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Biomedical subjects

B Kirchhof

Publications and source records attributed to B Kirchhof.

At least 91 records · Page 5Linked to original sources
PubMed1992

Contact cw-Nd:YAG laser cyclophotocoagulation for treatment of refractory glaucoma.

Contact cw-Nd:YAG laser transscleral cyclophotocoagulation was performed on 42 patients (44 eyes) with glaucoma who were not responding to medical treatment or had failure of prior surgical procedures. No selection was made as to the type of glaucoma (congenital, primary, secondary due to trauma or inflammation). We applied between 16 and 60 exposures 0.5-2 mm posterior to the limbus. Prior to cyclophotocoagulation the mean intraocular pressure (IOP) was 40.4 mm Hg (+/- 8.0). As a result of the treatment, the mean IOP was lowered to 21.1 mm Hg (+/- 5.2). In eyes with congenital, neovascular, and inflammatory glaucoma, a therapeutic effect could only be achieved by repeated coagulations. The patients were followed for a mean of 4.8 months (3-7 months). One eye developed a transient choroidal detachment. In two eyes, iris hemorrhages were noted. Contact cyclophotocoagulation is generally well tolerated. Randomized studies are to be carried out to confirm whether cyclophotocoagulation is an effective tool in the treatment of glaucoma. Until then, cyclophotocoagulation should be restricted to cases not responding to conventional therapy.

Adult↗
PubMed1990

Thrombin generation in prothrombin-complex-preparations; its effect on a chromogenic substrate, fibrinogen and platelets.

The kinetics of thrombin generation in various prothrombin-complex-preparations (PCC) were investigated using a chromogenic substrate assay. The rate of thrombin formation and the total activity of thrombin generated varied considerably among different preparations. The thrombin generation velocity influenced the rate of fibrinogen to fibrin conversion, measured as plasma viscosity alteration per unit of time. It also influenced thrombin induced platelet aggregation with regard to maximum aggregation and aggregation velocity. The kinetic parameters measured photometrically and coagulometrically showed reduced generation velocities and less thrombin effects with thrombin formed in PCCs than with thrombin generated in plasma. The quantitative differences between thrombin effects in various PCCs on platelet aggregation did not correlate with the data of the amidolytic and fibrinogenolytic measurements. The significance of the results is discussed with regard to the question of whether, or to what extent, PCCs could cause or accelerate a disseminated intravascular coagulation.

Blood Coagulation Factors↗
PubMed1990

Recurrent Salzmann's corneal degeneration.

Three keratoplasties were carried out on two patients because of nodular degeneration of the cornea. Progress after keratoplasty could be followed up in one eye for 17 months and in the other two eyes, for 2.5 and 9 years, respectively. The implant with the short follow-up of only 17 months remained glass-clear; nothing abnormal was discovered during the checkups. In the case of the other patient in whom a longer follow-up period was possible, the following findings were evident: (1) a remarkably late epithelial immune response in one eye (after 18 months) with subsequent incomplete reepithelisation and formation of fine, superficial, cloudy opacity (observation period 2.5 years); (2) formation of dense but flat, superficial areas of opacity in the cornea of the other eye (observation period 9 years). These areas may be regarded as a precursor of Salzmann's corneal degeneration. No difference could be found between the histological findings in the explants and those in a degenerative pannus or an older scar caused by inflammation of the Bowman membrane.

Aged↗
PubMed1990

Attempts to standardize platelet aggregation measurements: simplified screening tests.

We present a standardized measurement of collagen and ADP-induced platelet aggregation with the help of a personal computer. The calculator improves the recording of measurements and the automatic calculation of parameters to define the strength of aggregation in various aggregation phases, as well as aggregation and disaggregation velocities. The dose-effect relationships between aggregants and five calculated parameters after addition of ADP and four after addition of collagen are demonstrated in the light of measurements taken in 40 healthy persons. Comparison of these measurements with those of 8 volunteers 24 h after they had taken 250 mg of acetylsalicylic acid and those of of 5 patients with typical illnesses associated with hypo- and hyperaggregability shows that analysis of the aggregation with two reagent concentrations (1, 2 and 4 micrograms/ml collagen, 1, 2 and 4 mumols/ml ADP) and the resulting values allow one to distinguish between normal, hypo- and hyperaggregable platelets.

Adenosine Diphosphate↗
PubMed1989

Macrophage modulation of retinal pigment epithelial cell migration and proliferation.

Macrophages are fully differentiated cells that do not synthesize an extracellular matrix and do not contract; they do, however, produce substances that modify the behavior and functions of other cells, particularly those involved in the inflammatory and immune responses. Since macrophages are a ubiquitous component of periretinal membranes, we sought to determine whether they modulate proliferation and/or migration of retinal pigment epithelial (RPE) cells, functions that may be essential for the development of proliferative vitreoretinopathy (PVR). Using an in vitro assay, we found that macrophage supernatant contains factors that stimulate proliferation and migration of cultured human RPE cells. Since interleukin-1 (IL-1) is a product of activated macrophages that modulates a number of cellular functions, we also examined its effect on RPE proliferation and migration. We found that IL-1 increased migration but did not affect proliferation, and thus could not duplicate the effect of macrophage supernatant. Injection of activated macrophages into the vitreous of rabbits which had a retinal hole stimulated RPE cell proliferation in the area of the retinal hole, where the RPE cells were exposed. These findings suggest the ability of macrophages to modulate functions of RPE cells that are thought to be critical for the development of PVR. Macrophages may thus be an important part of the vitreous environment that favors the development of PVR.

Animals↗
PubMed1989

[Keratopathy following vitrectomy with silicone oil injection].

We present a retrospective study on keratopathy following vitrectomy and injection of SF96 silicone oil (viscosity 1000 centipoise, n = 232 eyes) and the purified OP 1000 silicone oil (viscosity 1000 centipoise, n = 129 eyes). In cases with aniridia, with closed inferior basal iridectomy (IBI) or without IBI, keratopathy was found in 74 of the 166 eyes (45%) injected with silicone SF96 and in 14 of the 30 eyes (47%) injected with silicone OP 1000. An intact IBI reduced the incidence of keratopathy to 0% (SF96, 0/45 eyes) or 6% (OP1000, 5/88 eyes) when the anterior chamber was free of silicone. When silicone oil was in contact with the corneal endothelium (due to periretinal reproliferation, hypotony, overfilling or droplet formation), there was corneal decompensation in 66% (SF96, 14/21 eyes) or 55% (OP1000, 6/11 eyes). The keratopathy presents as calcified band keratopathy or diffuse bullous corneal edema as in "endothelial decompensation." These variations in keratopathy are in agreement with the following basic diagnoses: 77% (43/56 eyes) of trauma patients (n = 130) develop calcified band keratopathy, and 47% (24/51 eyes) of patients with idiopathic proliferative vitreoretinopathy (n = 182) present with diffuse bullous corneal edema.

Cornea↗
PubMed1989

Pathogenesis of proliferative vitreoretinopathy. Modulation of retinal pigment epithelial cell functions by vitreous and macrophages.

RPE cell migration and proliferation are believed to play a role in the pathogenesis of PVR. Since PVR develops in situations where vitreous contacts the RPE, we sought to determine whether human vitreous contains factors that stimulate proliferation and migration of RPE cells. We found that postmortem human vitreous stimulates migration but not proliferation of human RPE cells in vitro under serum-free conditions. A significant vitreous growth factor activity for RPE cells and fibroblasts, however, could be released by admixture of albumin with the vitreous. These findings suggest that vitreous contributes modulators that stimulate some functions of RPE cells that are believed to play a role in the pathogenesis of PVR (fig. 22). Since macrophages are a ubiquitous component of periretinal membranes, we sought to determine whether they modulate proliferation and/or migration of RPE cells, functions that may be essential for the development of PVR. Using an in vitro assay, we found that macrophage supernatant contains factors that stimulate proliferation and migration of cultured human RPE cells. Since IL-1 is a product of activated macrophages that modulates a number of cellular functions, we also examined its effect on RPE proliferation and migration. We found that IL-1 increased migration but did not affect proliferation, and thus could not duplicate the effect of macrophage supernatant. Injection of activated macrophages into the vitreous of rabbits which had a retinal hole stimulated RPE cell proliferation in the area of the retinal hole, where the RPE cells were exposed. These findings suggest the ability of macrophages to modulate functions of RPE cells that are thought to be critical for the development of PVR (fig. 22). We initiated studies to define modulation of cultured RPE cell morphology by exposure to vitreous or to macrophage-conditioned media. Vitreous, serum, and albumin alone had no effect on the epithelial appearance of RPE cells in vitro. However, macrophage-conditioned media and vitreous-serum or vitreous-albumin mixtures induced a reversible fibroblast-like appearance in these cells. These findings show that macrophages produce a morphoplastic substance for RPE cells, and suggest that vitreous also contains a factor(s) that affects RPE cell shape, and that requires mediation by serum components (fig. 22).

Animals↗
PubMed1989

Vitreous modulation of migration and proliferation of retinal pigment epithelial cells in vitro.

Retinal pigment epithelial (RPE) cell migration and proliferation are believed to play a role in the pathogenesis of proliferative vitreoretinopathy (PVR). Since PVR develops in situations where vitreous contacts the RPE, we sought to determine whether human vitreous contains factors that stimulate proliferation and migration of RPE cells. We found that postmortem human vitreous stimulates migration but not proliferation of human RPE cells under serum-free conditions in vitro. Stimulation of proliferation of RPE cells and fibroblasts was observed, however, following admixture of albumin with the vitreous. These findings suggest that vitreous contributes modulators that stimulate some functions of RPE cells that are believed to play a role in the pathogenesis of PVR.

Cell Division↗
PubMed1988

Human retinal pigment epithelial cell cultures: phenotypic modulation by vitreous and macrophages.

In proliferative vitreoretinopathy (PVR), retinal pigment epithelial (RPE) cells migrate into the vitreous, where they may acquire a fibroblast-like morphology. Such cells may eventually form contractile periretinal membranes, resulting in traction retinal detachment. Among the environmental influences that could cause this change in RPE phenotype, exposure to vitreous and to macrophages is most obvious, as macrophages are invariably found in epiretinal membranes and precede membrane formation in experimental traction retinal detachment. We initiated studies to define modulation of cultured RPE cell morphology by exposure to vitreous or to macrophage-conditioned media. Vitreous, serum, and albumin alone had no effect on the epithelial appearance of RPE cells in vitro. However, macrophage-conditioned media and vitreous-serum or vitreous-albumin mixtures induced a reversible fibroblast-like appearance in these cells. These findings show that macrophages produce a morphoplastic substance for RPE cells, and suggest that vitreous also contains a factor(s) that affects RPE cell shape, and that requires mediation by serum components.

Actins↗
PubMed1988

Lack of association between haemostatic variables and the presence or the extent of coronary atherosclerosis.

Blood samples were taken for haemostatic analysis from 225 patients with angina pectoris who were admitted to hospital for coronary angiography. beta thromboglobulin, platelet factor 3, platelet factor 4, factor VII:C, factor VIII:C, von Willebrand factor antigen, activated partial thromboplastin time, fibrinogen, antithrombin III, protein C:Ag, plasminogen, and antiplasmin were measured before angiography. Patients who had had a myocardial infarction in the two months before the investigation were excluded from the study. Multiple linear regression analysis showed that none of the haemostatic variables contributed independently to the prediction of an angiographic score that indicated the extent of coronary atherosclerosis. History of myocardial infarction, male sex, worsening of angina pectoris, serum triglycerides, and ejection fraction were independently associated with the angiographic score. There were some significant correlations between haemostatic variables and conventional risk factors for coronary heart disease. Thus data obtained from haemostatic analyses of peripheral venous blood do not permit the presence or the extent of atherosclerosis in coronary arteries to be predicted.

Adult↗
PubMed1987

Diffuse epithelial ingrowth after perforating keratoplasty.

Diffuse epithelial ingrowth was observed in 2 patients after perforating keratoplasty. Both cases involved a corneal graft after perforating injury with aphakia. In the first patient, the epithelial invasion was probably stimulated by a spatula synecholysis. In this case, the diagnosis was only made by histological investigation after enucleation. In the second patient the epithelial ingrowth was observed 8 months after keratoplasty. The clinical diagnosis was made on the basis of the typical slitlamp findings. In this case, the epithelial invasion led to hypotension with high resistance of outflow measured by electrotonography. In a very close chronological relation to the probable fall of chamber fluid secretion, development of a band-shaped keratopathy was observed.

Adult↗
PubMed1987

Complications after modern filter operations in glaucoma.

As long as the indications and limitations of laser trabeculoplasty have not yet been established by follow-up over several years, conventional surgical filter operation will not be superfluous. The reduction of the complications brought about by introduction of the scleral flap technique is described. Apart from cicatricial obliteration of the filtering zone, bulbar hypotension due to overfiltration as well as to external fistula and above all the resulting ciliary body-choroid detachment still occurs after trephination with the scleral flap (goniotrephination, trabeculectomy). Attention is drawn to the tension of the scleral flap adapted to the normalized intraocular pressure and reliable preclusion of an external fistula by perfusion test at the end of the operation. The membrane formation probably deriving from the internal Tenon's capsule which leads to a 'pseudofiltering bleb' is discussed as a rare complication (1.5%) which is of basic interest.

Cicatrix↗
PubMed1987

Keratopathy following pars plana vitrectomy with silicone oil filling.

Out of 196 aphakic and 4 phakic eyes with silicone oil in the anterior chamber (all vitrectomized, postoperative follow-up 6 months to 5 years) we found 83 eyes (42%) with keratopathy. They present clinically and histologically as calcific band keratopathy (55 eyes) or diffuse bullous corneal edema (28 eyes). Time of onset, course and frequency in correlation to preoperative diagnosis are analyzed. Pathogenesis, prevention and therapy of keratopathy are discussed.

Cicatrix↗
PubMed1986

Histopathological findings in eyes after silicone oil injection.

Eight eyes were examined histologically after silicone oil injection. Intraretinal deposits suggestive of silicone were not present in attached retinas, but were frequently observed in detached retinas when subretinal silicone occurred. This may possibly be due to defects in the horizontal conducting structures of the retina such as those occurring in persistent detachment with disorganization of the retina. Morphologically, the retina was essentially normal 3.5 years after the silicone injection. This observation contradicts the idea that silicone oil has a toxic effect.

Eye↗
PubMed1986

[Computer tomography findings of orbital changes within the scope of juvenile neurofibromatosis].

The computerized tomography of 9 cases of neurofibromatosis is compared with routine X-rays. Gliomas of the optic nerve, sphenoidal dysplasias, plexiform neurofibromas and buphthalmos are shown in detail. CT today is an indispensable procedure for the diagnosis of neurofibromatosis of the orbit. Often it is up to the ophthalmologist to initiate CT in collaboration with other disciplines. This holds for diagnosis, surgical interventions and the follow-up examinations.

Adolescent↗
PubMed1986

[Genesis of papillar pit. Microscopy study in a newborn infant].

The rare microscopic picture of a pit of the optic disk is described. The recess extended from the physiological cup of the optic disk to the former cleft of the optic stalk at the point of entry of the ophthalmic artery. There was no disk coloboma. This result is in good agreement with von Szily's paper on the genesis of crater-like holes in the optic disk as a residue of the cavity of the primordial epithelial papilla. In this case there was no communication of the vitreous cavity with a subretinal space, which is suspected of being the cause of the frequent concomitant serous detachment of the macula.

Abnormalities, Multiple↗
PubMed1985

[Computed tomography of the orbit. I. Trauma-induced changes].

The CT findings in 120 patients following trauma to the orbits, and in 60 patients with iatrogenic abnormalities, have been analysed. CT has been found to be extremely useful in the diagnosis of trauma and postoperative changes by its ability to demonstrate fractures, foreign bodies, haematomas, abscesses, soft tissue displacement or perforation of orbital structures, as well as showing prosthetic material.

Adolescent↗