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At least 919 records · Page 51Linked to original sources
PubMed1985

Prognosis of traction retinal detachment in proliferative diabetic retiopathy.

Considering the complications which may arise when traction retinal detachment (TRD) is treated surgically, the correct assessment of its course is important. The evolution of TRD in proliferative diabetic retinopathy is described and its pathogenesis discussed. In order to predict the course of a specific clinical situation we have to assess the activity of retinopathy and the localization and extension of vitreoretinal adhesions. Some guide lines for proper evaluation and proper management of the often complicated clinical picture of TRD in proliferative diabetic retinopathy are presented.

Diabetic Retinopathy↗
PubMed1991

Vitronectin and proliferative intraocular disorders. I. A colocalisation study of the serum spreading factor, vitronectin, and fibronectin in traction membranes from patients with proliferative vitreoretinopathy.

The presence of a scaffold for cellular spreading and proliferation is a precondition for the development of traction membranes in proliferative vitreoretinopathy (PVR). This study shows the presence of the serum spreading factor, vitronectin, in the extracellular matrix of periretinal membranes removed during vitreoretinal surgery. By means of a double label immunofluorescence protocol, a partial colocalisation of vitronectin with fibronectin at the magnification of light microscopy can be detected. Fibronectin is a high-molecular glycoprotein with multiple biological functions including the mediation of cell attachment and migration. Both proteins share a special cell recognition site which could be a target for experimental pharmacological approaches to PVR. Preliminary studies of vitreous aspirates using electrophoresis and Western blotting indicate that vitronectin may play a more important role in post-traumatic PVR as compared to PVR following rhegmatogenous retinal detachment.

Blotting, Western↗
PubMed1984

Cell traction models for generating pattern and form in morphogenesis.

During early development migratory mesenchymal cells navigate to distant sites where they aggregate to form a variety of embryonic organ rudiments. We present here a new model for mesenchymal cell morphogenesis based on the mechanical interaction between motile cells and their extracellular environment. The model is based on two properties of motile cells: (a) they are capable of generating large traction forces which can deform the extracellular matrix through which they move, and (b) the deformations they produce in their environment affect the direction of their movements. We derive field equations which describe the motion of cells in an elastic extracellular matrix and show that these equations can generate a variety of spatial patterns, such as the formations of skin organ primordia, especially feather germs, cartilage condensation patterns which presage bone formation in limb development, and melanocyte density patterns which form animal coat patterns.

Animals↗
PubMed1982

[Inner retinal traction breaks resembling a sharkmouth in areas of peripheral cystoid degeneration (author's transl)].

10 predominantly diabetic eyes from a mixed collection of 1,561 enucleated specimens showed extended, linear, ridgelike elevations of the inner retinal layers within areas of cystoid degeneration. These ridges lie peripherally and run parallel to the ora. The posterior slope of each ridge contains a chain of inner retinal holes which extend into the cavities of the cystoid degeneration. The changes, viewed from behind, resemble an open sharkmouth. The posterior border of the vitreous base adheres to the crest of the ridge behind which the vitreous itself is detached. The ridges and inner holes are thought to result from vitreous traction, chronic rather than acute, acting on peripheral areas of cystoid degeneration which can presumably be elevated more easily than normal retina.

Adult↗
PubMed2002

[Traction retinal detachment, optic atrophy, apallic syndrome after shaking trauma in an infant].

INTRODUCTION: Ophthalmological examinations are important in children with suspected shaken baby and/or battered child syndrome. Retinal and epiretinal haemorrhages can indicate non-accidental injuries. We observed a case of extensive retinal hemorrhages, edema of the optic disc followed by development of optic atrophy, neovascularisation and tractional retinal detachment over the course of months. CASE REPORT: A 6-week-old infant with no history of systemic disease or trauma was admitted to the children's hospital because of a disorder of consciousness, respiratory insufficiency, taut fontanel and dilated pupils with sluggish reaction to light. A subdural haematoma was diagnosed. Ophthalmological examination showed no signs of trauma in the anterior segment. Ophthalmoscopy revealed extensive retinal haemorrhages and swollen optic nerve heads. During the next months optic atrophy, subretinal fibrosis at the posterior pole, neovascularisation at the optic disc and non-rhegmatogenous retinal detachment developed. The child is in a persistent vegetative state. DISCUSSION: Non-accidental injuries can cause direct trauma and indirect traumatic sequelae. Retinal haemorrhages, especially in conjunction with unexplained trauma or changes of consciousness should arouse suspicion of shaken baby syndrome. The ophthalmologist should emphasize this and strongly recommend further investigation if not previously undertaken.

Battered Child Syndrome↗
PubMed2003

[Retinal photoablation with the Erbium:YAG laser. Initial experimental results for traction-free removal of tissue].

BACKGROUND: To investigate the potential of an Er:YAG laser for precise and traction-free removal of retinal layers in vitro. MATERIAL AND METHODS: Retinal ablation in porcine retinal explants was performed using a free running Er:YAG laser focused either into a low-OH quartz fiber or a sapphire fiber. The explants were treated under air or perfluorodecaline (PFD). The ablation depth was evaluated by optical coherence tomography (OCT) and histology sections. RESULTS: A radiant exposure of 5.0 J/cm(2) under air and PFD resulted in complete transsection of the neurosensory retina. Between 3.5 and 2.0 J/cm(2) the ablation depth and the defect patterns varied markedly and adjacent thermal zones areas were seen. Below 2.0 J/cm(2) no defects could be created in air, whereas under PFD the ablation extended into the ganglion cell layer. Ablations using a sapphire fiber and 2.0 J/cm(2) showed a significantly higher reproducibility of ablation depth, and homogeneous defect patterns limited to the nerve fiber layer could be produced without thermal damage. CONCLUSIONS: The Er:YAG laser system with a low-OH quartz fiber allowed ablation of inner retinal layers in vitro, but revealed a variable ablation depth and low reproducibility.However, a sapphire fiber showed markedly improved results. Therefore its use during vitreoretinal surgery seems possible not only as a cutting device but also as a tool for the ablation of fine retinal structures.

Animals↗
PubMed2005

Rapid spontaneous resolution of vitreomacular traction syndrome documented by optical coherence tomography.

A 48-year-old woman presented with a 2-week history of metamorphopsia and reduced vision in her left eye. Visual acuity was 20/30 OS. Slit lamp biomicroscopy fundus evaluation revealed a dull foveal reflex. Optical coherence tomography (OCT) showed attachment of the posterior hyaloid to the macula and significant macular elevation. One month after presentation, visual complaints disappeared. OCT revealed complete posterior vitreous detachment and normal foveal thickness. Although rare, rapid spontaneous resolution of vitreomacular traction syndrome can occur. OCT is a helpful diagnostic tool for following these patients.

Female↗
PubMed2006

A viscoelastic traction layer model of muco-ciliary transport.

A new mathematical model of the transport of mucus and periciliary liquid (PCL) in the airways by cilia is presented. Mucus is represented by a linearly viscoelastic fluid, the mat of cilia is modelled as an 'active porous medium.' The propulsive effect of the cilia is modelled by a time-dependent force acting in a shear-thinned 'traction layer' between the mucus and the PCL. The effects of surface and interface tension are modelled by constraining the mucus free surface and mucus-PCL interface to be flat. It is assumed that the epithelium is impermeable to fluid. Using Fourier series, the system is converted into ODEs and solved numerically. We calculate values for mean mucus speed close to those observed by Matsui et al. [J. Clin. Invest., 102(6):1125-1131, 1998], (approximately 40 microm s(-1)). We obtain more detail regarding the dynamics of the flow and the nonlinear relationships between physical parameters in healthy and diseased states than in previously published models. Pressure gradients in the PCL caused by interface and surface tension are vital to ensuring efficient transport of mucus, and the role of the mucus-PCL interface appears to be to support such pressure gradients, ensuring efficient transport. Mean transport of PCL is found to be very small, consistent with previous analyses, providing insight into theories regarding the normal tonicity of PCL.

Cilia↗
PubMed1979

Clinical results in vitrectomy for diabetic traction retinal detachment.

A series of 75 eyes underwent pars plana vitrectomy for progressive diabetic traction retinal detachment of the macula. In all cases, the media was sufficiently clear to allow preoperative macular examination. The overall visual improvement was higher in phakic eyes (80%) than aphakic eyes (72%) and the rate of neovascular glaucoma was less in phakic eyes. The difference was not statistically significant, however. The final visual acuity corresponded to the degree of preoperative visual deterioration. Thus, surgery during the rapidly evolving proliferative and retracting process did not adversely affect the visual success rate when compared to previous reports on longstanding vitreous hemorrhage.

Aphakia, Postcataract↗
PubMed1983

Vitrectomy for diabetic traction retinal detachment involving the macula.

We analyzed the surgical results for 197 eyes that underwent vitrectomy for diabetic traction detachment of the macula. The retina was successfully reattached in 130 of the 197 cases (66%), although the final level of vision depended on the amount of permanent macular damage from the previous detachment and on the effects of the retinal vascular disease. At the final examinations, 112 eyes (57%) had improved visual acuities, 68 eyes (35%) were worse, and 17 eyes (9%) were unchanged. Thirteen eyes (7%) had final visual acuities of 20/40 or better, 103 eyes (52%) had final visual acuities of 20/50 to 20/800, and 81 eyes (41%) had final visual acuities worse than 20/800. Two preoperative factors were associated with a worse prognosis for achieving a final visual acuity of 20/800 or better: preoperative vitreous hemorrhage (P less than .01) and the absence of preoperative scatter retinal photocoagulation (P less than .01). Additionally, two surgical factors, lens removal and the creation of iatrogenic retinal breaks, were associated with a poorer visual prognosis (P less than .002 and P less than .01, respectively). The group of eyes that underwent lens removal during vitrectomy also had a significantly higher incidence of postoperative iris neovascularization compared to eyes in which the lenses were not removed (P less than .05).

Cataract Extraction↗
PubMed1989

Ultrastructural studies of vitreomacular traction syndrome.

We performed electron microscopic studies on seven specimens removed from the posterior retina at the time of vitrectomy for vitreomacular traction syndrome. Fibrous astrocytes were the predominant cell type in all cases. Fibrocytes were present in two cases and myofibrocytes were seen in three cases. Additional cellular and extracellular features included fragments of internal limiting membrane in six cases, old collagen in all cases, new collagen in one case, occasional macrophages in four cases, and fibrous astrocytes with myofibroblastic differentiation in one case.

Eye Diseases↗
PubMed1986

Drawbacks of traction-absorbing wiring (TAW) in displaced fractures of the olecranon.

Drawbacks of traction-absorbing wiring (TAW) in displaced fractures of the olecranon were observed in 29 out of 55 consecutive patients. Sliding of the K wires, with resulting skin troubles in 24 patients (10 patients with perforation of the skin), required premature removal of the implant. Minor operative modifications in the TAW technique are suggested in order to avoid these drawbacks.

Adolescent↗
PubMed1988

Closed traction lesions of the brachial plexus--an epidemic among young motorcyclists.

One-hundred-and-sixty patients with closed traction lesions of the brachial plexus sustained in motorcycle accidents were asked about their accident. One-hundred-and-six responded. Most were young men with limited experience of riding motorcycles. Riders with less than one year's experience were more likely to be injured in the absence of another vehicle than were more experienced riders. Two-thirds of those responding felt the present training requirements for motorcyclists to be inadequate.

Accidents, Traffic↗
PubMed1995

A hook-traction technique for Norplant removal.

We describe a simple technique to facilitate the removal of difficult-to-remove Norplant implants. Through a standard skin incision for Norplant removal, the fibrous capsule surrounding the implant is secured using either a dermatologic skin hook or a 25-gauge hypodermic needle fashioned into a hook with a hemostat. Traction is applied to bring the fibrous sheath into the incision site, where the implant tip is dissected free using a scalpel. The precisely localized countertraction afforded by this technique provides increased accuracy and speed for the removal of difficult-to-extract implants. Tissue trauma is minimized and the need to extend the skin incision is reduced.

Contraceptive Agents, Female↗
PubMed1992

Radial nerve rupture after a traction injury: a case report.

A case in which a patient sustained a closed rupture of the radial nerve at the lateral intramuscular septum from a traction injury is presented. No humeral fracture occurred, and the patient regained substantial function after delayed primary repair.

Adult↗
PubMed1987

Disability following closed traction lesions of the brachial plexus sustained in motor cycle accidents.

102 patients with closed traction lesion of the brachial plexus resulting from motor cycle accidents have been studied. The majority were young men, with the dominant arm involved in 64%. 74% of the patients underwent early operative exploration and 54% of these were amenable to at least partial repair. 65% of the patients had sustained irreparable pre-ganglionic injury to at least three roots of the plexus. 74% of the patients had sustained additional injuries in the accident. Subsequent reconstructive procedures were performed in 26% of patients. 60% of the patients regained employment, but 76% complained of persistent pain in the limb.

Accidents, Traffic↗
PubMed1993

Lesions found when operating traction injuries of the brachial plexus.

Traumatic traction injuries occurring mostly during road traffic accidents frequently cause severe lesions of the brachial plexus. 108 patients with such lesions were surgically explored in the last 5 years by one surgeon. By contrast, 101 patients with other lesions to the brachial plexus or various injuries to neighbouring nerves were operated on during the same period. Among the former, root avulsions were found in 73 patients, 33 presenting with 4 or all roots avulsed. In 14 of these patients the subclavian artery was ruptured. Out of 17 patients with infraclavicular distal plexus lesions 7 presented with a rupture of the axillary artery. The severity of the lesions to nerves and vessels in the shoulder girdle region seems to have increased over the past 10 years. The different injury patterns seen at operation are presented.

Brachial Plexus↗
PubMed1990

The pathogenesis of vitreoretinal proliferation and traction: a working hypothesis.

Traction retinal detachment due to proliferative vitreoretinopathy (PVR) is a serious complication of ocular trauma, retinal detachment, and previous vitreoretinal surgery. The cause is the active proliferation of fibroblasts, glial cells, and retinal pigment epithelial cells in the periretinal spaces, leading to the formation of contractile cellular membranes. The generation of growth and mitosis stimulation for these cells has remained obscure. We postulate that invading macrophages and local microglia secrete growth factors, notably PDGF (platelet-derived growth factor), which in turn mediates the mitogenic effects of transferrin (TF), a protein present in huge amounts in native vitreous, in plasma and in intraocular proliferative tissue.

Eye Diseases↗