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Sosnowik S, Swain DL, Fan S, Toris CB, Gong H. Morphological changes to Schlemm's canal and the distal aqueous outflow pathway in monkey eyes with laser-induced ocular hypertension. Exp Eye Res 2022; 219:109030. [PMID: 35283108 PMCID: PMC9133064 DOI: 10.1016/j.exer.2022.109030] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 01/31/2022] [Accepted: 03/06/2022] [Indexed: 11/04/2022]
Abstract
Though roughly 30-50% of aqueous outflow resistance resides distal to Schlemm's canal (SC), the morphology of the conventional outflow pathway distal to SC has not been thoroughly evaluated. This study examined the morphological changes along proximal and distal aspects of the conventional aqueous outflow pathway and their association with decreased outflow facility in an experimental model of glaucoma in cynomolgus macaques. Nd:YAG laser burns were made to 270-340 degrees of the trabecular meshwork (TM) of one eye (n = 6) or both eyes (n = 2) of each monkey to induce ocular hypertension. Distinct regions of the TM were left unlasered. Contralateral eyes (n = 5) were not lasered and were utilized as controls. Monkeys were sacrificed ≥58 months after their last laser treatment. All eyes were enucleated and perfused at 15 mmHg for 30 min to measure outflow facility. Two pairs of eyes were also perfused with fluorescein to examine segmental outflow. All eyes underwent perfusion-fixation for 1 h. Anterior segments were cut into radial wedges and processed for light and electron microscopy. Width, height, and cross-sectional area (CSA) of SC were compared between high- and low-flow regions of control eyes, and between non-lasered regions of laser-treated eyes and control eyes. Number and CSA of intrascleral veins (ISVs) were compared between non-lasered and lasered regions of laser-treated eyes and control eyes, and between high- and low-flow regions of control eyes. Scleral collagen fibril diameter was compared between control eyes and lasered and non-lasered regions of laser-treated eyes. Median outflow facility was significantly decreased in laser-treated eyes compared to control eyes (P = 0.02). Median CSA and height of SC were smaller in high-flow regions than low-flow regions of control eyes (P < 0.05). Median width of SC was not significantly different between high- and low-flow regions of control eyes (P > 0.05). Median CSA, width, and height of SC were not different between non-lasered regions and control eyes (P > 0.05). SC was partially or completely obliterated in lasered regions. Median number of ISVs was significantly decreased in lasered regions compared to non-lasered regions (P < 0.01) and control eyes (P < 0.01). Median CSA of ISVs did not differ between these groups (P > 0.05). Median number and CSA of ISVs were not significantly different between high- and low-flow regions of control eyes (P > 0.05). Lasered regions displayed looser scleral stroma and smaller median diameter of collagen fibrils adjacent to the TM compared to non-lasered regions (P < 0.05) and control eyes (P < 0.05). Dense TM, partial to complete obliteration of SC, and a decreased number of patent ISVs may account in part for the decreased outflow facility in monkey eyes with laser-induced ocular hypertension. The significance of changes in scleral structure in laser-treated eyes warrants further investigation.
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Affiliation(s)
- Shayna Sosnowik
- Department of Ophthalmology, Boston University School of Medicine, Boston, MA, USA
| | - David L Swain
- Department of Ophthalmology, Boston University School of Medicine, Boston, MA, USA; Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA, USA
| | - Shan Fan
- Department of Ophthalmology and Visual Science, University of Nebraska Medical Center, Omaha, NE, USA
| | - Carol B Toris
- Department of Ophthalmology and Visual Science, University of Nebraska Medical Center, Omaha, NE, USA; Department of Ophthalmology and Visual Sciences, The Ohio State University, Columbus, OH, USA
| | - Haiyan Gong
- Department of Ophthalmology, Boston University School of Medicine, Boston, MA, USA; Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA, USA.
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Almogbil HH, Nasrallah FP, Zderic V. Feasibility of Therapeutic Ultrasound Application in Topical Scleral Delivery of Avastin. Transl Vis Sci Technol 2021; 10:2. [PMID: 34851358 PMCID: PMC8648056 DOI: 10.1167/tvst.10.14.2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Purpose Macromolecules have been shown to be effective in vision-saving treatments for various ocular diseases, such as age-related macular degeneration and diabetic retinopathy. The current delivery of macromolecules requires frequent intraocular injections and carries a risk of serious adverse effects. Methods We tested the application of therapeutic ultrasound as a minimally invasive approach for the delivery of Avastin into the diseased regions of the eye. Avastin (bevacizumab) is an anti-vascular endothelial growth factor (VEGF) antibody with a molecular weight of 149 kDa. We tested the effectiveness and safety of Avastin delivery through rabbit sclera in vitro using a standard diffusion cell model. Ultrasound at frequencies of 400 kHz or 3 MHz with an intensity of 1 W/cm2 was applied for the first 5 minutes of 1-hour drug exposure. Sham treatments mimicked the ultrasound treatments, but ultrasound was not turned on. Absorbance measurements of the receiver compartment solution were performed at 280 nm using a spectrophotometer. Results Absorbance measurements indicated no statistical difference between the sham (n = 13) and 400 kHz ultrasound group (n = 15) in the delivery of Avastin through the sclera. However, the absorbance values were statistically different (P < 0.01) between the 3 MHz ultrasound group (0.004, n = 8) and the matched sham group (0.002, n = 7). There was 2.3 times increase in drug delivery in the 3 MHz ultrasound when compared to the corresponding sham group. Histological studies indicated no significant damage in the ultrasound-treated sclera due to ultrasound application. Conclusions Our preliminary results provided support that therapeutic ultrasound may be effective in the delivery of Avastin through the sclera. Translational Relevance Our study offers clinical potential for a minimally invasive retinopathy treatment.
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Affiliation(s)
- Hanaa H Almogbil
- Department of Biomedical Engineering, The George Washington University, Washington, DC, USA
| | | | - Vesna Zderic
- Department of Biomedical Engineering, The George Washington University, Washington, DC, USA
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Terubayashi Y, Morishita S, Fukumoto M, Sato T, Kida T, Ikeda T. Scleral patch grafting for scleral wound thinning after pars plana phacoemulsification and aspiration: A case report. Medicine (Baltimore) 2019; 98:e15598. [PMID: 31083249 PMCID: PMC6531146 DOI: 10.1097/md.0000000000015598] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
RATIONALE Here we report the case of a patient who required closure with an autologous scleral patch graft during reoperation after developing marked scleral thinning in the late stage after pars plana phacoemulsification and aspiration (PPPEA). To the best of our knowledge, this is the first reports of the procedure being used for the treatment of a thinned scleral section post PPPEA. PATIENT CONCERNS This study involved a 73-year-old woman who had undergone vitreous surgery combined with PPPEA for retinal detachment in her right eye 8 years earlier and subsequently underwent intraocular lens (IOL) ciliary sulcus suture fixation. DIAGNOSES She became aware of visual disturbance in her right eye and slit-lamp examination revealed the dislocation of the IOL. INTERVENTIONS To remove the dislocated IOL and resuture the nasal loop back onto the ciliary sulcus of the patient's right eye, a 25-guage trocar was placed on the superior temporal side. OUTCOMES Subsequent removal of the trocar from the patient's right eye left an approximately 3-mm-wide oval-shaped gap at the trocar insertion site due to extreme thinning of the sclera in that area; that is, the location where the PPPEA was performed. Since suture fixation failed to stop intraocular fluid leakage, an inferior free half-thickness scleral flap was created to patch the scleral wound. Postsurgery, the leakage in that eye stopped and the intraocular pressure was stable. No complications were observed during the 1-year-postoperative follow-up period. LESSONS Since thermal injuries during PPPEA may lead to postoperative scleral thinning, surgeons should avoid the site of a prior PPPEA when constructing a scleral wound during reoperation.
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Soliman S, Kletke S, Roelofs K, VandenHoven C, Mckeen L, Gallie B. Precision laser therapy for retinoblastoma. EXPERT REVIEW OF OPHTHALMOLOGY 2018. [DOI: 10.1080/17469899.2018.1478729] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Affiliation(s)
- Sameh Soliman
- Department of Ophthalmology and Visual Sciences, Hospital for Sick children, Toronto, Canada
- Department of Ophthalmology, Faculty of Medicine, University of Alexandria, Alexandria, Egypt
| | - Stephanie Kletke
- Department of Ophthalmology and Visual Sciences, Hospital for Sick children, Toronto, Canada
| | - Kelsey Roelofs
- Department of Ophthalmology, Alberta children hospital, University of Calgary, Calgary, Canada
| | - Cynthia VandenHoven
- Department of Ophthalmology and Visual Sciences, Hospital for Sick children, Toronto, Canada
| | - Leslie Mckeen
- Department of Ophthalmology and Visual Sciences, Hospital for Sick children, Toronto, Canada
| | - Brenda Gallie
- Department of Ophthalmology and Visual Sciences, Hospital for Sick children, Toronto, Canada
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Enhanced mechanical properties of acrylate based shape memory polymer using grafted hydroxyapatite. JOURNAL OF POLYMER RESEARCH 2018. [DOI: 10.1007/s10965-018-1511-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Kutikov AB, Reyer KA, Song J. Shape Memory Performance of Thermoplastic Amphiphilic Triblock Copolymer poly(D,L-lactic acid- co-ethylene glycol- co-D,L-lactic acid) (PELA)/Hydroxyapatite Composites. MACROMOL CHEM PHYS 2014; 215:2482-2490. [PMID: 26457046 PMCID: PMC4597908 DOI: 10.1002/macp.201400340] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Biodegradable polymer/hydroxyapatite (HA) composites are desired for skeletal tissue engineering. When engineered with thermal-responsive shape memory properties, they may be delivered in a minimally invasive temporary shape and subsequently triggered to conform to a tissue defect. Here we report the shape memory properties of thermoplastic amphiphilic poly(D,L-lactic acid-co-ethylene glycol-co-D,L-lactic acid) (PELA, 120 kDa) and HA-PELA composites. These materials can be cold-deformed and stably fixed into temporary shapes at room temperature and undergo rapid shape recovery (< 3 s) at 50 °C. Stable fixation (>99% fixing ratio) of large deformations is achieved at -20 °C. While the shape recovery from tensile deformations slows with higher HA contents, all composites (up to 20 wt% HA) achieve high shape recovery (>90%) upon 10-min equilibration at 50 °C. The permanent shapes of HA-PELA can be reprogramed at 50 °C, and macroporous shape memory scaffolds can be fabricated by rapid prototyping.
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Affiliation(s)
- Artem B. Kutikov
- Dept. of Orthopedics & Physical Rehabilitation, Dept. of Cell & Developmental Biology, University of Massachusetts Medical School, 55 Lake Ave North, Worcester, MA 01655, USA
| | - Kevin A. Reyer
- Dept. of Orthopedics & Physical Rehabilitation, Dept. of Cell & Developmental Biology, University of Massachusetts Medical School, 55 Lake Ave North, Worcester, MA 01655, USA
| | - Jie Song
- Dept. of Orthopedics & Physical Rehabilitation, Dept. of Cell & Developmental Biology, University of Massachusetts Medical School, 55 Lake Ave North, Worcester, MA 01655, USA
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Wollensak G. Thermomechanical stability of sclera after glyceraldehyde crosslinking. Graefes Arch Clin Exp Ophthalmol 2010; 249:399-406. [DOI: 10.1007/s00417-010-1504-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2010] [Revised: 07/28/2010] [Accepted: 08/26/2010] [Indexed: 11/24/2022] Open
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High performance shape memory polymer networks based on rigid nanoparticle cores. Proc Natl Acad Sci U S A 2010; 107:7652-7. [PMID: 20375285 DOI: 10.1073/pnas.0912481107] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Smart materials that can respond to external stimuli are of widespread interest in biomedical science. Thermal-responsive shape memory polymers, a class of intelligent materials that can be fixed at a temporary shape below their transition temperature (T(trans)) and thermally triggered to resume their original shapes on demand, hold great potential as minimally invasive self-fitting tissue scaffolds or implants. The intrinsic mechanism for shape memory behavior of polymers is the freezing and activation of the long-range motion of polymer chain segments below and above T(trans), respectively. Both T(trans) and the extent of polymer chain participation in effective elastic deformation and recovery are determined by the network composition and structure, which are also defining factors for their mechanical properties, degradability, and bioactivities. Such complexity has made it extremely challenging to achieve the ideal combination of a T(trans) slightly above physiological temperature, rapid and complete recovery, and suitable mechanical and biological properties for clinical applications. Here we report a shape memory polymer network constructed from a polyhedral oligomeric silsesquioxane nanoparticle core functionalized with eight polyester arms. The cross-linked networks comprising this macromer possessed a gigapascal-storage modulus at body temperature and a T(trans) between 42 and 48 degrees C. The materials could stably hold their temporary shapes for > 1 year at room temperature and achieve full shape recovery <or= 51 degrees C in a matter of seconds. Their versatile structures allowed for tunable biodegradability and biofunctionalizability. These materials have tremendous promise for tissue engineering applications.
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van Nimwegen SA, L'Eplattenier HF, Rem AI, van der Lugt JJ, Kirpensteijn J. Nd:YAG surgical laser effects in canine prostate tissue: temperature and damage distribution. Phys Med Biol 2008; 54:29-44. [DOI: 10.1088/0031-9155/54/1/003] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Hovhannisyan V, Lo W, Hu C, Chen SJ, Dong CY. Dynamics of femtosecond laser photo-modification of collagen fibers. OPTICS EXPRESS 2008; 16:7958-68. [PMID: 18545505 DOI: 10.1364/oe.16.007958] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
In this work, we investigate the non-ablative, non-thermal photo-modification of collagen fibers by femtosecond Ti:Sa laser. The effect was induced and simultaneously registered during the repetitive laser scanning of type I collagen (rat tail and bovine Achilles' tendon), and bovine cornea. An irreversible increase in two-photon autofluorescence and a decrease in second harmonic generation intensities were associated with the collagen femtosecond laser photo-modification. Confocal spectral imaging revealed the formation of new fluorescent species. Controllable nonlinear photo-modification of collagen fibers and bovine cornea with approximately 2 microm spatial resolution was demonstrated.
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Flyckt VMM, Raaymakers BW, Lagendijk JJW. Modelling the impact of blood flow on the temperature distribution in the human eye and the orbit: fixed heat transfer coefficients versus the Pennes bioheat model versus discrete blood vessels. Phys Med Biol 2006; 51:5007-21. [PMID: 16985284 DOI: 10.1088/0031-9155/51/19/018] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Prediction of the temperature distribution in the eye depends on how the impact of the blood flow is taken into account. Three methods will be compared: a simplified eye anatomy that applies a single heat transfer coefficient to describe all heat transport mechanisms between the sclera and the body core, a detailed eye anatomy in which the blood flow is accounted for either by the bioheat approach, or by including the discrete vasculature in the eye and the orbit. The comparison is done both for rabbit and human anatomies, normo-thermally and when exposed to homogeneous power densities. The first simplified model predicts much higher temperatures than the latter two. It was shown that the eye is very hard to heat when taking physiological perfusion correctly into account. It was concluded that the heat transfer coefficient describing the heat transport from the sclera to the body core reported in the literature for the first simplified model is too low. The bioheat approach is appropriate for a first-order approximation of the temperature distribution in the eye when exposed to a homogeneous power density, but the discrete vasculature down to 0.2 mm in diameter needs to be taken into account when the heterogeneity of the temperature distribution at a mm scale is of interest.
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Affiliation(s)
- V M M Flyckt
- Department of Radiotherapy, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands.
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de Graaf P, Castelijns JA, Moll AC, Imhof SM, Schouten-van Meeteren AYN. Atrophic chorioretinal scar and focal scleral bowing following thermochemotherapy with a diode laser for retinoblastoma. Ophthalmic Genet 2006; 27:33-5. [PMID: 16543200 DOI: 10.1080/13816810500481907] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
One of the treatment options for intraocular retinoblastoma is thermochemotherapy with diode laser combined with chemotherapy. Very little is known about the evolution of laser scars resulting from diode laser treatment for retinoblastoma. We report a case of atrophic chorioretinal scar and focal scleral bowing after thermochemotherapy with diode laser for retinoblastoma.
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Rem AI, Oosterhuis JA, Keunen JEE, Journée-De Korver HG. Transscleral thermotherapy with laser-induced and conductive heating in hamster Greene melanoma. Melanoma Res 2005; 14:409-14. [PMID: 15457098 DOI: 10.1097/00008390-200410000-00012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The purpose of this study was to investigate the cytotoxic effect of heat as induced by transscleral thermotherapy (TSTT), which may be of interest in the treatment of patients with choroidal melanoma. The aim of TSTT is to heat both the sclera and the tumor up to a cytotoxic temperature of about 60 degrees C. TSTT was performed in hamsters with subcutaneously implanted Greene melanoma covered by a specimen of human donor sclera of thickness 0.5, 0.7 or 0.9 mm. A newly developed applicator, which combines conductive episcleral heating at 60 degrees C with laser-induced heating, was used at laser powers ranging from 500 to 1500 mW delivered by an 810 nm diode laser, beam diameter 3 mm, and exposure time 1 min. Temperatures were measured at the scleral surface and at the sclera-tumor interface. The extent of tumor necrosis was examined by light microscopy and the sclera was examined by polarized light microscopy. Maximal depth of tumor necrosis without scleral damage was 4.4 (SD 1.5) mm. The temperature at the scleral surface after TSTT was 58.8 (SD 2.4) degrees C. The temperature at the sclera-tumor interface ranged from 56.4 (SD 3.7) degrees C at 500 mW to 65.3 (SD 4.4) degrees C at 1250 mW laser power. Structural changes to the scleral collagen started to develop at 1250 mW. TSTT with combined laser-induced and conductive heating caused cytotoxic temperatures in the tumor and the sclera, which were well tolerated by the scleral collagen.
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Affiliation(s)
- Alex I Rem
- Department of Ophthalmology, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, The Netherlands.
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Fantner GE, Birkedal H, Kindt JH, Hassenkam T, Weaver JC, Cutroni JA, Bosma BL, Bawazer L, Finch MM, Cidade GAG, Morse DE, Stucky GD, Hansma PK. Influence of the degradation of the organic matrix on the microscopic fracture behavior of trabecular bone. Bone 2004; 35:1013-22. [PMID: 15542025 DOI: 10.1016/j.bone.2004.05.027] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2003] [Revised: 05/25/2004] [Accepted: 05/27/2004] [Indexed: 01/24/2023]
Abstract
In recent years, the important role of the organic matrix for the mechanical properties of bone has become increasingly apparent. It is therefore of great interest to understand the interactions between the organic and inorganic constituents of bone and learn the mechanisms by which the organic matrix contributes to the remarkable properties of this complex biomaterial. In this paper, we present a multifaceted view of the changes of bone's properties due to heat-induced degradation of the organic matrix. We compare the microscopic fracture behavior (scanning electron microscopy; SEM), the topography of the surfaces (atomic force microscopy; AFM), the condition of bone constituents [X-ray diffraction (XRD), thermogravimetric analysis (TGA), and gel electrophoresis], and the macromechanical properties of healthy bovine trabecular bone with trabecular bone that has a heat-degraded organic matrix. We show that heat treatment changes the microfracture behavior of trabecular bone. The primary failure mode of untreated trabecular bone is fibril-guided delamination, with mineralized collagen filaments bridging the gap of the microcrack. In contrast, bone that has been baked at 200 degrees C fractures nondirectionally like a brittle material, with no fibers spanning the microcracks. Finally, bone that has been boiled for 2 h in PBS solution fractures by delamination with many small filaments spanning the microcracks, so that the edges of the microcracks become difficult to distinguish. Of the methods we used, baking most effectively weakens the mechanical strength of bone, creating the most brittle material. Boiled bone is stronger than baked bone, but weaker than untreated bone. Boiled bone is more elastic than untreated bone, which is in turn more elastic than baked bone. These studies clearly emphasize the importance of the organic matrix in affecting the fracture mechanics of bone.
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Affiliation(s)
- Georg E Fantner
- Department of Physics, University of California Santa Barbara, CA 93106, USA.
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Zaldivar RA, Aaberg TM, Sternberg P, Waldron R, Grossniklaus HE. Clinicopathologic findings in choroidal melanomas after failed transpupillary thermotherapy. Am J Ophthalmol 2003; 135:657-63. [PMID: 12719073 DOI: 10.1016/s0002-9394(02)02171-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
PURPOSE To review the clinicopathologic features of eyes enucleated after failed transpupillary thermotherapy. DESIGN Retrospective review. METHODS Pathology reports in the L.F. Montgomery Laboratory between 1998 and 2002 were searched for enucleated eyes with choroidal melanoma that had been treated only by transpupillary thermotherapy (TTT) prior to enucleation. The clinical features of the patients, including ultrasonography examination, were reviewed and compared with the pathologic findings. RESULTS Seven eyes from seven patients had been enucleated, representing 8% of eyes treated with TTT at our institute during the period studied. The primary indication for enucleation was tumor growth. The melanomas tended to grow laterally, with minimal if any increase in thickness. Five of the seven eyes histologically demonstrated extrascleral extension, which was detected by ultrasonography prior to enucleation in only one of those eyes. CONCLUSIONS Choroidal melanoma may continue to grow along a path of least resistance after TTT. The melanoma may extend laterally in the choroid and through emissary canals. Early extrascleral extension may be difficult to detect by ultrasonography.
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Affiliation(s)
- Renzo A Zaldivar
- Department of Ophthalmology, Emory University, Atlanta, Georgia, USA
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Ross EV, Zelickson BD. Biophysics of nonablative dermal remodeling. SEMINARS IN CUTANEOUS MEDICINE AND SURGERY 2002; 21:251-65. [PMID: 12512648 DOI: 10.1053/sder.2002.36767] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This article explores the physics of nonablative skin remodeling as well as the histologic sequelae. Although there have been several studies of nonablative skin remodeling, the exact mechanisms of action and thus the optimum device-specific parameters are not yet known. The article is divided into a discussion of the physics of laser-tissue interactions, followed by a review of the types of devices used for nonablative skin remodeling, and the histologic findings that follow treatment.
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Affiliation(s)
- E Victor Ross
- Dermatology Department, Naval Medical Center San Diego, San Diego, CA 92134, USA.
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Abstract
During the past 20 years of enucleation, which was the standard treatment for choroidal melanoma over more than a century, has largely been replaced by eye salvaging therapies such as radiotherapy or local resection. In 1995 transpupillary thermotherapy (TTT) using an infrared diode laser was introduced as a new conservative therapy for patients with choroidal melanoma. TTT can be defined as a heat treatment modality, which is delivered through a dilated pupil to the tumour surface. The technique uses a wide diode laser beam diameter with a low irradiance and a long exposure time. TTT induces tumour necrosis at sub-photocoagulation levels by a direct cell destructive effect with only a few ocular complications. TTT can be performed as sole therapy or combined with plaque radiotherapy, thus permitting a lower radiation dose. For amelanotic tumours dye-enhanced TTT with indocyanine green can be used. In this paper we review the role of sole or combined TTT, related to the current other treatment modalities for choroidal melanoma.
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Affiliation(s)
- J G Journée-de Korver
- Department of Ophthalmology, Ocular Oncology Service, Leiden University Medical Centre, P.O. Box 9600, 2300 RC Leiden, The Netherlands.
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Rem AI, Oosterhuis JA, Korver JG, van den Berg TJ. Transscleral laser thermotherapy of hamster Greene melanoma: inducing tumour necrosis without scleral damage. Melanoma Res 2001; 11:503-9. [PMID: 11595888 DOI: 10.1097/00008390-200110000-00010] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The feasibility of using transscleral thermotherapy (TSTT) to induce necrosis of choroidal melanoma without causing damage to the sclera was investigated. Fifty-two subcutaneously implanted hamster melanomas covered by human donor sclera were irradiated for 1 min with an 810 nm laser using a 3 mm spot diameter, with and without cooling of the scleral surface. Immediately after irradiation the temperature of the scleral surface was measured with an infrared camera. Irradiation at 2000 mW, without cooling of the sclera, resulted in tumour necrosis to a mean depth of 4.4 mm and a mean diameter of 5.5 mm, without causing damage to the scleral collagen; the surface temperature of the sclera was 44.5 degrees C, and the estimated temperature at the sclera-tumour interface was 60.1 degrees C. There was a sharp demarcation between the viable and the necrotic part of the tumour. TSTT at 2500 mW, without cooling of the sclera, caused maximal tumour necrosis to a mean depth of 5.2 mm and a mean diameter of 5.9 mm; the scleral layers adjacent to the tumour had an estimated temperature of 67.6 degrees C and showed signs of damage in 14% of the experiments. Cooling of the sclera resulted in less thermal damage to the sclera but also less tumour necrosis. Results indicate that TSTT has potential in the treatment of choroidal melanoma.
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Affiliation(s)
- A I Rem
- Department of Ophthalmology, Leiden University Medical Centre, PO Box 9600, 2300 RC Leiden, The Netherlands.
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