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Biomedical subjects

F Koerner

Publications and source records attributed to F Koerner.

At least 19 recordsLinked to original sources
PubMed2006

Vitrectomy for juvenile uveitis: prognostic factors for the long-term functional outcome.

PURPOSE: This study evaluated the long-term effect of pars plana vitrectomy (PPV) in children and adolescents with chronic uveitis on visual function, anatomical outcome, and the requirement of systemic treatment. Further, predictive preoperative factors associated with a beneficial visual outcome were assessed. METHODS: Retrospective review of 29 eyes of 23 consecutive paediatric and juvenile patients below 20 years of age with chronic uveitis who underwent a PPV for visually significant opacities in 25 eyes, vitreous haemorrhage in three eyes, and retinal detachment in one eye. The clinical diagnosis was chronic intermediate uveitis in 22 eyes and retinal vasculitis of different origin in seven eyes. RESULTS: LogMAR visual acuity improved from an average of 0.91 to 0.33 (P<0.001). Cystoid macular oedema (CME) was significantly reduced in eight of 10 eyes postoperatively (P=0.021). In the multiple regression analysis, a low preoperative logMAR visual acuity and the presence of a CME had a negative influence on the final logMAR visual acuity. Furthermore, the appearance of chronic uveitis relapses was significantly reduced from 15 eyes before to seven eyes after surgery (P=0.042). CONCLUSIONS: PPV has a beneficial effect on the course and the complications of chronic uveitis in paediatric and juvenile patients with respect to the anatomical and visual outcome. Preoperative logMAR visual acuity and clinically significant CME were the most accurate predictors for the functional outcome.

Adolescent↗
PubMed2006

PVR recurrence and the timing of silicon oil removal.

BACKGROUND: Following vitrectomy for PVR-associated retinal detachment, placement of an encircling band, filling with silicone oil (SO) and successful retinal reattachment, a recurrence of PVR can develop. Retinal redetachment after SO removal is usually due to secondary or residual PVR. We wanted to ascertain whether the anatomical and functional outcomes of surgery in patients with a reattached retina and recurrent PVR can be improved by delaying the removal of SO. PATIENTS AND METHODS: 112 consecutive patients with PVR-associated retinal detachment who had undergone vitrectomy with SO filling, were monitored for at least 6 months after SO removal. Prior to SO removal, the retina posterior to the encircling band had to be completely reattached. Patients who developed PVR after SO filling were divided into two groups according to the duration of SO retention: 12 - 18 months (group 2: n = 48); > 18 months (group 3: n = 21). Individuals without PVR recurrence after SO filling and in whom the SO was consequently removed within 4 - 12 months served as control (group 1: n = 43). Anatomical success, intraocular pressure (IOP) and best-corrected visual acuity (BCVA) served as the primary clinical outcome parameters. RESULTS: Six months after SO removal, the anatomical success rates (86.3 %, 88.8 % and 84.6 %, in groups 1, 2 and 3, respectively; log rank = 0.794) and the BCVAs (p = 0.861) were comparable in the three groups. Mean IOP (p = 0.766), and the frequency of complications such as PVR recurrence (p = 0.936), bullous keratopathy (p = 0.981) and macular pucker (p = 0.943) were likewise similar. Patients in whom SO was retained for more than 18 months had the highest IOPs and required the heaviest dosage with anti-glaucoma drugs. CONCLUSIONS: In patients who develop a recurrence of PVR after vitrectomy and SO filling the surgeon can observe and treat retinal changes for up to 18 months without impairing the anatomical and functional outcomes. The retention of SO for more than 18 months does not improve the anatomical outcome. However, it can impair the functional outcome by precipitating the development of a persisting secondary glaucoma.

Comorbidity↗
PubMed2005

Primary retinal reattachment surgery: anatomical and functional outcome in phakic and pseudophakic eyes.

AIM: To compare the anatomical and functional success of primary scleral buckling, performed either alone or in combination with vitrectomy, for primary retinal detachment (RD) in phakic eyes and in eyes had undergone uneventful phacoemulsification and had received posterior chamber lens implantations. METHODS: A total of 243 consecutive patients were included in this retrospective, nonrandomized comparative study. In all, 165 phakic and 78 pseudophakic individuals with primary RD underwent scleral buckling alone or in combination with vitrectomy and were followed up for 6 months. Pre-, intra- and postoperative findings including anatomical success, best-corrected visual acuity (BCVA), complications, and the development of proliferative vitreoretinopathy (PVR), macular pucker, or secondary cataracts were recorded. Cases requiring more than one surgical intervention were defined having failed, although further surgical intervention might have led to success. RESULTS: At 6 months after scleral buckling alone, the anatomical success was similar in phakic (88.98%) and pseudophakic (87.65%) eyes (log rank=0.310). The corresponding results after scleral buckling with vitrectomy were 82.13 and 77.63% for phakic and pseudophakic eyes, respectively (log rank=0.799). At 6 months after scleral buckling alone, BCVA was similar in phakic and pseudophakic eyes (0.62+/-0.30 vs 0.70+/-0.29; P=0.227). Likewise, after scleral buckling with vitrectomy, BCVA did not differ significantly (P=0.322) between phakic (0.34+/-0.32) and pseudophakic eyes (0.50+/-0.27). CONCLUSION: The anatomical and functional outcome of primary retinal reattachment surgery, involving scleral buckling alone or in combination with vitrectomy, is similar in phakic and pseudophakic eyes.

Adult↗
PubMed2005

[Pars plana vitrectomy for idiopathic vitreous floaters].

BACKGROUND: The aim of this study was to evaluate the role of pars plana vitrectomy (PPV) in patients with persistent vitreous floaters (VF) in phakic (56.7 %) or pseudophakic (43.3 %) eyes. SUBJECTS AND METHODS: A retrospective study of 24 consecutive patients (30 eyes) who underwent a 2-port-PPV using indirect opthalmoscopy between 1992 and 2003 was carried out. Main outcome measures were postoperative visual acuity (PVA), incidence of postoperative complications and patient satisfaction, which has been assessed retrospectively using a detailed questionnaire. RESULTS: Symptoms resolved in all patients. PVA was significantly better (0.91 +/- 0.2 vs. 0.84 +/- 0.2 preoperative visual acuity) or equal in 25 patients (83.3 %). One pseudophakic patient (3.3 %) experienced a retinal detachment 48 months after surgery. In 5 of 17 phakic eyes (35 %) a cataract extraction had to be performed during the follow-up period. All patients were satisfied with their overall visual function. DISCUSSION: This study shows PPV to be a safe and effective primary treatment for visually disturbing VF. In spite of the small number of cases with a lower PVA (5 eyes/16.7 %), which in the most severe case corresponded to a reduction of VA from 1.0 to 0.6 due to a nuclear sclerosis of the lens, all patients were satisfied. As vitreoretinal complications may occur, a critical patient selection and a careful preoperative assessment of specific risks of vitrectomy are mandatory.

Adult↗
PubMed2005

Comparison of intra-arterial thrombolysis with conventional treatment in patients with acute central retinal artery occlusion.

BACKGROUND: Several case series and a recent meta-analysis indicate that intra-arterial thrombolysis (IAT) is effective for the treatment of acute central retinal artery occlusion (CRAO). METHODS: A total of 37 patients with acute monocular blindness because of unilateral thromboembolic CRAO were treated with IAT using urokinase within six hours of the onset of symptoms. Visual outcome was compared with a control group of 19 patients, also seen within six hours, who did not undergo thrombolytic treatment. In both groups some patients were treated by paracentesis and/or acetazolamide. Predictors of visual outcome were evaluated. RESULTS: Visual improvement was more likely with IAT (p = 0.01) as were the chances to regain visual acuity of >0.6 significantly better (p = 0.04): 8/37 patients (22%) regained visual acuity of >0.6 in the IAT group and none (0/19) in the control group. Younger patients were more likely to regain some vision with (p = 0.012) or without IAT (p = 0.026). Three patients had minor treatment related cerebral ischaemic events, two had transient ischaemic attacks and one a minor stroke. There were no haemorrhagic complications. CONCLUSIONS: This series of patients with CRAO demonstrated that IAT enhanced the chances of visual improvement compared with conventional treatment only. Furthermore, younger patients have a better chance to achieve some visual recovery.

Acute Disease↗
PubMed2001

Human breast cancer cells generated by oncogenic transformation of primary mammary epithelial cells.

A number of genetic mutations have been identified in human breast cancers, yet the specific combinations of mutations required in concert to form breast carcinoma cells remain unknown. One approach to identifying the genetic and biochemical alterations required for this process involves the transformation of primary human mammary epithelial cells (HMECs) to carcinoma cells through the introduction of specific genes. Here we show that introduction of three genes encoding the SV40 large-T antigen, the telomerase catalytic subunit, and an H-Ras oncoprotein into primary HMECs results in cells that form tumors when transplanted subcutaneously or into the mammary glands of immunocompromised mice. The tumorigenicity of these transformed cells was dependent on the level of ras oncogene expression. Interestingly, transformation of HMECs but not two other human cell types was associated with amplifications of the c-myc oncogene, which occurred during the in vitro growth of the cells. Tumors derived from the transformed HMECs were poorly differentiated carcinomas that infiltrated through adjacent tissue. When these cells were injected subcutaneously, tumors formed in only half of the injections and with an average latency of 7.5 weeks. Mixing the epithelial tumor cells with Matrigel or primary human mammary fibroblasts substantially increased the efficiency of tumor formation and decreased the latency of tumor formation, demonstrating a significant influence of the stromal microenvironment on tumorigenicity. Thus, these observations establish an experimental system for elucidating both the genetic and cell biological requirements for the development of breast cancer.

Animals↗
PubMed2001

Influence of refractive correction on peripheral visual field in static perimetry.

PURPOSE: To determine the influence of refractive errors on peripheral visual field thresholds in automated static perimetry. METHODS: In 47 subjects (age 16-49 years), the difference of perimetric thresholds was tested in the peripheral visual field without and with contact lens correction, using a custom-made program (Goldmann stimulus size III) with the automated perimeter Octopus 2000 R. Refractive errors ranged from -16.75 to +12.5 diopters. Sixty-four test locations on three concentric rings between 30 degrees and 50 degrees in 19 hyperopic and 28 myopic eyes were tested. RESULTS: All rings in myopic eyes revealed a significant influence of refraction on the differential light sensitivity in the peripheral visual field. In hyperopic eyes only the inner ring showed a significant influence of refraction. The decrease in sensitivity, measured in dB/diopter, for the myopic inner ring was 0.75; for the myopic middle ring it was 0.46; for the myopic outer ring it was 0.22; and for the hyperopic inner ring it was 0.40. CONCLUSIONS: A significant association between refractive errors and differential light sensitivity exists in the peripheral visual field of myopic eyes. Therefore, contact lens wear is recommended when performing automated perimetry of the peripheral visual field of myopic patients with higher refractive errors.

Adolescent↗
PubMed2001

Ovarian hormone receptors in human mammary stromal cells.

Mesenchymal cells of the rodent breast express both estrogen and progesterone receptors. Searches for these molecules in the human breast have yielded conflicting results. Following immunohistochemical staining of samples of normal human breast tissue, the authors detected estrogen receptor alpha protein and progesterone receptor protein in extralobular (non-specialized) fibroblasts and estrogen receptor alpha protein in adipocytes. Tissues from young teenage girls and pregnant women contained the greatest number of receptor positive fibroblasts. These observations confirm prior reports of the presence of ovarian hormone receptors in mammary fibroblasts. The findings also illustrate similarities in the organization of the rodent and human breasts and thereby suggest that regulation of the gland by ovarian hormones involves similar mechanisms in both species.

Adipocytes↗
PubMed2001

Lobular carcinoma in situ and infiltrating ductal carcinoma: frequent presence of DCIS as a precursor lesion.

Infiltrating ductal carcinoma (IDC) occurs frequently in patients with lobular carcinoma in-situ (LCIS). LCIS is not thought to be the direct precursor of the invasive component. The authors analyzed 15 cases of coexisting LCIS and IDC and found ductal carcinoma in situ (DCIS) in 12. The DCIS and IDC were of similar grade and located in the same area. Selected cases stained with E-cadherin demonstrated a different immunophenotype for the lobular and ductal lesions. These results support the notion that DCIS is the direct precursor of IDC occurring in patients with LCIS.

Adult↗
PubMed2000

Atypical cystic lobule of the breast: an early stage of low-grade ductal carcinoma in-situ.

The authors describe the characteristics of atypical cystic lobules (ACLs), which represent a step in the formation of low-grade ductal carcinoma in-situ. The authors define ACLs as a proliferation of luminal cells showing low-grade cytological atypia without architectural atypia. ACLs were compared with conventional hyperplasia, low-grade ductal carcinoma in-situ, and lobular neoplasia. 1) In about 40% of the cases, atypical cystic lobules merged with fully established micropapillary/cribriform ductal carcinoma in-situ. 2) Immunohistochemical staining for hormone receptors, keratin nineteen, and cyclin D1 revealed that atypical cystic lobules demonstrate a consistent immunophenotype, which differs from that of normal lobules and benign lesions and matches the one of low-grade ductal carcinoma in-situ. 3) ACLs are sometimes calcified. Osteopontin-positive histiocytes infiltrated all Kossa-positive (type II microcalcification) cribriform and comedo-type carcinomas and ACLs. The similarities in cytological and immunohistochemical features, the close proximity of the two types of proliferation, and the similarities with respect to calcification suggest that atypical cystic lobules represent an early stage in the formation of certain types of low-grade ductal carcinoma in-situ.

Breast↗
PubMed1999

Atypical cystic lobules: an early stage in the formation of low-grade ductal carcinoma in situ.

Evidence from many studies has established the neoplastic potential of ductal carcinoma in situ, but the origin and the morphological characteristics of the early stages of this proliferation remain unidentified. Workers writing in the early twentieth century observed a cystic transformation of lobules and proposed that it represented one such early stage, and contemporary European and Japanese pathologists have reached the same conclusion. We describe the characteristics of this cystic transformation, which we call us "atypical cystic lobules," and present evidence to support the proposal that the alteration is a step in the formation of low-grade ductal carcinoma in situ. Atypical cystic lobules are a proliferation of luminal cells showing low-grade cytological atypia without architectural atypia. The study group comprised 21 cases of atypical cystic lobules from specimens also showing conventional low-grade ductal carcinoma in situ or lobular neoplasia. Immunohistochemical staining for hormone receptors, keratin 19, and cyclin D1 revealed that atypical cystic lobules demonstrated a consistent immunophenotype, which differs from the pattern shown by normal lobules and benign lesions and matches that of low-grade ductal carcinoma in situ. In about 40% of the cases, atypical cystic lobules merged with fully established micropapillary/cribriform ductal carcinoma in situ. The similarities in the cytological and immunohistochemical features and the proximity of the two types of proliferation suggest that atypical cystic lobules represent an early stage in the formation of certain types of low-grade ductal carcinoma in situ.

Bile Duct Neoplasms↗
PubMed1999

High prevalence of glaucoma in patients with sleep apnea syndrome.

OBJECTIVE: To determine the prevalence of glaucoma in sleep apnea syndrome (SAS), an entity characterized by repetitive upper airway obstructions during sleep, inducing hypoxia and sleep disruption with the risk of cardiovascular and neurologic sequelae. DESIGN: Cross-sectional study. PARTICIPANTS: A total of 114 white patients consecutively referred for polysomnographic evaluation of suspected SAS. INTERVENTION: Complete ophthalmologic examination, including computerized perimetry and simultaneous stereoscopic optic disc photographs. MAIN OUTCOME MEASURES: Spearman rank correlations between the respiratory disturbance index during night sleep (RDI), a value used to diagnose and grade SAS, and visual acuity, intraocular pressure (IOP), visual field indices, presence or absence of glaucomatous optic disc changes, and diagnosis of glaucoma. Each correlation was controlled for age and body mass index. To compare proportions of patients harboring glaucoma, the binomial test was used. RESULTS: Sixty-nine (60.5%) of the 114 patients had an RDI > or =10, which indicates SAS. Three patients had primary open-angle glaucoma, and two had normal-tension glaucoma. All patients with glaucoma had SAS. The observed prevalence of glaucoma in patients with SAS (5 of 69, 7.2%) was significantly higher than expected in a white population (2%) (P = 0.01). The RDI correlated positively with IOP (P = 0.025), visual field loss variance (P = 0.03), glaucomatous optic disc changes (P = 0.001), and diagnosis of glaucoma (P = 0.01). CONCLUSIONS: Patients with SAS constitute a high-risk population for glaucoma and should therefore be screened for glaucoma.

Adult↗
PubMed1999

Uncommon morphologic patterns of lobular neoplasia.

Discussions of the morphology of lobular neoplasia (atypical lobular hyperplasia and lobular carcinoma in-situ) usually emphasize the commonplace characteristics. Occasional cases deviate from the expected appearance and thereby cause diagnostic confusion. Unusual cytologic alterations include the formation of signet-ring cells and the presence of nuclear pleomorphism. The growth of lobular neoplasia in breast tissue altered by atrophy, sclerosing adenosis, collagenous spherulosis, and benign tumors gives rise to unexpected patterns that one might mistake for normal tissue, invasive carcinoma, or ductal carcinoma in situ. Solid involvement of ducts by lobular neoplasia and uncommon forms of "pagetoid" growth both resemble the appearance of atypical ductal hyperplasia or ductal carcinoma in situ. The authors illustrate these unusual cytologic and architectural findings and discuss features that permit proper diagnosis and interpretation.

Animals↗
PubMed1999

Vitrectomy for macular pucker and vitreomacular traction syndrome.

During the course of a so-called posterior vitreous detachment, a thin layer of the posterior vitreous cortex often remains adherent to the underlying retina. Tangential stretch of this vitreous pseudomembrane may cause vitreomacular traction syndrome, edema, and macular hole formation. The same process appears to underlie the development of true epimacular membranes (idiopathic macular pucker). Vitrectomy is generally agreed to be the most appropriate treatment for these clinical situations. We evaluated the incidence of vitreomacular adhesion and of visual improvement after vitrectomy of eyes with macular pucker (group 1; n=60) and vitreomacular traction syndrome (group 2; n=50). Vitreomacular attachment was assessed during vitrectomy under the condition of continuous air infusion. In the two groups, complete or partial vitreous attachment to the macula was observed in 57.4% and 74%, respectively. We conclude that vitreomacular adhesion is a common feature of the two clinical situations. Visual improvement was achieved in 73% of both groups. High rates of postoperative visual acuities of 20/50 or better (60.6% in group-1; 65.7% in group-2 cases) occurred only in eyes with preoperative values of 20/100 or better. It is reported that the visual outcome of vitreoretinal surgery for the two clinical conditions deteriorates with increasing duration after initial manifestation. Vitrectomy should not be postponed in patients who complain of disturbing visual symptoms such as reduced visual acuity, metamorphopsia and disturbance of binocular reading.

Adolescent↗
PubMed1999

[Diseases of the vitreo-macular interface].

BACKGROUND: A pathological vitreomacular adhesion is a common pathogenetic mechanism of various clinical entities such as idiopathic epimacular membrane, vitreomacular traction syndrome, and macular hole. Vitrectomy is recommended for these disorders. Anatomical and functional results in 207 operated eyes are discussed. PATIENTS AND METHODS: The results of a vitrectomy in 3 groups of patients were compared: idiopathic epimacular membrane (group 1, n = 52), vitreomacular traction syndrome (group 2, n = 48); macular hole (group 3, n = 107; 33 eyes without and 74 eyes with retinal detachment). After excision of the vitreous gel, a thin layer of epimacular vitreous cortex was identified and excised by gentle aspiration under continuous air infusion. In 50 of the 107 eyes of group 3, the vitrectomy was combined with the application of a drop of autologous blood to the macular hole. RESULTS: A vitreomacular adhesion existed in 56% of group 1, 74% of group 2, and 84% of group 3. The visual acuity improved in 54%, 62% and 50% of eyes of the 3 groups, respectively. More eyes with an initial visual acuity of at least 40/200 achieved final vision of 80/200 or better (57%, 65% and 48% of group 1 to 3, respectively) than eyes with acuities of less than 80/200. A postoperative cataract was the main reason for reduced visual results in all cases. In group 3-eyes with retinal detachment and/or myopia, a significant postoperative visual improvement was achieved only after application of autologous blood to the macular hole. CONCLUSION: A pathological vitreomacular adhesion was identified in the majority of patients with idiopathic epimacular membranes, vitreomacular traction syndrome, and macular hole, respectively. Vitreoretinal surgery for syndromes with vitreomacular traction is indicated as it warrants a significant improvement of visual function and relief of metamorphopsia.

Aged↗
PubMed1999

Eye injuries caused by cow horns.

PURPOSE: To assess ocular injuries caused by cow horns; to investigate clinical findings, treatment, and visual outcome in a population of dairy farmers; and to propose possible preventive measures. METHODS: A retrospective review was conducted to identify patients seen over a 45-month period with cow horn-inflicted eye injuries. Eleven patients were identified and their charts reviewed for demographics, mechanism of injury, initial and final visual acuity, surgeries performed, and anatomic outcome. RESULTS: The mean age of the patients was 64 years. Seven patients had open-globe injuries with vitreous hemorrhage. In five cases, pars plana vitrectomy was performed. Final best-corrected visual acuity was < or = hand motion in five patients, between 20/160 and 20/80 in three patients, and better than 20/32 in three patients. CONCLUSION: The majority of the cow horn injuries studied caused severe permanent impairment of vision. Owing to the blunt nature of the horns, a significant amount of energy is imparted into the eye. To prevent these injuries, coagulation of the horns should be performed 2 weeks after a calf's birth or farmers should be advised to wear safety glasses.

Accidents, Occupational↗