Intraocular neovascularization and retinal energy metabolism.
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Energy Metabolism↗
Biomedical subjects
D J Wilson
Publications and source records attributed to D J Wilson.
Posterior half amputation of the chick wing bud: the response of the developing vasculature, and subsequent wound healing.
Experimental analyses examining pattern formation in the developing chick limb have concentrated on the skeleton, muscles and nerves, and have rarely considered blood vessels. To investigate the relationship between the vasculature and limb development, posterior amputations were performed on 3.5-4 day chick limb-buds. It has been shown that the removal of the posterior half alters the developmental fate of the anterior tissue: it becomes necrotic and fails to differentiate into the complement of skeletal parts predicted by fate maps. The possibility that this developmental failure results from interference with the future arterial supply was examined by Indian ink injection between 3-48 h after operation. Scanning electron microscopy (SEM) and resin histology were used to examine the wound repair at similar post-operative intervals. Results from the Indian ink injections showed that within 6 h of operation a collateral circulation was established by means of a branch from the truncated primary subclavian artery. The capillary density in the operated limbs appeared normal when compared to the contralateral limb. The results support the view that the poor developmental performance of the anterior half is due to removal of the zone of polarizing activity (ZPA) rather than to experimentally-induced alteration to the vascular supply. Histological and SEM examination of the wound healing process showed that epithelialization of the cut surface occurred within 24 h, and that the peridermal cells of the bilayered ectoderm appeared to initiate the regrowth. The wound site was not visible 48 h after operation, showing that wound healing at these developmental ages occurs quickly, with no scar tissue formation.(ABSTRACT TRUNCATED AT 250 WORDS)
Amputation, Surgical↗
Epidermal growth factor promotes chick embryonic angiogenesis.
The response of the early extraembryonic vasculature to epidermal growth factor (EGF) was studied. Millipore filter discs containing 10ng-1 microgram of EGF were placed onto the advancing edge of the area vasculosa of 3-day chick embryos, and the effect examined macroscopically and histologically 24 hours after disc application. The capillary density at the site of application increased significantly, and the effect was seen to be dose-dependent; a similar but more marked response was observed in the vessel cross-sectional area per unit length. This change in vascularity was accompanied by tortuous folding of the mesoderm and endoderm (which normally lie parallel to the ectoderm in a trilaminar arrangement) into the yolk substance: this may indicate precocious development of all three layers (ectoderm, mesoderm and ectoderm) of the membrane, and the proliferative effects of EGF may not be confined to the vascular endothelium.
Angiogenesis Inducing Agents↗
Ultrasonic imaging of soft tissues.
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Connective Tissue↗
Magnetic resonance imaging of the knee.
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Humans↗
Cystic degeneration of fibrous dysplasia masquerading as sarcoma.
An area of fibrous dysplasia of bone may undergo rapid enlargement which may be due to either cystic degeneration or malignant transformation. These complications may be clinically and radiologically indistinguishable and, unless both are borne in mind, incorrect management may follow. Magnetic resonance imaging was used in one of our cases and was the only imaging modality to demonstrate the true nature of the condition.
Adult↗
Intramembranous osteogenesis and angiogenesis in the chick embryo.
Membrane bone formation was examined in the developing chick frontal bone of Stage 32-36 embryos using alizarin red whole mounts, wax and resin histology, transmission electron microscopy and India ink injection techniques. Mineralised bone was seen at Stage 36, but was presaged by the appearance of twin mesenchymal condensations at Stage 35. The condensations appeared dorsolateral to the upper edge of the interorbital septum near its centre. The mesenchymal cells of the condensation were fusiform in shape and initially exhibited a close-packed, layered configuration which was avascular. Consequent differentiation of the central cells first into preosteoblasts and then into definitive osteoblasts, accompanied by secretion of bone matrix, coincided with blood vessel invasion of the frontal anlagen. It is suggested that these vascular changes associated with the onset of bone cell differentiation indicate that osteogenic cells may secrete an angiogenesis factor.
Animals↗
Patient evaluation and treatment planning for dental implants.
By supplying additional abutment support, dental implants provide an alternative to removable partial dentures, and offer edentulous patients an enhanced quality of life. However, predictability of success must be the determining factor when considering implants as the treatment of choice. Systematic evaluation of the regional anatomy and the condition of the natural teeth is mandatory. A new caliper technique for measuring the available bone makes predictability of success now even more attainable.
Dental Abutments↗
Ridge mapping for determination of alveolar ridge width.
Ridge mapping is a measurement procedure to ensure that the diameter of an endosseous screw implant does not exceed the dimensions of available bone. The long-term success of implants is a prime aim. To achieve this, it is essential for the initial evaluation of the dimensions of the resorbing alveolar process to be absolutely accurate. Ideally, an implant should be covered by at least 1 mm of bone on all sides. The major problem is estimating the thickness of bone, since the mucosal contour can mask the actual dimension of the alveolar ridge. Use of ridge mapping with the Wilson Bone Caliper makes possible a reliable evaluation procedure at the initial stage of treatment planning.
Alveolar Process↗
Soft tissue disease.
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Diagnostic Imaging↗
Internal structure of the intestinal villus: morphological and morphometric observations at different levels of the mouse villus.
The internal structure of the mouse jejunal villus was examined from apex to base in transverse serial sections. The villi were arbitrarily divided into apical (1-160 microns), middle (161-320 microns) and basal (321-480 microns) thirds. Histological and ultrastructural morphometry was performed on villous epithelium, stroma, blood vessels and lacteals at the three levels. The cross sectional area and the number of cells/section increased apico-basally in both the villous epithelium and the stroma, but the increase was greater in the latter. The enterocytes in the villous basal third were narrow and had oblong nuclei. The enterocytes gradually became wider and their nuclei attained a more round or oval shape towards the villous apex. The microvilli of these cells also increased in length from the villous base to apex. Although the number of capillaries/section was approximately the same at the three levels examined, it appeared that the apical third was relatively more vascular if the overall apico-basal increase in the villous size was taken into consideration. The villi had a single lacteal, whose cross sectional area generally increased towards the villous base. The results of this study indicate that the internal structure of the intestinal villus is not uniform along its length. Therefore, it is important that when studying normal and abnormal villi, like should be compared with like so as to ensure that the normally occurring variations in the villous morphology are not confused with those induced by disease or experimental processes.
Animals↗
Macular grid photocoagulation. An experimental study on the primate retina.
We studied the effect of macular grid photocoagulation on the retinal vessels, retina, retinal pigment epithelium, and choroid of normal cynomolgus monkeys. Argon blue-green laser photocoagulation, similar to that employed for treating macular edema due to branch retinal vein occlusion, resulted in a decreased retinal capillary area at both one and five months after treatment. The photoreceptors and retinal pigment epithelium between laser lesions were altered at three days after treatment, but their appearance returned to normal by five months. The significance of these findings is discussed with regard to resolution of macular edema and improvement in vision following grid photocoagulation.
Animals↗
Temporomandibular joint arthrography: dynamic study by videorecording.
Temporomandibular joint symptoms are common. Patients not successfully treated by conservative methods require accurate assessment of the internal derangements of the joint. Temporomandibular joint arthrography using only videorecorded intensifier fluorography displays the anatomy and function accurately with a low radiation dose.
Arthrography↗
Skeletal hyperostosis and extraosseous calcification in patients receiving long-term etretinate (Tigason).
In an ongoing study of patients on long-term etretinate (Tigason) therapy, 13 patients with a congenital or inherited disorder of keratinization and 10 patients with psoriasis were examined to investigate the incidence of, and the factors associated with, skeletal hyperostosis. Skeletal scintigraphy, plain radiographs, haematological and biochemical analyses were performed. Using all criteria, 7 of 13 patients with a congenital or inherited disorder of keratinization showed evidence of hyperostosis. No single investigation was able to detect all these cases; in particular, skeletal scintigraphy was positive in only nine of the 13 patients who showed hyperostosis. Eleven of the 13 patients with hyperostosis gave a history of musculoskeletal symptoms compared with three of the 10 patients without hyperostosis. There was no clear association with total dose or duration of treatment. Serum chemistry and haematological studies were normal. In two patients the 24-h urinary calcium excretion was significantly elevated, an abnormality which has not been described previously. Annual lateral thoracic spine radiographs with additional views of symptomatic areas are recommended for patients on long-term etretinate therapy.
Adult↗
Histopathologic study of the effect of retinal detachment surgery on 49 eyes obtained post mortem.
We studied 49 eyes obtained post mortem from 43 patients who had previously had retinal detachment surgery to evaluate some of the factors known to complicate retinal detachment. The retina had been successfully reattached in 44 of 49 eyes. We found epiretinal membranes in 37 eyes (75.5%), and in 15 eyes (30.6%) these membranes caused some degree of macular pucker. Other important findings included atrophy of the photoreceptor layer in 13 eyes (26.5%), intrusion of the implant in ten eyes (21.7%), cystoid macular edema in five eyes (10.2%), ciliochoroidal effusion in five eyes (10.2%), anterior segment necrosis in four eyes (8.2%), and choroidal neovascularization in three eyes (6.1%).
Choroid↗
Argon laser panretinal photocoagulation for diabetic retinopathy. Scanning electron microscopy of human choroidal vascular casts.
Plastic casts of the choroid of a 76-year-old diabetic man who received panretinal photocoagulation for proliferative diabetic retinopathy were studied with the scanning electron microscope. Despite a 14-month interval between the last panretinal photocoagulation session and death, numerous choriocapillaris-filling defects were present and correlated with photocoagulation lesions present on antemortem fluorescein angiograms.
Aged↗
Retinal dystrophy in Jeune's syndrome.
Jeune's syndrome is an autosomal-recessive condition characterized by multiple organ abnormalities, the most severe of which affect the skeleton, kidneys, and eyes. Severe respiratory insufficiency frequently results in death in infancy, but several patients have been reported to survive to adulthood. For this reason the prognosis for patients with ocular abnormalities is of interest in counseling families. We report a sibship of two patients who showed evidence for progression by visual field and electroretinogram testing when followed up over 3.7 years. Progressive electroretinographic abnormalities consisted of the following: progressive decrease in responses mediated by dark-adapted rods and both dark- and light-adapted cones in the first patient and progressive increase in b-wave implicit time elicited by 30-Hz flicker stimulation in the second patient.
Abnormalities, Multiple↗
Effects of extracapsular cataract extraction on the lens zonules.
The zonules of 27 postmortem eyes were studied grossly using a histologic staining technique that allowed easy visualization of the zonules. Large disinsertions of the zonules were present in 5 of the 20 eyes that had undergone extracapsular cataract extraction (ECCE).
Cataract Extraction↗