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Biomedical subjects

A Tarkkanen

Publications and source records attributed to A Tarkkanen.

At least 91 records · Page 5Linked to original sources
PubMed1989

Prognosis of conjunctival melanomas in relation to histopathological features.

Twenty-six patients (age 29-85 years) with primary malignant melanoma of the conjunctiva were analysed for usefulness of various histopathological and immunohistochemical features of the primary, recurrent and metastatic tumours in evaluating their prognosis. The mean follow-up time was 5.5 years, ranging from 8 months to 17 years. Eight patients developed metastases and seven have died. The mean time from diagnosis to death due to metastasis was 3.8 years (range 1-6 years). The site of the primary tumour seemed to be most closely correlated to high metastatic risk. Only two of the sixteen limbal melanomas metastasised, whereas two of the four bulbar, all three tarsal and the only diffuse primary tumour caused metastatic disease. Two of the metastasising primary tumours were less than 1.5 mm thick, but all exceeded 0.8 mm in thickness. The mitotic rate, the amount of inflammatory infiltrate, the cell type or the presence of adjacent intraepithelial involvement did not obviously correlate to treatment outcome. Furthermore, the expression of S-100 protein and neuron-specific enolase (NSE), both suggested to be prognostic indicators in cutaneous melanoma, did not correlate to the tendency of the conjunctival melanomas to recur or metastasise.

Adult↗
PubMed1989

Glycoconjugates in exfoliation syndrome. A lectin histochemical study of the ciliary body and lens.

The binding of ten biotin-coupled lectins with different carbohydrate specificities to exfoliative material and neighbouring tissues was studied in 16 formalin-fixed and paraffin-embedded human eyes. Eight of the eyes were exfoliation positive while the rest were exfoliation negative. Exfoliative material reacted intensely with Lens culinaris (LCA), Canavalia ensiformis (ConA) and Ricinus communis (RCA-I) agglutinins. Positive reaction was also seen with wheat germ (WGA), peanut (PNA) and soybean (SBA) agglutinins. The superficial zonular lamella, zonular fibers and the non-pigmented epithelium of the ciliary body had a rather similar lectin-binding profile to exfoliative material. The lens capsule was essentially unreactive with all the lectins used. The lens epithelium reacted faintly with ConA, LCA, WGA and RCA-I. Pre-treatment with neuraminidase to remove sialic acid resulted in increased binding of PNA and SBA to exfoliative material, zonular fibers and the zonular lamella, and in decreased binding of WGA to the non-pigmented epithelium of the ciliary body, zonular fibers and the zonular lamella. The results indicate that alpha-mannosyl, beta-galactosyl, N-acetyl-D-glucosaminyl and N-acetylneuraminic acid residues are present in glycoconjugates of exfoliative material and neighbouring tissues.

Aged↗
PubMed1989

Acute bilateral corneal hydrops caused by high temperature and high moisture in the Finnish sauna. A clinical and histological case report of a patient with keratoconus.

A 44-year-old healthy male with bilateral keratoconus developed acute hydrops of both his corneas with an interval of 3 years. On both occasions he had bathed in a hot, humid Finnish sauna the preceding evening. Penetrating keratoplasty had to be performed in the acute stage in both instances, as medical therapy brought no improvement. The contributory role of hot, moist air to the development of acute hydrops is discussed. Histopathological examination of the corneal buttons revealed clear-cut breaks in Descemet's membrane with marked posterior stromal oedema.

Acute Disease↗
PubMed1989

Orbital metastasis from cutaneous malignant melanoma.

Orbital metastasis is a rare presenting sign of a cutaneous malignant melanoma. Fewer than 30 cases of orbital metastases have been published so far. A 69-year-old man was remitted to our clinic for removal of an orbital tumour verified with CT. Fine-needle aspiration biopsy revealed the tumour to be a metastasis from a cutaneous malignant melanoma diagnosed 4 years earlier. The patient died 3 months after detection of the orbital metastatic tumour. This case illustrates the value of simple fine-needle aspiration biopsy in the diagnosis of orbital tumours.

Aged↗
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

Rabies: ocular pathology.

Ocular pathology in the first European case of human bat-borne rabies is described. The patient was a 30-year-old bat scientist who seven weeks after bat bite developed neurological symptoms and died 23 days later. Rabies virus antigens were detected in brain smears. After extensive virological studies the virus turned out to be a rabies-related virus, closely resembling the Duvenhage virus isolated from bats in South Africa in 1980. By light microscopy focal chronic inflammatory infiltration of the ciliary body and of the choroid was found. PAS-positive exudate was seen in the subretinal and in the outer plexiform layers of the retina, and retinal veins showed endothelial damage and perivascular inflammation. Many of the retinal ganglion cells were destroyed. The presence of rabies-related viral antigen in the retinal ganglion cells was shown by positive cytoplasmic immunofluorescence, though electron microscopy failed to identify definite viral structures in the retina. By immunohistochemistry glial fibrillary acidic protein was observed in the Müller's cells, which are normally negative for this antigen but express it as a reactive change when the retina is damaged. Synaptophysin, a constituent of presynaptic vesicles of normal retinal neurons, was not detected in the retina.

Adult↗
PubMed1989

Plasmin and plasminogen activator activities in tear fluid during corneal wound healing after anterior keratectomy.

Plasmin can degrade fibronectin and laminin, two important components of the extracellular matrix facilitating cell sliding and healing following a wound. In this study we investigated the relationship between the tear fluid level of plasmin and plasminogen activator and the healing of a corneal wound. Anterior keratectomy (AKE) was performed for seven rabbits (11 eyes). Eight eyes were rewounded after re-epithelialization. Tear fluid samples were collected with capillaries before wounding and during wound healing. Plasmin and plasminogen activator (PA) activities were determined using radial caseinolysis procedures. After AKE the plasmin concentrations increased rapidly, from a mean (+/- SEM) of 3.9 +/- 0.9 micrograms/ml to a mean of 37.9 +/- 7.8 micrograms/ml (p less than 0.01), and decreased during wound healing. Rewounding also resulted in an increase in plasmin concentration in the tear fluid (from a mean of 2.9 +/- 0.6 micrograms/ml to a mean of 5.0 +/- 1.1 micrograms/ml; p greater than 0.05). The PA activity showed an inverse trend as it decreased after AKE from a mean of 2.0 +/- 0.6 IU/ml to a mean of 0.3 +/- 0.1 IU/ml (p less than 0.001). During wound healing and re-epithelialization, the PA activity increased again, to 2.1 +/- 0.3 IU/ml (p less than 0.001). Abrasion of the newly grown epithelium in eight eyes caused a second elevation of PA activity which was not significant. This study demonstrates a close association between the healing of corneal wounds and changes in the plasmin and PA activities in tear fluid. Determination of the activity of these enzymes may therefore be useful for monitoring corneal wound healing.

Animals↗
PubMed1989

Synaptophysin in the human retina and retinoblastoma. An immunohistochemical and Western blotting study.

Fifty-four formalin-fixed and paraffin-embedded intraocular retinoblastoma specimens and three human eyes enucleated because of orbital tumors were studied for the presence of synaptophysin, a neuron-associated integral membrane glycoprotein of presynaptic vesicles, by using the monoclonal antibody SY38. Normal human brain was used as control. In the human retina, synaptophysin-like immunoreactivity was present in both plexiform layers, but could not be detected in neuronal perikarya. However, in reactive retinas present in retinoblastoma eyes, synaptophysin was often observed in perikarya and processes of photoreceptors. Positive neoplastic cells were found in 45 of the 54 retinoblastomas. Differentiated tumors tended to contain greater numbers of positive cells than undifferentiated ones, a third of which were entirely negative. Identical immunoreactivity was seen in frozen specimens from human retina and from three retinoblastomas. Using Western blotting, a major polypeptide comigrating with human brain synaptophysin was detected in human retina, and a similar but slightly slower migrating band in retinoblastoma. The results support a primarily neuronal origin for this tumor and point to the possibility that synaptic elements, previously observed in a few cases, may be more frequent in retinoblastoma than had been thought.

Blotting, Western↗
PubMed1989

[Acute keratitis and contamination of contact lens care systems with Bacillus cereus].

Two patients, both contact lens wearers, were treated for acute keratitis in both eyes. Routine microbiologic tests done for all four eyes confirmed merely the presence of Staphylococcus epidermidis in the conjunctival flora; neither fungi nor any viruses were detected on the patients' corneas. However, the contact lens soaking solutions were contaminated with a large number of microorganisms, including above all--or solely--Bacillus cereus. Two of the contact lenses used were also colonized by fungi of the genus Rhodotorula, Cryptococcus albicans and Wangiella dermatidis. The acute inflammation was treated quickly and effectively in all cases by specific antimicrobial therapy. Bacterial contamination of lens care systems is well known as a potential cause of keratitis in contact lens wearers. Although the clinical importance of Bacillus cereus in ocular surface pathology is still unknown, the cases reported here indicate that this microorganism may be of pathological significance in lens care systems. The authors therefore recommend including the lens care systems in routine bacteriologic tests in all cases of corneal infection where the patient wears contact lenses.

Acute Disease↗
PubMed1988

Management of traumatic hyphema in children. An analysis of 340 cases.

Three hundred forty children with nonperforating traumatic hyphema were examined to verify or refute the possible protective action of the antifibrinolytic agent, tranexamic acid, against rebleeding. In the retrospective study group, 219 children were treated with strict bed rest, binocular patching, and sedation but did not receive antifibrinolytic agents. In the prospective study group, 121 children received systemically administered tranexamic acid; some of these children were confined to bed rest (26 cases) and some were allowed free ambulation within their rooms (95 cases). In the children who were treated with bed rest but who did not receive the antifibrinolytic agent, the frequency of secondary hemorrhage was 9.6%. Tranexamic acid reduced the incidence of secondary hemorrhage significantly: none of 26 eyes of patients who received systemically administered tranexamic acid and were confined to bed rest rebled, and only one (1.1%) of 95 eyes of children who received tranexamic acid and were allowed free ambulation in the hospital rebled.

Bed Rest↗
PubMed1988

Recurrent medulloepithelioma of the ciliary body. Immunohistochemical characteristics.

A predominantly benign medulloepithelioma of the ciliary body was diagnosed in an 8-year-old girl and resected by iridocyclectomy. It recurred twice during 30 months. Highly malignant histopathologic features developed, and the eye finally perforated and had to be enucleated. No recurrence or metastases have subsequently developed. Histologically, the tumor was a nonteratoid medulloepithelioma consisting of elements resembling embryonic retina, nonpigmented ciliary epithelium, and neuroblasts, but had also areas of obvious glial and neuronal differentiation as judged by immunohistochemistry. The neuroepithelial tumor cells were positive for neuron-specific enolase, vimentin, and often for S-100 protein. The neuroblastic cells were generally positive for neuron-specific enolase and synaptophysin, but were intermixed with glia-like tumor cells positive for vimentin, glial fibrillary acidic protein, and S-100 protein. The results suggest that even a nonteratoid medulloepithelioma may be, unlike retinoblastoma, a truly multipotential tumor.

Child↗
PubMed1988

Respiratory arrest after retrobulbar block.

We describe a patient who suffered respiratory arrest some minutes after retrobulbar block before cataract extraction. She was managed by artificial respiration for 20 min, and after the had recovered from this potentially fatal complication cataract extraction was performed without complications and without any neurological sequelae. Retrobulbar blocks, as well as other retrobulbar, injections, should be performed only in safe situations. Individuals trained in airway maintenance and ventilatory support should be immediately available, and the patient must be monitored for at least 10 min after the retrobulbar injection.

Adult↗
PubMed1988

Elevation of tear fluid plasmin in corneal disease.

Plasmin concentration was determined in tear fluid from 76 eyes showing corneal epithelial disorders, such as corneal ulcers and erosions due to trauma or contact lens wear. Nearly 70% of the eyes with corneal disease had plasmin in their tear fluid, whereas plasmin was present in only 20% of the eyes in a control group of 50 eyes. Re-examination of the plasmin positive control eyes revealed conjunctival bacterial growth or mild subclinical viral infection in most cases. We conclude that plasmin is released into the tear fluid in the presence of corneal or conjunctival lesions or infections, suggesting a pathogenic role of plasmin in these disorders. The significance of the occurrence of plasmin in tear fluid during corneal wound healing is discussed.

Adult↗
PubMed1988

Combined procedure for the management of glaucoma and cataract.

Thirty eyes of 29 patients (12 male and 17 female) with an age range 50-86 years (mean 76 years) were operated by combined technique for cataract and glaucoma with a follow-up ranging between 6-18 months (mean 6.8 months). Seventeen eyes had capsular glaucoma and 13 eyes simple glaucoma. The surgical technique of trabeculectomy, extracapsular cataract extraction and posterior chamber lens implantation is described. The pre-operative IOP was 31.5 mmHg +/- 7.8 on maximum tolerated medical therapy and the post-operative IOP 17.8 mmHg +/- 3.9. Fourteen eyes had to be treated with topical timolol X 2 daily after the operation. Twenty-eight eyes had a pre-operative visual acuity of less than or equal to 0.3. Of these, 17 had a visual acuity of less than or equal to 0.1, and were severely visually handicapped. Visual acuity improved markedly in 24 eyes and remained unchanged in 6 eyes. Every patient but one (with vitrectomy and no lens implantation) experienced considerable subjective visual increase. The main complications consisted of vitreous loss in one eye and fibrinous effusion into the anterior chamber in 7 capsular glaucoma eyes. Pre-operative precautions and post-operative care are important. The combined triple procedure is recommended for the management of patients with uncontrolled glaucoma and cataract.

Aged↗
PubMed1988

Effects of intracamerally or subconjunctivally injected cross-linked hyaluronic acid on the intraocular pressure and on the anterior segment of the rabbit eye.

Cross-linked hyaluronic acid (CLH), a viscoelastic substance with a high viscosity, was injected into the left anterior chamber of 5 rabbits without simultaneous withdrawal of aqueous humour. The right eyes of the same rabbits received an equal amount of sodium hyaluronate (Healon). The intraocular pressure (IOP) of the CLH injected eyes increased four-fold immediately after the injection. One week post injection the IOP had decreased to the pre-injection level where it remained until the euthanatization of the animals 32 days post injection. Biomicroscopically CLH was seen as a slightly opaque curly mass in the anterior chamber in the eyes that otherwise were quiet in four of the rabbits. In one rabbit the injected cross-linked substance reacted immediately with aqueous and turned white. The eye was quiet and showed no inflammatory signs. In all intracamerally injected eyes, slight to moderate aqueous flare was present 4 h post injection. Aqueous flare was still present 1 day post injection in 4 eyes, but was absent 4 days post injection. Histologically no apparent inflammatory reaction was present. Occasional giant cells were seen on the anterior surface of the iris in three animals. Slight accumulation of mononuclear cells was found in the iridocorneal angle of the CLH injected eyes. At histology few mononuclear cells were also found surrounding the subconjunctivally injected CLH still present in 4 additional rabbits when euthanatized 28, 42 and 49 days post injection. The contralateral eye of these 4 animals received an equal amount of sodium hyaluronate subconjunctivally. The substance had been resorbed completely. No reactive or inflammatory signs were present.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Histopathology of enucleated intraocular melanomas irradiated with cobalt and ruthenium plaques.

Eight malignant uveal melanomas irradiated with Stallard's 60Co applicator or Lommatzsch's 106Ru/106Rh applicator were studied by light microscopy and immunohistochemistry to analyse tumour cell morphology, antigenic expression and inflammatory cell infiltration in relation to radiation dose. The tumours were enucleated 1 to 24 months after irradiation because they did not regress or continued to grow. One patient has later died of metastatic disease. Eight uveal melanomas that were not irradiated were studied for comparative purposes. Radiation necrosis was found only in two cases. In four irradiated and in one control melanoma conspicuous collagen fibres were present in the basal part of the tumour. No difference was noted between the two groups in the number of mitotic figures or in the morphology of tumour cells. In all cases but one, more than half of the tumour cells were variably positive for S-100 protein. Neuron-specific enolase-positive melanoma cells were few in number and occurred in small clusters, and were somewhat more common in irradiated cases. A few lymphocytes and macrophages, which were preferentially found near the choroid, infiltrated every melanoma, but only single cells were associated with radiation necrosis. A mild scleritis near the tumour was present irrespective of irradiation. Although the melanomas were quite large for irradiation, the lack of necrosis in optimally irradiated basal parts of the tumour additionally indicates substantial radioresistance.

Adult↗
PubMed1988

Use of soft contact lenses for the study of external ocular microbiology.

In the diagnosis of corneal ulcers, bacterial cultures from scrapings, investigations on viral and fungal growth, as well as staining of smears from the lesion often lead to the correct diagnosis. We report four cases of corneal ulcer where all the methods mentioned failed to reveal the causative microorganism. After the patients had received various medical treatments without any clinical improvement, soft therapeutic contact lenses were fitted, worn overnight, and removed the next morning with sterile forceps. The contact lenses were cultured in blood and Mac Leod agars. Growth of various bacteria was then detected. The infection subsided after the antibiotic treatment was changed according to the bacterial resistance. We conclude that, in selected cases, soft contact lenses may be used for microbiological studies.

Adult↗