Structural details of rat extraocular muscles and three-dimensional reconstruction of the rat inferior rectus muscle and muscle-pulley interface.

Light microscopy, electron microscopy and morphometry revealed structural details and allowed generation of a three-dimensional reconstruction of the pulley and muscle-pulley interface of extraocular muscle. The inferior rectus orbital layer was bifurcate in shape and extended anterior to the pulley. The putative pulley structure itself was asymmetric; loosely attached at the orbital aspect it adhered tightly to the global aspect of muscle. Orbital multiply innervated fiber proportion increased anterior to the pulley insertion site. Additionally longitudinal variation in juxtaposition of orbital and global layers was noted. These newly described structural details provide novel mechanistic insight for extraocular muscle function in rats.

Anatomy, histology, histochemistry and fine structure of the Harderian gland in the South American armadillo Chaetophractus villosus (Xenarthra, Mammalia).

The anatomical, histological, histochemical and ultrastructural characteristics of the Harderian gland of the armadillo Chaetophractus villosus were described. The gland is the largest structure in the bony orbit. It is situated in the anteroventral region of the orbit. Obvious structural differences are not observed between males and females. The gland is compound-branched tubulo-alveolar, being characterized by a single layer of columnar cells surrounded by myoepithelial cells. It possesses a single excretory duct opened into the inner canthus. All glandular cells show yellow-green autofluorescence and additionally some glandular lumen may contain dense autofluorescent solid accretions. There are two peculiar and outstanding cytoplasmic features. One is represented by the smooth endoplasmic reticulum (SER), forming a closely woven meshwork. The other one is represented by "membranous bodies" apparently derived from the SER, RER and cytoskeleton with a "Star of David" configuration situated in the supranuclear region. Three types of vesicles are detected in the cytoplasm. Histochemical staining methods reveal lipids, proteins, neutral and acidic containing glycoconjugates in secretory vesicles. The mechanism of secretion appears either merocrine or apocrine. The epithelium of the intra- and inter-lobular excretory ducts suggests secretory activity. Tubulo-acinar glands similar to those seen in the lacrimal gland and nictitans glands are found related to the intralobular and main excretory ducts. The capillary network is characterized by fenestrated endothelium. The stroma possesses unmyelinated axons and plasma cells. The normal secretion of the secretory endpieces, particularly lipids, proteins and glycoconjugates, is complemented by mucous and serous secretions released by ductal cells and glands associated to the ducts.

The cavernous body of the human efferent tear ducts: function in tear outflow mechanism.

PURPOSE: To determine the structure and function of a system of large blood vessels integrated in the bony canal between the orbit and the inferior nasal duct. METHODS: Thirty-one dissected lacrimal systems of adults were analyzed by using gross anatomy, histology, and electron microscopy as well as corrosion vascular casts. RESULTS: More than two thirds of the bony canal between orbit and inferior nasal duct is filled by a plexus of wide-lumened veins and arteries. The vascular system is embedded in the wall of the lacrimal sac and nasolacrimal duct and is connected to the cavernous tissue of the inferior turbinate. Three types of blood vessels can be distinguished inside the vascular tissue that surrounds the lumen of the lacrimal passage: barrier arteries, capacitance veins, and throttle veins. CONCLUSIONS: The surrounding vascular plexus of the lacrimal sac and nasolacrimal duct is comparable to a cavernous body. While regulating the blood flow, the specialized blood vessels permit opening and closing of the lumen of the lacrimal passage, effected by the bulging and subsiding of the cavernous body, and at the same time regulate tear outflow. Other functions such as drainage of absorbed tear fluid components and a role in immunologic response are under discussion as well. Malfunctions in the cavernous body may lead to disturbances in the tear outflow cycle, ocular congestion, or total occlusion of the lacrimal passages. Variations in the conditions for swelling of the cavernous tissue may have led to the (mistaken) description of valves in the lacrimal passage.

Electron-microscopic identification of pseudoexfoliation material in extrabulbar tissue.

The structure and distribution of pseudoexfoliation material in extrabulbar tissues from five eyes with typical unilateral intraocular pseudoexfoliation syndrome and two intraocularly unaffected fellow eyes were examined by transmission electron microscopy. In all seven eyes, unevenly distributed pseudoexfoliation aggregates were found in limbal conjunctivae, extraocular rectus and oblique muscles, orbital connective-tissue septa, and the walls of the posterior ciliary arteries, vortex veins, and central retinal vessels passing through the optic nerve sheaths. Typical pseudoexfoliation fibers occurred in close association with connective-tissue components, especially elastic fibers; a moderate predisposition of pseudoexfoliation clumps to accumulate around blood vessels was observed. The findings of pseudoexfoliation material in similar extrabulbar locations in intraocularly uninvolved fellow eyes indicates that pseudoexfoliation fiber formation outside the globe precedes its intraocular manifestation. The intermingling of pseudoexfoliation fibers, microfibrils, and elastic and collagen fibers suggests that pseudoexfoliation fiber formation might result from a disordered synthesis and/or assembly of connective-tissue microfibrils.

Granular cell tumor (myoblastoma) of the orbit.

An 8-year-old white boy had a tumor in the left orbit with clinical manifestations of muscular impairment, exophthalmos, and reduced visual acuity. Five months after exenteration of the orbit the boy was healthy without tumor recurrence. Based on our observations with electron, light, and phase microscopy, and histochemical studies, we conclude that this tumor is benign, of histiocytic origin, and we propose the term granular cell histiocytoma be used to describe this entity.

Immunohistological and electron microscopical study of nodular fasciitis of the orbit.

We report the case of a 7-year-old Japanese girl with nodular fasciitis which was investigated by immunohistological and electron microscopical methods. An excised nodular lesion in her right orbit showed characteristic histological features of the disease. The fibroblastic cells showed myofibroblastic characteristics, such as immunohistochemically positive reactions against muscle specific actin and vimentin and characteristic electron microscopical appearances. The multinuclear giant cells did not react against any histiocytic markers, including HLA-DR, antimacrophage antigen, lysozyme, and S-100 protein, but the myofibroblastic markers and the electron microscopical study did reveal myofibroblastic characters.

Orbital involvement with desmoplastic melanoma.

A 79-year-old woman developed an orbital mass five and a half years after excision of a cutaneous melanoma from the side of the nose. The initial orbital biopsy was interpreted histopathologically as a malignant fibrous histiocytoma, but special stains and electron microscopy showed it to be a desmoplastic malignant melanoma which had apparently spread to the orbit from the prior skin lesion by neurotropic mechanisms. The occurrence of a desmoplastic neurotropic melanoma in the orbit has not been previously recognised. The problems in the clinical and pathological diagnosis of this rare type of melanoma are discussed.

Ultrastructure of the orbital pathway for cerebrospinal fluid drainage in rabbits.

An increasing number of physiological and morphological studies indicate that cerebrospinal fluid (CSF) drains via nonarachnoidal pathways in several mammalian species. Ultrastructural tracer studies were undertaken to examine the orbital route for CSF absorption in the rabbit. At the termination of the optic nerve subarachnoid space, an area of connective tissue containing numerous small tortuous channels is present. Ferritin (molecular weight 400,000) infused into the ventricles at normal and increased intraventricular pressure was present in these channels by 15 minutes postinfusion, and subsequently reached the intraorbital connective tissue. Elevating the intraventricular pressure did not noticeably alter the morphological appearance of this region or change the gross distribution pattern of the ferritin. Ferritin did not penetrate the scleral barrier to reach the choriocapillaris, nor did it breach the arachnoid barrier layer proximal to the transitional zone at the optic subarachnoid space to reach the dura mater. These results are very similar to those described for the hamster orbital region and the rabbit cribriform region. These experiments support the concept that macromolecules exit the subarachnoid space at the termination of the optic nerve via open channels, and that no significant barrier to drainage of macromolecules in CSF is present at this location.

Experimental evaluation of ceramic calcium phosphate as a substitute for bone grafts.

Tricalcium phosphate (Synthos) is a bioceramic material which can be carved with a scalpel and wired into place as a bone graft would be. The process of bone replacement of the prosthesis begins with an ingrowth of cellular loose connective tissue, which is replaced later by dense connective tissue. Around the periphery of this dense fibrous connective tissue, osteoid tissue becomes evident and on later specimens this mixture seems to be converted to bone--which at first is in the form of spicules but later takes on the characteristics of lamellar bone (with tricalcium phosphate particles seen within its lacunae). The progressive replacement occurs in a circumferential pattern, but most heavily at the bone-prosthesis interface. Although the periosteum is beneficial, we do not feel that the major source of bone formation is as the soft tissue or subperiosteal area. The replacement of the tricalcium phosphate prosthesis is slower than we originally thought, or than reported by others. We have noted pockets of tricalcium phosphate, incompletely replaced, in dogs up to 18 months after implantation. We believe this may be related to the larger sized prostheses we used (2 x 2 cm blocks) with, therefore, longer distances that the ingrowth and calcification had to traverse.

Extra-skeletal Ewing's sarcoma of the nasal fossa.

Extraskeletal Ewing's sarcoma is rarely found arising in the head and neck region. An unusual case arising in the nasal fossa in a young child is reported and the differential diagnosis, pathology and treatment discussed.

Spontaneous intraorbital hematoma mimicking orbital neoplasm--case report.

A 66-year-old female presented with spontaneous intraorbital hematoma manifesting as left exophthalmos after left eye discomfort persisting for 5 months. She had no history of head injury. Computed tomography revealed a round mass in her left orbit which was slightly high density with no postcontrast enhancement. A blood cyst was extirpated through frontotemporal craniotomy. Histological findings showed no tumor or vascular anomaly. Spontaneous intraorbital hematoma with insidious symptoms is extremely rare and should be considered in the differential diagnosis of orbital mass lesions.

Malignant fibrous histiocytoma of the lateral wall of the orbit.

A 58-year-old male presented with malignant fibrous histiocytoma originating from the lateral wall of the orbit, manifesting as left exophthalmos and diplopia on left lateral gaze. Magnetic resonance (MR) imaging demonstrated the tumor extending into the left orbit and under the temporalis muscle. The tumor was isointense with muscle on T1-weighted MR images and was surrounded by a low-intensity rim, which was proved to be the capsule after histological examination. The tumor was completely removed after detaching the lateral orbital rim and zygomatic arch using the dismasking flap method. He underwent one course of CYVADIC chemotherapy and has demonstrated no recurrence for 1 year and 6 months postoperatively.

[Clinical analysis of orbital cavernous hemangiomas].

CT and B-ultrasonography in combination with clinical manifestations facilitated the diagnosis and orientation of 40 cases of orbital cavernous hemangioma. The surgical approach depended on the size and location of the tumors as determined by axial and coronal CT, and mostly adopted was the route of lateral orbitotomy. The prevention of complications was discussed.

[Ultrastructure analysis and cytokines expression of orbital fibroblasts in the patients with thyroid-associated ophthalmopathy].

OBJECTIVE: To analyse the ultrastructure and cytokines expression from cultured orbital fibroblasts (OFs) in the patients with thyroid-associated ophthalmopathy (TAO). METHODS: Primary cultured OFs were obtained from 5 patients with TAO and 4 normal control subjects, some of subcultured OFs were treated by patients' serum with active TAO. Ultrastructures of OFs were observed by transmission election microscope. The cytokines in cultured supernatant were detected by enzyme linked immunosorbant assay (ELISA). RESULTS: There were no significant differences of ultrastructure of OFs from TAO patients and normal subjects. Nucleoli enlargement, microvillus prolongation and increase of endoplasmic reticular of OFs were detected after maintaining in culture. The IL-1, TNF-alpha and IFN-gamma were found in supernatant of OFs treated by patients' serum. IL-1 was found in supernatant of OFs in TAO patient and control subjects, and the IL-1 level of former was higher than the controls. CONCLUSION: There are no significant differences in ultrastructure of OFs from patients with TAO and normal subjects. The OFs treated with the serum of TAO patients showed proliferation and increasing cytokines secretion.

[The usage of light density heparin (fraxiparin) in the treatment of orbital phlegmonous cellulitis with orbital veins and thrombophlebitis of the cavernous sinus]. / Zastosowanie heparyny drobnoczasteczkowej (fraksiparyny) w leczeniu ropowicy oczodolu z zakrzepowym zapaleniem zyl oczodolowych i zatoki jamistej.

A case of 72 years old man, diabetic, suffering from phlegmonous cellulitis with orbital veins and sinus cavernous thrombophlebitis as a nasal vestibule furuncle complication is presented. Apart from the application of antibiotics and surgical procedure, the patient was treated from beginning with thrombolytics specimen, fraxiparine. The methods of treatment of cavernous sinus thrombosis with thrombolytic specimens evoke in the literature controversial opinions. In the author's opinion the early application of fraxiparine in presented case could be regarded as responsible for stopping the process orbital veins and sinus cavernous thrombosis and even causing it to recess. The complete cure without complications (e.g. blindness) is attributed by the authors to the anticoagulation treatment. The authors also stress that fraxiparine may by used for treatment of cavernous sinus thrombophlebitis even when the surgical procedure is planned.

Soft sheets of fibrillar bone from a fossil of the supraorbital horn of the dinosaur Triceratops horridus.

Soft fibrillar bone tissues were obtained from a supraorbital horn of Triceratops horridus collected at the Hell Creek Formation in Montana, USA. Soft material was present in pre and post-decalcified bone. Horn material yielded numerous small sheets of lamellar bone matrix. This matrix possessed visible microstructures consistent with lamellar bone osteocytes. Some sheets of soft tissue had multiple layers of intact tissues with osteocyte-like structures featuring filipodial-like interconnections and secondary branching. Both oblate and stellate types of osteocyte-like cells were present in sheets of soft tissues and exhibited organelle-like microstructures. SEM analysis yielded osteocyte-like cells featuring filipodial extensions of 18-20µm in length. Filipodial extensions were delicate and showed no evidence of any permineralization or crystallization artifact and therefore were interpreted to be soft. This is the first report of sheets of soft tissues from Triceratops horn bearing layers of osteocytes, and extends the range and type of dinosaur specimens known to contain non-fossilized material in bone matrix.

Reconstruction of orbital defect in rabbits with composite of calcium phosphate cement and recombinant human bone morphogenetic protein-2.

BACKGROUND: Calcium phosphate cement (CPC) is a biocompatible and osteoconductive bone substitute, and recombinant human bone morphogenetic protein-2 (rhBMP-2) has strong osteoinductibility, therefore we developed a composite bone substitute with CPC and rhBMP-2 and evaluate its reconstruction effect in rabbit orbital defect. METHODS: Thirty-six rabbits were randomly divided into two groups and a 5 mm × 5 mm × 2 mm bone defect in the infraorbital rim was induced by surgery in each orbit (72 orbits in all). The orbital defects were treated with pure CPC or composite of CPC and rhBMP-2. The osteogenesis ability of different bone substitute was evaluated by gross observation, histological examination, histomorphometrical evaluation, compressive load-to-failure testing, and scanning electron microscope (SEM). RESULTS: Gross observation showed that both bone substitutes were safe and effective for reconstruction of orbital defect. However, histological examination, histomorphometrical evaluation and SEM showed that CPC/rhBMP-2 group had faster speed in new bone formation and degradation of substitute material than CPC group. Compressive load-to-failure testing showed that CPC/rhBMP-2 group had stronger compressive strength than CPC group at every stage with significant difference (P < 0.05). CONCLUSION: Composite of CPC/rhBMP-2 is an ideal bioactive material for repairing orbital defect, with good osteoconductibility and osteoinductibility.

Repair of orbital wall defects using biocoral scaffolds combined with bone marrow stem cells enhanced by human bone morphogenetic protein-2 in a canine model.

Repair of orbital bone defects caused by trauma, infection or cancer is a continuous challenge in reconstructive surgery. Few studies have reported the application of tissue engineering for the repair of orbital bone defects in large animal models. Thus, we investigated the effects of tissue-engineered bone enhanced by the human bone morphogenetic protein-2 (BMP2) on the repair of orbital wall defects in a canine model. Autologous bone marrow stromal cells (BMSCs) from 16 Beagle dogs were isolated and cultured in vitro. Passage 2 cells were transfected with adenovirus containing human BMP2 (adv-BMP2) and tissue-engineered bone was constructed using BMP2-expressing BMSCs seeded on a biocoral scaffold. Circular defects (12-mm diameter) created bilaterally in the canine medial orbital wall, were treated with one of the following: adv-BMP2-transfected BMSC/coral composite (group I, n=8), BMSC/coral composite (group II, n=8), biocoral alone (group III, n=8), or were left untreated (group IV, n=8). Four samples from each group were harvested at 12 and 24 weeks after surgery, and the volume and density of newly regenerated bone were determined by micro-computed tomographic (micro-CT) measurement. The rate of new bone deposition and regeneration was measured by tetracycline/calcein labeling and histomorphometric analysis. The results showed that a canine 12-mm circular orbital defect was a critical-sized defect, and the micro-CT and histomorphometry detection results indicated that the combined delivery of BMSCs and BMP2 (group I) resulted in the highest regenerative effects on orbital bone defects, compared to the other groups without BMP2. Biocoral scaffolds combined with BMSCs enhanced by BMP2 could improve the healing of critical-sized medial orbital wall defects in canines.

Underdeveloped extraocular muscles in the naked mole-rat (Heterocephalus glaber).

The extraocular muscles (EOM), the effector arm of the ocular motor system, have a unique embryological origin and phenotype. The naked mole-rat (NMR) is a subterranean rodent with an underdeveloped visual system. It has not been established if their ocular motor system is also less developed. The NMR is an ideal model to examine the potential codependence of oculomotor and visual system development and evolution. Our goal was to compare the structural features of NMR EOMs to those of the mouse, a similar sized rodent with a fully developed visual system. Perfusion-fixed whole orbits and EOMs were dissected from adult NMR and C57BL mice and examined by light and electron microscopy. NMR orbital anatomy showed smaller EOMs in roughly the same distribution around the eye as in mouse and surrounded by a very small Harderian gland. The NMR EOMs did not appear to have the two-layer fiber distribution seen in mouse EOMs; fibers were also significantly smaller (112.3 +/- 46.2 vs. 550.7 +/- 226 sq microm in mouse EOMs, *P < 0.05). Myofibrillar density was less in NMR EOMs, and triad and other membranous structures were rudimentary. Finally, mitochondrial volume density was significantly less in NMR EOMs than in mouse EOM (4.5% +/- 1.9 vs. 21.2% +/- 11.6, respectively, *P < 0.05). These results demonstrate that NMR EOMs are smaller and less organized than those in the mouse. The "simpler" EOM organization and structure in NMR may be explained by the poor visual ability of these rodents, initially demonstrated by their primitive visual system.

Scanning electron microscopy of the orbital Harderian gland in the male Atlantic bottlenose dolphin (Tursiops truncatus).

The ultrastructure of the Harderian gland of Atlantic bottlenose dolphin (Tursiops truncatus) was examined by scanning electron microscopy (SEM). We found the following surface features: the typical round appearance of the ascinar glandular unit with a finely granular surface, a thin cortex and immediately below two types of cells: type I cells (characterized by small lipid vacuoles) and type II cells (characterized by large lipid vacuoles). It has been suggested that different cells forms represent a single cell type in varying activity states. Additionally, a coalescent tubular complex, a small balloon-like structures and large globular structures were observed. These structures may be reservoirs of secretion products.