Giemsa as a fluorescent stain for mineralized bone

We present evidence for a previously unrecognized differential staining effect of Giemsa solution in fluorescence microscopy. The effect consists of selective fluorescent staining of mineralized bone (and elastic fibers) in tissue sections and, like the classical Romanowsky effect, is based on the differential binding of Eosin Y to tissue structures in the presence of Azur II and Methylene Blue. This effect opens the way to new applications of the Giemsa solution in fluorescence microscopy and in confocal fluorescence microscopy.

Anatomical and histological re-examination of Appendices colli in the goat

Appendices colli (App. colli) were investigated by anatomical and histological methods in the goat. App. colli were composed of elastic cartilage located at central and the skin covering the cartilage, which included arterioles along the cartilage and nerve bundles. Three types of muscles connected to App. colli; superficial muscle bundles, a branch of the omohyoideus muscle, and a muscle arising from the pharyngeal raphe (appendico-pharyngeal muscle). The latter two muscles were connected to the root of the App. colli where the muscle fibers transformed into the perichondrium of the elastic cartilage. The appendico-pharyngeal muscle was innervated by branches from the glossopharyngeal nerve which were composed of myelinated nerve fibers. The subcutaneous area of the App. colli was supplied by cutaneous rami of the vagus and the second cervical nerves. The innervation and the musculature confirmed that the cartilage of the App. colli were derived from third and fourth branchial arches.

Organization of tracheal epithelium in the cartilaginous portion of adult rabbit and its persistence in organ culture

BACKGROUND

The rabbit trachea provides a model system to test the physiological responses of the airways to various agents. Since three-dimensional organization may affect responses of an organ, an organ culture model was established in serum free medium.

METHODS

Tracheas were fixed in situ, at steps in the preparation of organ cultures, and after one day to three weeks in organ culture. Samples were examined by light microscopy and scanning and transmission electron microscopy for surface morphology, distribution of cell types, and characteristics of the epithelial cell layer.

RESULTS

The normal tracheal mucosa was discovered to consist of extensive circumferential folds in the cartilaginous portion, which were enhanced upon isolation of the trachea from the animal. The folds consisted principally of differences in epithelial cell height rather than folding of the lamina propria. Enhancement of folding upon removal of the trachea coincided with increased secretion by Clara and possibly mucous cells. In organ culture, epithelial cell height initially increased, producing tall folds and cell types were retained in normal proportions. After prolonged culture, cilia were lost but glandular secretion continued.

CONCLUSIONS

Changes in the arrangement of basal cells and secretory activity in isolated trachea and in culture may give insight into the functional significance of the epithelial folds.

Cartilage grafts for head and neck augmentation and reconstruction. Autografts and homografts

This article reviews cartilage grafting in the head and neck, emphasizing its use in facial surgery. The harvesting and preparation of cartilage grafts are reviewed, and both autografts and homografts are discussed. The implementation of cartilage grafts in the nose, ear, eyelid, orbit, and larynx also is presented.

Localization of osteogenic protein-1 (bone morphogenetic protein-7) during human embryonic development: high affinity binding to basement membranes

Osteogenic protein-1 (OP-1) is a member of the bone morphogenetic protein subfamily of the transforming growth factor-beta (TGF-beta) superfamily. Since members of the TGF-beta superfamily have a role in tissue development the distribution of OP-1 in developing human embryos (gestational age 5-14 weeks) was examined by immunohistochemical methods. Positive staining for OP-1 was observed in: sclerotome, hypertrophied chondrocytes, osteoblasts, periosteum, epithelial cells of the adrenal "provisional cortex" and the convoluted tubules of developing kidneys. In the developing lungs, pancreas and skin, OP-1 was localized in basement membranes underlying the epithelium. In vitro binding studies of 125I-OP-1 to various extracellular matrix components revealed high affinity of OP-1 for type IV collagen and less for heparin, collagen types I and VI. Present findings suggest that, in addition to bone formation, OP-1 could have other important regulatory roles in human embryogenesis with high binding affinity to a basement membrane component.

Cartilage in the aortic valve and its relationship with the aortic valve morphology in Syrian hamsters

We conducted a light-microscopic histologic study of the aortic valves of 224 Syrian hamsters aged between 1 and 771 days. Most of the hamsters examined belonged to a single laboratory-inbred family with a high incidence of bicuspid aortic valves (BAVs). In 146 specimens the aortic valve was tricuspid, and in 107 of them the ventral commissure was more or less fused. The remaining 78 specimens showed a BAV with the aortic sinuses oriented ventrodorsally. In 33 BAVs a raphe was located in the ventral aortic sinus. Cartilaginous foci were present in the aortic valves of 86 specimens, 40-771 days old. The foci were located at two different sites, namely in the ventral wall of the valve and/or in the dorsal aortic sinus. Statistical analyses substantiate that (1) chondrogenesis begins earlier in BAVs, and especially in those having a raphe, than in tricuspid aortic valves and (2) the location of the cartilaginous foci is significantly associated with the morphology of the aortic valve. The present findings support the hypothesis that, in the Syrian hamster, cartilage forms in the aortic valve as a response to locally intense mechanical stimulation.

Relationship between the ossification center and cartilaginous anlage in the normal hindfoot in children: study with MR imaging

OBJECTIVE

Although many reports have documented when ossification centers can first be visualized on radiographs, few studies have evaluated the position of the ossification center within its cartilaginous anlage. In the skeletally immature child, the ossification centers of the tarsals are used to evaluate the positions of the tarsals and their interrelationships. It is convenient to assume that tarsal ossification begins in the center of its cartilaginous anlage and proceeds in a radial fashion; however, this may not be the case. Accordingly, we used MR imaging to evaluate the location of the ossification centers of the tarsals within their cartilaginous anlage in the mid and hindfoot in children.

MATERIALS AND METHODS

MR studies of 69 feet in 40 children, 3 months to 7 years old (mean, 2.5 years), were reviewed retrospectively. The location of the ossification center within its cartilaginous anlage and the percentage of ossification of the cartilaginous anlagen of the talus, calcaneus, cuboid bone, and navicular bone were determined from coronal and sagittal images. In the talus, the difference between the orientation of the long axis of its ossification center and the long axis of its cartilaginous anlage was measured on coronal and sagittal images.

RESULTS

Early talar ossification was centered on the neck of the talus; the proximal aspect of the bone ossified last. The long axis of the talar ossification center and the long axis of its cartilaginous anlage differed in orientation. Early calcaneal ossification was centered on the distal two thirds of the cartilaginous anlage of the calcaneus; the proximal aspect and the area of the subtalar joint ossified last. Early navicular ossification was centered on the central or lateral third of the navicular cartilaginous anlage; the medial aspect ossified last. The ossification center of the cuboid bone was in the middle of the cuboidal cartilaginous anlage.

CONCLUSION

Our results show that early ossification in the talus, calcaneus, and navicular bones does not begin in the center of the bones' cartilaginous anlagen. The orientations of the long axis of the talar ossification center and the long mid axis of its cartilaginous anlage are different. Therefore, part of the changes in the alignment of the tarsals seen on radiographs with growth is due to ossification beginning and proceeding eccentrically within the cartilaginous anlage and not to a true change in the alignment of the tarsals. These data provide new information about the normal development of the child's hindfoot and midfoot.

Ossification patterns of the tympanic facial canal in the human fetus and neonate

Dehiscences in the bony facial canal are comparatively common in the human adult. The highest incidence occurs in the tympanic segment of the facial nerve near the region of the oval window. Thirty-three fetal temporal bones, ranging from 16 to 40 weeks' gestation, and four from 1, 2, 4 and 12 weeks' postpartum neonates, were studied to evaluate the normal patterns of ossification of the fallopian canal of the tympanic facial nerve segment in the human. The tympanic facial nerve segment elongates three-fold during this period (from 1 mm to 3 mm). The ossification starts at 21 weeks' gestation anteriorly from apical otic ossification centers and at 26 weeks from canalicular ossification centers near the stapedius muscle. The ossification proceeds in an anterior-to-posterior direction as two periosteal shelves of bone surround the facial nerve. The superior periosteal bony ledge contributes 75% of the circumference of the fallopian canal. The anterior ossification center forms over 83% of the fallopian canal length. The two centers fuse post partum near the region of the oval window. The anatomic location of the facial nerve, nerve branching, and neural vasculature precede ossification. In 80% of the paired temporal bones, this ossification pattern appears to be symmetrical. The patterns and incidence of bony dehiscences within the tympanic fallopian canal segment can be explained by these observations. This study demonstrates that fallopian canal dehiscences are not congenital anomalies, but variations of normal developmental anatomic processes.

The relationship between Meckel's cartilage and the development of the human fetal mandible

This work studied the development of the ventral part of Meckel's cartilage and its relationship to the morphogenesis of the mandible in a series of human fetuses. The development of the cartilage was followed up to the end of the embryonic period (stage 23, 8th week) when the primary ossification centre, which was formed from a condensation of embryonic mesenchyme, had become two bony plates forming a trough in which lay the neurovascular bundle. From this trough invagination of the bony plate formed the dental crypt. The primary ossification centre disappeared around the sixth month of fetal life.

Cartilage canals in the tarsal navicular of the human foetus and infant

We have analysed the development of the cartilage canals in the tarsal navicular in 26 human foetuses and infants, aged between 12 weeks after gestation and 10 months, using a technique of transparentation and serial histological sections of the bone. The formation of cartilage canals starts in the first 12 to 13 weeks of gestation and can be seen by transparentation at 17 weeks after gestation. They increase in number with the age of the foetus or infant and develop a branching pattern almost to the centre of the tarsal navicular. They begin and are more numerous on the dorsal surface of the cartilage structure.

Immunoelectron microscopic study of proteoglycans in rat epiphyseal growth plate cartilage after fixation with ruthenium hexamine trichloride (RHT)

The localization of proteoglycans in rat epiphyseal growth plate cartilage was investigated immunoelectron microscopically by the post-embedding method, using mouse monoclonal antibody (2-B-6) which specifically recognizes 4-sulphated chondroitin or dermatan sulphate after digestion of proteoglycans with chondroitinase ABC. Fixation with ruthenium hexamine trichloride (RHT) and embedding in LR White served to preserve chondrocytes in the expanded state and matrix proteoglycans were observed as a reticular network of filaments. Immunoelectron microscopy revealed gold labelling of the secondary antibodies for the demonstration of proteoglycans on these filamentous structures and in elements of the Golgi apparatus. Filaments associated with matrix vesicles were also labelled. After fixation in the presence of RHT, it was clearly demonstrated that cartilage matrix proteoglycans are retained approximately in their original spatial distribution and their antigenicity is well preserved.

Direct observation of the magnetization exchange dynamics responsible for magnetization transfer contrast in human cartilage in vitro

Saturating irradiation far off-resonance can lead to diminution in the water signal seen in MRI, giving rise to magnetization transfer contrast. This results from transfer of magnetization between "solid" protons with restricted motion, which give rise to a band some tens of kilohertz wide, and the narrow signal from mobile protons. In the work reported here a high-power pulse spectrometer, which can detect signals from both mobile and immobile protons, was used to investigate the dynamics of magnetization transfer in cartilage in vitro. Magnetization transfer in modified Hoffman-Forsén inversion transfer experiments was well-described by a single rate constant model; full analytical solutions are offered for the resultant biexponential magnetization recovery curves. The use of pulsed methods to generate magnetization contrast may in some circumstances offer advantages over the steady-state saturation methods used hitherto.

Pedicle scapular apophysis transplantation in congenital limb malformations

Congenital segmental amputations are difficult to correct. Free interposition bone grafts with growth centers were tried experimentally by many investigators even at the beginning of this century. Attempts at clinical application of this principle, however, were mostly failures. More recently, with the advent of microsurgical techniques, new hope has arisen. In particular, toe transfers in children have confirmed the survival of such growth centers, as these transfers could be found to grow normally [1]. The transfer of vascularized epiphysis with its growth plate has been shown in animal limbs to achieve a rate of growth comparable with the normal site. Originally, two donor sites were used with acceptable results in children. These were the superior epiphysis of the fibula and the iliac crest. So far, in most clinical applications, they have been used as appositional transfers. However, a growth problem occurring at the donor site has proved to be quite crippling.

Bone and cartilage resorption in relation to tooth development in the anterior part of the mandible in cichlid fish: a light and TEM study

This paper presents ultrastructural features of the contact region between particular tooth germs and Meckel's cartilage prior to, during, and after initial resorption of the perichondral bone and of the cartilage in the cichlids Hemichromis bimaculatus and Astatotilapia burtoni. Imminent resorption opposite such teeth is announced by the presence, in this region, of a particular cell type, considered to be a stage in the cytodifferentiation of osteoclasts. Slightly later, an osteoclast with typical ruffled border is seen to open a fenestra in the perichondral bone which surrounds Meckel's cartilage. Although the action of the osteoclast is directed primarily towards the bone, it may also affect, to a much lesser extent, the underlying uncalcified cartilage. Typically, fibroblast-like cells invade the resorption cavity along with the osteoclast; the tooth germ soon follows. Capillaries are seen to invade the cartilage only at a later stage when a large cavity has been established. It is proposed that the fibroblast-like cells may have a dual function: degradation of cartilage and deposition of new bone. Although these processes are normally limited to the area surrounding tooth germs at specific loci, tooth germs in other positions may sometimes be seen invade the cartilage. They do so either passively, because of the existence of such a cavity, or as a result of their own resorption-inducing activity. Whatever the mechanism, attachment bone is being deposited within the erosion cavity and on the surface of the exposed perichondral bone. The stimuli possibly eliciting resorption of Meckel's cartilage are discussed. It is hypothesized that pressure exerted by the growing tooth germ may stimulate the osteoblasts covering the bone surface and, in this way, provoke osteoclastic bone resorption.

Cartilage and related tissues in the trunk and fins of teleosts

The structure and distribution of cartilage and related tissues in the dorsal fin, caudal fin and vertebrae of teleosts were studied in 11 species. With the exception of Zellknorpel, all the tissues previously described in teleost heads were present in the trunk and fins, although they were found in smaller quantities. The distribution of the supporting tissues indicates that they serve different functions. Hyaline cartilage was restricted to vertebral and fin bones undergoing endochondral ossification, fibro/cell-rich cartilage acted as an articular tissue, and hyaline-cell cartilage and its subtypes formed flexible and resilient supports in the caudal fin. Mucous connective tissue was packed as a space-filler around neurovascular bundles in fin rays, and chondroid bone was found beneath articular surfaces. The differences between cranial, and trunk and fin supporting tissues may reflect developmental as well as functional differences between the cranial and postcranial skeleton.

The membranous skeleton: the role of cell condensations in vertebrate skeletogenesis

Elements of the vertebrate skeleton are initiated as cell condensations, collectively termed the 'membranous skeleton' whether cartilages or bones by Grüneberg (1963). Condensations, which were identified as the basic cellular units in a recent model of morphological change in development and evolution (Atchley and Hall 1991) are reviewed in this paper. Condensations are initiated either by increased mitotic activity or by aggregation of cells towards a centre. Prechondrogenic (limb bud) and preosteogenic (scleral ossicle) condensations are discussed and contrasted. Both types of skeletogenic condensations arise following epithelial-mesenchymal interactions; condensations are identified as the first cellular product of such tissue interactions. Molecular characteristics of condensations are discussed, including peanut agglutinin lectin, which is used to visualize prechondrogenic condensations, and hyaluronan, hyaladherins, heparan sulphate proteoglycan, chondroitin sulphate proteoglycan, versican, tenascin, syndecan, N-CAM, alkaline phosphatase, retinoic acid and homeo-box-containing genes. The importance for the initiation of chondrogenesis or osteogenesis of upper and lower limits to condensation size and the numbers of cells in a condensation are discussed, as illustrated by in vitro studies and by mutant embryos, including Talpid3 in the chick and Brachypod, Congenital hydrocephalus and Phocomelia in the mouse. Evidence that genes specific to the skeletal type are selectively activated at condensation is discussed, as is a recent model involving TGF-beta and fibronectin in condensation formation. Condensations emerge as a pivotal stage in initiation of the vertebrate skeleton in embryonic development and in the modification of skeletal morphology during evolution.

Finite element model of facial soft tissue. Deformation following surgical correction

The finite element method is used to predict facial deformation following orthognathic surgery for mandibular prognathism. The deformation is calculated using a model that assumes severe skeletal class III malocclusion. The possibilities and limitations of this method for clinical application are described.

Craniovertebral junction: normal anatomy with MR correlation

The anatomy of the craniovertebral junction, although complex, may be well visualized by routine MR imaging. This essay discusses the anatomy of the complex articulations of the craniovertebral junction. Representative MR images and gross anatomic photographs are presented to illustrate the intricate ligamentous and articular anatomy. Knowledge of the normal anatomy of the occipitoatlantoaxial region is necessary in order to understand the common disorders that affect this area. The most common disorders are trauma and arthropathies, but also include congenital abnormalities and neoplasm. The resultant abnormal mechanics may lead to neurologic sequelae or pain.

The Oriental nose: an anatomical basis for surgery

Fifteen Oriental noses were examined macrosurgically and microscopically. Five soft tissue layers overlying the osseocartilaginous framework are identified: the skin, the subcutaneous areolar plane, the vascular-fibromuscular layer, the deep areolar plane and perichondrium/periosteum. Two natural planes of dissection are represented by these areolar planes which separate the nose into an overlying skin envelope, a vascular-fibromuscular layer and an underlying osseocartilaginous framework. The cartilaginous framework provides projection, support and shape to the dorsum and tip of the nose but not to the alar lobule as this is devoid of cartilage. As there is no cartilage in the Alar lobule, the term 'Alar Cartilage' is misleading and the term 'Tip Cartilage' is introduced to replace it. The skin of the nose is specialised and has the ability to retain its shape even after dissection. This is due to an arrangement of elastin fibres in the upper dermis and the subcutaneous areolar plane which confers elasticity to the skin especially in the region of the Alar lobule which is a skin and fibromuscular sandwich. The vascular fibromuscular layer is like a sheet draping the osseocartilaginous framework. The main arteries of the nose lie on this layer. Injection studies of the blood supply reveal many arterial variations but always a distinct alar artery, columellar artery and alar plexus that have not been previously named. The alar groove is a junction between the alar lobule which is soft tissue alone and the tip which is soft tissue, supported by cartilage. The alar groove lies over the lateral edge of the tip cartilage and here there is muscular attachment to the fibromuscular layer.

Viability of chondroplastic graft

The operation of chondroplastic graft augmentation rhinoplasty was described in a previous paper by the present author. Seventeen months following one such clinically successful operation, the opportunity was taken at a subsequent nasal procedure to remove a small portion of the original graft and submit this to histological examination. The results of this confirm the viability of a graft harvested and implanted by this technique.

Evolution of the infant spinal column: evaluation with MR imaging

The appearance of the normal lumbar spinal column was examined in spinal magnetic resonance images obtained in 50 pediatric patients aged 2 years or less. The ossification centers of the developing vertebral bodies, the cartilage, and the disks were studied with a 1.5-T imager by using both short- and long-repetition-time spin-echo sequences. Many of the structures of the spine were noted to undergo dynamic changes in appearance, both in signal intensity and in morphologic characteristics, with growth. The vertebrae and cartilage, especially, transform markedly in infancy and proceed through three characteristic stages of evolution. Stage I, from birth to 1 month of age, is characterized by markedly hypointense ossification centers and hyperintense, prominent cartilage. Stage II, from approximately 1 to 6 months of age, is characterized by increasing signal intensity in the ossification centers, progressing from the endplates in, and decreasing prominence of the cartilage, Stage III, from approximately 7 months of age on, is characterized by increasingly rectangular and centrally intense vertebral bodies and diminishing cartilage. The variability of the signal intensities, with that of muscle used as the standard, and morphologic characteristics of different components of the spine at different stages of development can create significant confusion. Careful analysis, however, permits one to follow the evolution of the lumbar spine and to date it on the basis of its appearance.

Ca2+ ion sequestration by guinea-pig tracheal cartilage: its influence on trachealis reactivity to KCl

1. The contractile response of guinea-pig isolated trachealis to KCl has been studied in the presence and absence of cartilage. 2. Dissection of cartilage from the trachealis resulted in both a rightward displacement of the concentration-response curve to KCl (EC50 value: intact strip, 26.9 +/- 3.7 mM n = 5; dissected strip, 38.7 +/- 2.6 mM n = 5; P less than 0.05), and a reduction in the contractile response to KCl (30 mM) observed in a nominally Ca(2+)-free medium. 3. Removal of cartilage from the trachealis did not alter the responsiveness of the tissue to CaCl2 (2.5 mM) when added to K+ depolarized tissues. 4. Muscle-denuded cartilage rings were prepared by surgical removal of the trachealis muscle. Autoradiographic studies, and a direct comparison of Ca2+ (2.5 mM) uptake with that of sorbitol (2.5 mM) showed that cartilage per se had a high capacity to accumulate Ca2+ ions by a process which was resistant to iodoacetate (100 microM), diflunisal (100 microM) and boiling. 5. The uptake of 45Ca into isolated cartilage was unaltered by the addition of orthovanadate (500 microM), verapamil (10 microM), diltiazem (10 microM) or Bay K 8644 (10 microM), but was significantly reduced (P less than 0.05) in the presence of LaCl3 (1-10 mM). 6. We conclude, like previous studies, that cartilage may supply a pool of Ca2+ ions to airway smooth muscle during the generation of tension in a noninally Ca(2+)-free medium, and that LaCl3 may provide an experimental tool to elucidate further the role of non-muscle Ca(2+)-depots in smooth muscle contraction.

Quantitative differences in the histology of the attachment zones of the meniscal horns in the knee joint of man

The attachment zones of the meniscal horns of 7 dissecting room cadavers were examined by routine histology. All the knees were devoid of gross pathological change and no discoid menisci were included. Significant differences are reported in the thickness of the zones of uncalcified fibrocartilage and cortical calcified tissue (calcified fibrocartilage and underlying lamellar bone) and in the percentage of bone:bone marrow. There was a thicker zone of uncalcified fibrocartilage and a greater quantity of calcified tissue at the horns of the lateral than the medial meniscus. The differences in uncalcified fibrocartilage were largely attributable to the posterior horns, but the variations in calcified tissue mainly reflected differences between the anterior horns. It is suggested that the greater mobility of the lateral meniscus and the blending of its anterior horn with the anterior cruciate ligament are important factors accounting for the quantitative differences in the meniscal attachment zones.