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PubMed2006

Effect of the size and location of osteochondral defects in degenerative arthritis. A finite element simulation.

Physiological studies have shown that focal articular surface defects in the human knee may progress to degenerative arthritis. Although the risk of this evolutive process is multifactorial, defect size is one of the most important factors. In order to determine the influence of osteochondral defect size and location on the stress and strain concentrations around the defect rim, a finite element model of the human knee was developed. From our results, it became clear that the size and location of cartilage defects drastically affect to those variables. No stress concentration appeared around the rim of small defects, being the stress distribution mainly controlled by the meniscus contact. On the contrary, important rim stress concentration was found for large osteochondral defects. This alteration of the stress distribution has important clinical implications regarding the long-term integrity of the cartilage adjacent to osteochondral defects.

Cartilage, Articular↗
PubMed2004

One day exposure to FGF-2 was sufficient for the regenerative repair of full-thickness defects of articular cartilage in rabbits.

OBJECTIVES: Administration of fibroblast growth factor (FGF)-2 for 2 weeks induces a successful cartilaginous repair response in 5-mm full-thickness articular cartilage defects in rabbits. The purpose of this study was to investigate the effects of a short time exposure to FGF-2 on the repair of the defects. METHODS: Five-mm-diameter cylindrical defects, which do not repair spontaneously, were created in the femoral trochlea of the rabbit knees. The defects were administered sterile saline or FGF-2 (150pg/h) via an osmotic pump for the initial 1 day, 3 days, or 2 weeks, and we assessed the FGF-2 action on the proliferation and migration of mesenchymal cells in the reparative tissue. Using a total of 126 rabbits, we performed three sets of experiments. We also studied the effect of FGF-2 on migration of marrow-derived mesenchymal cells in vitro. RESULTS: FGF-2 treatment for 1 day or 3 days induced the sequential chondrogenic repair responses that led to successful cartilaginous resurfacing of defects within 8 weeks as well as the 2-week treatment did. We confirmed by a radioisotope study that FGF-2 injected was rapidly eliminated from the defects (a residual ratio of 50% within 30min). The effect of FGF-2 on cultured marrow-derived cells suggested that FGF-2 facilitated the mobilization and migration of replicating mesenchymal cells from bone marrow. CONCLUSIONS: Only 1 day exposure to FGF-2 is sufficient for induction of the chondrogenic repair response in 5-mm-diameter full-thickness defects of articular cartilage in rabbits. FGF-2 stimulated the recruitment of mesenchymal cells into the defects, which was a limiting step for the induction of cartilage.

Animals↗
PubMed2005

Magnetic resonance imaging characterization of osteochondral defect repair in a goat model at 8 T.

OBJECTIVE: This study was performed to non-invasively visualize and characterize osteochondral (OC) repair in ex vivo goat stifles using an 8 T magnetic resonance imaging (MRI) scanner and to compare the MR morphology with images obtained from 1.5 T, gross morphology and histology. METHODS: Mature, neutered male goats were assigned to an 8-week (n = 4) or 16-week (n = 4) study period. Two cylindrical OC defects (7 mm diameter, full cartilage thickness and 1mm into subchondral bone) were surgically created in the right stifle: one in the medial femoral condyle (MFC) and the other in the trochlear groove (TG). The implant matrices (non-woven or foam) were secured in the defect using a bottom anchored fixation device (FD). The contralateral left stifles served as time zero controls. At the day of necropsy, implants were placed at both defect sites (MFC and TG) on the normal left stifles. Following necropsy, the ex vivo goat stifles (intact and encapsulated) were disarticulated. Within 24 h postnecropsy, MR scans of the stifles along the mid-sagittal plane of the OC defect were acquired at 8 T and 1.5 T. MR relaxation times, T1 and T2, were measured at the region of repair tissue (RT) and adjacent native cartilage. Immediately after MR imaging, the stifles were dissected, grossly examined, and a sagittal OC block corresponding to the MR region of interest was prepared for formalin fixation. RESULTS: The high-resolution MR images enabled visualization of cartilage and bone integrity surrounding the implant as well as delineating the margins of RT/implant matrix and the FD. On spin echo sequence, the RT variably appeared as high, intermediate or low MR signal intensity; whereas, the FD always appeared as low signal intensity. In general, the MR signal intensity of 8-week RT was slightly higher compared to 16-week RT; however, there was no difference in RT morphology of stifles implanted with the non-woven matrix or foam matrix. Subchondral sclerosis appeared as low signal intensity. The 8 T MR images showed better delineation of the stifle tissues compared to the images acquired at 1.5 T. The T2 relaxation time of the RT appears to indicate (inconclusive due to small number of samples) a slight variation in the RT type between 8 weeks and 16 weeks. At both study times, the defects grossly appeared whitish to reddish but did not have the characteristic hyaline appearance typical of articular cartilage (AC). The gross appearance of the MFC and TG RT differed, which was predominantly mottled and recessed with fissuring of adjacent native AC in the MFC. Histologically, the RT of both 8-week and 16-week postsurgical defects predominantly comprised fibrovascular connective tissue with only few samples showing the presence of fibrocartilaginous and/or hypertrophic chondrocytes within the defect RT at 8 weeks. Also, compared to 8-week, the 16-week RT appeared to be more fibrotic. CONCLUSION: Using 8 T scanner, high-resolution MR images of ex vivo encapsulated goat stifles confirmed the capability of high-field MR imaging to distinguish the defect RT from the FD and adjacent joint tissues. The extent of OC repair and adjacent bone lesions (at 8 weeks and 16 weeks) observed in the MR images compared well with those observed on the corresponding histological sections.

Animals↗
PubMed2006

Expression of the PTH/PTHrP receptor in chondrogenic cells during the repair of full-thickness defects of articular cartilage.

OBJECTIVE: We studied the accumulation of parathyroid hormone (PTH)/PTHrP receptor-positive mesenchymal cells using double immunohistochemistry and examined whether this correlated with the subsequent regeneration of 3-mm-diameter full-thickness defects of articular cartilage. MATERIALS AND METHODS: Cylindrical full-thickness articular cartilage defects (3 mm) were artificially created in the femoral trochlea of male adolescent Japanese white rabbits (n = 210) with a hand-drill. Recombinant human PTH(1-84) was then administered into the defect cavities with an osmotic pump for either 2 or 4 weeks post-injury. Following PTH treatment, the repair processes in the cartilage defects were histologically examined. Double immunostaining analyses for the PTH/PTH-related peptide (PTHrP) receptor and proliferating cell nuclear antigen (PCNA) in the regenerating tissues were then performed. RESULTS: Activation of PTH/PTHrP receptor signaling by hPTH(1-84) results in the inhibition of chondrogenic differentiation in full-thickness articular cartilage defects. At the conclusion of the 2-week PTH treatment, the defect cavities were filled with undifferentiated mesenchymal cells, which were similar to the controls. In addition, almost all of these cells localized at the center of the injuries were both PTH/PTHrP receptor- and PCNA-positive. In contrast, after prolonged PTH treatment for 4 weeks, there was no indication of a cartilaginous repair response and cells that had migrated to the defect cavities were found to have irreversibly lost expression of the PTH/PTHrP receptor. CONCLUSIONS: The chondrogenic capacity of cells that had migrated to the area of these defect cavities is closely associated with their ability to express the PTH/PTHrP receptor. Moreover, these cells maintain their chondrogenic potential within only a limited time-span of 2 weeks.

Animals↗
PubMed2004

Reconstruction of skull bone defects using the hydroxyapatite cement with calvarial split transplants.

PURPOSE: We sought to present a new method for primary reconstruction of traumatic or tumor calvarial defects. PATIENTS AND METHODS: Forty-one patients underwent reconstruction of calvarial bone defects between October 1998 and December 2001. Among them were 19 patients who needed reconstruction of the calvaria due to traumatic bone loss. Five of these trauma cases had insufficient primary reconstruction of the calvaria. Tumor resection caused calvarial defects in 22 patients. For primary reconstruction of the skull bone defects, calvarial split grafts were used to cover the defect as accurately as possible. The monocortical layers of the calvaria were fixed with titanium miniplates. Irregular defects surrounding the transplanted regions were filled with hydroxyapatite cement. In one case of posttraumatic bone loss, hydroxyapatite cement alone was sufficient to reconstruct the defect. RESULTS: The follow-up of each patient was at least 6 months; the longest period was 38 months. Evaluated clinical and radiologic results are stable, showing no measurable side effects. CONCLUSION: Hydroxyapatite cement alone or in combination with calvarial split grafts gave clinically and aesthetically stable results in the reconstruction of skull bone defects. The cement can be used for many reconstruction possibilities in craniofacial surgery.

Adult↗
PubMed2004

Reconstruction of mandibular defects with autologous tissue-engineered bone.

PURPOSE: Maxillofacial reconstructive procedures often require bone graft harvesting, which results in donor site morbidity; the use of tissue-engineered bone would eliminate this problem. In this study, a novel scaffold design and new fabrication protocol were used to produce autologous tissue-engineered constructs (scaffolds seeded with cells) to reconstruct segmental mandibular defects in a minipig model. MATERIALS AND METHODS: Porcine mesenchymal stem cells were isolated from the ilium. They were expanded in culture and seeded onto poly-dl-lactic-coglycolic acid scaffolds. The constructs were placed in a bioreactor and incubated for 10 days in medium and osteogenic supplements. Four full-thickness bony defects (2 x 2 cm) were created in the same pig's mandible. The constructs (n = 2) were placed into 2 of the defects as autologous grafts. One unseeded scaffold and 1 empty defect served as controls. At 6 weeks postimplantation, the pig was sacrificed, the mandible was harvested, and the grafted sites were evaluated by clinical, radiographic, and histologic methods. RESULTS: The construct-implanted defects appeared to be filled with hard tissue resembling bone, whereas controls were filled with fibrous tissue. Radiographically, the tissue-engineered constructs were uniformly radiodense with bone distributed throughout. The interface between native bone and constructs was indistinct. Complete bone ingrowth was not observed in control defects. Osteoblasts, osteocytes, bone trabeculae, and blood vessels were identified throughout the defects implanted with constructs. CONCLUSION: This "proof-of-principle" study indicates that porcine mandibular defects can be successfully reconstructed by in vitro cultured autologous porcine mesenchymal stem cells on a biodegradable polymer scaffold with penetration of bone and blood vessels.

Animals↗
PubMed2004

Evaluation of a poly-l-lactic acid membrane and membrane fixing pin for guided tissue regeneration on bone defects in dogs.

OBJECTIVES: The purpose of the study was to clarify the usefulness of a poly-l-lactic acid and membrane fixing pin, used in combination with guided bone regeneration, on bone defects in dogs. STUDY DESIGN: Osteotomies bone defects were created in 8 beagle dogs. Group I: one defect was covered with test membrane and held by fixing pins. Group II: the other defect was covered test membrane and not held by fixing pins. The control group received no membrane. The dogs were killed after 24 or 36 weeks of healing. Sections were stained and evaluated microscopically. Data were analyzed statistically. RESULTS: The degradation and resorption of test membrane was not observed at 24 weeks but was noted at 36 weeks. After 24 and 36 weeks, most of Group I defects were completely closed with new bone, while in the control defects, only a small amount of new bone was observed at the bottom of the bone defects. After 36 weeks, the percentage of new bone volume (62.2%) in the space beneath the test membrane and membrane fixing pin (Group I) was greater than that without a membrane fixing pin-53.2% (Group II), whereas only 43.9% of the defect area in the control group was filled with new bone. CONCLUSION: The results of this study show that a poly-l-lactic acid membrane and membrane fixing pin permit bone regeneration that can be ensured by excluding surrounding soft tissues from the wound area.

Absorbable Implants↗
PubMed2006

Circumferential and longitudinal defect detection using T(0,1) mode excited by thickness shear mode piezoelectric elements.

Different kinds of defects, such as corrosions, notches and cracks etc, exist in pipes. Mode choice is important since unfortunately not all ultrasonic guided wave modes are suitable for these kinds of defect detection. T(0,1) mode which is non-dispersive is the lowest and fastest torsional mode and most suitable for defect detection in pipes. Two completely different artificial defects including longitudinal and circumferential defects are processed successively in a 4-m-long, 60-mm-OD, 3.5-mm-wall steel pipe. T(0,1) mode at 45 kHz is excited to detect these defects using thickness shear mode piezoelectric elements. Experimental results show that two kinds of defects are detectable using T(0,1) mode. Comparing with longitudinal modes, torsional modes are dominant in pipe inspection for their sensitivities to different kinds of defects.

Journal Article↗
PubMed2001

Association of retinal vessel caliber and visual field defects in glaucoma.

PURPOSE: This study evaluates the asymmetry of peripapillary retinal vessel caliber between inferior and superior hemispheres in eyes with visual field defects predominantly in one hemifield. DESIGN: Observational case series. METHODS: In a retrospective study, 64 eyes of 64 patients with primary open-angle glaucoma who had a marked difference in visual field defects between hemifields and who had no history of diabetes, trauma, or vascular occlusive disease were studied. The diameters of the superior and inferotemporal vessels were measured at the optic disk border with calipers on an enlarged image. RESULTS: In 64 eyes, the average ratio of the superior temporal artery diameter to inferotemporal artery diameter was significantly greater in the eyes with predominantly superior visual field defects as compared with those with inferior defects (1.10 +/- 0.22 vs. 0.92 +/- 0.19, respectively, P =.002, two-tailed t test). This indicates that the arteriole corresponding to the hemifield with the greater visual field defect was narrower than the arteriole in the other hemifield. This relationship was confirmed using chi(2) analysis (P =.002) comparing the proportions of eyes with ratios greater or less than normal vessel caliber ratios (normal ratio = 0.95 from data reported by Jonas and associates to the location of the dominant field defect. No statistically significant relationship was detected between retinal vein diameter and localized visual field defects, as determined by both the unpaired t test and chi(2) analysis. CONCLUSION: In eyes with primary open-angle glaucoma, this study demonstrates a strong association between decreased peripapillary arteriole diameter and visual field defects in the corresponding hemifield. This reflects either an ischemic basis for glaucomatous damage or vascular constriction when there are fewer axons to nourish.

Adult↗
PubMed1995

Variability of the relative afferent pupillary defect.

PURPOSE: Afferent asymmetry of visual function is detectable in both normal and pathologic conditions. With a computerized test, we assessed the variability in measuring afferent asymmetry of the pupillary light reflex, that is, the relative afferent pupillary defect. METHODS: In ten normal subjects, pupillary responses to an alternating light stimulus were recorded with computerized infrared pupillography. The relative afferent pupillary defect for each test was determined by using a new computer analysis. The 95% confidence interval of each determination of relative afferent pupillary defect was used to represent the short-term fluctuation in its measurement. To optimize the test for clinical use, we studied the influence of stimulus intensity, duration, and number on the variability of the relative afferent pupillary defect. RESULTS: When the relative afferent pupillary defect was based on only a few light alternations (stimulus pairs), there was excessive variability in its measurement (95% confidence interval > 0.5 log units). With approximately 200 stimulus pairs, the 95% confidence interval was reduced to less than 0.1 log unit (relative afferent pupillary defect +/- 0.05 log unit). Also, there was less variability when the dark interval between alternating light stimulation was less than one second. CONCLUSIONS: Computerized infrared pupillography can standardize the alternating light test and minimize the error in quantifying a relative afferent pupillary defect. A reproducible relative afferent pupillary defect measurement is desirable for defining afferent injury and following the course of disease.

Adult↗
PubMed2001

Challenging abdominal wall defects.

BACKGROUND: We propose a simple algorithm for management of patients with challenging abdominal fascial defects. METHODS: The medical records of 64 patients with complicated abdominal wall defects representing a consecutive series by a single surgeon over a 4-year period were reviewed. Group I patients presented with massive fascial defects and closed wounds. They were reconstructed with autogenous tissue using either the separation of parts (SOP) procedure or free tensor fascia lata (TFL) grafts. Group 2 patients had fascial defects with open wounds. Wound closure was first accomplished with either STSG or primary skin closure over viscera. These patients, now "converted" into patients with closed wounds, were reconstructed months later as in group 1. RESULTS: Average defect size was 320 cm2. Wound closure was achieved in one procedure in all patients with open wounds. Time to discharge after this procedure averaged 9 days. The only morbidity of wound closure was skin graft donor site pain. Average time from temporary staged closure with skin grafts to definitive closure with autogenous tissue was 5 months. Repair of closed fascial defects with autogenous tissue was performed in 51 patients. Average time to discharge after autogenous tissue repair was 6.6 days. Recurrence of hernia was noted in 2 (3.9%) patients with an average follow-up of 24 months. CONCLUSIONS: Treatment of challenging abdominal wall defects can be accomplished simply and safely utilizing the above surgical algorithm. Open wounds are converted into closed wounds and fascial defects are repaired with autogenous tissue. This treatment plan has proved to be effective in a wide variety of situations.

Abdominal Injuries↗
PubMed2003

Microradiography to evaluate bone growth into a rat mandibular defect.

Microradiography has been evaluated to measure bone healing into a 5.0mm outer diameter mandibular defect in the rat. This method provides high-resolution radiographs of the defects that can be used for an accurate measurement of bone defect healing. In 12 rats, the defect widths of 42-day-old mandibular defects have been measured both using microradiographs and histological sections. The defect width+/-S.D. measured 3.42+/-0.98 mm microradiographically and 3.47+/-1.11 mm histologically. Both methods were accurate in determining defect widths but microradiography has the advantage over histology that an image is obtained from the entire defect, making it possible to measure areas of bone growth.

Animals↗
PubMed2003

Ciliary beat pattern is associated with specific ultrastructural defects in primary ciliary dyskinesia.

BACKGROUND: The main symptoms of primary ciliary dyskinesia (PCD) are nasal rhinorrhea or blockage and moist-sounding cough. Diagnosis can be difficult and is based on an abnormal ciliary beat frequency, accompanied by specific abnormalities of the ciliary axoneme. It is unknown whether determining ciliary beat pattern related to specific ultrastructural ciliary defects might help in the diagnosis of PCD. OBJECTIVE: We sought to determine ciliary beat pattern and beat frequency (CBF) associated with the 5 common ultrastructural defects responsible for PCD. METHODS: Nasal brushings were performed on 56 children with PCD. Ciliary movement was recorded using digital high-speed video imaging to assess beat frequency and pattern. Electron microscopy was performed. RESULTS: In patients with an isolated outer dynein arm or with an outer and inner dynein arm defect, 55% and 80% of cilia were immotile, respectively. Cilia that moved were only flickering. Mean CBF (+/- 95% CI) was 2.3 Hz (+/- 1.2) and 0.8 Hz(+/- 0.8), respectively. Cilia with an isolated inner dynein arm or a radial spoke defect had similar beat patterns. Cilia appeared stiff, had a reduced amplitude, and failed to bend along their length. Immotile cilia were present in 10% of cilia with an inner dynein arm defect and in 30% of radial spoke defects. Mean CBF was 9.3 Hz (+/- 2.6) and 6.0 Hz (+/- 3.1), respectively. The ciliary transposition defect produced a large circular beat pattern (mean CBF, 10.7 Hz [+/- 1.1]). No cilia were immotile. CONCLUSIONS: Different ultrastructural defects responsible for PCD result in predictable beat patterns. Recognition of these might help in the diagnostic evaluation of patients suspected of having PCD.

Adolescent↗
PubMed2000

Effect of the knobbed acrosome defect in bovine sperm on IVF and embryo production.

An IVF and culture system was used to determine the effect of the knobbed acrosome defect in bovine spermatozoa on fertilization and early embryonic development. Three bulls affected with knobbed acrosomes were identified as K+ (flattened acrosome), K2+ (indented acrosome) or K3+ (deep indentation of the acrosome) based on the predominant type of acrosomal aberration present in sperm of the respective bulls. After swim-up, all semen traits, except for acrosome morphology, were similar between bulls with varying degrees of the knobbed acrosome defect and a control bull, C. The mean number of spermatozoa bound to the zona pellucida was lower (P< 0.05) for the bulls with the knobbed acrosome defects (40.3 +/- 2.3, 29.5 +/- 1.6, 14.6 +/- 1.3, respectively, for Bulls K+, K2+ and K3+) than for Bull C (52.3 +/- 2.3). The percentages of zonae pellucidae penetrated by spermatozoa from Bulls K+ (51.2%), K2+ (49.5%) and K3+ (37.1%) were lower than that of Bull C (84.5%). No sperm with knobbed acrosome defects were found to have penetrated the zona pellucida. Fertilization rates for bulls with the knobbed acrosome defect, K+ (63.0%), K2+ (62.7%) and K3+ (22.6%), were significantly lower than that of the control bull (82.8%). Percentages of cleaved embryos, morulae and blastocysts produced were also lower for the bulls with knobbed acrosomes than that of the control bull. Results indicate that sperm with the knobbed acrosome defect had a reduced ability to bind to the zona pellucida, depending upon the severity of the defect, and that these aberrant spermatozoa did not penetrate the zona pellucida. The apparently normal spermatozoa coexisting in the inseminate of bulls with a high percentage of knobbed spermatozoa were also functionally deficient; oocytes penetrated by these spermatozoa had a reduced potential for fertilization, and resulting zygotes had a reduced ability for cleavage and embryonic development to the blastocyst stage. The results of the present study do not support the hypotheses that the knobbed acrosome defect is compensable.

Acrosome↗
PubMed2000

Bone regeneration in segmental defects with resorbable polymeric membranes: IV. Does the polymer chemical composition affect the healing process?

Diaphyseal segmental defects 10 mm in length in the radii of 36 skeletally mature rabbits were covered with tubular microporous membranes prepared from poly(L/D-lactide) (18 rabbits) and poly(L/DL-lactide) (18 rabbits) to determine whether chemical composition of the membrane affected the bone healing in the defect. The results of a previous study in which similar defects of the rabbits radii were not covered with membranes or covered with poly(L-lactide) membranes were used as controls. The control defects were rapidly filled with overlying muscle and soft tissues, producing a radio-ulnar synostosis. The osseous activity of control defects was limited to the bone ends. The defects covered with membranes were progressively filled with new bone. At 1 year, complete bone regeneration in the defects covered with the poly(L/D-lactide) membrane was found in 16 cases, no regeneration in 1 animal and pseudoarthrosis in 1 animal. For the poly(L/DL-lactide) membrane there was complete bone regeneration in 17 cases (1 animal died during surgery). The quality of the interface between the new bone and the membrane seemed to be affected by the chemical structure of the polylactides used for membranes preparation. For poly(L/D-lactide), the connective tissue layer entirely separated the new bone from the polymeric membrane. This has been observed before for poly(L-lactide) membranes. In the case of poly(L/DL-lactide) the new bone was formed in some places in direct contact with the membrane and the membrane fragments were osteointegrated. The differences in chemical composition of the polylactide membranes did not have an evident effect on the bone regeneration process in segmental defects of the rabbit radii.

Animals↗
PubMed1982

The onset and evolution of glaucomatous visual field defects.

Long-term follow-up was recorded on the visual fields of 251 patients with chronic open-angle glaucoma and 826 patients with ocular hypertension. Observation periods exceeded ten years for 73 patients with manifest glaucoma. Initial glaucomatous defects appeared in 98 eyes of 72 patients while under continuous observation. Initial defects were characteristically shallow and were located most commonly in the superior Bjerrum region adjacent to the blind spot. Three-dimensional (contiguous area) static perimetry provided superior resolution in detecting and characterizing the full extent of such shallow defects. The chronologic course of initial defects defects was marked in 22 of the 98 eyes by a phenomenon of a transiently appearing defect. Disappearance and reappearance of transient defects did not occur synchronously with short-term fluctuations in intraocular pressure. Ten-year follow-up of 63 eyes with manifest glaucomatous defects showed a high incidence (73%) of progression to dense involvement of the originally affected altitudinal hemifield. All eyes were treated continuously, but visual field loss occurred in spite of only marginally elevated levels of intraocular pressure.

Female↗
PubMed1999

Localized wedge-shaped defects of retinal nerve fiber layer and disc hemorrhage in glaucoma.

OBJECTIVE: To evaluate frequencies of localized wedge-shaped defects of the retinal nerve fiber layer (RNFL) in eyes with and without disc hemorrhage in normal-tension glaucoma (NTG) and primary open-angle glaucoma (POAG). This study also aims to define a topographic correlation between disc hemorrhage and localized RNFL defects in POAG. DESIGN: Cross-sectional study. PARTICIPANTS AND CONTROLS: The authors studied 83 eyes of 83 patients with NTG (male/female = 23/60; age, 58.8+/-12.9 years) and 20 eyes of 20 patients with POAG (male/female = 9/11; age, 61.6+/-11.4 years); subjects in both groups had developed new disc hemorrhage at the time of enrollment. The authors randomly selected 45 eyes of 45 patients with NTG (male/female = 20/25; age, 62.0+/-9.3 years) and 24 eyes of 24 patients with POAG (male/female = 13/11; age, 56.3+/-14.5 years) with no history of disc hemorrhage during the follow-up period of more than 2 years. METHODS: Visual field in the patients with POAG was matched to that of the patients with NTG regarding global indices for both the hemorrhage and the nonhemorrhage groups. Localized wedge-shaped defects of RNFL were identified by scanning laser ophthalmoscopy using an argon-blue laser. MAIN OUTCOME MEASURES: The frequency of localized RNFL defects and the relationship between the locations of disc hemorrhages and localized RNFL defects were determined. RESULTS: Localized wedge-shaped defects of RNFL occurred significantly more often in the hemorrhage group than in the nonhemorrhage group in both NTG (Fisher's exact probability test, P < 0.0001) and POAG (P < 0.05) patients. Regardless of the presence of disc hemorrhage, there was no significant difference in the frequency of localized RNFL defects between patients with NTG and those with POAG. Most disc hemorrhages were present in the vicinity of the border between localized RNFL defects and relatively healthy-looking RNFL in both patients with POAG and those with NTG. CONCLUSION: Disc hemorrhage is associated with localized damage of RNFL in both NTG and POAG.

Cross-Sectional Studies↗
PubMed1984

Congenital ocular defects in food-producing animals.

Congenital ocular defects in neonates pose a diagnostic challenge to veterinarians. Defects are usually obvious at birth, but detection depends on the nature and extent of the defect. In addition to congenital ocular defects, other abnormalities may be manifest including multiple system involvement with embryonic mortality, fetal death, mummification, abortion, dysmaturity, premature birth, full-term stillbirth, or nonviable or viable neonate. Many defective neonates are not reported or escape monitoring systems. Although congenital ocular defects are rare, they are important and should be diagnosed. All congenital defects should be regarded as genetic until proven otherwise. Many ocular defects are inherited as simple autosomal recessive traits. Polygenic inheritance appears to be of increasing importance.

Animals↗