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Biomedical subjects

G Geerling

Publications and source records attributed to G Geerling.

At least 19 recordsLinked to original sources

[Congenital ectropion in ichthyosis congenita mitis and gravis].

BACKGROUND: Congenital ichthyosis is a generalized hyperkeratinization of the skin at birth. Depending on clinical aspects and severity, three forms of congenital ichthyosis have been defined: mitis, tarda, and gravis. Desquamation of the parchment-like hyperkeratinized skin begins shortly after birth and may require several weeks to complete. Skin alterations in the eyelid cause shortening of the anterior lamella, subsequently resulting in ectropion. This affects the upper eyelid more often than the lower and can lead to complications such as chronic palpebral or bulbar conjunctivitis and keratinization or exposure keratopathy. Here we present two case reports illustrating the course of ichthyosis congenita mitis and gravis. PATIENTS AND METHODS: Patient 1 (ichthyosis congenita mitis): a male baby prematurely born at 34+2 weeks of gestation was delivered by cesarean section. The entire body was covered by a parchment-like hyperkeratinized skin. Both eyes showed ectropion of the upper and the lower eyelid, which was more obvious with enforced lid closure. Frequent application of external ointment and spontaneous desquamation led to resolution of the ectropion. Patient 2 (ichthyosis congenita gravis): a male baby prematurely born at 35+4 weeks of gestation was delivered by cesarean section. At birth the child showed the signs of a collodion baby with ectropion of all four eyelids in combination with a characteristic "fish mouth" and rudimentary external ears. The child died on the 14th day of life of septicaemia. CONCLUSION: In mild forms of congenital ichthyosis surgical treatment of eyelid ectropion is not required. In more severe cases a skin graft may become necessary. Various although limited sources of graft material which are discussed can be considered.

Abnormalities, Multiple↗

[Phototherapeutic keratectomy. Undesirable effects, complications, and preventive strategies].

The conceptual advantage of phototherapeutic keratectomy (PTK) include the option to remove diseased tissue on a micrometer scale. Although less invasive than other forms of corneal surgery, it remains a surgical procedure which carries inherent risks. In phototherapeutic indications this risk is higher than in otherwise healthy eyes undergoing photorefractive surgery. Potential general complications include wound-healing problems, infection, inflammation, or a recurrence of the underlying disease. More specifically, PTK is associated with unwanted refractive changes, such as a hyperopic shift or an irregular astigmatism. In this review, we discuss these problems along with prevention and treatment strategies in detail.

Corneal Diseases↗

[Phototherapeutic keratectomy. Basic principles, techniques and indications].

Phototherapeutic keratectomy (PTK) involves the removal of corneal tissue with an excimer laser for therapeutic and/or functional purposes. In contrast to photorefractive keratectomy, a change in manifest refraction is not the primary goal of the treatment. The main indications are poor epithelial adherence, corneal opacities or an irregular corneal surface, as well as combinations of these. We describe the basic techniques, such as large area and focal PTK and provide recommendations on use of different masking agents. Numerous well established and rare clinical examples are described in terms of achievable PTK results.

Corneal Diseases↗

[Squamous cell carcinoma of the conjunctiva with orbital invasion: orbital exenteration or minimally invasive procedure?].

BACKGROUND: Here we present a case of a female patient with squamous cell carcinoma with orbital invasion who insisted on a globe-sparing excisional biopsy rather than a more invasive procedure. CASE: A 48-year-old patient presented with a conjunctival tumor at the medial canthus of the right eye. The visual acuity in this eye was 1.0. MRI showed a 25 mm x 12 mm tumor, with orbital invasion, no metastasis, but on CT scan damage of the lamina papyracea was suspected. Histology of a punch biopsy confirmed a moderately differentiated, squamous cell carcinoma. As requested by the patient, simple tumor excision with a 5-mm safety margin, reconstruction of the lower fornix with amniotic membrane, and adjuvant mitomycin C therapy were performed. Intraoperatively the medial orbital wall was found to be intact. No local or systemic recurrence has occurred 3.5 years postoperatively. The patient's VA is still 1.0; no visual field defects are detectable, and there are only minor upper lid levator restriction and diplopia in maximum upgaze. CONCLUSION: In view of this case the choice of surgical treatment for malignant tumors of the conjunctiva with orbital invasion - between exenteration or a minimally invasive procedure - should be carefully discussed with the patient. A follow-up of 5 years is strongly recommended.

Carcinoma, Squamous Cell↗

[Current state of mechanical corneal surgery - results of a questionnaire to members of the cornea section of the German Society of Ophthalmologists].

AIM: The aim of this study was to obtain an overview on the surgical and the perioperative management strategies involved in mechanical corneal surgery in Germany, Switzerland and Austria. METHOD: A questionnaire was sent to 60 ophthalmological hospitals. RESULTS: Within one year the responding centres (n = 48) performed 3171 penetrating and 166 lamellar keratoplasties, 224 limbal stem cell--and 817 amniotic-membrane transplantations. In high-risk cases, 33 % of the centres did not use HLA-matched grafts. Predominantly manual trephine systems were used. Of the responding institutions 96 % used 10.0 nylon sutures and 64 % used a double running anti-torque technique for normal-risk keratoplasty. In tectonic and high-risk keratoplasties, interrupted sutures were used predominantly (70 % and 56 %). Suture removal was performed between one month (first suture) and up to 36 months (last suture) postoperatively. CONCLUSIONS: Procedures considered to be standard--such as penetrating keratoplasty--are performed with numerous and significant technical variations. The likely influence of such variations on the long-term outcome should be further evaluated.

Cornea↗

An optimised protocol for the production of autologous serum eyedrops.

BACKGROUND: Serum eyedrops have been successfully used in the treatment of severe dry eye, persistent epithelial defects and other severe ocular surface disorders. A number of clinical studies showed a variable efficacy of this approach, but the parameters for the production of this blood product varied significantly. In order to establish an optimised protocol for the production of serum eyedrops, we examined the effect of various clotting times, centrifugation forces, types of diluent and dilutions on the concentration of growth factors, fibronectin, and vitamins in serum and tested the epitheliotrophic capacity of these serum modifications in a cell culture model of human SV-40-immortalised corneal epithelial cells (HCE-T). METHODS: Serum samples were prepared with a clotting time of 20, 60 or 120 min, a centrifugation force of 500 xg or 3,000 xg, and diluted with BSS or isotonic saline. The concentrations of EGF, TGF-beta1, PDGF-AB, FGF, HGF, fibronectin, vitamin A and vitamin E in these samples were evaluated with ELISA and HPLC. HCE-T cells were incubated for 24, 48, 72, 96 and 144 h with 100, 50, 25, 12.5, 6.25 and 3.125% serum in diluent, and cell proliferation, migration and differentiation were evaluated by means of a luminescence-based ATP assay, a colony-dispersion assay and scanning electron microscopy. RESULTS: Using a longer clotting time resulted in an increased concentration of all the epitheliotrophic factors examined in serum; the difference was statistically significant for EGF, TGF-beta1 and HGF. Increasing the g force of centrifugation from 500 xg to 3,000 xg resulted in significantly less TGF-beta1, but more EGF and vitamin A. Cell proliferation was better supported by serum prepared with 3,000 xg and diluted with BSS. Serum prepared with a longer clotting time yielded better cell migration and differentiation. CONCLUSION: Clotting time, centrifugation and diluents have a significant impact on the composition and epitheliotrophic effects of serum. A long clotting time (>or=120 min), a sharp centrifugation (3,000 xg for 15 min) and dilution with BSS improve the ability of serum eyedrops to support proliferation, migration and differentiation of corneal epithelial cells.

Adult↗

[Gas permeable scleral lenses as a conservative treatment option for extreme corneal ectasias and severe dry eye].

PURPOSE: Due to their exclusive scleral contact zone, non-ventilated gas permeable scleral contact lenses can be used to correct extreme keratectasia, even if corneal fitted contact lenses failed previously. As the gap between the scleral lens and the cornea is filled with fluid substitutes, they also can be used for patients with severe aqueous-deficient dry eyes. PATIENTS, MATERIAL AND METHOD: Scleral lens fitting was attempted in 13 eyes (9 patients, group I) of patients with extreme corneal ectasia and 9 eyes (5 patients, group II) with severe ocular surface disease. Best corrected visual acuity, keratometry, Schirmer's test, foreign body sensation, and total daily lens wearing time were recorded prior to and after scleral lens fitting. RESULTS: Scleral lenses were successfully fitted and used on a long-term basis in 6 of 13 eyes (4 patients) of group I and 4 of 9 eyes of group II. In 9 eyes visual acuity increased by at least 2 lines, but long-term lens wear was not possible due to severe foreign body sensation or fornix shortening. CONCLUSIONS: Modern gas permeable scleral lenses can successfully be used for nonsurgical rehabilitation of severe corneal ectasia and dry eyes.

Adult↗

[Lavasept as an alternative to PVP-iodine as a preoperative antiseptic in ophthalmic surgery. Randomized, controlled, prospective double-blind trial].

BACKGROUND: To reduce the risk of endophthalmitis PVP-iodine is typically used preoperatively. Since iodine is contraindicated in patients with a specific allergic history or severe thyroid disorder we studied the effect of Lavasept, which contains Polyhexanid as an antiseptic alternative. PATIENTS AND METHODS: In a randomized controlled double-blind trial 3 drops of 0.2% Lavasept, 1.25% PVP-iodine or Ringer's solution were applied preoperatively to 67 patients, which have had a minimum of 5 colony forming units (cfu's) in the conjunctival swap. The effectiveness and tolerability were measured. RESULTS: After application of Lavasept or PVP-iodine, the number of cfu was statistically significantly reduced. Lavasept reduced the number of bacterial colonies significantly better than PVP-iodine (p=0.05). All test solutions were equally well tolerated. CONCLUSION: The use af Lavasept is safe, well tolerated and reduces the microbiological contamination of the conjunctival fornix effectively. lt provides a more effective reduction of the cfu's than PVP-iodine 1.25% and this effect tends to be prolonged. Lavasept is a good alternative option in ophthalmology for preoperative antisepsis.

Anti-Infective Agents, Local↗

[Lamellar keratoplasty. Back to the future?!].

In 1840 Mühlbauer was the first to describe a technique for anterior lamellar keratoplasty (LKP). However, in the second half of the twentieth century penetrating keratoplasty (PKP) became the gold standard. Although it is associated with a higher risk for serious complications -- it is technically easier to perform and avoids wound healing reactions in the lamellar interface and thus resulting in better visual acuity. In view of the pathology, replacing all layers of the cornea including healthy parts can be considered therapeutic "overkill" for many corneal graft indications. Several innovative surgical techniques have recently been described which allow the lamellar dissection of recipient and donor cornea with good reproducibility in almost every desired depth. This now allows the recipient endothelium and Descemet's membrane to be selectively replaced or preserved and to avoid formation of an optical barrier in the lamellar interface in eyes undergoing lamellar keratoplasty for optical indications. The most important principal advantage of an anterior LKP -- to minimize the risk of an immune reaction in the graft -- is even more important in tectonic indications. From the large number of variations, the surgical technique, results, and problems with anterior and posterior LKP for optical indications as well as lamellar segment keratoplasty and epikeratoplasty for tectonic indications are discussed.

Corneal Transplantation↗

[Keratoplasty -- a simple classification/terminology of current treatment options].

Thanks to technical advances the surgical options for corneal grafting have been widely expanded in recent years. Promoted by new instruments and techniques for intrastromal dissection a number of variations of lamellar keratoplasty, including descriptive terms and abbreviations have been suggested. This creative chaos, however, lacks simplicity, specificity and structure. Following a short definition of the basic terms we here present a simplified and clearly structured classification, which also incorporates the Anglo-American terminology and should, therefore, be acceptable for the wider international ophthalmic community.

Corneal Transplantation↗

Topical treatment of ocular surface defects: comparison of the epitheliotrophic capacity of fresh frozen plasma and serum on corneal epithelial cells in an in vitro cell culture model.

Accelerated healing of ocular surface disorders was reported using serum for topical application. It is supposed that growth factors, fibronectin and vitamins in serum support the proliferation of corneal epithelial cells. The use of fresh frozen plasma (FFP) instead of serum is theoretically attractive, as it is more easily available from blood banks. In this study, serum and FFP were investigated for composition of epitheliotrophic factors and effect on corneal epithelial cells. Whole blood was taken from five donors. Serum and FFP were prepared, and the concentrations of epithelial growth factor (EGF), Platelet-derived growth factor (PDGF), transforming growth factor-beta1, fibronectin and vitamin A were determined. Immortalized human corneal epithelial cells were used to investigate growth, migration and differentiation in response to both blood products. Significant differences were found regarding the mediator composition of serum and FFP. Serum rather than FFP was significantly superior in stimulating cell growth, migration and differentiation. The epitheliotrophic capacity of blood products depends upon the composition of growth factors and vitamins. Blood clotting strongly influences the growth factor pattern. The superior epitheliotrophic capacity of serum might be due to the higher concentration of proliferation mediators such as EGF and PDGF and its higher content of vitamin A.

Cell Line, Transformed↗

[Polyhexamethylbiguanid (PHMB) as preoperative antiseptic for cataract surgery].

BACKGROUND: We examined the efficacy and tolerability of Lavasept (polyhexamethylenbiguanid or PHMB)-an iodine-free antiseptic-in comparison to polyvinylpyrolidon iodine and Ringer's solution, as an alternative preoperative antiseptic. PATIENTS AND METHODS: In a randomized controlled double-blind trial 3 drops of Lavasept, 1.25%, PVP-iodine or Ringer's solution were applied preoperatively in 29 patients. The number of colony forming units (cfu) grown from conjunctival smears and conjunctival hyperaemia, corneal epitheliopathy and ocular surface pain were assessed preoperatively, intraoperatively and 1 day postoperatively. RESULTS: Despite intraoperative application of PVP-iodine, 40% of patients receiving Ringers solution still presented with more than 5 colony forming units (cfu) at the end of the procedure, while all patients that had additional preoperative Lavasept or PVP-iodine achieved relative sterility with less than 5 cfu (p < 0.05). While the effect of Lavasept lasted until the next day, conjunctival microbial colonisation recurred in eyes treated with PVP-iodine. As expected conjunctival hyperaemia and corneal epitheliopathy increased significantly postoperatively but no differences were observed between the 3 solutions tested. CONCLUSION: The preoperative application of Lavasept reduces the conjunctival flora safely and effectively. The microbicidal efficacy is equal to PVP-iodine, but potentially longer lasting. No signs of local or systemic intolerability were observed. Lavasept may be used as a potential alternative preoperative antiseptic and is suitable for iodine-intolerant patients.

Adult↗

[Epitheliotrophic capacity of serum and plasma eyedrops. Influence of centrifugation].

BACKGROUND: Serum eyedrops are a new modality for the treatment of ocular surface disorders. We examined the influence of the preparation of blood products in a cell culture model and compared it with plasma. MATERIAL AND METHODS: Serum and plasma were obtained from full blood of ten healthy volunteers and centrifuged at 500 and 3000 G. EGF, PDGF, TGF-beta1, fibronectin, and vitamin A were quantified by means of ELISA and HPLC. Cultures of human corneal epithelial cells were incubated with the four blood products in dose-response experiments and the intracellular ATP quantified. RESULTS: EGF, PDGF, and vitamin A were present in serum in significantly higher concentrations than in plasma. The concentration of fibronectin was not influenced by the preparation. Support of proliferation was best by 25% platelet-poor serum. Serum supported the differentiation and migration of epithelial cells better than plasma. CONCLUSION: The biochemical character of serum eyedrops is determined by the parameters chosen to produce the blood product. Plasma does not seem to offer an epitheliotrophic capacity equivalent to serum eyedrops. Their production should be optimized before any meaningful randomized controlled clinical trial can be attempted.

Adenosine Triphosphate↗

Autologous serum eye drops for ocular surface disorders.

Tears have antimicrobial, nourishing, mechanical, and optical properties. They contain components such as growth factors, fibronectin, and vitamins to support proliferation, migration, and differentiation of the corneal and conjunctival epithelium. A lack of these epitheliotrophic factors--for example, in dry eye, can result in severe ocular surface disorders such as persistent epithelial defects. Recently, the use of autologous serum in the form of eye drops has been reported as a new treatment for severe ocular surface disorders. Serum eye drops may be produced as an unpreserved blood preparation. They are by nature non-allergenic and their biomechanical and biochemical properties are similar to normal tears. In vitro cell culture experiments showed that corneal epithelial cell morphology and function are better maintained by serum than by pharmaceutical tear substitutes. Clinical cohort studies have reported its successful use for severe dry eyes and persistent epithelial defects. However, the protocols to prepare and use autologous serum eye drops varied considerably between the studies. As this can result in different biochemical properties protocol variations may also influence the epitheliotrophic effect of the product. Before the definitive role of serum eye drops in the management of severe ocular surface disease can be established in a large randomised controlled trial this has to be evaluated in more detail. In view of legislative restrictions and based upon the literature reviewed here a preliminary standard operating procedure for the manufacture of serum eye drops is proposed.

Cornea↗

[Long-term follow-up after autologous submandibular gland transplantation in scarring keratoconjunctivitis with absolute dry eyes].

INTRODUCTION: An autologous submandibular gland can be transplanted to the temporal fossa and following microvascular anastomosis to the temporal artery and vein and implantation of the secretory duct into the superotemporal conjunctival fornix to provide continuous substitute lubrication. Here we report our experiences with this procedure. PATIENTS AND METHODS: In a prospective, controlled clinical cohort study, we investigated the development of the Schirmer- test, fluorescein-break up time (F-BUT), degree of discomfort, use of pharmaceutical tear substitutes, visual acuity, Rose Bengal staining and conjunctival hyperemia in 14 eyes with a successful submandibular gland transplant and 11 dry eyes without salivary lubrication. RESULTS: Over a mean postoperative period of 3.3 years the transplantation group showed significant improvements of the Schirmer-Test, FBUT, use of pharmaceutical tear substitutes, discomfort and Rose Bengal staining up to the last follow-up when compared to the preoperative and control groups. CONCLUSION: Transplantation of an autologous submandibular gland can improve the lubrication and discomfort of absolute tear deficiency on a long term basis, but the salivary tear film only partially stabilises the ocular surface. The procedure is however able to provide symptomatic relief in extreme cases of absolute dry eyes.

Adolescent↗

Sight and comfort: complex procedures in end-stage Stevens-Johnson syndrome.

BACKGROUND: We describe our complex surgical techniques in the management of a patient with end-stage ocular surface disease from Stevens-Johnson syndrome. METHODS AND RESULTS: Her severe discomfort due to absolute ocular dryness in the right eye was successfully treated with submandibular gland autotransplantation. Impending loss of the left eye due to repeated perforation and infection was prevented with a penetrating corneal graft covered by a new modification of a Cutler-Beard-type full-thickness lower lid skin advancement-flap. Visual rehabilitation was achieved by means of osteo-odonto-keratoprosthesis. CONCLUSION: The procedures described allow the preservation of eyes doomed for enucleation, relief from severe discomfort and rehabilitation from corneal blindness. Due to their complex nature they require the collaborative subspecialist surgical skills of opthalmologists and maxillofacial surgeons.

Adult↗

[Autologous serum-eye-drops for ocular surface disorders. A literature review and recommendations for their application].

The natural tear film has mechanical, optical, antimicrobial and nutritional properties. Tear film components, such as EGF, fibronectin and vitamin A, play a vital role in the proliferation, migration and differentiation of the corneal and conjunctival epithelium. In ocular surface disease, such as severe dry eye, the epithelia may be depleted of these nutritional factors. Replacing the aqueous component of tears alone,by using pharmaceutical tear substitutes,often has little effect on the ocular surface.Eye-drops prepared from autologous serum are a new treatment option for severe ocular surface disease. They can be produced according to the regulations on drug use as an unpreserved blood preparation. Autologous serum eye-drops are non-allergenic and their biomechanical and biochemical properties are similar to normal tears. In cell culture experiments, serum was found to be superior to preserved or unpreserved pharmaceutical products in the maintenance of human keratinocyte morphology and function. It supports the migration of corneal epithelial cells and the differentiation of conjunctival epithelial cells. The first clinical cohort studies report its successful use for severe dry eyes and persistent epithelial defects. In these studies, however, varying methods for the preparation and different concentrations of autologous serum eye-drops were used. These methodological variations determine the biochemical properties and thus the epitheliotrophic effect of serum eye-drops. In this review we summarise the currently available clinical evidence, discuss relevant legislatory restrictions and describe a standard operating protocol for the use of serum eye drops. This has to be evaluated and optimised in more detail before any meaningful, randomised, controlled trial can attempt to establish the role of serum eye-drops in the management of severe ocular surface disease.

Blood Proteins↗