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Biomedical subjects

F Koerner

Publications and source records attributed to F Koerner.

14 recordsLinked to original sources
PubMed1992

Clinical use of recombinant plasminogen activator for intraocular fibrinolysis.

In a preliminary clinical study, recombinant tissue plasminogen activator (rt-PA) was injected into the anterior chamber of 18 eyes and into the vitreous cavity of 2 eyes in a total of 20 patients. The clinical indications were severe fibrin formation after filtering operations for glaucoma (8 eyes), diabetic neovascular glaucoma (3), fibrin and hemorrhage after vitrectomy (3), keratoplasty (3), posterior chamber lens implantation (1), trauma (1), and endophthalmitis (1). Complete fibrinolysis within a minimum of 2 h was achieved in 81% of 26 injections. Although doses of about 12 micrograms rt-PA were generally given, in our observations, 6 micrograms proved to be sufficient for rapid fibrinolysis in selected cases. Injections of rt-PA should not be considered before the 3rd postoperative day so as to avoid rebleeding and recurrent fibrin formation. No toxic intraocular side effect was observed after the use of rt-PA in this study.

Adult↗
PubMed1991

[Vitrectomy in secondary complications caused by intraocular foreign body].

Endophthalmitis and reduced vision as late complications of penetrating ocular injuries cause specific diagnostic problems. A persisting endopthalmitis may be caused by unnoticed organic foreign bodies (f.b.) like lashes or a splinter of glas. Endophthalmitis recurring months or years after a perforating injury indicates the possibility of a spontaneous mobilization of a f.b. Vitrectomy and removal of the f.b. is the therapy of choice in either situation. Five typical cases are presented: lashes encapsulated in the ciliary body following a limbal perforation; an intraretinal incarceration of a lash of unknown history; spontaneous dislocation of a glas splinter from the ciliary body into the anterior chamber; delayed spontaneous translocation of a 10 x 11 mm metallic f.b. from tenon's space transsclerally into the subretinal space leading to endophthalmitis one year after a severe perforating injury; secondary mobilization of an intraretinal piece of stone during a posterior hyaloid detachment. In each case, vitrectomy was performed and the f.b. removed via pars plana. Secondary surgery for retinal detachment or PVR was necessary in 2 cases. The final visual acuity was 20/20 in 3 cases and 10/20 or better in 2 cases.

Adult↗
PubMed1990

Patterns of failure following curative resection of gastric carcinoma.

To identify patterns of failure following curative resection of gastric carcinoma, the records of 130 patients undergoing resection with curative intent at the Massachusetts General Hospital were reviewed. The total local-regional failure rate was 38% (49/130 patients), with 21 patients having local-regional failure alone and 28 patients having local-regional failure and distant metastases. The incidence of local failure rose with the more advanced stages of disease. Tumors staged B2, B3, C2, and C3 had local-regional failure rates in excess of 35%. This group of patients might benefit from adjuvant radiation therapy to the tumor bed and regional lymphatics. Local-regional failure rate was highest in the anastomosis or stump 33/130 (25%), followed by the stomach bed 27/130 (21%). The overall incidence of distant metastases was 52% (67/130 patients) and rose in the more advanced disease stages. Tumors staged B2, B3, C2, and C3 had rates of distant metastases greater than 50%. Sixty-one patients (77%) had failure in the abdomen (liver, peritoneal surface, adrenal, kidney, and spleen, but excluding tumor bed, anastomosis, or regional nodes). Patients with Stage B2, B3, C2, and C3 tumors had total abdominal failure rates greater than 40%. The highest failure rates in the liver were in Stages B3 and C3, in which the subsequent development of liver metastasis was 40% and 47%, respectively. Peritoneal seeding occurred in 30/130 (23%) of patients and was highest in Stages C2 and C3, with rates of 27% and 41%, respectively.

Abdomen↗
PubMed1990

[Measuring the vascular caliber in diabetic retinopathy before and following photocoagulation].

The calibers of 4 retinal arterioles and 4 venoles of each of 58 patients with diabetic retinopathy (DR) were measured on fundus photographs before and after photocoagulation (PC). The measurements were repeated at approximately one-year intervals following photocoagulation (PC) of one eye of each patient. The mean caliber of arterioles and venoles of DR patients was 15.4% greater than in nondiabetic subjects. This finding may be interpreted as an autoregulatory response to relative tissue hypoxia. Following PC there was a significant reduction in both arterial and venous vessel caliber. In a multivariate regression analysis, the reduction in venous caliber correlated significantly with the number of coagulation spots. A weak correlation was found with arterial hypertension, change in visual acuity, and change in a calculated DR score. The reduction in pathologic vessel calibers following PC is indicative of an improvement in retinal hemodynamics. Photographic quantification of retinal vessel changes may be of prognostic value, i.e., for assessing the course of DR before and after treatment by PC.

Diabetic Retinopathy↗
PubMed1989

[Clinical diagnosis of proliferative vitreoretinopathy].

The clinical features of a proliferative vitreoretinopathy (PVR) are systematically described. The patient's history reveals moderate lost of vision and metamorphopsia. Ophthalmoscopy, biomicroscopy of the fundus with the contact lens, and black-and-white photography usually lead to the correct diagnosis. Early stages of PVR are characterized by increased reflectance and a cellophane appearance of the inner retinal surface and tortuosity of both small and larger vessels. Advanced epiretinal tissue formation causes development of surface wrinkling and single or multifocal star-folds. In cases of retinal detachment with PVR, the retina is immobile, the detachment being concave due to traction or bullous if there are secondary breaks. In the final stages of posterior and/or anterior PVR the detached retina forms a narrow or closed funnel.

Fluorescein Angiography↗
PubMed1978

[Retinal circulation time in diabetic retinopathy treated with photocoagulation (author's transl)].

A preliminary report is given on studies of the retinal circulation in diabetic retinopathy before and after photocoagulation treatment. The local retinal circulation time RCT of selected retinal areas was calculated by means of a fluorescein long-term infusion technique. In 7 eyes with diabetic retinopathy (DR) the mean RCT was significantly higher (2.0 +/- 0.58 sec. range 1.27-2.6) than in 15 control eyes (1.11 +/- 0.34 sec, range 0.50-1.82, Niesel 1976). Assuming an increase of blood flow in DR (L'Esperance 1971, Kohner 1975) the increase of RCT by a factor 2 would imply an increase of the vascular volume by a factor hardly less than 3 indicating the marked impairment of retinal hemodynamics in DR. After photocoagulation, the mean RCT was significantly shortened only in eyes with preoperative RCT values above 2 sec. The reduction of local RCT correlated with the extent of treated retinal areas. The cross-sectional area of the retinal veins measured near the optic disc was generally reduced independently of the extent of coagulation treatment. Taking also the obvious postoperative reduction of the total retinal vascular volume into account, photocoagulation resulted in a marked decrease of blood flow not only in extensively treated but also in areas with little coagulation effects. In DR the disturbed retinal circulation in general tends to normalize following extensive photocoagulation.

Blood Volume↗
PubMed1978

[Controlled suction in vitrectomy (author's transl)].

A peristaltic pump (type "Perpex", J. H. Guldener, Zürich, Switzerland) was modified for controlled aspiration in vitrectomy (fig. 1). The surgeon operates start, instantaneous stop and back flush with a single foot pedal. Suction and cutting device are controlled independently. Suction flow can continuously be varied between 0 and 16 ml/min (fig. 2). This less critical function is operated by the assistent. The upper limit of suction flow depends on infusion resistance and preselected differential pressure (fig. 3). The infusion resistance and its reciprocal, the inflow rate, vary considerably with different instruments. In four devices infusion resistance was measured and found to vary by a factor of up to 4.6. Low infusion resistance allows high suction flow and thus shorter operation time for certain conditions such as "ochre membranes" or intrasurgical bleedings. Further aids which we use in combination with a Zeiss OPMI-8 are an intense external xenon light source for variable slit illumination which makes the use of intravitreal fiber optics unnecessary, and a mirror combination to achieve an 11 degrees semi-coaxial stereoscopic view of the operation field for the assistent.

Eye Diseases↗
PubMed1977

Diabetic retinopathy study. Data acquisition and its reliability.

The documentation of ophthalmologic data of patients with diabetic retinopathy (DR) is described. Special attention has been paid to the standardized grading of opacities of the dioptric media as well as to the assessment of classified arteriolar abnormalities. The reproducibility of these judgments was determined by a double evaluation test. The reliability of the assessment of classified retinal lesions on panorama fundus photographs was reported elsewhere. A further section of the questionnaire that concerns the documentation of the patient's history, of general medical and laboratory findings, and of reasons why individual patients "drop out" from the study, is described in this contribution.

Animals↗
PubMed1976

Diabetic retinopathy study. Assessment and comparison of retinal lesions for computer analysis.

A method of documentation of a diabetic retinopathy (dR) is described. Panorama fundus photographs (PPhs) of each eye are taken every 3-6 months. The retinopathy is classified according to qualitative, quantitative, and topographic criteria. The retinal lesions are assessed according to a subjective grading scale. Data of direct readings and of comparisons between two PPhs of one eye are transferred to punch cards for storage and computer processing. In a double evaluation of 200 PPhs, the overall reliability of readings was found to be approximately 95%.

Diabetic Retinopathy↗
PubMed1976

Diabetic retinopathy study. Preliminary results from 215 patients treated uniocularly with photocoagulation.

Preliminary results of a controlled study on diabetic retinopathy are reported. Two hundred and fifteen patients with proliferative (PDR) and nonproliferative (NPDR) retinopathy were uniocularly treated by Xenon photocoagulation and followed for a minimum of 6 months--6 years. Intra- and epiretinal new vessel formations (RNF) decreased in treated but increased in untreated eyes at a high statistical significance. A transition of background retinopathy into the proliferative stage was significantly retarded after photocoagulation. An improvement of new vessel formations on the disc (DNF) was not evident after 3 years of follow-up. The progression of preretinal neovascularization (PRNF) was significantly reduced only for 1--2 years after treatment. The incidence of massive vitreous hemorrhages, however, which showed the highest quotient of contingency with PRNF was much lower in treated eyes also after 3 years. The difference was significant only in extensively photocoagulated eyes with more than 100 lesions on average. The effect of photocoagulation on diabetic maculopathy with preservation of a useful visual acuity was highly significant only in diabetics under 60 years of age, the effect increasing with time as the control eyes fared worse. By contrast, in patients over 60 years of age, the course of maculpathy was not influenced, and a linear decrease of visual acuity occurred in both treated and untreated eyes.

Age Factors↗
PubMed1975

Traumatic kidney rupture in hydronephrosis.

The hydrostatic pressure, intrapelvic volume, and specific elasticity and strength of strips of tissue from the parenchyma and the pelvis of eight hydronephrotic kidneys were investigated and compared with the tissue characteristics of the pelvis of four control kidneys. Hydronephorsis manifested itself by a sixfold reduction of tissue strength, and dynamically by a ninefold reduction of the energy absorptive capacity of the parenchyma as compared with the pelvis. Its further response to trauma appeared to be influenced by internal pressure, the law of mass variation, and the energy absorptive capacity of surrounding anatomical structures. The vulnerability of the hydronephrotic kidney in situ depends on its volume and topography, the parenchyma being the part that may be regarded as the site most predisposed to rupture.

Biomechanical Phenomena↗
PubMedDate not supplied

A mydriatic eye-drop combination without systemic effects for premature infants: a prospective double-blind study.

Eye drops used for diagnostic mydriasis may produce systemic side effects in preterm infants. Studies on the pupil dilating and systemic effect of various mydriatic agents yielded conflicting results. We conducted a prospective randomized double-blind study on the systemic effect of two mydriatic eye-drop combinations. Thirty-nine preterm infants were randomly assigned to two groups. An eye-drop combination of 2.5% phenylephrine and 0.5% tropicamide (group D) was compared with the combination of 0.5% cyclopentolate and 0.5% tropicamide (group F). Either eye-drop combination was followed by 0.5% tropicamide given 20 minutes later. Heart rate (HR) and the systolic, mean, and diastolic blood pressure (BP) were recorded before and after eye-drop instillation and after ophthalmoscopy. A control session with NaCl eye drops was added for each infant. A significant increase of BP and HR peak values was observed within 7 to 10 minutes after the cyclopentolate/tropicamide combination only. On the other hand, the mydriatic effect of the phenylephrine/tropicamide combination was significantly superior to that of the cyclopentolate/tropicamide combination. We recommend the combination of 2.5% phenylephrine and 0.5% tropicamide to achieve a sufficient diagnostic mydriasis without systemic side effects in preterm infants.

Blood Pressure↗