defect). Geometrically standardized intraoral radiographs were quantitatively evaluated for bone changes (density, area) in the defect region using digital subtraction radiography (DSR). Clinical and radiographic data were statistically analyzed using the Wilcoxon-signed-rank test (alpha=0.05). Postoperative membrane exposures occurred in 9 PLA and 13 PG-910 treated sites. After 12 months of healing, both barrier types provided significant PPD reductions and PAL gain [median (25/75 percentile)]: deltaPPD [PLA: 3.0 (2.0/4.0) mm; PG-910: 3.0 (2.0/4.5) mm]; deltaPAL [PLA: 3.0 (2.5/4.0) mm; PG-910: 2.0 (1.0/4.0) mm]. V-rAG amounted to 60% in PLA sites and 54% in PG-910 sites. DSR revealed significant bone density gain after 12 months. 58.3% of the initial defect area in PLA sites and 54.0% of the initial defect area in PG-910 sites showed bone density gain. Neither clinical nor radiographic data revealed any significant difference between the 2 barrier types after 12 months. In conclusion, this 12-month study demonstrated that PLA and PG-910 membranes provided similar favorable regeneration results in deep intrabony periodontal defects.

Adult↗
PubMedDate not supplied

Radiographic detection of defects of the nasal boundaries.

The sensitivity of conventional radiography for lesions of the cribriform plate, naso-orbital wall, lateral nasal wall and hard palate was investigated in 13 canine cadaver heads by creating measured defects in these structures. The location of the perforations were marked with a thin copper wire and the radiographic appearance of the defects was evaluated retrospectively by a single reviewer. Despite demarcation cribriform plate destruction of 2 mm could not be detected. Defects of 3 mm were detected in only 2 heads, 4 mm defects in 1 further head, an oblong 4 x 10 mm defect in 7 heads and in the remaining 3 heads only a 10 x 10 mm defect became visible as such. The naso-orbital wall had to be destroyed in its whole vertical length for detection of a defect in ventrodorsal or dorsoventral views. Therefore conventional radiography is of low diagnostic value for these lesions. Defects of 2 mm in the lateral nasal wall and the hard palate could be detected confidently in all heads indicating high sensitivity of conventional radiography. Soft tissue opacification did not alter the detectability of any nasal border structure lesion.

Animals↗