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K Tervo

Publications and source records attributed to K Tervo.

At least 19 recordsLinked to original sources
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

Distribution of integrins alpha 6 and beta 4 in the rabbit corneal epithelium after anterior keratectomy.

Integrins are heterodimeric cell-surface receptor glycoproteins involved in cell-matrix and also in cell-cell interactions. The alpha 6 beta 4 integrin heterodimer has been shown to be a component of the hemidesmosome. In response to wounding, hemidesmosomes are disassembled, the epithelium migrates to cover the denuded area, and eventually the hemidesmosomes reappear. In the present investigation the distribution of the integrin alpha 6 and beta 4 subunits after anterior keratectomy was studied by indirect immunohistochemistry. Labeling for the alpha 6 subunit was observed around the entire cell surface, right to the leading edge. The immunoreaction for the beta 4 subunit was confined to the basal cell membrane facing the basement membrane as in the normal cornea. Cells at the leading edge of the migrating epithelium did not show any labeling for beta 4. Patchy labeling for beta 4 was first observed in the region midway between the wound margin and the leading edge. Because integrins are only expressed as heterodimers, the alpha 6 subunit may be complexed with the beta 1 subunit, instead of with beta 4, at the leading edge of the migrating epithelium. We also suggest that this alpha 6 beta 1 heterodimer may play a role in the reformation of the adhesion complex.

Animals↗
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

Integrins as receptors for extracellular matrix proteins in human cornea.

Extracellular matrix (ECM) proteins form distinct protein families that play a role during tissue maturation, wound healing and maintenance of tissue architecture. Recent studies show that there are tissue type-specific variations in their expression. ECM proteins function by complexing with each other and also by interacting with their cellular receptors, called integrins. Integrins are heterodimeric membrane glycoproteins that are partly cell type-specifically expressed in human tissues. Like other stratified epithelia, corneal epithelium expresses alpha 2 beta 1, alpha 3 beta 1, alpha 6 beta 1, 4, and alpha v beta 1 integrins that mediate attachment to the basement membrane and cell-cell interactions.

Basement Membrane↗
PubMed1992

Integrins in the normal and healing corneal epithelium.

Integrins are heterodimeric plasma membrane glycoproteins involved in cell-matrix and cell-cell interactions. The present communication reviews the distribution of several of the currently known integrin subunits in the corneal epithelium. The corneal epithelium contains the following integrin heterodimers: alpha 2 beta 1, alpha 3 beta 1, and alpha 6 beta 4. The expression of alpha v with an unknown beta subunit is also recognized, whereas the expression of alpha 4 and alpha 5 subunits remains controversial. Some of the changes occurring in the distribution of integrins in response to wounding will also be discussed.

Basement Membrane↗
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

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↗
PubMed1991

Integrins in human corneal epithelium.

Monoclonal antibodies (Mabs) were used for immunohistochemical location of integrin beta- (beta 1,3, and 4) and alpha subunits (alpha 1-6 and alpha v) in the epithelium of both normal and tissue-cultured human cornea. Immunoreaction for the beta 1 integrin subunit was the most intense at the membranes of the basal epithelial cells and weaker at the superficial cell membranes. Anti-beta 4 immunofluorescence appeared in the basal part of the epithelium only, apposing the basement membrane. Both anti-alpha 2 and anti-beta 3 Mabs showed an immunoreaction with distribution similar to the beta 1 integrin subunit. Immunoreaction for the alpha 6 integrin subunit resembled the distribution of the beta 4 subunit. Anti-alpha v showed a faint immunoreaction at the basal and lateral aspects of the basal cell layer. Antisera against beta 3, alpha 1, alpha 4, and alpha 5 integrin subunits showed no specific reactions. The present results suggest that both the normal and tissue-cultured human corneal epithelium contain alpha 2 beta 1, alpha 3 beta 1, and probably also alpha v beta 1 and alpha 6 beta 4 integrin dimers or complexes. We discuss their role as possible receptors for some known ligands.

Adult↗
PubMed1991

Immunohistochemical demonstration of cellular fibronectin and tenascin in human epiretinal membranes.

The occurrence of fibronectin, cellular fibronectin and tenascin was studied immunohistochemically in epiretinal membranes from 5 patients with retinal detachment and 3 patients with macular pucker, and in preretinal membranes from 3 patients with proliferative diabetic retinopathy. Positive immunofluorescence for these proteins was seen in all specimens studied. The presence of cellular fibronectin suggests that local production of fibronectin occurs in these membranes. The expression of tenascin, an extracellular matrix glycoprotein, originally found to modulate organosenesis in tendinous and glial tissue, suggests that this glycoprotein also participates in the regulation of cellular growth in these membranes.

Adolescent↗
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

Expression of tenascin and cellular fibronectin in the rabbit cornea after anterior keratectomy. Immunohistochemical study of wound healing dynamics.

Anterior keratectomy (AKE) was done on rabbits, and the appearance of immunohistochemically demonstrable tenascin (TN) or cellular fibronectin (cFN) was studied at different times (5 min to 14 months) after the operation. The substance TN was first observed 12 hr after wounding in the posterior stroma; cFN appeared with the same localization 12 hr later. During postoperative week 1, both TN and cFN immunoreactions shifted to more anterior parts of the cornea, and 9 days after wounding, they were localized in the most anterior part of the stroma only. Thereafter the reactions gradually decreased in intensity but still were visible 3 months after AKE. No reaction for TN or cFN was present 14 months postoperatively.

Animals↗
PubMed1990

Immunohistochemical demonstration of epidermal growth factor in the lacrimal and submandibular glands of rats.

The extraorbital and intraorbital lacrimal glands, the Harderian glands, and the submandibular glands of five rats were excised after ethanol perfusion under general anesthesia. Indirect immunohistochemistry with antibodies specific to epidermal growth factor (EGF) was performed. EGF-like immunofluorescence (EGF-LI) was shown to be present both in the lacrimal glands (extra- and intraorbital) and in the submaxillary gland. In the lacrimal glands the specific immunoreaction appeared within the lumen of the acini and the cells of the tubular ducts close to the acini. Only faint EGF-LI was observed within the acinar cells. The submandibular glands showed intense EGF-LI only in the cells of the granular convoluted tubules. The Harderian gland did not show any EGF-LI. The results strongly support the idea that the lacrimal gland is a source of EGF in tear fluid (TF). Diseases of the lacrimal gland therefore may lead to decreased concentrations of EGF in tears. This may account in part for the pathophysiology of tear deficiency syndromes and may serve as the basis of a new rationale for the external application of EGF.

Animals↗
PubMed1990

Immunohistochemical demonstration of tenascin in the normal human limbus with special reference to trabeculectomy.

Sections from the anterior segment of the fetal and adult human eye and from limbal tissue excised during standard trabeculectomies were studied immunohistochemically with monoclonal antibodies against human tenascin or monoclonal antibodies against cellular fibronectin (cFN). In the fetal eye, tenascin-like immunoreactivity (TEN-LI) was observed in the area of the developing limbus. In the adult eye TEN-LI was most intense at the corneoscleral margin in the stromal tissue and decreased towards the posterior sclera. No reaction was observed in the corneal stroma, but the epithelium showed moderate immunofluorescence. All tissues obtained during trabeculectomy showed similarly strong TEN-LI. The sections from trabecular specimens incubated with antibodies against cFN were negative.

Anterior Eye Segment↗
PubMed1989

Plasminogen activator and its inhibitor in the experimental corneal wound.

Anterior keratectomy was performed to 10 eyes of 8 adult rabbits. The animals were killed 3-24 hr after wound closure. The corneas were excised and subjected to histochemical demonstration of urokinase-type plasminogen activator (u-PA), tissue-type PA (t-PA) and plasminogen activator inhibitor [PAI-1) using commercial antibodies. A strong immunoreaction for u-PA, a weaker reaction for PAI-1 and a very weak t-PA-like immunoreaction appeared in the anterior stroma of the wounded area. None of the antisera used showed any immunostaining in the cornea outside the wound. The role of the plasminogen activator-plasmin system in the healing of the corneal wound is discussed.

Animals↗
PubMed1989

Demonstration of tenascin-like immunoreactivity in rabbit corneal wounds.

Tenascin, a novel extracellular matrix protein, was demonstrated immunohistochemically in rabbit corneas that had healed after anterior keratectomy. Tenascin-like immunofluorescence (T-LI) appeared in the corneal stroma at the wound area only. The wound edge showed the most intense specific fluorescence. The corneal epithelium, in general, displayed a moderate T-LI. Wounding did not induce any change in epithelial T-LI or T-LI located in the stroma outside the wound.

Animals↗
PubMed1989

[Cluster headache].

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Cluster Headache↗
PubMed1987

Updating of methods for prevention of HIV transmission during ophthalmological procedures.

The presence of HIV (human immunodeficiency virus) particles in the tear fluid, on the conjunctival surface or in the contact lenses of patients with chronic HIV infection has made it necessary to establish better for guide-lines for decontamination of instruments during ophthalmological procedures. The methods are now at the stage of evolution. The present paper describes the disinfection procedures used in the Helsinki University Eye Hospital and updates the present decontamination protocols.

Acquired Immunodeficiency Syndrome↗