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Biomedical subjects

A Tarkkanen

Publications and source records attributed to A Tarkkanen.

At least 19 recordsLinked to original sources
PubMed1995

Clinically successful contact transscleral krypton laser cyclophotocoagulation. Long-term histopathologic and immunohistochemical autopsy findings.

OBJECTIVE: To report long-term histopathologic findings 10 months after contact transscleral krypton cyclophotocoagulation. METHODS: The tissue response in a successfully treated eye was analyzed by light microscopy and a panel of 11 antibodies to epithelial, mesenchymal, and inflammatory cells. RESULTS: A 75-year-old man with uncontrolled angle recession glaucoma was treated with transscleral contact krypton cyclophotocoagulation (17 burns, 3.5 J each) 10 months before his death. The intraocular pressure fell from 28 to 17 mm Hg 6 months after therapy. Confluent scars straddled the posterior pars plicata and the anterior pars plana. The ciliary processes were destroyed, but the sclera and zonules were intact. Vimentin and cytokeratin 8 and 18 persisted in the degenerated ciliary epithelium. The inner connective-tissue layer and the ciliary muscle had atrophied, as shown with antibodies to the HNK-1 epitope, desmin, and alpha-smooth-muscle actin. Macrophages with phagocytized pigment and single T cells were present instead. No unusual inflammatory infiltrate was present in the choroid of either eye. CONCLUSIONS: Clinically effective ablation of ciliary processes is achieved with contact krypton laser. Little chronic inflammation and no signs of sympathetic ophthalmia were present. Atrophy of the ciliary muscle may reduce accommodative capacity in younger patients undergoing cyclophotocoagulation.

Actins↗
PubMed1995

Lectin and immunohistochemical comparison of glycoconjugates in the conjunctiva of patients with and without exfoliation syndrome.

AIMS--The study was carried out to search for labelling similar to that of intraocular exfoliation material in the conjunctiva by light microscopy using lectin and immunohistochemistry. METHODS--Ten formalin fixed and paraffin embedded conjunctival biopsy specimens both from patients with and without exfoliation syndrome were studied with a panel of 11 lectins and with three monoclonal antibodies to the HNK-1 carbohydrate epitope, all of which react with intraocular exfoliation material. RESULTS--The lectin binding profile was essentially the same in specimens from patients with and without exfoliation syndrome. The superficial epithelium reacted similarly with Phaseolus vulgaris (PHA-E), Caragana arborescens (CAA), Helix pomatia (HPA), concanavalin A (ConA), and wheat germ (WGA) agglutinins. Binding was also detected with peanut (PNA) and Bauhinia purpurea (BPA) agglutinins, particularly in patients with exfoliation. The basement membrane generally reacted with Ricinus communis (RCA-I), PHA-E, Vicia villosa (VVA), ConA, and Lens culinaris (LCA) agglutinins. The stroma was weakly labelled with RCA-I, PHA-E, ConA, and LCA. Lectin binding to the vascular endothelium was moderate with RCA-I, PHA-E, CAA, ConA, LCA, and WGA. Inconsistent labelling was also detected with PNA, BPA, and Erythrina cristagalli agglutinin (ECA). The subendothelial region reacted weakly but consistently with PHA-E, ConA, and LCA, and inconsistently with PNA. Pretreatment with neuraminidase did not change that pattern. Antibodies to the HNK-1 epitope reacted only with myelinated stromal nerve branches. CONCLUSION--No evidence of abnormal deposits in any specimen was found. The carbohydrate composition of intraocular exfoliation material may differ from that of exfoliation-like fibres often detected in the conjunctiva by electron microscopy.

Antigens, CD↗
PubMed1994

The HNK-1 epitope in the inner connective tissue layer of the human ciliary body in exfoliation syndrome and various types of glaucoma.

Possible changes in the expression of the HNK-1 carbohydrate epitope in the inner connective tissue layer of the human ciliary body, located between the ciliary epithelium and muscle, was studied using 2 formalin-fixed, paraffin-embedded eyes with exfoliation syndrome, 33 eyes with different types of glaucoma, and 21 morphologically normal control eyes. A strong immunoreaction delineating cell process was observed in this layer with monoclonal antibodies HNK-1 and VC1.1 recognizing the HNK-1 epitope in control specimens, whereas partly granular immunoreaction was present in eyes with exfoliation syndrome. Exfoliation material was also immunoreactive. In all types of advanced glaucoma, the immunoreaction was mostly granular in nature and greatly diminished. No difference in HNK-1 immunoreactivity between control and glaucoma eyes was seen in the retina and ciliary epithelium. Elevated intraocular pressure, either directly or by decreasing blood flow to the ciliary body, may cause degenerative or metabolic changes in the inner connective tissue layer cells that bear or secrete molecules sharing the HNK-1 epitope. The partly granular immunoreactivity in eyes with exfoliation syndrome only indicates changes in this epitope even without an increase in intraocular pressure.

Adult↗
PubMed1992

Expression of tenascin and fibronectin in the rabbit cornea after excimer laser surgery.

In order to investigate the effects of excimer laser surgery on corneal wound healing, 25 rabbits underwent anterior keratectomy at a depth of 100 or 300 microns with a Meditec MEL 50 excimer laser. After various intervals the animals were killed and the cornea excised and investigated immunohistochemically for the expression of extracellular matrix (ECM) proteins, fibronectin and tenascin. Fibronectin was shown to occur earlier than tenascin, and the two also had different distribution patterns. Wound depth showed no clear effect on the localization and time of ECM protein expression. This study indicates that corneal wounds caused by excimer laser radiation and those caused by mechanical surgery differ as to healing mechanisms.

Animals↗
PubMed1992

Exfoliation syndrome in patients scheduled for cataract surgery.

A series of 305 consecutive patients 30 years of age or older scheduled for cataract surgery was examined to find out the frequency of exfoliation syndrome, the predominant type of cataract, and the intraocular pressure status. The mean age of 222 (72.8%) females and 83 (27.2%) males was 71.7 (+/- 11.1) years (range 32 to 91 years). Exfoliation was detected in 77 (25.2%) patients. It was unilateral in 37 (48.0%) patients, the affected eye being in 29 (78.4%) cases scheduled for cataract surgery, and bilateral in 40 (52.0%) patients. Exfoliation was increased steadily with age. It was most often seen on the anterior lens capsule (88.9%). Krukenberg's spindle was seen in 31 (20.4%) eyes of patients with and in 12 (2.6%) eyes of patients without exfoliation (p less than 0.001). Nuclear sclerosis predominated in eyes with (83.8%) as compared to those without (61.9%) exfoliation (p less than 0.01). Posterior subcapsular cataract was less common in eyes with exfoliation (1.5%) than in eyes (21.1%) without it (p less than 0.001). A tendency to slightly higher preoperative intraocular pressure was measured in eyes with exfoliation as compared to those without it, and glaucoma occurred much more frequently (33.8% vs 10.8%) in the former group (p less than 0.001). Exfoliation and capsular glaucoma, which must be promptly detected to avoid surgical complications, are frequent in patients scheduled for cataract surgery.

Adult↗
PubMed1992

Pseudomembranous and membranous conjunctivitis. Immunohistochemical features.

A 63-year-old man, who had for one month been on sulfasalazine therapy, developed general malaise, high fever, severe stomatitis, and bilateral necrotizing pseudomembranous conjunctivitis with corneal erosion, identical to that seen in the Stevens-Johnson syndrome. Topical therapy with antibiotics and aprotinin rapidly healed the corneal surfaces, while densely adherent true membranes developed on the conjunctiva, and were removed surgically several times during the next week. After the acute stage, subtle subepithelial conjunctival scarring, superficial punctate keratitis, dry eye syndrome and fluctuating irregular corneal astigmatism became evident, but good visual acuity, lid function and ocular motility were retained. Histopathologic study of conjunctival membranes from two cases of membranous conjunctivitis revealed polymorphonuclear leukocytes within a matrix composed of fibrin, tenascin and fibronectin. In older membranes, histiocytes were additionally found. Surgical debridement of such membranes removes a substratum of inflammatory debris that is likely to promote secondary infection, fibrosis and symblepharon formation, and may decrease rather than increase subsequent scarring of the necrotized conjunctiva.

Adult↗
PubMed1992

Surface-associated activation of plasminogen on gram-positive bacteria. Effect of plasmin on the adherence of Staphylococcus aureus.

In this article we review a novel type of plasminogen activation on staphylococcal and streptococcal cells. The activation mechanism implies a specific binding of glu-plasminogen to bacterial surface via the lysine-binding sites of plasminogen. Association of plasminogen with bacterial surfaces greatly enhances the t-PA mediated activation which takes place only poorly in solution. The end product, surface-associated plasmin, is enzymatically active, protected against high molecular weight plasmin inhibitors and capable of converting itself from glu-plasmin to the lys-form. The modification is associated with an increased affinity of the bound lys-plasmin towards the binding molecules on bacterial surface. This novel way of retaining plasmin on the surface may be important for the bacteria to invade and penetrate surrounding tissues. Our data on the effect of plasmin on staphylococcal adherence indicate that plasmin is not very effective in cleaning bacteria from surfaces coated with extracellular matrix components, fibronectin and fibrinogen.

Bacterial Adhesion↗
PubMed1992

Experience with plasmin inhibitors.

The involvement and role of the plasminogen activator-plasmin system in normal and pathological wound healing is reviewed. The methods currently available for demonstrating plasmin activity are briefly described. The article also reviews some other serine proteases potentially involved in pathological wound healing processes. The current ophthalmological therapeutic measures used to regulate tissue proteolysis are also described.

Cornea↗
PubMed1992

Radiotherapy of malignant melanoma of the uvea with I-125 seeds.

Nineteen patients with malignant uveal melanomas were treated with I-125 applicators. There were 10 males and 9 females with a median age of 61 years (range 42-76). The tumour was located in the choroid in 12 eyes and in the choroid and ciliary body in 7 eyes. The size of the tumours was 7-18 mm in maximal basal diameter (median 12), 5-16 mm in minimal basal diameter (median 10), and 5.5-15 mm in thickness (median 8.5). The volume of the tumours was 123-1890 mm3 (median 540). All tumours were classified as large (T3). For the irradiation, a computer program, which calculates three-dimensional dose distribution of I-125 seeds in gold plaques, was developed. By modifying the seed positions, activity and the orientation, patients can be treated individually. Iodine-125 emits low energy photons, ideal for intraocular tumour therapy and tissue. Extra-ocular tissue located behind the applicator can be completely shielded by a 0.5 mm gold layer. The dose at the apex of the tumour ranged from 30 to 120 Gy (median 93). The treatment time ranged from 44 to 600 h (median 235). Preliminary results are good. After a median follow-up of 6 months, the tumour growth has been arrested in all eyes and in 10 eyes the tumour has decreased in size.

Adult↗
PubMed1992

Cytoskeleton in neuroectodermally derived epithelial and muscle cells of the human iris and ciliary body.

The cytoskeleton of epithelial and muscle cells of the human iris and ciliary body was analyzed by immunohistochemistry in three morphologically normal formalin-fixed, paraffin-embedded eyes and in 34 eyes containing a uveal melanoma. Both layers of the iris epithelium reacted with monoclonal antibodies (MAb) V9 and Vim 3B4 to vimentin, whereas the ciliary epithelia additionally reacted with MAb CAM 5.2, CK5, KS-B17.2, and CY-90, recognizing cytokeratins 8 and 18. The same cytokeratin MAb labeled the retinal pigment epithelium, which lacked vimentin. The muscle portion of the anterior iris epithelium, which forms the dilator muscle, as well as the sphincter and ciliary muscles, reacted with MAb DE-U-10 to desmin and 1A4 to alpha-smooth muscle actin. The dilator and ciliary muscles also reacted with V9 and Vim 3B4 to vimentin, and some dilator fibers were weakly immunopositive for cytokeratin 8 and 18 with CY-90 and CAM 5.2. The antigenic profile of iris and ciliary epithelia infiltrated by melanoma cells remained unchanged. The intraocular epithelia, which are developmentally related but differ in function, and the intraocular muscles, which differ in origin but are functionally related, have distinct cytoskeletal profiles and may provide insights into the functional significance of intermediate filament expression.

Adult↗
PubMed1992

Wound healing of the ocular surface.

Wound healing is a complex, long-lasting regulatory sequence that involves expression of a number of genes, which are active during the individual's development. Some of the phenomena differ from normal tissue turnover and growth only quantitatively. This article reviews the current data on corneal wound healing, with particular reference to mesenchymal matrix proteins and their integrin receptors, to growth factors and to proteolytic enzymes. Some inflammatory mediators are also discussed. The theoretical basis for therapeutic interventions is also discussed briefly, in the light of present knowledge.

Cell Adhesion↗
PubMed1992

An immunohistochemical and prognostic analysis of cytokeratin expression in malignant uveal melanoma.

A group of 52 patients with malignant uveal melanoma treated by primary enucleation in 1977-1979 was studied to determine the frequency of immunoreactivity for cytokeratins (CK) in primary and metastatic melanoma, the CK types present, and the prognostic significance of CK expression. By immunohistochemistry, monoclonal antibody (MAb) V9 to vimentin reacted with all 52 formalin-fixed, paraffin-embedded primary tumors and all 31 metastases from 11 patients. MAb CAM 5.2 to CK 8 and 18 reacted with 20 and MAb CY-90 to CK 18 with 25 primary melanomas, whereas MAb KS-B17.2 and MAb CK5 to CK 18 labeled 8 and 6 tumors, respectively. Antibodies to CK 13 and CK 19 each labeled single cells in one specimen, and other CK types were not detected. In 6 primary melanomas, only a few tumor cells were immunopositive for CK 8 and 18, but in 17 cases up to one quarter, and in 2 tumors more than one quarter, of them were labeled. The positive cells were spindle, epithelioid, or intermediate in shape, and tended to be more frequent in mixed than in spindle cell melanomas. MAbs CAM 5.2 and CY-90 did not react with any of the 16 liver metastases, but labeled 7 of 15 other metastases. Metastases were somewhat more common when the primary tumor was immunoreactive for CK 8 and 18, apparently because CKs were more frequent in mixed cell melanomas. Although CK expression is of diagnostic significance and can denote low levels of epithelioid differentiation, it is not an independent prognostic factor in malignant uveal melanoma.

Adolescent↗
PubMed1991

Epidermal growth factor in human tear fluid: a minireview.

This minireview deals with the presence of epidermal growth factor (EGF) in human tear fluid. It explains the occurrence of EGF in tear fluid, the origin of EGF and its dependency on tear fluid dynamics. The alterations in tear fluid EGF concentrations that occur during diseases of the ocular surface are described and discussed in the context of the current knowledge about the interaction between EGF and EGF receptors. The possible clinical implications of topical treatment with EGF are considered.

Epidermal Growth Factor↗
PubMed1991

Ocular irritation leads to the appearance of proteolytic activity in the aqueous humor.

Aqueous humor (AH) collected from healthy eyes of man and rabbit was analysed for proteolytic activity using a casein-agar assay. Normal AH collected during surgery or rabbit AH aspirated before ocular irritation contained no caseinolytic activity. In rabbits, mechanical irritation of the iris and subconjunctival as well as intracameral injection of capsaicin led to ocular irritative response. AH samples collected after such manipulation contained a considerable caseinolytic activity. On the other hand, anterior chamber puncture alone did not seem to induce elevation of caseinolytic activity in AH. The clinical significance of this phenomenon and the mechanisms behind it are discussed.

Animals↗
PubMed1991

Immunocytochemical localization of carbonic anhydrase, NaK-ATPase and the bicarbonate chloride exchanger in the anterior segment of the human eye.

We examined immunohistochemically the localization of three transport enzymes (carbonic anhydrase, Ca-II; sodium-potassium-activated adenosine triphosphatase, NaK-ATPase; bicarbonate-chloride exchanger, band III) in the anterior segment of the human eye. In accord with earlier studies, NaK-ATPase was primarily found in the corneal endothelium, but also in the corneal basal epithelial cell membranes. In addition, immunoreactivity for NaK-ATPase was observed in the non-pigmented epithelium of the ciliary processes and between the two epithelial cell layers. Ca-II immunoreactivity was found in the corneal endothelium as well as in the non-pigmented epithelial layer of the ciliary processes. Interestingly, band III immunoreactivity was found in the corneal endothelium, as similar to Ca-II, but not in the ciliary processes. These results show that, similar to many other tissues, Ca-II and band III immunoreactivities colocalize in the same cytologic site in the human corneal endothelium. Immunocytochemical detection of these key transport enzymes not only gives their accurate and reliable anatomical distribution, but also provides information on the electrolyte transport at these sites.

Anion Exchange Protein 1, Erythrocyte↗