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PubMed2000

Bilateral accessory iliac horns: pathognomonic findings in Nail-patella syndrome. Scintigraphic evidence on bone scan.

Nail-patella syndrome is a rare hereditary (autosomal dominant) disorder, also called hereditary osteo-onychodysplasia and Fong's syndrome. Its incidence is 4.5 per million population in the United States. Patients have a characteristic tetrad of pathologic symptoms including fingernail dysplasia, hypoplastic or absent patellas, radial head dislocation, and iliac horns. Soft-tissue changes and renal dysplasia have also been associated with the syndrome. Iliac horns are bilateral accessory outgrowths consisting of cortex and medulla continuous with the iliac bone. They are located at the site of attachment of the gluteus medius muscles and project posterolaterally. These smooth bony outgrowths are asymptomatic, frequently palpable, and, because they have no effect on gait, they need not be treated. Iliac horns are the pathognomonic feature of Nail-patella syndrome; that is, they occur in approximately 80% of cases and are observed only in this condition. Four patients (two female, two male) with Nail-patella syndrome have been examined in the authors' department: three family members, including a 37-year-old woman, her 18-year-old son, and her 15-year-old daughter, and an unrelated 26-year-old man. All patients, regardless of age or sex, had similar pelvic findings on their bone scans. Although whole-body scans were obtained in all patients, significant scintigraphic findings were observed only in the pelvis in all the patients examined. This is most likely the result of the mild nature of the related deformities, which do not yield scintigraphically detectable osteoblastic changes. A representative image showing these independent ossification on a Tc-99m MDP bone scan is presented. A conventional pelvic radiographic image of the same patient's pelvis is presented for comparison.

Adolescent↗

PubMed1999

Penicillin reduces new bone formation in acute otitis media.

OBJECTIVE: Previous studies have shown that acute otitis media alters modeling dynamics in bone tissue structures surrounding the middle ear cavity. Initial resorption is followed by formative activity, which is seen as massive osteoneogenesis. However, neither resorptive nor formative activity occurs in the otic capsule, supporting the theory on existence of a perilymphatic barrier of specialized bone. STUDY DESIGN: To investigate the effect of penicillin administration on the pathological bone modeling in acute otitis media, we employed a rat model of acute pneumococcal otitis media. METHODS: Five rats were sacrificed on postinoculation days 4, 8, 16, 90, and 180, preceded by oral administration of penicillin V 100 mg/kg per day, initiated on day 2 and lasting 5 (2) days. Using a light microscope, bone histomorphology was registered and the thickness measured in four well-defined localities, followed by comparison with a previous study of untreated animals. RESULTS: Measured bone thickness was unaffected by treatment on day 4, but significantly reduced in two localities on day 8 and in all localities on following days of sacrifice. Bone cytomorphology and histomorphology were otherwise unaffected by penicillin administration. CONCLUSION: Penicillin reduces new bone formation in acute otitis media, leaving other features of histomorphology unchanged.

Acute Disease↗

PubMed2001

[Intramedullary fixation of humerus shaft fractures. An analysis of complications of 2 implants with special reference to outcome after management with the unreamed humerus interlocking nail].

INTRODUCTION: Operative treatment of humeral shaft fractures has gained a new impetus with the development of intramedullary interlocking systems for the humerus. Because of the anatomical structure of the humeral marrow cavity, a regular jamming of nail into bone is not to be expected, so that the stability of these systems needs to be achieved through an interlocking mechanism. Among the commercially available interlocking nailing systems the unreamed humeral nail (UHN) and the Seidel-nail (SHN) can be regarded as the standard implants. DESIGN: In a retrospective study comparing two groups of patients, each treated with one of the two systems, problems and advantages, as well as disadvantages were analyzed, and the complications inherent in the systems examined. PATIENTS: Between 1988-1992, 47 patients with humeral shaft fractures were treated with a Seidel interlocking nail: 25 acute and 18 pathological fractures as well as 4 non-unions (Group 1). Between 1997-1999, 34 patients with humeral shaft fractures were treated with the unreamed humeral nail (UHN). A total of thirty-five (n = 35) nailings (30 acute and 4 pathological fractures, as well as one re-osteosynthesis after emergence of a non-union) were carried out. Three primary palsies of the radial nerve ensued: two with loss of sensitivity, and one complete paralysis (Group 2). METHODS: Based on pre- and postoperative X-rays and follow-up examinations, the healing process and complications inherent in each of the systems were evaluated. RESULTS: Intra-operative complications of Seidel-nailing (Group 1) were seen in 5 cases: failure of the proximal target device in 2 (4.2%) cases; the breaking of the long screwdriver during the distal locking in 1 (2.1%) case; blockade of nail-insertion due to the spreading distal lamellas in 1 (2.1%) case; in 1 (2.1%) case it was impossible to find the imbus of the distal locking screw with the screwdriver. Incorrect surgical technique resulting in further fragmentation of the shaft required revisions in 2 (4.2%) cases. In 3 cases (6.4%), the insertion of the nail was insufficient, so that an impingement resulted. In 12 cases, postoperative complications after Seidel-nailing resulted: 3 (6.4%) radial nerve palsies, of which 2 (4.2%) were transitory; 3 (6.4%) infections; in 3 (6.4%) cases, loosening of the locking bolt inserted in the frontal plane; in 1 (2.1%) case, loosening of the distal spreading screw. The system failed in treating 2 (of 4) non-unions, whereas successful ossification and repair occurred in all acute fractures. In Group 2 (UHN) the acute fractures of 33 cases healed without complications. Intra-operative complications of the unreamed nail: in 2 cases (5.6%), failure of the target devices resulted in malpositoning of interlocking screws. The following intra-operative complications of the retrograde technique were observed: burst of a fragment at the insertion site in 1 case (2.8%); intra-articular positioning of the most proximal interlocking screw in another case (2.8%). Postoperative complications of the unreamed nail: breaking of a proximal and a distal interlocking screw in 1 case (2.8%), which had no influence on the healing progress. In 1 case (2.8%) both proximal interlocking screws came loose and a non-union ensued. After re-osteosynthesis with the same technique, bony repair was achieved. CONCLUSION: The possibilities of operative methods in treatment of humeral shaft fractures are enhanced by intramedullary interlocking systems. Comparing with the Seidel nail, the unreamed humeral nail (UHN) has two advantages: it can be inserted anterogradely as well as retrogradely, and it provides the possibility of compressing the fracture, resulting in a high rotational stability. Due to these results, the application of the UHN is recommended.

Adult↗

PubMed1997

[Heterotopic (extraosseous) calcification (calcinosis). Etiology, pathogenesis and clinical importance].

Heterotopic tissue calcification represents a pathological event which goes along with active extra- and intracellular metabolic processes. The heterotopic calcification is not the manifestation of tissue ageing. Aetiologically, metastatic calcification, dystrophic calcification and genetic-hereditary calcification are distinguished. Two pathogenetic mechanisms play a role during the heterotopic calcification. The intracellular calcification is based upon the function of mitochondria as regulator of the calcium concentration and as "lime-catcher". The extracellular calcification is initiated by membraneous organelles--so-called matrix vesicles. The further steps are the production of hydroxylapatite crystals which are eliminated from the matrix vesicles in the extracellular spaces. Special types of heterotopic calcification are hypercalcaemias (tumour-associated hypercalcaemias, primary and tertiary hyperparathyroidism, drug-induced hypercalcaemias), tumoral calcinosis, intratumoral calcifications, calcifications of different organs (lung, heart, vessels, joints, ligaments, skin or kidney). Some calcifications of organs show partly overlapping aetiological factors and pathogenetic mechanisms.

Aging↗

PubMed1985

Postinflammatory ossicular fixation: CT analysis with surgical correlation.

Postinflammatory ossicular fixation is a common problem encountered by the otologic surgeon upon exploration because of conductive hearing loss in patients with chronic otitis media. These nonotosclerotic noncongenital lesions take three pathologic forms: fibrous tissue fixation (chronic adhesive otitis media), hyalinization of collagen (tympanosclerosis), and new bone formation (fibro-osseous sclerosis). Fibrous tissue fixation appears on CT as nonbony, noncalcific soft-tissue debris encasing some or all of the ossicular chain. Tympanosclerosis appears as unifocal or multifocal punctate or weblike calcifications in the middle ear cavity or on the tympanic membrane. This debris may be in direct apposition to the ossicular chain or may replace the suspensory ligaments in symptomatic patients. New bone formation has been identified only in the attic and is the least common manifestation. Thick bony webs or generalized bony encasement may be present at CT. More than 300 patients with the clinical diagnosis of chronic otitis media have been examined. This study encompasses 23 proved cases.

Adult↗

PubMed1988

Arthroscopic treatment of sports-related anterior osteophytes in the ankle.

Osteophytes on the anterior aspect of the tibia and anterior talus are common in athletes such as dancers, runners, and high jumpers who impact with quick and forceful dorsiflexion to this area. This pathology is often confirmed easily on lateral x-ray films. Excision, debridement, and/or abrasion arthroplasty can be performed arthroscopically to remove osteophytic bone. The joint space is easily approached and managed using small joint or even regular-sized arthroscopic instruments. Care is taken to reshape the anterior tibia and/or talus to its original contour, thus avoiding impingement of the joint space and scuffing of adjacent articular cartilage. Proper abrasion depths and punch lesions may be needed to expose bleeding capillary bone. This allows a regeneration of a fibrocartilage covering that not only decreases pain but also permits a return to functional and athletic activities. Postoperative treatment, including physical therapy, is described. Three case studies are presented that adequately demonstrate this problem, along with the corrective measures taken. Each case concludes with a brief summary of follow-up.

Adult↗

PubMed2005

Auditory brainstem implant (ABI): new frontiers in adults and children.

UNLABELLED: Previous studies have considered only patients with neurofibromatosis type 2 (NF2) older than 12 years as candidates for an auditory brainstem implant (ABI). Our study expands the potential criteria to include both children and adult subjects with other cochlear or cochlear nerve malfunctions who either would not benefit at all from a cochlear implant (eg, cochlear nerve aplasia or avulsion) or whose benefit was or would be severely compromised (eg, cochlear ossification, cochlear fracture). STUDY DESIGN: In our department, over the period from April 1997 to September 2002, 29 patients, 20 adults and 9 children, were fitted with ABIs. Their ages ranged from 14 months to 70 years. Thirteen subjects had tumors, 10 NF2 and 3 solitary vestibular schwannoma, and 16 patients had a variety of nontumor (NT) cochlear or cochlear nerve diseases. A retrosigmoid-transmeatal approach was used in T and a retrosigmoid approach in NT patients. The electrode array was inserted into the lateral recess of the fourth ventricle and correct electrode positioning was monitored with the aid of electrically evoked auditory brainstem responses (EABRs). RESULTS: Correct implantation was achieved in all patients. No complications were observed due to implantation surgery or related to ABI activation or long-term use. Auditory sensations were induced in all patients with various numbers of electrodes (from 5 to 15). Different pitch sensations were identifiable with different electrode stimulation. Closed-set word recognition, open-set sentence recognition, and speech tracking scores achieved by the patients are reported in detail. The auditory performance of the patients showed significantly better outcomes than controls (Multicentric European clinical investigations on ABI with NF2). CONCLUSION: We have shown that the indications for the ABI can be extended to include NT patients with severe cochlear and/or cochlear nerve abnormalities. The degree of auditory benefit varies as a function of the underlying pathological conditions, with NT subjects exhibiting significantly better outcomes than the T patients.

Adolescent↗

PubMed2001

[Clinical aspects of tracheopathia osteoplastica].

Tracheopathia osteoplastica is a rare condition of the tracheobronchial tree characterized by the formation of multiple osseous or cartilaginous submucosal nodules which protrude into the lumen. Clinical features, pathological-anatomical, and radiological findings are described and discussed on the basis of three recent cases and a literature review.Two female patients (age 56 and 62 years) and one male (age 44 years) presented with recurrent tracheobronchitis, a "difficult intubation" at the time of an emergency situation requiring tracheostomy. The diagnosis was confirmed by tracheoscopy. CT scans showed radiodense nodular thickening of the tracheal wall compromising the lumen in all patients, whereas plain chest radiography revealed scalloped linear calcification in only one case. Histologically the nodules consisted of lamellar-type bone covered by normal mucosa. None of the patients needed therapeutic measures as there was no impairment of ventilatory function. The long-term observations (>15 years) of a few authors suggest that the disease is of benign course and does not deteriorate.

Adult↗

PubMed2000

Cellular interactions and signaling in cartilage development.

The long bones of the developing skeleton, such as those of the limb, arise from the process of endochondral ossification, where cartilage serves as the initial anlage element and is later replaced by bone. One of the earliest events of embryonic limb development is cellular condensation, whereby pre-cartilage mesenchymal cells aggregate as a result of specific cell-cell interactions, a requisite step in the chondrogenic pathway. In this review an extensive examination of historical and recent literature pertaining to limb development and mesenchymal condensation has been undertaken. Topics reviewed include limb initiation and axial induction, mesenchymal condensation and its regulation by various adhesion molecules, and regulation of chondrocyte differentiation and limb patterning. The complexity of limb development is exemplified by the involvement of multiple growth factors and morphogens such as Wnts, transforming growth factor-beta and fibroblast growth factors, as well as condensation events mediated by both cell-cell (neural cadherin and neural cell adhesion molecule) and cell-matrix adhesion (fibronectin, proteoglycans and collagens), as well as numerous intracellular signaling pathways transduced by integrins, mitogen activated protein kinases, protein kinase C, lipid metabolites and cyclic adenosine monophosphate. Furthermore, information pertaining to limb patterning and the functional importance of Hox genes and various other signaling molecules such as radical fringe, engrailed, Sox-9, and the Hedgehog family is reviewed. The exquisite three-dimensional structure of the vertebrate limb represents the culmination of these highly orchestrated and strictly regulated events. Understanding the development of cartilage should provide insights into mechanisms underlying the biology of both normal and pathologic (e.g. osteoarthritis) adult cartilage.

Body Patterning↗

PubMedDate not supplied

The pathology of acute chondro-osseous injury in the child.

Skeletal tissues from children sustaining acute skeletal trauma were analyzed with detailed radiologic and histologic techniques to assess the failure patterns of the developing skeleton. In the physis- and epiphysis-specific fracture propagation varied, usually going through the portion of the hypertrophic zone adjacent to the metaphysis. However, the physeal fracture in types 1 and 2 sometimes involved the germinal zone. There may also be microscopic propagation at oblique angles from the primary fracture plane, splitting cell columns apart longitudinally. The cartilage canals supplying the germinal zone appear to be "weak" areas into which the fracture may propagate, especially in infancy. Incomplete type 1 physeal fractures, which cannot be detected by routine radiography, may occur. Types 1, 2, and 4 physeal injuries may be comminuted. In type 3 injuries, discrete segments of physis that include the germinal zone may "adhere" to the metaphysis, separating the cells from their normal vascularity. In types 2 and 3, comminution may occur at the site of fracture redirection from the physis. Direct type 5 crushing of the physeal germinal zone does not occur, even in the presence of significant pressure-related changes within other areas of the epiphysis. Type 7 separation between cartilage and bone at any chondro-osseous epiphyseal interface may occur, but is similarly impossible to diagnose radiographically. In the metaphysis torus, fractures result from plastic deformation of the cortex, coupled with a partial microfracturing that may be difficult to visualize with clinical radiography. Some of the energy absorption may also be transmitted to the physis, causing metaphyseal hemorrhage adjacent to the growth plate and variable microscopic damage within the physis. In the diaphysis, the greenstick fracture is associated with longitudinal tensile failure through the developing osteons of the "intact" cortex. The inability of these failure patterns to "narrow" after the fracture force dissipates is the probable cause of retained bowing (plastic deformation). In both torus and greenstick fractures, the fractured bone ends show micro-splitting through the osteoid seams. In the diaphysis, metaphysis, and epiphyseal ossification center there may be areas of focal hemorrhage and microfracture that correlate with the reported MRI phenomenon of "bone bruising." Again, such injury cannot be diagnosed during routine radiography.

Animals↗

PubMed2001

Arthroscopic resection of the distal aspect of the clavicle with concomitant subacromial decompression.

BACKGROUND: Arthroscopic subacromial decompression and arthroscopic resection of the acromioclavicular joint as separate procedures have been well documented. However, there is little information on the success rate of resection with concomitant decompression. In this study, we retrospectively evaluated the results of a consecutive group of patients who underwent arthroscopic resection of the acromioclavicular joint with concomitant subacromial decompression. METHODS: We evaluated the surgical results in thirty-one consecutive patients (thirty-two shoulders) with acromioclavicular pathology with concomitant subacromial impingement. The mean age of the patients at the time of surgery was thirty-six years (range, eighteen to sixty-seven years). Twenty-five patients, including four professional athletes, were actively involved in sports activities. The mean duration of follow-up was four years and ten months (range, three to eight years). The follow-up examination included clinical evaluation, chart review, radiographic analysis, and isokinetic testing of both upper extremities. RESULTS: Of the twenty-five patients who participated in sports, twenty-two (including the four professional athletes) returned to their previous level of sports activity. Twenty-six patients had no pain, three reported mild pain on strenuous repetitive overhead activity, two (both weight-lifters) had occasional pain in the acromioclavicular joint and the lateral aspect of the shoulder with bench-pressing, and two (both baseball players) had mild pain in the posterior aspect of the shoulder with throwing. All of the patients were satisfied with the results. In the absence of a complete rotator cuff tear, isokinetic strength-testing of both upper extremities failed to demonstrate any weakness of the involved shoulder. The mean functional score for individual activities was 2.7 points (range, 2.1 to 3.0 points) preoperatively and 3.9 points (range, 3.6 to 4.0 points) postoperatively (p = 0.0001). No patient had superior migration of the clavicle. The amount of distal clavicular resection averaged 9 mm (range, 7 to 15 mm). One patient had heterotopic ossification at the resection site, with mild pain on direct palpation of the acromioclavicular joint and on strenuous overhead activity. Five patients had calcification at the anterior deltoid insertion into the acromion that was asymptomatic, with no impingement on overhead activity and no pain on direct palpation. CONCLUSIONS: We found excellent results with arthroscopic resection of the acromioclavicular joint and concomitant subacromial decompression. When this procedure is performed on properly selected patients, the results are similar to those of an open approach.

Acromioclavicular Joint↗

PubMedDate not supplied

Metalloproteinases (MMPs -2, -3) are involved in TGF-beta and IGF-1-induced bone defect healing in 20-month-old female rats.

Matrix metalloproteinases are important in the physiological and pathological degradation of extracellular matrix including that of bone and cartilage. The process of bone defect healing is associated with formation of cartilage callus and cancelous bone. With maturation and aging, the response of skeletal tissues to injury is limited. The ability of growth factors to enhance bone defect healing in aged rats was studied. Partial bone defects were induced in femurs of aged rats. A single dose of IGF-1, TGF-beta+IGF-1 or saline was inserted in the defect and bones were examined after 2 and 4 weeks. Morphology revealed that after 2 weeks of treatment with TGF-beta the defects were filled with mesenchyme-like tissue and delicate bone trabeculae. Positive staining for metalloproteinase-2 (MMP-2) was shown at the sites of new bone formation. In defects treated with IGF-1 or TGF-beta+IGF-1 nodules of cartilage and fine bone trabeculae along with positive staining for both MMP-2 and MMP-3 were demonstrated in the healing defects. After 4 weeks radiology revealed mineralization in defects treated with TGF-beta and less pronounced mineralization after treatment with IGF-1, or with TGF-beta+IGF-1, whereas only partial healing of the defects was observed in control specimens. MMP-2 and MMP-3 were detected at sites of new bone formation after treatment with TGF-beta, IGF-1, and TGF-beta+IGF-1. It is concluded that TGF-beta and IGF-1 induced bone defect healing in aged rats. TGF-beta induced bone formation while IGF-1 induced cartilage and than bone formation via endochondral ossification. The localization of MMP-2 and MMP-3 in the healing defects reflected the synthesis of bone or cartilage matrices in the defect, reflecting the involvement of MMPs in the process of bone formation and endochondral ossification. The ability to induce bone defect healing in aging is of great clinical importance and understanding the involvement of MMPs in this process can contribute to future treatment with growth factors to enhance bone defect healing in 20-month-old female rats.

Journal Article↗

PubMed1994

Pathology of prelingual profound deafness: magnitude of labyrinthitis fibro-ossificans.

Quantitative histologic studies were performed on 15 temporal bones from eight adult persons who were known to have prelingual bilateral profound hearing loss. The pathologic changes are characterized by severe degeneration of the structures of the cochlear duct, often with degeneration of the vestibular sense organs, causing a reparative host response that features osteoneogenesis and fibrous proliferation followed by retrograde neuronal degeneration. The pathology is consistent with meningogenic bacterial or viral labyrinthitis that occurred subclinically or went undiagnosed. Bone and fibrous tissue are present in varying extent in the scala tympani of 12 of the 15 temporal bones. Six cochleae from four subjects with fibro-osseous proliferation in the scala tympani extending as far as the ascending part of the basal turn have neuronal populations ranging from 963 to 5,355 (mean 2,826, 8% of neonatal normal, 35,500). In three cochleae from two subjects with no fibro-osseous proliferation in any area of the scala tympani the neuronal population ranges from 11,322 to 20,484 (mean 15,438, 43% of neonatal normal). Relative to cochlear implantation, computed tomographic imaging provides a means for determining the extent of fibro-osseous proliferation in the scala tympani, which in turn alerts the surgeon to surgical obstacles to optimal implantation as well as providing a basis for judging the extent of loss of cochlear neuronal population.

Aged↗

PubMed1997

Intraoperative control by somatosensory evoked potentials in the treatment of cervical myeloradiculopathy. Results in 210 cases.

Somatosensory evoked potentials (SEPs) were used for continuous monitoring of 210 patients during anterior surgery for cervical myeloradiculopathy, to test how effectively they help avoid irreversible neurological damage during surgery. The pathologies differed in severity and were treated by diskectomy or by extended corporectomy using the Senegas technique. Intraoperative SEP changes were recorded in 84 patients (40%); in 13 (6.2%) of these, changes in SEP amplitude and latency were caused by mechanical stress. SEPs revealed transient episodes of regional ischaemia or neurophysiological anomalies during anaesthesia (mainly hypotension) in 27 patients (12.8%). The traces detected incipient and potentially dangerous mechanical pressure on, or metabolic anomalies of, the spinal cord during manipulation and placement procedures of spinal fixation devices. They were particularly sensitive indicators of ischaemia; one of the most common causes of irreversible injury. The traces of 44 patients (21.0%) improved markedly during surgery. There were no false-negatives in this series and, thanks to the fact that SEPs gave immediate warnings of incipient ischaemia to the surgical team, we had no case of irreversible medullary or nerve-root deficit.

Adult↗

PubMed2005

Experimental and clinical studies of malleus fixation.

OBJECTIVES/HYPOTHESIS: Preoperative clinical diagnosis of malleus fixation can be difficult. "Fixation" of the malleus can be caused by various disorders or diseases: fibrous tissue, bony spurs, and neo-osteogenesis around the malleus head or stiffening of the anterior malleal ligament. The conductive hearing loss produced by these disorders or diseases has not been well characterized. The study goals were 1) to determine the effects of various types of malleus fixation using a cadaveric temporal bone preparation and 2) to assess the clinical utility of umbo velocity measurements in preoperative differential diagnosis of malleus fixation and stapes fixation. METHODS: Umbo and stapes velocity were measured in 18 fresh cadaveric human temporal bones with laser vibrometry before and after controlled application of adhesives to the malleus, stapes, or both ossicles. RESULTS: Each simulated pathological condition produced a specific degree of loss in stapes velocity: stiffening of anterior malleal ligament, 0 to 8 dB; fibrous tissue around malleus head, less than 10 dB; bony bar to malleus head, 10 to 30 dB; and extensive neo-osteogenesis around malleus head, greater than 35 dB. Simulated malleus fixations generally produced similar reductions in both umbo and stapes velocity. Stapes fixation reduced stapes velocity with little change in umbo velocity. Because the change in stapes velocity would be similar to conductive hearing loss, experimental results were directly compared with clinical measurements of umbo velocity in surgically confirmed cases of malleus or stapes fixation. The effects of malleus and stapes fixations between the clinical and experimental data were similar. CONCLUSION: The study showed that measurements of umbo velocity and air-bone gap can enable one to diagnose malleus fixation and specifies how to differentiate malleus from stapes fixation.

Aged↗

PubMed2006

Morphology of the lateral pterygoid muscle associated to the mandibular condyle in the human prenatal stage.

The lateral pterygoid muscle (LPM) inserts at the condyle and the articular disc and plays a central role in mandibular movement via the Temporomandibular Articular Complex. The aim of this study was to examine the association between the morphology of LPM muscular fascicles and the degree of mineralization of the mandibular condyle in the prenatal stage employing structural, ultrastructural and microanalytical evaluation. Sixteen human fetuses at 11-37 weeks of gestation, with no apparent pathology and resulting from spontaneous abortions, were included in the study. Samples from lateral pterygoid muscle and the mandibular condyle were processed for light microscopy and electron microscopy and microanalysis. Desmin immunolabeling (dilution 1: 25 Dako) and alpha sarcomeric actin immunolabeling (dilution 1:50 Dako) employing the avidin-biotin system were used in paraffin embedded samples. Contralateral samples were examine by transmission electron microscopy. Four condyles (at 17-21 weeks of gestation) were used to measure the relative content of calcium and phosphorous employing the X-ray diffraction microanalytical technique. At 11-16 weeks of gestation, the LPM was composed of secondary myotubes associated to satellite cells and nerve fibers. At 18 weeks, the muscle exhibited multiple compact fascicles and the condyle showed a thin, external, subperiostal mineralized layer with few central bone spicules. At 20 weeks, at the site of insertion of the LPM, the bone trabeculae of the condyle contained an electrondense matrix with abundant mineralization nuclei. At 17-21 weeks of gestation no significant variations in the contents of phosphorous and calcium were observed. At 24 weeks, transmission electron calcium and microscopy studies revealed a marked increase in the functional units of the muscle fascicles. Also, at this age muscle fibers exhibited differences in the expression of desmin and alpha sarcomeric actin. At 37 weeks the muscle became multipennate in appearance, exhibiting a more complex organization than younger fetuses. Alpha sarcomeric actin labeling became light with age. This results suggest that between 16 and 22 weeks of gestation the differentiation and maturation process of the muscle fibers precedes and prevails over the development and mineralization process from mandibular condyle. The rudimentary performance of the prenatal LPM would be one of the factors that regulate the process of ossification at the level of the mandibular condyle. The rate of ossification would increase starting from 22 of gestation week.

Actins↗

PubMed2002

Ectopic mineralization of articular cartilage in the bullfrog Rana catesbeiana and its possible involvement in bone closure.

Mineralization of the articular cartilage is a pathological condition associated with age and certain joint diseases in humans and other mammals. In this work, we describe a physiological process of articular cartilage mineralization in bullfrogs. Articular cartilage of the proximal and distal ends of the femur and of the proximal end of the tibia-fibula was studied in animals of different ages. Mineralization of the articular cartilage was detected in animals at 1 month post-transformation. This mineralization, which appeared before the hypertrophic cartilage showed any calcium deposition, began at a restricted site in the lateral expansion of the cartilage and then progressed to other areas of the epiphyseal cartilage. Mineralized structures were identified by von Kossa's staining and by in vivo incorporation of calcein green. Element analysis showed that calcium crystals consisted of poorly crystalline hydroxyapatite. Mineralized matrix was initially spherical structures that generally coalesced after a certain size to occupy larger areas of the cartilage. Alkaline phosphatase activity was detected at the plasma membrane of nearby chondrocytes and in extracellular matrix. Apoptosis was detected by the TUNEL (TDT-mediated dUTP-biotin nick end-labeling) reaction in some articular chondrocytes from mineralized areas. The area occupied by calcium crystals increased significantly in older animals, especially in areas under compression. Ultrastructural analyses showed clusters of needle-like crystals in the extracellular matrix around the chondrocytes and large blocks of mineralized matrix. In 4-year-old animals, some lamellar bone (containing bone marrow) occurred in the same area as articular cartilage mineralization. These results show that the articular cartilage of R. catesbeiana undergoes precocious and progressive mineralization that is apparently stimulated by compressive forces. We suggest that this mineralization is involved in the closure of bone extremities, since mineralization appears to precede the formation of a rudimentary secondary center of ossification in older animals.

Age Factors↗

PubMed2005

Gestational age discrepancies due to acquisition artifact in the forensic fetal osteology collection at the National Museum of Natural History, Smithsonian Institution, USA.

Previously, numerous techniques have been used to assess either lunar or gestational age from fetal remains, such as from the external dimensions of the fetus, presence or absence of external features and ossification centers. One of the largest fetal collections in the U.S. is assessed with regard to errors in its biologic profile (ancestry, sex and age), the nature of the collection process, the methods of collection and the subsequent considerations for usage. Hrdlicka recorded the age, ancestry, sex and external measurements on card catalogs in the early 1900s for future use. For the purpose of this pilot study, measurements on 38 suitable fetuses stored at NMNH were used to calculate lunar age and compare with the recorded age in the card catalog. The differences between the age assessments are as follows: 20 showed no difference, 11 were discrepant by one month, 6 varied by 2 months and 1 diverged by 5 months. The average difference between lunar ages is 0.74 months, reflecting a nearly three-week difference. The purpose of this paper is to demonstrate that such discrepancies exist and to confirm specimens with accurate ages, which can be marked for future research. Moreover, it is also the purpose of this paper to demonstrate that such bias artifact exists in museum collections, and that this artifact needs to be eliminated from the sample materials prior to study.

Age Determination by Skeleton↗