Search PubMed⌕ Search

Biomedical subjects

G K Lang

Publications and source records attributed to G K Lang.

At least 55 records · Page 3Linked to original sources
PubMed2000

[Merkel cell tumor of the eyelids: review of the literature and report of 2 patients].

BACKGROUND: The Markel cell carcinoma is a rare malignant skin tumor. The tumor was first described in 1972 by Toker and he named it trabecular carcinoma. We had the opportunity to treat two patients with a Merkel cell carcinoma of the upper and lower eyelid and reviewed the literature using the "Medline" database concerning Merkel cell carcinomas of the ocular adnexa. HISTORY AND SIGNS: A 76-year-old female patient was referred to our hospital because of an inflammatory tumor of the left upper eyelid present for two months. A 91-year-old male patient noticed for four weeks a painless itching lesion at the left lower eyelid. The remaining ophthalmologic examination in these patients was unremarkable. THERAPY AND OUTCOME: Both tumors were excised. Histological and immunohistochemical examination verified a Merkel cell carcinoma in both cases. The 76-year-old female patient exhibited no recurrent tumor after a follow-up of 18 months. The 91-year-old male patient had a recurrent tumor inferior to the temporal lower eyelid 7 months after tumor excision, however, lymph node metastasis is not present as of yet. The patient underwent radiation therapy with cobalt of the left orbit with a total dose of 60 Gy. CONCLUSION: Merkel cell carcinomas can occur everywhere on the skin; the eyelids are affected in 10% of all cases. Best histochemical markers are cytokeratin 20 and neurospecific enolase. A review of the literature revealed 31 patients with Merkel cell carcinomas involving the eyelids. Female patients were more often affected than male patients. The upper eyelid was more frequently involved than the lower eyelid. Recurrent disease is frequent.

Aged↗
PubMed2000

[Diffuse retinal pigmented epitheliopathy associated with systemic corticosteroid therapy].

BACKGROUND: It is well known that topical as well as systemic treatment with corticosteroids may have ocular side effects. The most common are the development of cataract and increase of intraocular pressure, however, alteration of the retinal pigment epithelium may also occur. PATIENT: A 64-year old male experienced a progressive decrease of visual acuity over a time period of 6 weeks. Ophthalmologic examination revealed a severe diffuse retinal pigment epitheliopathy with serous detachment of the neurosensory retina. This patient was treated with systemic methylprednisolone for chronic glomerulonephritis. After cessation of the treatment with systemic corticosteroids visual acuity improved and the serous retinal detachment resolved. CONCLUSION: Ophthalmologic examination including biomicroscopy of the retina is recommended on a regular basis for patients treated with systemic corticosteroids. With development of pigment epithelial changes steroids should be reduced or discontinued if possible.

Anti-Inflammatory Agents↗
PubMed2000

Growth factor combinations modulate human retinal pigment epithelial cell proliferation.

PURPOSE: Retinal pigment epithelial (RPE) cell proliferation is an important step in the pathogenesis of ocular diseases such as proliferative retinopathy. Growth factors play a major role in modulating the development and progression of these diseases. The aim of this study was to examine the effects of single growth factors as compared to growth factor combinations on the stimulation of RPE cell proliferation. METHODS: Human RPE cells were treated with 10 ng/ml IGF-1, PDGF, bFGF, EGF, VEGF, and TGFbeta(2), or with the combination of each of the growth factors. RPE cell proliferation was determined by [(3)H]-thymidine incorporation after growth factor stimulation for 24 hr. RESULTS: RPE cell proliferation was significantly increased when PDGF and bFGF were combined as compared to the single growth factor (p<0.005). There was a decrease in DNA synthesis for combined growth factors as compared to the single growth factor for IGF-1 plus TGFbeta(2) (p<0.05), IGF-1 plus VEGF (p<0.005), PDGF plus TGFbeta(2) (p<0.005), VEGF plus TGFbeta(2) (p<0.005 as compared to VEGF), and bFGF plus TGFbeta( 2) (p = 0.01 as compared to bFGF). The remaining growth factor combinations showed no significant synergistic effect on human RPE cell proliferation. CONCLUSIONS: These data lead to the implication that DNA synthesis in human RPE cell culture is synergistically affected by certain growth factor combinations, but not by all of them. This observation may be important for a better understanding of growth factor interactions occuring in proliferative diseases in the eye.

Cell Division↗
PubMed1999

[Motif expressing soft print lenses. Effect on visual function].

BACKGROUND: Contact lenses which change the structure and color of the iris are used not only for many therapeutic situations but also for cosmetic reasons. The purpose of this study was to investigate whether such lenses cause impairment of visual functions. MATERIAL AND METHODS: In healthy volunteers with an uncorrected visual acuity of 20/20 a clear soft-fitting lens and a special effect soft contact lens (Crazy lens, Bach Optic, Cologne) were tested in changing sequence. The following parameters were studied: visual acuity, contrast sensitivity (MCT 8000, VisTech Cons., Dayton, Ohio), Goldmann visual field, mesopic vision (Nyktometer, Rodenstock, Munich), and subjective wear comfort on a scale from 1 (excellent) to 10 (poor). Statistical analysis was performed using the Wilcoxon test and the Mann-Whitney U-test. RESULTS: Nine volunteers with a mean age of 29.9 +/- 5.1 years were analyzed. Visual acuity was reduced to 0.9 +/- 0.23 in the Crazy lens group compared to 1.2 +/- 0.13 in the clear lens group. Mesopic vision without glare was reduced from 1:2.5 to 1:7.4. Goldmann visual field displayed a significant constriction of following isopters: III/4, I/4, and I/3. Contrast sensitivity was significantly reduced in a photopic condition with and without glare and in a scotopic condition without glare; there was, however, an increase in contrast sensitivity in a scotopic condition with glare. Furthermore a decrease in wear comfort from 2.8 +/- 1.4 with the clear fitting lens to 5.7 +/- 2.1 with the print-lens was found. CONCLUSION: The tested special-effect contact lenses are associated with a reduction of many visual functions, including visual acuity and contrast sensitivity. This may interfere in some wearers with the ability to drive a car.

Adult↗
PubMed1999

[Ultrasound biomicroscopy in iris lesions].

INTRODUCTION: It is difficult to classify lesions of the iris, especially when they are posterior or in the iridociliary angle of the eye. METHOD: We used an ultrasound biomicroscope (Humphrey, Zeiss, Oberkochen, Germany) with a high-frequency sound head (30 and 50 Hz). This study included all patients with unspecified iris processes who were examined at the University Eye Clinic and Hospital of Ulm between September 1996 and February 1997. Fifteen patients, aged between 9 to 82 years (average age = 48.9 years), were prospectively evaluated. RESULTS: A cyst of the iris or ciliary body causing a tumor of the iris was found in six cases (40%). Seven patients (47%) showed a solid tumor of the iris and two patients (13%) a solid tumor of the ciliary body. CONCLUSION: The ultrasound biomicroscope can be used to assess lesions of the iris caused by a cyst or a solid tumor. The increasing size and depth expansion of a solid tumor may be helpful for differentiating between a malignant or benign process. Up to now it has not been possible to use the ultrasonic reflectivity of the tumor to decide if it is malignant.

Adolescent↗
PubMed1999

[Decreased serum level of free bioavailable IGF-I in patients with diabetic retinopathy].

BACKGROUND: Growth factors like IGF-I have been implicated in the pathogenesis of diabetic retinopathy. To investigate the role and bioavailability of IGF-I we measured not only total but also free serum levels of IGF-I in diabetic patients. METHODS: A total of 159 patients with and without diabetic retinopathy were investigated (60 diabetic patients without and 99 with clinically and angiographically diagnosed diabetic retinopathy). One hundred ten healthy volunteers served as controls. The data were analyzed by Student's t-test, analysis of variance and correlation; P < 0.05 was considered statistically significant. RESULTS: Diabetic patients with retinopathy showed significantly lower serum levels of free IGF-I than diabetics without retinopathy. Free IGF-I was negatively correlated with glycosylated hemoglobin 1c. IGFBP-3 levels were diminished in type 2 patients with diabetic retinopathy, while type 1 patients with diabetic retinopathy showed higher IGFBP-1 levels. CONCLUSION: Diabetic patients with retinopathy showed significantly reduced serum levels of free IGF-I. Low IGF-I was associated with poor metabolic control.

Biological Availability↗
PubMed1999

[Contusion of the optic nerve after minor blunt ocular trauma: case report and literature review].

INTRODUCTION: Isolated trauma of the optic nerve usually occurs in association with blunt skull trauma involving fractures of the skull and optic canal, but rarely occurs from blunt ocular trauma. CASE REPORT: A 7-year old boy fell and struck his left eye against a toy antenna. The initial examination revealed a visual acuity of 0.2 and slight edema of the optic nerve head. Perimetry revealed a defect in the superior and nasal visual fields. CT and MRI scans of the orbit were normal. Nine months after the injury, vision had improved to 1.0. On examination, optic nerve atrophy had developed and perimetry continued to display a defect in the superior visual fields. DISCUSSION: The mechanism of optic nerve damage secondary to trauma can be classified as primary or secondary. Primary damage occurs as a result of external forces at the moment of trauma, e.g., rupture of nerve fibers or of capillary vessels. Secondary damage may not be present initially, but may occur later on and results from compromised blood supply to the optic nerve, e.g., following edema or angiospasm. In our patient, it is not clear whether the damage was primary or secondary. CONCLUSION: Damage to the optic nerve can be caused by blunt skull trauma and, rarely, also by blunt ocular trauma. This fact is of importance when considering legal and reimbursement issues.

Child↗
PubMed1999

[Photorefractive keratectomy. Free-running vs. q-switched Er:YAG laser (scanning mode)].

BACKGROUND: Examination of morphology in plane corneal ablation (in vitro) induced by an Er:YAG-laser (2.94 microns) in two modes: free-running (50 microseconds) and q-switched (200 ns). METHODS: Sequences of different fluences in each mode were applied to freshly enucleated swine eyes. Parameters of free-running mode: fluences 1.21-4.77 J/cm2, frequency 80 Hz, spot size 500 microns FWHM, hexagonal spot shape. Parameters of q-switched mode: fluences 0.79-2.33 J/cm2, frequency 20 Hz, spot size 500 microns FWHM, round spot shape. RESULTS: Histology showed thermal damage of 10-25 microns in depth caused by the free-running mode compared with 4.5-7.5 microns by the q-switched mode. In both gross photography and scanning electron microscopic examination, the surface was found to be more homogeneous and smoother in the q-switched mode. CONCLUSIONS: Depending on the different application modes, both laser systems could be used for a defined corneal ablation in photorefractive keratectomy. However, at the moment, results using the Er:YAG laser are not as favorable as with the excimer laser.

Animals↗
PubMed1999

Histologic and morphometric analysis of the choroid, Bruch's membrane, and retinal pigment epithelium in postmortem eyes with age-related macular degeneration and histologic examination of surgically excised choroidal neovascular membranes.

OBJECTIVE: Age-related macular degeneration (AMD) is the leading cause of irreversible blindness in industrialized countries. Different risk factors have been associated with AMD. We performed a histopathologic and morphometric study to compare eyes with different stages of AMD to age-matched eyes. This study aimed to investigate the correlation among morphometric characteristics of choroidal vessels, the retinal pigment epithelium, and Bruch's membrane, to study the association between these characteristics and the presence and type of AMD, and to identify morphologic risk factors for exudative AMD. Furthermore, we histologically analyzed surgically removed choroidal neovascular membranes secondary to underlying diseases other than AMD to discern whether the cellular and extracellular components of the membranes of eyes with AMD are similar to those with diseases other than AMD. METHODS: We analyzed 51 eye bank eyes (Georgia Eye Bank, Atlanta, GA) from 40 donors with different stages of AMD and compared them with 40 age-matched controls. The eyes were processed for light microscopy. The degree of calcification of Bruch's membrane, fragmentation of Bruch's membrane, number and types of drusen, basal laminar deposit, and seven morphometric variables of the choroid were assessed in the macular and extramacular regions. Surgically excised subfoveal membranes were processed and evaluated by light and transmission electron microscopy. RESULTS: There were no statistically significant differences observed between eyes with neovascular and non-neovascular AMD. The single most important difference between eyes with and without AMD was the amount of basal laminar deposit (P < 0.001). Eyes with AMD displayed fewer large choroidal vessels in the submacular choroid than eyes without AMD (mean density values of all choroidal vessels [arteries and veins] were 3.5 +/- 1.5 mm(-1) and 5.7 +/- 1.6 mm(-1), P < 0.001, respectively). The submacular choriocapillaris density was higher in eyes with AMD (mean density, 0.62 +/- 0.06) than in eyes without AMD (mean density, 0.51 +/- 0.08 [P < 0.001]). The diameter of the larger choroidal vessels in the peripheral choroid was higher in eyes with AMD (mean diameter, 30 +/- 8 microm) than in eyes without AMD (mean diameter, 21.4 +/- 6.2 microm [P < 0.001]). The peripheral choriocapillaris density displayed the same pattern as the macular region in eyes with and without AMD. There was a statistically significant difference observed in the degree of calcification and fragmentation of Bruch's membrane in eyes with exudative AMD (mean degree of calcification, 1.6; median number of breaks in Bruch's membrane, five) as compared with controls (mean degree of calcification, 0.8; median number of breaks in Bruch's membrane, zero). The difference for these two variables between eyes with nonexudative AMD (mean degree of calcification, 0.8; median number of breaks in Bruch's membrane, one) and controls (mean degree of calcification, 0.8; median number of breaks in Bruch's membrane, zero) failed to reach statistical significance. Eyes with AMD displayed significantly more soft, diffuse, and large drusen, as well as basal laminar deposit, in the macular area than controls. CONCLUSION: Combining our data with data from the literature, we conclude that AMD can be interpreted as a dynamic process with early proliferation and subsequent atrophy of capillaries of the choriocapillaris. Calcification and fragmentation of Bruch's membrane; soft, diffuse, and large drusen; and basal laminar deposit, but not hard drusen, strongly correlate with the histologic presence of AMD. The degree of calcification and fragmentation of Bruch's membrane is prominent in eyes with exudative AMD. The formation of choroidal neovascular membranes represents a stereotypic, nonspecific wound repair response independent of the underlying disease.

Aged↗
PubMed1999

[Conjunctival pseudolymphoma in infectious mononucleosis].

BACKGROUND: The most frequent manifestation of an infection with Epstein-Barr virus is the mostly unilateral transient follicular conjunctivitis. PATIENT: A 19-year-old man was evaluated for a unilateral salmon colored subconjunctival mass that had developed over one week. Additionally, the patient had painful cervical lymph nodes and a sore throat. Blood tests demonstrated a lymphocytosis and a high titer for Epstein-Barr-Virus-IgG and -IgM which was consistent with infectious mononucleosis. A biopsy form the conjunctival mass showed a mixed cellular infiltrate including lymphocytes, plasma cells, histocytes, and cells with a prominent eosinophilic nucleolus. The lesion displayed a spontaneous regression over the following 8 weeks. CONCLUSION: Infectious mononucleosis should be considered with a conjunctival tumor which may mimic a lymphoma.

Adult↗
PubMed1999

[Sebaceous hyperplasia of the lower eyelid].

BACKGROUND PATIENT: A 61-year-old man was evaluated for a yellow tumor located at the lid margin of his lower eyelid, which had recurred for the second time after surgical excision. The patient's ocular examination was otherwise unremarkable as was the general examination with the exception of the presence of a polyp in the colon and a family history of multiple colorectal carcinomas. The eyelid tumor was excised and histologic examination showed a sebaceous hyperplasia. CONCLUSION: When one encounters a sebaceous tumor involving the eyelid the possibility of Muir-Torre syndrome should be considered. Muir-Torre syndrome is an autosomal dominant genodermatosis characterized by at least a single sebaceous gland tumor (either a hyperplasia, an adenoma, an epithelioma, or a carcinoma) and a minimum of one internal malignancy.

Colonic Polyps↗
PubMed1999

[Deep penetrating nevus of the eyelid].

BACKGROUND: A 52-year-old woman was evaluated for a pigmented tumor in her right lower eyelid, which has developed over the last year. The tumor measured 3 x 4 mm. The patient's ophthalmologic and medical history was normal. Clinically, a malignant melanoma was suspected, and an excision was carried out in local anesthesia. The histopathology was suggestive for a deep penetrating nevus. CONCLUSION: Deep penetrating nevus is a variant of benign pigmented nevi with deep dermal and subcutaneous involvement. The pattern should be recognized and differentiated form malignant melanoma.

Eyelid Neoplasms↗
PubMed1999

[Prevalence of systemic and ocular diseases in age-related cataract patients].

BACKGROUND: Cataract patients often display concomitant ocular and systemic diseases which may influence the decision between general and regional anesthesia. The aim of this study was to quantify co-morbidity of these patients and assess the influence of the two types of anesthesia an the anesthesiological risk on the frequency of intra- and post-operative complications and visual outcome. METHODS: In this prospective study, in patients scheduled for cataract extraction at the University Eye Hospital and Clinic of Ulm (tertiary eye care center) all systemic and ocular diseases as well as intra- and postoperative complications were analyzed. The prevalence of the co-morbidity in our patients was compared to other studies including age-matched controls. The anesthesiological risk was quantified using the classification scheme of the American Society of Anesthesiologists (ASA). RESULTS: Eighty-eight patients with a mean age of 70.4 +/- 11.7 years were analyzed. Sixty-one% of patients displayed systemic as well as ocular co-morbidity. Only systemic or ocular comorbidity was present in 32% and 5% of patients, respectively. Two% of patients exhibited neither ocular nor systemic comorbidity. In 61% of patients the surgery was performed in regional anesthesia and in 39% in general anesthesia. The prevalence of systemic and ocular co-morbidity as found in our study was significantly higher as compared to that in the general population of the same age. Visual improvement and the frequency of intra- and postoperative complications were independent on type of anesthesia and anesthesiological risk. CONCLUSIONS: Patients who were scheduled at our institution for cataract surgery exhibited a high frequency of ocular as well as systemic co-morbidity. This can be interpreted in such a way that patients with a high level of co-morbidity are referred to tertiary eye care centers for cataract surgery.

Age Factors↗
PubMed1999

[Ocular bacteriosis in a patient with aplastic anemia].

BACKGROUND: For more than a century it has been recognized that bacteria may infect the eye by way of the blood stream. Until fifty years ago, eyes so afflicted nearly always were blinded and a majority of the victims died from overwhelming sepsis. Although effective antibiotics are available today the prognosis is still guarded. CASE REPORT: A 39-year-old physician died 6 years after he was diagnosed for idiopathic aplastic anemia. He had developed pseudomonas aeruginosa bacteremia and later a therapy refractive pneumonia caused by aspergillus which had led to respiratory failure. The patient had experienced a marked loss of visual acuity in his left eye ten days before he died. Ophthalmic examination at that point displayed signs of endophthalmitis, hyphaema, and heterochromic irises. The eyes were obtained postmortem and histologic examination of the left eye displayed numerous bacilli forming cuffs around blood vessels and a sheet between the necrotic retinal pigment epithelium and Bruch's membrane. No inflammatory response to the bacilli was present. The bacilli could be demonstrated with a Giemsa stain and could also be identified with electron microscopic examination. DISCUSSION: The histologic results in our patient displayed numerous bacilli without inflammatory reaction which was a result of the aplastic state. Therefore, this disease was classified as "ocular bacteriosis". The blood-ocular barrier undergoes direct assault with intraocular inflammation and the impermeability to blood-borne antibiotics is lost. However, with the lack of an inflammatory reaction the permeability to antibiotics may be too low and the achieved concentration insufficient.

Adult↗
PubMed1999

[Eccrine spiradenoma of the eyelid].

PATIENT: A 60-year-old woman was evaluated for a nodular tumor in her right upper eyelid, which has developed over the last four years. The tumor measured 10 x 8 mm and was ulcerated. The patient's ophthalmologic und medical history was normal. Clinically, a basal cell carcinoma was suspected, and an excision was carried out under local anaesthesia. The histopathology was suggestive for an eccrine spiradenoma. CONCLUSION: Eccrine spiradenomas rarely involve the eyelids. This tumor represents a benign, usually painful, sweat gland tumor. The possibility of sweat gland tumor should be kept in mind in the diagnosis of eyelid tumors. The complete excision is the only therapeutic option.

Adenoma, Sweat Gland↗
PubMed1999

Effect of thalidomide, octreotide, and prednisolone on the migration and proliferation of RPE cells in vitro.

PURPOSE: The retinal pigment epithelium (RPE) is involved in the pathogenesis of age-related macular degeneration. The purpose of this study was to assess the effect of thalidomide, octreotide, and prednisolone on the proliferation and migration of bovine RPE cells in vitro. METHODS: The migration assay was performed in double-chamber-wells separated by a membrane filter with 8 microm pores. Cells were allowed to migrate vertically for 7 hr, afterwards the cells on both filtersides were fixed, stained, and the migrated cells were counted. To examine RPE proliferation, bovine RPE cells were seeded subconfluently followed by an incubation with octreotide, thalidomide or prednisolone in a concentration gradient for 24 hr. Stimulation or inhibition of DNA synthesis was measured by [(3)H]-thymidine incorporation. Statistical analysis was performed with the paired student's t-test. RESULTS: Statistically significant (p < 0.05) inhibition of RPE cell proliferation was measured for thalidomide at a concentration of 10-50 microg/ml, for octreotide at a concentration of 5 x 10(-4) and 5 x 10(-5) M, and for prednisolone at a concentration of 250 and 500 microg/ml as compared to the negative control. RPE cell migration was significantly (p < 0.05) inhibited by thalidomide at a concentration of 10 microg/ml, by octreotide at a concentration of 5 x 10(-5) M, and also by prednisolone at a concentration of 500 microg/ml as compared to the negative control. CONCLUSIONS: Although the main effect of thalidomide, octreotide, and prednisolone when treating patients with choroidal neovascular membranes is probably related to the inhibition of angiogenesis it should be kept in mind that these substances may additionally inhibit RPE proliferation and migration.

Animals↗