PubMed Health⌕ Search

Biomedical subjects

H Mietz

Publications and source records attributed to H Mietz.

At least 37 records · Page 2Linked to original sources
PubMed1997

Histopathologic and electron-microscopic features of corneal and scleral collagen fibers in osteogenesis imperfecta type III.

BACKGROUND: This report describes the histopathologic and electron-microscopic features of an eye from a patient with osteogenesis imperfecta type III. In particular, the diameters of corneal stromal and scleral collagen fibers were determined. METHODS: The eyes of an 18-year-old white male with osteogenesis imperfecta type III were examined by light and electron microscopy and the pathological features were compared with an age-matched control eye. RESULTS: The cornea was clear. The sclera had a blue color and was moderately thinned, especially at the equator. Light microscopy revealed absence of Bowman's layer. Transmission electron microscopy confirmed complete absence of Bowman's layer without evidence of scarring or inflammation. The collagen fibers of the corneal stromal lamellae were about 25% narrower than in the control, but the cornea was otherwise unremarkable ultrastructurally. The collagen fibers of the sclera were approximately 50% narrower than in the control and were much more uniform in size. Prominent portions of elastic fibers, which are usually only present in a small number in the inner portion of the sclera, were present throughout the sclera. CONCLUSION: We propose that it is the uniformity of the scleral collagen fibers which gives the sclera translucence, producing the blue color often observed clinically in osteogenesis imperfecta. Absence of Bowman's layer of the cornea did not interfere with the stability of the cornea in this case. This appears to be the first published pathological examination of the eye in osteogenesis imperfecta type III.

Adolescent↗
PubMed1997

Early conjunctival changes following treatment with metipranolol and preservatives are not reversible with dexamethasone.

BACKGROUND: Topical medication for the treatment of glaucoma alters the cellular and extracellular composition of the superficial and deep conjunctival layers. We sought to determine whether, after short-term use of metipranolol with preservatives, subsequent application of steroids or metipranolol without preservatives affects these conjunctival changes. METHODS: Rabbits received topical metipranolol over a period of 6 months. For the following 2 months, one group received metipranolol without preservatives, and another group steroids. For controls, animals were treated with preservatives only or metipranolol with preservatives for 6 months. Superior bulbar conjunctiva was examined by light microscopy, immunohistochemistry, and transmission electron microscopy. RESULTS: On light microscopic and immunohistochemical examination of conjunctival specimens from all groups, there was an increase of subepithelial collagen deposition in all treated groups. Treatment with steroids or preservative-free metipranolol did not alter the initial effects. By electron microscopy, additional extracellular matrix changes were seen as well as degenerative changes of tissue fibroblasts. CONCLUSION: The animal model used was able reliably to produce conjunctival changes following antiglaucomatous therapy. The changes seen were early changes, because there was no increase of inflammatory cells. Steroids did not significantly affect the changes. The beneficial effect of steroids used prior to glaucoma surgery remains controversial.

Administration, Topical↗
PubMed1997

Unilateral retinoblastoma in an adult: report of a case and review of the literature.

PURPOSE: The authors report the clinical, cytologic, and histopathologic findings of a unilateral retinoblastoma occurring in a 26-year-old woman. This tumor usually affects young children; the mean age at the time of diagnosis usually ranges from 10 to 25 months. METHODS: Histopathologic examination of the enucleated right eye included using standard techniques, as well as immunohistochemical stains of formalin-fixed, paraffin-embedded tissues. RESULTS: Histologic examination of sections of the eye showed a retinal tumor that was centered in the equatorial region and had the typical features of a poorly differentiated retinoblastoma. Focal choroidal invasion and seeding of the anterior and posterior chambers were observed. Immunoreactivity of the tumor cells for neuron-specific enolase confirmed that the tumor is a neuronal neoplasm consistent with retinoblastoma. CONCLUSION: Retinoblastoma occurring in adults is a rare finding. In most large series of retinoblastomas, no adults are included. Only eight patients 20 years of age or older with retinoblastomas have been documented previously. In the current case, the patient had no evidence of orbital recurrence or metastasis 6 years after enucleation of the eye. It may be important for clinicians to consider this diagnosis when confronted with a retinal mass of unknown etiology in adults.

Adult↗
PubMed1997

Orbital emphysema as a complication of bungee jumping.

Bungee jumping is a dangerous sport with increasing popularity in the western world. We report the case of a 28-yr-old man who sustained an orbital emphysema as a result of bungee jumping. He jumped head first from a 160-ft high bridge over a river. At the end of the jump he dived into the water with his head in a reclined position. The sudden dive into the water caused an increase of the air pressure in the nose and paranasal sinuses, which led to an emphysema of the right orbit resulting from a skull fracture not detectable by x-ray. The patient was treated with oral antibiotics. Five days later, he had no clinical complaints and the ophthalmologic examination was normal. This variation of bungee jumping may bear severe risk factors for health in addition to those known from the classic jumps.

Adult↗
PubMed1997

Effect of mitomycin C on the optic nerve in rabbits.

AIM: To prevent scarring after surgical optic nerve sheath decompression, it has been suggested that treating the area of fenestration with mitomycin C (MMC) might be effective. An animal model was used to test whether this toxic substance may cause optic neuropathy. METHODS: The optic nerves of 15 rabbits were exposed to balanced salt solution (BSS) or mitomycin C (MMC) in a concentration of 0.2 or 0.5 mg/ml. The unoperated fellow eyes and the eyes that received BSS served as controls. Steady state visual evoked potentials (VEPs) at 40, 50, and 60 Hz were recorded before and 4 weeks after surgery. The nerves were examined by light and electron microscopy after 5 weeks. RESULTS: VEPs in all non-operated eyes and eyes treated with BSS before and 4 weeks after surgery demonstrated responses at all three stimulus frequencies tested. Eyes operated with MMC had extinguished responses for one, two, or all the different temporal frequencies after 4 weeks with marked reduction in VEP amplitude. Eyes operated with MMC at a concentration of 0.5 mg/ml had significantly more reduced VEP responses than those where MMC 0.2 mg/ml was used. On histopathological examination, special stains for myelin and axons showed normal axons and myelin. On electron microscopy, no distinct abnormalities were seen among nerves operated with MMC and controls. CONCLUSION: The data from this study suggest that in rabbits, the application of MMC to the optic nerve has a dose dependent toxic effect in the short term postsurgical follow up period. While a functional alteration could be demonstrated reproducibly by steady state VEPs, the extent was not obvious on histopathological examination of the nerves.

Animals↗
PubMed1997

Combined subretinal and sub-retinal pigment epithelium neovascular membranes in age-related macular degeneration: a clinicopathologic study of six cases.

BACKGROUND AND OBJECTIVE: Subfoveal neovascular membranes are usually located either in the subsensory retinal space or below the retinal pigment epithelium (RPE). This article describes the clinical and histopathologic features of subfoveal membranes with both subretinal and sub-RPE components (combined membranes). PATIENTS AND METHODS: Six surgically excised subfoveal neovascular membranes from six patients were examined histopathologically. Preoperative and postoperative clinical information was obtained from each patient. RESULTS: Clinically, the combined membranes had no special characteristic features. The most common fluorescein angiographic finding postoperatively was a window defect of the RPE. Visual acuity improved in three patients and became worse in the other three patients. CONCLUSIONS: All patients with combined subfoveal neovascular membranes had age-related macular degeneration. In this disease, a single subfoveal membrane may extend into both the subretinal and the sub-RPE spaces. Patients may benefit from surgical removal of the membrane.

Aged↗
PubMed1996

Suitability and clinical application of a multiplex nested PCR assay for the diagnosis of herpes simplex virus infections.

A novel multiplex nested polymerase chain reaction (PCR) assay was designed and evaluated for routine diagnosis of herpes simplex virus (HSV) infections in patients with either putative HSV infection of the central nervous system or suspected HSV keratitis. Single-tube amplification of HSV type 1 (HSV-1) or type 2 (HSV-2) DNA extracted from cerebrospinal fluid (CSF) or from keratectomy specimens was followed by differentiation of the virus type-specific PCR products either by agarose gel analysis or by DNA enzyme immunoassay. Among 417 CSF specimens obtained from 395 consecutive patients with clinically suspected HSV infection, 11 (2.6%) were positive for HSV-1 DNA and four (1.0%) probes were positive for HSV-2 DNA. None of the specimens was positive for both HSV-1 and HSV-2 DNA. The genome of HSV-2 was detected in a CSF sample obtained from a woman with meningoencephalitis and genital herpes. The presence of PCR inhibitors was detected in six of 111 (5.4%) reconstructed CSF samples. Inhibition could be removed following extraction with a commercial kit. HSV-1 DNA, but no HSV-2 DNA, was detected in corneal buttons obtained from patients with suspected herpetic keratitis. No contamination has been recorded during the 2-year routine use of this test, which has met the specific requirements of a diagnostic laboratory.

DNA, Viral↗
PubMed1996

Histopathology of episcleral fibrosis after trabeculectomy with and without mitomycin C.

BACKGROUND: The aim of the study was to investigate the histopathologic features of scar tissue which have proliferated at the site of trabeculectomy of surgical failures after procedures with and without the use of the antimetabolite mitomycin C (MMC). METHODS: We obtained seven surgical specimens after trabeculectomy without MMC and five specimens after trabeculectomy with MMC, which were compared with 23 controls. Sections were stained with hematoxylin and eosin, Verhoeff-van Gieson, Grocott methenamine silver, and alcian blue. An immunohistochemical stain was performed for alpha-smooth muscle actin. RESULTS: Specimens from eyes operated without MMC showed dense scar tissue with many fibroblasts, much ground substance, parallel-oriented collagen fibers, and contractile intracellular proteins within the fibroblasts. Specimens from eyes operated with MMC consisted of tissue with only few fibroblasts which did not exhibit contractile proteins. Collagen fibers were arranged randomly with less ground substance. CONCLUSION: Even after 1-10 months, the scar tissue was distinctly different in the two groups. These results suggest that the use of MMC has long-term effects in vivo. Surgical failures related to scar formation are possible and not reduced to zero.

Actins↗
PubMed1996

Pyogenic granuloma of the cornea: report of a case and review of the literature.

BACKGROUND: Pyogenic granulomas are ulcerated vascular proliferations, often accompanied by inflammatory infiltrates, which rarely affect the eye. Only few reports on pyogenic granulomas of the cornea have been presented. METHODS: The enucleated globe containing the corneal tumor was examined histopathologically, and special immunohistochemical stains were performed. RESULTS: The lesion had a yellowish appearance with marked vascularization. The inflammatory infiltrate was mainly composed of mononuclear cells, with no multinucleated giant cells, and was located anterior to Bowman's layer, leaving the corneal stroma unaffected. Immunohistochemical studies outlined the high vascular content, even in dense cellular areas, and confirmed the inflammatory nature of the mononuclear infiltrates. CONCLUSIONS: Pyogenic granuloma of the cornea represents a clinical and morphological entity developing in a traumatized eye with corneal vascularization. Although the origin of these lesions remains obscure, there have been no signs of malignancy. Therefore, enucleation of an eye with a pyogenic granuloma should be avoided.

Aged↗
PubMed1996

Spherophakia, nanophthalmia, hypoplastic ciliary body and glaucoma in brachydactyly-associated syndromes.

Three juvenile patients showing a systemic disorder associated with small stature, brachydactyly and glaucoma were discovered to have spherophakia and a nanophthalmic axial length of the eye between 20.29 and 21.26 mm. According to clinical and radiological criteria only one patient was classified as having Marchesani syndrome; one patient suffered from an acrofacial disorder, and the third displayed typical ocular signs of Rieger syndrome. Pupillary block mechanism had led to glaucoma in all three patients. Despite iridectomy and trabeculotomy, two of them had unregulated intraocular pressure (IOP) and showed partial angleblock by progressive anterior synechiae after surgery. Ultrasonographic biomicroscopy revealed in all cases considerable hypoplasia of the ciliary body. We conclude that the clinical combination of spherophakia and brachydactyly is not necessarily limited to Marchesani syndrome. In the wide range of brachydactyly-associated syndromes an ophthalmic examination should always be performed in order to rule out ocular complications such as spherophakia and secondary glaucoma. We could not confirm Marchesani's hypothesis of a hyperplastic ciliary body in the spherophakia-brachydactyly syndrome, considering our nanophthalmic eyes. Pressure-reducing surgery in eyes with spherophakia and nanophthalmia seems to run a high risk of inducing an extensive formation of anterior synechiae.

Abnormalities, Multiple↗
PubMed1996

The toxicology of mitomycin C on the ciliary body.

Over the past few years, the use of mitomycin C (MMC) to reduce surgical failures following filtering procedures has largely increased. After topical application, significant amounts of MMC can be detected intraocularly. In both rabbit and human eyes, a reduction of the normal and elevated intraocular pressures could be achieved with subconjunctival injections of MMC without filtering procedures. Histopathologic examination of the ciliary body in a human eye shortly after surgery with MMC revealed moderate, diffuse toxic changes of the two layers of the ciliary epithelium. By fluorophotometry, eyes after trabeculectomy with MMC had a decreased production of aqueous humor compared with eyes that underwent trabeculectomies without antimetabolites. Independent studies suggest that the toxicity of MMC for the ciliary epithelium may be a significant factor contributing to postoperative hypotony.

Animals↗
PubMed1996

Long-term intraocular toxic effects of topical mitomycin C in rabbits.

PURPOSE: To detect whether toxic intraocular effects of mitomycin C (MMC) after extraocular application are long-standing or are reversible over time. METHODS: We placed sponges soaked with MMC on the intact sclera of rabbit eyes after incision of the conjunctiva. Controls received sponges soaked with balanced salt solution. Concentrations of MMC were 0.1 and 0.2 mg/ml. The eyes were examined histologically after 6 and 12 months. RESULTS: In all MMC-treated eyes, pathologic changes of the ciliary epithelium were present, which included irregular cell surfaces, intracytoplasmatic vacuoles, swelling of mitochondria, and disorganization of the endoplasmic reticulum. Nerves within the ciliary body also exhibited mild-to-moderate loss of axons in nonmyelinated nerves and increase of interstitial collagen deposition. Capillaries within the ciliary body consistently had a thickened basement membrane, which was arranged in two to three layers in multiple areas. The changes seen were similar in eyes examined at 6 and 12 months after application of MMC. CONCLUSIONS: These results suggest that toxic intraocular changes are dose dependent and do not recover over time. The impact of these findings on humans is unclear, but may further emphasize the high toxic potential of MMC.

Administration, Topical↗
PubMed1996

Use of a scleral shield for the application of mitomycin-C during trabeculectomy: preliminary clinical results.

BACKGROUND AND OBJECTIVE: To reduce intraocular concentrations of mitomycin-C (MMC), the authors used a scleral shield instead of a surgical sponge for the application of MMC during surgery. PATIENTS AND METHODS: A total of 20 patients were operated on using the scleral shield with MMC. These patients were observed for 6 months postoperatively. RESULTS: The rate of hypotony was 25% (5 of 20 patients). Visual acuity was not markedly reduced, and no case of hypotony maculopathy developed. The success rate and complications were not different from those of previous studies using the surgical sponge. CONCLUSION: The scleral shield may be advantageous for reducing the rate of hypotony maculopathy.

Adult↗
PubMed1995

Intraocular toxicity to ciliary nerves after extraocular application of mitomycin C in rabbits.

Prolonged postoperative hypotony is a severe complication frequently associated with trabeculectomies performed with a single perioperative application of Mitomycin C. We performed an animal experiment using 8 pigmented rabbits applying different concentrations of Mitomycin C, ranging from 0.05 to 1.0 mg/ml, under the conjunctiva on the intact sclera for 5 minutes. The eyes were examined by light and electron microscopy after 4 weeks. The nerves within the ciliary body in areas adjacent to the region of treatment showed toxic effects related to the concentrations of Mitomycin C applied. In cases where small concentrations were used, only the unmyelinated nerves were damaged with the myelinated remaining intact. In eyes treated with high concentrations, both groups of nerves exhibited severe signs of destruction. This effect is likely to compromise the production of aqueous humor in rabbits, and possibly also in humans.

Animals↗
PubMed1995

Short-term clinical results and complications of trabeculectomies performed with mitomycin C using different concentrations.

Despite the fact that trabeculectomies performed with Mitomycin C (MMC) have a high rate of success as repeatedly reported, the rate of complications encountered draws much of the attention of this substance to those cases that are unsatisfactory. To ascertain a possible relationship between some of these complications and concentrations of MMC used, we performed, in a prospective study, trabeculectomies for complicated cases of glaucoma with either concentrations of 0.5 mg/ml of MMC (group 1) or 0.2 mg/ml of MMC (group 2). The two groups were followed-up for 6 months and consisted of 49 and 40 cases, respectively. Two eyes in the first group and 3 in the second had to be considered as surgical failures that developed increasingly high pressures. Complications included hypotony most frequently (33%, both groups) with severely decreased vision in 3 cases (6%) of the first group and 8 (20%) in the second. Other results including visual acuities, IOP, and the rate of other complications were not significantly different in both groups and indicate that there may be no large difference between the two concentrations of MMC used.

Adolescent↗
PubMed1995

Detection of herpes simplex virus after penetrating keratoplasty by polymerase chain reaction: correlation of clinical and laboratory findings.

BACKGROUND: The study was carried out to investigate the possible correlation of clinical findings, histopathologic features and detection of herpes simplex virus DNA in corneal buttons obtained after penetrating keratoplasty. METHODS: We examined 47 consecutive corneal buttons sent for histopathologic examination by light microscopy and using the polymerase chain reaction for the detection of HSV1 and HSV2. Twenty-one corneal buttons from eyes with bullous keratopathy served as controls. RESULTS: The 47 cases were graded from the clinical information available as unproven, suspected and clinically proven cases of herpetic keratitis. This grading did not correlate to specific histopathologic features or to the results of HSV1 DNA testing. None of the cases were positive for HSV2 DNA. CONCLUSION: HSV DNA was detected in some of the cases of clinically unsuspected herpetic keratitis. This technique of demonstrating the presence or absence of HSV in the cornea after keratoplasty is more reliable than clinical data or histopathologic findings and may be important in cases of recurrent inflammatory episodes involving grafts after keratoplasty.

Cornea↗
PubMed1995

Ocular concentrations of mitomycin C after extraocular application in rabbits.

To determine the intraocular concentrations of Mitomycin C (MMC) after extraocular application, we used pigmented rabbits and placed sponges soaked with MMC under the conjunctiva on top of the intact episclera. First, we soaked the sponges with volumes ranging from 0.025 ml to 0.3 ml of the solution containing MMC and sampled aqueous humour after 30 minutes. The concentrations, as determined by high performance liquid chromatography, did not correlate to the amount of MMC given. Then, we soaked the sponges with different concentrations of MMC with a volume of 0.1 ml and sampled aqueous humour, vitreous humour and sclera after 60 minutes. The concentrations of MMC were higher in the vitreous than in the aqueous, and, relative to these values, very high in the sclera. These results indicate that the amount of MMC reaching the interior of the eye after standard extraocular application may be highly variable, and that the concentrations of MMC in the sclera and formed vitreous can be considerably higher than in the aqueous humour.

Administration, Topical↗