Microstructural analysis of bony alterations in a historic case of actinomycosis.

OBJECTIVE: Actinomycosis infection of bone is rare and its diagnosis challenging. Here, we aim to identify and verify its microstructural features and the potential value for differential diagnosis. MATERIALS: We investigated the dry preparation of the lumbar vertebrae and pelvic ring of a purported case of actinomycosis documented by a post-mortem examination in 1891. METHODS: Macroscopic inspection, conventional radiology, µCT, 3D reconstruction, and histological examination were employed. RESULTS: All approaches revealed new periosteal bone deposition with increased vascularisation of the os coxa, vertebrae, and sacrum. The µCT revealed cortical loss underneath the new bone formation; the 3D reconstruction and histological examination revealed plexiform bone and granular structures. CONCLUSIONS: The plexiform bone is the result of reactive rapid growth and remodelling processes, and is consistent with pathomorphological findings summarised in the autopsy report (soft tissue abscesses and formation of fistulas caused by "Actinomycosis intestine et ossis ilei sin."). SIGNIFICANCE: This is the first case of a historically documented case of actinomycosis infection investigated by µCT and histology. Different degrees of tissue damage and inflammatory reaction in form of plexiform bone, which has not been reported previously, was identified. LIMITATIONS: The noted bone tissue modifications are not solely pathognomic of actinomycosis; they characterise other diseases, as well. Histological evaluation is not appropriate for identifying the aetiology of the granular structures observed here; but clinically such aggregations appear in tissue affected by actinomycosis. SUGGESTIONS FOR FURTHER RESEARCH: Histochemical and molecular-genetic analyses are obligatory to affirm the diagnosis based on micromorphological features.

Histomorphometric Analysis of Callus Formation Stimulated by Axial Dynamisation in a Standardised Ovine Osteotomy Model.

The cyclic axial dynamisation of a stabilised fracture is intended to promote callus formation and bone healing. Most studies focused on biomechanical properties or the quantity of new bone formation. Far less is known about the quality of newly formed callus tissues, such as tissue distribution and arrangement within the callus. The aim of this current study was to investigate the effect of cyclic, axial dynamisation on the quantity and quality of callus in an established delayed fracture healing model. In 41 sheep transverse osteotomies with a gap size of 3 mm were stabilised with a unilateral external fixator. In 32 of these, fracture ends were axially stimulated with displacement amplitudes of 0.8 mm, 0.4 mm, 0.2 mm, or 0.0 mm, respectively, for six weeks. In the remaining 9 sheep of the control group, an additional external fixator was mounted to achieve almost total rigidity. Animal material originating from a past animal experiment was reanalysed in this study. Histological thin-ground sections were histomorphometrically analysed regarding the histological structure and composition of the defect region. A slight tendency towards an increase in size of total callus area, area of new bone (nB.Ar), and cartilage (Cg.Ar) was detected with increasing displacement amplitudes compared to the control group. At the anterior callus side nB.Ar and Cg.Ar were significantly larger than at the posterior side in all groups independent of treatment. Regarding the quality of callus, areas of very compact bone were predominant in the treatment groups whereas in the control group a slight shift to more porous bone was observed. No difference of callus compactness was observed between the anterior and the posterior side. The established method to assess the local compactness of callus areas is a useful tool to quantitatively determine the spatial distribution of new bone tissue within the callus. The application of this method in combination with biomechanical testing might reveal interesting relations between tissue distribution and bone strength that, with traditional histomorphometry, cannot be identified.

Comparison of a resorbable magnesium implant in small and large growing-animal models.

Fracture treatment in children needs new implant materials to overcome disadvantages associated with removal surgery. Magnesium-based implants constitute a biocompatible and bioresorbable alternative. In adults and especially in children, implant safety needs to be evaluated. In children the bone turnover rate is higher and implant material might influence growth capacity, and the long-term effect of accumulated particles or ions is more critical due to the host's prolonged post-surgery lifespan. In this study we aimed to investigate the degradation behavior of ZX00 (Mg-0.45Zn-0.45Ca; in wt.%) in a small and a large animal model to find out whether there is a difference between the two models (i) in degradation rate and (ii) in bone formation and in-growth. Our results 6, 12 and 24 weeks after ZX00 implantation showed no negative effects on bone formation and in-growth, and no adverse effects such as fibrotic or sclerotic encapsulation. The degradation rate did not significantly differ between the two growing-animal models, and both showed slow and homogeneous degradation performance. Our conclusion is that small animal models may be sufficient to investigate degradation rates and provide preliminary evidence on bone formation and in-growth of implant materials in a growing-animal model. STATEMENT OF SIGNIFICANCE: The safety of implant material is of the utmost importance, especially in children, who have enhanced bone turnover, more growth capacity and longer postoperative lifespans. Magnesium (Mg)-based implants have long been of great interest in pediatric orthopedic and trauma surgery, due to their good biocompatibility, biodegradability and biomechanics. In the study documented in this manuscript we investigated Mg-Zn-Ca implant material without rare-earth elements, and compared its outcome in a small and a large growing-animal model. In both models we observed bone formation and in-growth which featured no adverse effects such as fibrotic or sclerotic encapsulation, and slow homogeneous degradation performance of the Mg-based implant material.

In vivo degradation performance of micro-arc-oxidized magnesium implants: a micro-CT study in rats.

Biodegradable Mg alloys are of great interest for osteosynthetic applications because they do not require surgical removal after they have served their purpose. In this study, fast-degrading ZX50 Mg-based implants were surface-treated by micro-arc oxidation (MAO), to alter the initial degradation, and implanted along with untreated ZX50 controls in the femoral legs of 20 male Sprague-Dawley rats. Their degradation was monitored by microfocus computed tomography (µCT) over a total observation period of 24weeks, and histological analysis was performed after 4, 12 and 24weeks. While the MAO-treated samples showed almost no corrosion in the first week, they revealed an accelerated degradation rate after the third week, even faster than that of the untreated ZX50 implants. This increase in degradation rate can be explained by an increase in the surface-area-to-volume ratio of MAO-treated implants, which degrade inhomogeneously via localized corrosion attacks. The histological analyses show that the initially improved corrosion resistance of the MAO implants has a positive effect on bone and tissue response: The reduced hydrogen evolution (due to reduced corrosion) makes possible increased osteoblast apposition from the very beginning, thus generating a stable bone-implant interface. As such, MAO treatment appears to be very interesting for osteosynthetic implant applications, as it delays implant degradation immediately after implantation, enhances fracture stabilization, minimizes the burden on the postoperatively irritated surrounding tissue and generates good bone-implant connections, followed by accelerated degradation in the later stage of bone healing.

Short-term teriparatide delivery and osseointegration: a clinical feasibility study.

Teriparatide is an anabolic osteoporosis therapeutic agent that can improve healing after fractures and periodontal surgeries. Clinical studies investigating the effects of teriparatide on the osseointegration of titanium implants have not been performed. We conducted an open-label randomized controlled feasibility study and included 24 individuals with edentulous lower jaws. The participants received 2 study implants in the mandible during interforaminal dental implant surgery. They were randomly assigned to receive either 20 µg of teriparatide once daily for 28 days or no treatment. Study implants were retrieved from 23 participants after 9 weeks and were subjected to histomorphometric analyses. Endpoints were new bone-volume-per-tissue-volume (NBV/TV) and new bone-to-implant-contact (NBIC). We report here that median values of NBV/TV in the control and the teriparatide groups were 15.4% vs. 17.6% in the periosteal compartment, 11.3% vs. 16.5% in the cortical compartment, and 7.3% vs. 12.0% in the medullary compartment, respectively. NBIC median values in the control and the teriparatide groups were 3.3% vs. 4.1% in the periosteal compartment, 5.0% vs. 4.4% in the cortical compartment, and 0.3% vs. 1.4% in the medullary compartment, respectively. The results provide the first histological data on the osseointegration of titanium study implants in individuals treated with teriparatide. ClinicalTrials.gov number, NCT00089674.

Atrophy of the residual alveolar ridge following tooth loss in an historical population.

OBJECTIVES: To study the natural aetiopathology of jaw atrophy after tooth loss, unaltered by prosthetic procedures, an historical population without modern dental treatment was examined. METHODS: Based on the hypothesis that there are predictable changes in shape during jaw-atrophy, frequency and degree of atrophy as well as clinical aspects of bone quality and resorption were determined in the skeletal remains of 263 individuals. The potential association between age and frequency/severity of atrophy was analysed. RESULTS: Atrophy in at least one jaw segment was present in 45.2% of the analysed jaw specimens. The residual ridge underwent a series of changes in shape and height following the pattern of resorption described for modern populations. The severity of these alterations was associated with the age of the individual and the region within the jaw. Atrophy was frequently related to structural degradation of the covering cortical layer. CONCLUSIONS: These findings prove that atrophy of the jaw evidently does occur, displaying similar patterns of resorption in a population without modern prosthetics, where the negative effect of ill-fitting dentures is excluded. The basic information about alterations of shape and the cortical layer covering the residual crest might help to provide a deeper insight into aetiopathological mechanisms of this common oral disease.

Caries frequency and distribution in an early medieval Avar population from Austria.

OBJECTIVE: The aim of this study was to determine frequency and distribution of dental caries in an early medieval Avar population from Central Europe, namely Vienna. METHODS: The evaluation of caries was carried out in an anthropological sample consisting of the remains of 136 individuals and included 2215 permanent teeth. Age and sex estimations were based on dental development and on skeletal ageing methods. The presence of dental caries was determined according to clinical aspects using a dental probe. RESULTS: The frequency of ante mortem tooth loss in the sample was 23.8%; the total caries frequency was calculated as 14.9%. The highest caries rate was recorded in the second mandibular molar (34.6%). The most affected tooth surface was found to be the root with 12.7%, followed by the approximal surface with 8.6%, but only 7.7% of the occlusal surfaces were affected by caries. CONCLUSION: This study revealed that Avars suffered from higher caries rates than most other medieval European populations, but experienced a similar dental caries distribution. Attrition of the occlusal surface resulting from a diet containing abrasive particles with accompanying posteruptive tooth movement is considered the major factor causing this premodern caries pattern.

Periodontal histomorphometry and status of aged sheep subjected to ovariectomy, malnutrition and glucocorticoid application.

OBJECTIVE: Ageing, hypogonadism, malnutrition, and the application of glucocorticoids have adverse effects on skeletal homeostasis. Herein we determined to which extent the periodontium undergoes catabolic changes under these conditions in a sheep model. METHODS: Six old sheep with a mean age of 7.5+/-1.0 years were subjected to ovariectomy, calcium/vitamin D-restricted diet, and intramuscular administration of approximately 2g methylprednisolone. Six adult sheep with a mean age of 3.8+/-0.9 years remained untreated and served as controls. First and second premolars of both jaws were subjected to histological analysis. The distances from the gingival margin (GM) and from the alveolar bone crest (ABC) to the cemento-enamel junction (CEJ) were determined. Periodontal attachment was given as the ratio between the dimension of the periodontal ligament and the alveolar bone. Clinical data were collected by counting the number of teeth missing, teeth with gingival recession, and teeth with a probing depth > 4 mm. RESULTS: We report that distance between GM and CEJ (2.1+/-1.7 mm and 6.6+/-2.6mm maxilla; -0.4+/-1.4 mm and 3.2+/-1.5 mm mandible), and between ABC and CEJ (-3.4+/-1.3mm and 1.8+/-2.7 mm maxilla; -3.5+/-1.1mm and -0.1+/-1.4mm mandible) are significantly lower in test than in control animals. In line with these findings, periodontal attachment was 67% in the maxilla and 86% in the mandible of the test group and almost completely preserved in the control group. Clinical evaluation showed that the overall number of teeth with recessions was significantly higher in the test compared to the control group (4.9+/-2.4 and 2.3+/-3.6), but not the number of teeth missing and teeth with a probing depth>4mm. CONCLUSIONS: Together these findings suggest that in sheep, the cumulating effects of ageing, hypogonadism, malnutrition and glucocorticoid application can cause substantial catabolic changes of the periodontium.

Biphasic calcium phosphate ceramics in small bone defects: potential influence of carrier substances and bone marrow on bone regeneration.

OBJECTIVES: Synthetic calcium phosphate bone substitutes such as hydroxyapatite (HA), beta-tricalcium phosphate (beta-TCP) or mixtures are alternatives to autogenous bone grafts. TricOs T((R)) and Collagraft((R)) are resorbable bone substitutes consisting of biphasic calcium phosphate and a bioactive matrix. Both products have a similar HA to beta-TCP ratio, but differ by their matrix. It was the aim of this study to determine the influence of matrix and autologous bone marrow on bone regeneration in a rabbit femoral condyle model. MATERIAL AND METHODS: A critical-sized bicortical channel with a diameter of 4.5 mm was drilled through the femoral condyles in male New Zealand rabbits. Collagraft((R)) with bone marrow harvested from the posterior iliac crest or TricOs T((R)) with and without bone marrow was introduced into the defect. Rabbits were euthanized 8 weeks later. The percentage of newly formed bone was determined by micro-computed tomography. RESULTS: There was no significant difference between bone ingrowth at 8 weeks. Thus, TricOs T((R)) without bone marrow showed similar bone ingrowth as Collagraft((R)) with bone marrow. Furthermore, no increase of bone ingrowth could be achieved by adding bone marrow to TricOs T((R)) in the present setting. CONCLUSION: Both bone substitutes showed similar bone ingrowth in this investigation. Using TricOs T((R)) without bone marrow could avoid donor site morbidity due to harvesting of bone marrow. Further prospective clinical trials will be needed to investigate this approach.

Comparison of the validity of three dental methods for the estimation of age at death.

The aim of the present study was to compare the accuracy, precision, and bias of two macroscopic and one histological age at death estimation methods on human teeth. The sample was comprised of 67 permanent teeth, obtained from 37 individuals aged 20-91 years. Age was predicted according to the methods proposed by Lamendin et al. (LAM), Bang and Ramm (BR), and the quantification of tooth cementum annulations (TCA). TCA was found to be most accurate in all age groups. Its mean absolute error of the estimated age was about half as high as the mean absolute error for both LAM and BR. BR achieved approximately the same mean absolute error as TCA for old adults only. LAM displayed the highest precision in the young and the old age group whereas TCA was more precise in the middle age group. TCA was found to be the most precise method when the precision was calculated for all ages. Considering the bias, all methods displayed a tendency to overestimate age in young and to underestimate it in old specimens. The exception to this rule was TCA, which provided unbiased estimates for young adults. The higher accuracy and precision recommends favouring TCA over LAM and BR, provided that the required know-how and equipment are available.

The chronology of third molar mineralization in the Austrian population--a contribution to forensic age estimation.

The aim of the present study was to determine the chronology of third molar mineralization and to establish Austrian reference data. Therefore, a cross-sectional study was undertaken by evaluating 610 panoramic radiographs in order to assess the mineralization status of the mandibular third molars of Austrian male and female individuals (275 males and 335 females) between the ages of 12 and 24. The evaluation was carried out using the eight grade scheme of Demirjian et al. (1973). Mean ages, standard deviations, standard errors and percentile distributions are presented for each stage of development. Significant differences between the left and right mandibular third molars were not found. Males reach the developmental stages earlier than females, statistically significant differences were noted in stages E and F. Both mandibular third molars were observed in the majority of the individuals of the Austrian sample (477 individuals, 78.2%). For medicolegal purposes the likelihood of whether an Austrian individual is older than 18 years or not was determined.

Bcl-2 expression as a novel immunohistochemical marker for ruptured tubal ectopic pregnancy.

Programmed cell death by apoptosis occurs in fetal and maternal tissues during early pregnancy and plays an important role during implantation, decidualization, and in fetal development. In the regulation of apoptosis, bcl-2 is one of the central controlling genes, and acts by protecting the cell against apoptosis. It is postulated that invasiveness of ectopic trophoblast towards and through the muscularis zone of the tubal wall consequently leading to tubal rupture might be due to disturbed regulation of apoptosis. By means of immunohistochemistry and a computerized image analysis, bcl-2 immunostaining was localized and quantified in 36 randomly selected paraffin-embedded ectopic trophoblast tissue specimens collected from women undergoing surgery for ruptured (n = 18) and non-ruptured (n = 18) tubal ectopic pregnancies. Immunostaining was found in the villi syncytiotrophoblast in all patients, while the percentage of positive bcl-2 immunostained area (%PA) (P = 0.0009) and staining intensity (P = 0.0042) were consistently greater in the group of ruptured ectopic pregnancies. Including the variables %PA and saturation into a logistic regression model for a probability threshold of 0.5 (<0.5 = non-ruptured ectopic pregnancy, >0.5 = ruptured ectopic pregnancy) to identify tubal rupture, a sensitivity and specificity of 94.4% were found. It is suggested that elevated bcl-2 immunostaining in the syncytiotrophoblast layer reflects unlimited cell survival of ectopic trophoblast and could lead to the establishment of a circulating marker for tubal rupture.

Immunohistochemical expression of matrix metalloproteinases 1 and 2 (MMP-1 and MMP-2) and tissue inhibitor of metalloproteinase 2 (TIMP-2) in ruptured and non-ruptured tubal ectopic pregnancies.

OBJECTIVE: Recent evidence suggests that matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) are crucial for trophoblast implantation in normal pregnancy. To evaluate the expression of MMP-1, MMP2, and the tissue inhibitor of MMP-2 (TIMP-2) along the invasive pathway of trophoblast in ruptured and non-ruptured tubal ectopic pregnancies, we performed a retrospective immunohistochemical study. METHODS: In 15 tissue specimens of patients with ruptured (N = 7) and non-ruptured (N = 8) first trimester tubal ectopic pregnancies who underwent laparoscopic salpingectomy, immunohistochemical staining against MMP-1, MMP-2, and TIMP-2 was performed. Serial paraffin sections were photographed and digitized for a computerized quantitative image analysis. Mean percentages of positive stained areas by MMP-1, MMP-2, and TIMP-2 antibodies in the extravillous trophoblast were determined for ruptured and non-ruptured tubal ectopic pregnancies and compared. RESULTS: In our 15 tissue specimens of ectopic pregnancies MMP-1 and TIMP-2 were found to be more prominent in the immunohistochemical distribution pattern than MMP-2. However, no statistically significant difference could be detected between the mean percentages of positive stained area by MMP-1, MMP-2, and TIMP-2 antibodies in ruptured and non-ruptured tubal pregnancies. DISCUSSION: For the first time, we measured the comparative immunohistochemical expression of MMP-1, MMP-2, and TIMP-2 in ruptured and non-ruptured tubal ectopic pregnancies. Although our results did not show any statistically significant difference between ruptured and non-ruptured tubal ectopic pregnancies, we conclude that MMP-1, MMP-2, and TIMP-2 are functionally involved in the highly proliferative early first part of ectopic implantation.