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Biomedical subjects

A Tarkkanen

Publications and source records attributed to A Tarkkanen.

At least 109 records · Page 6Linked to original sources
PubMed1988

Suprasellar meningioma 47 years after bilateral retinoblastoma.

Development of an additional primary tumour, a suprasellar meningioma, is reported 47 years after successful treatment of bilateral retinoblastoma. The left eye of the patient was enucleated at the age of 1.5 years and the left orbit radiated with a total dose of 1200 rads. The right eye was treated by orthovoltage radiation only at the age of 4 years, the total dose being 5100 rads. The right eye became blind and phthisical, and it was enucleated at the age of 42 years. No active retinoblastoma was found. At the age of 48 years a large suprasellar meningioma was diagnosed and partially removed.

Eye Neoplasms↗
PubMed1988

Expression of intermediate filaments and synaptophysin show neuronal properties and lack of glial characteristics in Y79 retinoblastoma cells.

The expression of intermediate filaments and synaptophysin in Y79 retinoblastoma cells was studied. The cells grew normally in suspension as floating aggregates. Sodium butyrate and dibutyryl cyclic AMP induced adherence and rapid spreading of Y79 cells on laminin-coated substratum and many of the cells presented long cellular extensions. As judged by immunostaining with monoclonal and polyclonal antibodies, most untreated Y79 cells expressed synaptophysin, whereas only vimentin intermediate filaments were detected in a few cells. A more bright fibrillar vimentin-positivity, which responded by coiling to disruption of microtubules, could be seen in the spread cells. Furthermore, especially when exposed to butyrate, a distinct fibrillar positivity could be revealed in some of the spread cells with antibodies recognizing a phosphorylated epitope in neurofilaments. Western blotting results showed the presence of the molecular weight 57,000 vimentin polypeptide and the molecular weight 38,000 synaptophysin polypeptide in both undifferentiated and spread Y79 cells, and a phosphorylated molecular weight 200,000 neurofilament polypeptide in spread cells only. In contrast, both immunostaining and Western blotting results with several antibodies indicated lack of glial fibrillary acidic protein in Y79 cells suggesting hence, a lack of glial differentiation. The present results do not support the hypothesis that retinoblastomas would originate from a common precursor cell of neurons and glia, and show the presence of mainly neuronal features in Y79 retinoblastoma cells.

Blotting, Western↗
PubMed1987

A lectin cytochemical study of glycoconjugates in the human retina.

The binding to morphologically normal human retina of eleven biotin- or peroxidase-coupled lectins with different carbohydrate specificities was studied. Eight formalin-fixed and paraffin-embedded eyes were examined. Photoreceptor cells bound Lens culinaris (LCA), wheat germ (WGA), peanut (PNA) and Ricinus communis (RCAI) agglutinins, and concanavalin A (ConA). The outer segment region was labeled more strongly that the inner segment region, and PNA labeled only cones. All these lectins except PNA bound to both plexiform layers, and all but PNA and RCAI to the nuclear layers. Pretreatment with neuraminidase to remove sialic acid resulted in increased binding of RCAI and PNA, which now labeled both rods and cones, and in decreased binding of WGA. Bandeiraea simplicifolia (BSAI), Dolichos biflorus (DBA), soybean (SBA), Ulex europaeus (UEAI), and Lotus tetragonolobus (LTA) agglutinins, as well as pokeweek mitogen (PWM) reacted only with retinal vascular endothelial cells, which were also labeled with the other lectins. The results indicate that alpha-mannose, alpha-glucose, beta-galactose, N-acetyl-D-glucosamine and N-acetylneuraminic acid are present in glycoconjugates of human neuroretina.

Acetylglucosamine↗
PubMed1987

Tarsorraphy in the treatment of persistent corneal lesions.

Altogether 38 tarsorraphies were carried out to 19 patients with corneal epithelial defects resistant to conventional therapy. The main operative indications were lagothalmos, dry eyes and inadequate blinking (6 patients). Corneal ulcer was detected in 17 eyes, six of which perforated. All patients had been treated from one week to 16 months (mean 3.5 months) without healing. Retarsorraphy was needed in 6 eyes. In perforations tarsorraphy was combined to tissue adhesive (3 eyes) or to therapeutic contact lens (4 eyes) or to conjunctival flap (2 eyes). The corneal epithelium healed in all except 2 cases (one perforation, one ulcer that is slowly improving). Five of the 6 perforations could also be cured without grafting. One eye of a severely debilitated patient was treated with a Gundersen's conjunctival flap and total tarsorraphy, but remained hazy. We consider, that tarsorraphy is valuable in treating corneal lesions due to lagophthalmos, dry eyes or disturbed lid function. It can also be used in threatening of manifest corneal perforation, if combined with the use of tissue adhesive or therapeutic contact lens.

Adolescent↗
PubMed1987

Capsule thickness of cataractous lenses with and without exfoliation syndrome.

Lens capsule thickness was measured in 105 cataractous lenses with and without exfoliation syndrome. The lenses were removed by intracapsular cryoextraction. Forty lenses (38%) showed exfoliation, while 65 (62%) were exfoliation negative. Thickness values were measured by light microscopy from the central anterior capsule, central posterior capsule and from the equator. The mean thickness values were for the central anterior capsule 8.2 +/- 3.2 mu, for the central posterior capsule 3.2 +/- 1.4 and for the equator 3.9 +/- 1.3. There was no statistical difference between the exfoliation-positive and exfoliation-negative lenses. The capsule thickness varied greatly throughout the present material. The highest value, 22.4 mu, was measured from an exfoliation-negative central anterior lens capsule of a male patient aged 33 years. The lowest value, 0.6 mu, was measured from an exfoliation-positive central posterior capsule of a male patient aged 64 years. The central posterior capsule is the thinnest area of the lens capsule. The findings call for great caution in polishing the posterior capsule during extracapsular cataract surgery. The higher complication rate in eyes with exfoliation syndrome cannot be explained by thinner lens capsules but rather on the more friable zonules.

Adult↗
PubMed1987

Early vitrectomy in the treatment of post-operative purulent endophthalmitis.

In 1979-85, 12 cases of purulent postoperative endophthalmitis (PPE) were treated with broad-spectrum antibiotics, corticosteroids and vitreous surgery. In 11 eyes endophthalmitis developed after cataract surgery, in 6 of them after an intraocular lens (IOL) implantation, in one eye after trabeculectomy. Signs related to an intraocular infection appeared 2 to 32 days after surgery, earlier in eyes with an IOL or post-operative complications than in those without. All 5 eyes where vitrectomy was performed within 24 h from the beginning of symptoms retained useful vision (0.1-0.6), whereas 2 of the 7 eyes where vitrectomy was performed later were lost. In the latter two the causative agent was streptococcus. No IOL implants were removed.

Aged↗
PubMed1987

Plasmin in tear fluid of patients with corneal ulcers: basis for new therapy.

In a patient with chronic corneal ulcer, resistant to conventional therapy, analysis of tear fluid revealed a high plasmin activity which could be inhibited by aprotinin, an inhibitor of serine proteinases. Therapy with topical aprotinin resulted in rapid epithelialization. After this initial patient, within a period of four months tear fluid specimens of altogether 48 patients with corneal lesions were analyzed, and 32 were found to be positive for proteolytic activity. Of these 18 were treated with topical aprotinin which rapidly promoted corneal epithelial healing. Six of these patients had been treated with conventional therapy for 3-10 weeks but proved to be completely therapy-resistant. Our observations on three successfully treated patients with chemical burns of the cornea indicated appearance of plasmin in tear fluid after a few days correlating with cessation of epithelialization. In all patients, in which tear fluid plasmin activity was followed, the activity disappeared during aprotinin therapy correlating with corneal re-epithelialization. In some patients with low proteolytic activity aprotinin was combined with fibronectin with a beneficial therapeutic effect. No proteolytic activity was found in the tear fluid of control individuals. These preliminary data indicate that in patients with treatment-resistant corneal lesions inhibition of proteolytic activity can assist in epithelial healing. Such an inhibition is likely to be a prerequisite for the proteinase-sensitive cell adhesion proteins such as fibronectin to promote epithelialization.

Administration, Topical↗
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↗
PubMed1987

Exfoliation syndrome in enucleated haemorrhagic and absolute glaucoma.

Occurrence of exfoliation syndrome was studied in 172 eyes enucleated for haemorrhagic and absolute glaucoma in 1962-82, using histopathological techniques. Exfoliation was found in 33% of haemorrhagic glaucoma cases and in 22% of absolute glaucoma. In patients over 70, exfoliation was found in 53% of the haemorrhagic cases and in 46% of the absolute glaucoma cases. Capsular glaucoma may provoke haemorrhagic glaucoma and may lead to blindness and enucleation of eye with or without vascular catastrophe.

Adult↗
PubMed1987

Bilateral absolute phakolytic glaucoma. A clinical and ultrasonographic case study.

We describe an unusual case of absolute bilateral phakolytic glaucoma. On admission for cataract surgery the 75-year-old patient was found to be totally blind, no light perception in either eye. The ocular tensions were about 75 mmHg in both eyes, corneas hazy, the fundi could not be seen. The swollen lens of the right eye had slightly subluxated downwards. In the left eye the ultrasound showed a luxated swollen lens in the vitreous space. The ultrasound also revealed totally excavated optic discs. This patient had been on the waiting list for 8 months. Information of the stage of the cataracts of patients on the waiting lists for operation is of paramount importance in the prevention of lens induced problems which may lead to irreversible visual deterioration.

Aged↗
PubMed1987

Hereditary X-linked retinoschisis and bilateral congenital retinal detachment.

Differential diagnosis and histopathological findings of bilateral congenital retinal detachment in a 10-month-old boy are presented. By ultrasonography, the presence of bilateral retinoblastoma was suspected. Histopathological examination of the more seriously affected eye revealed retrolental mass composed of tightly packed retinal folds fused together by fibrovascular tissue. The retina was partly disorganized, with the ganglion cells scanty or missing. Large retinoschisis cysts were not found, but areas of splitting in the inner retina were present. Examination of the family members disclosed congenital retinoschisis in the maternal grandfather and his two brothers. These findings indicate that the most probable etiology of bilateral congenital retinal detachment of the patient was hereditary X-linked retinoschisis. Surgery for retinal detachment of the fellow eye was not successful.

Genetic Linkage↗
PubMed1986

Neuronal intranuclear inclusion disease. Clinical ophthalmological features and ophthalmic pathology.

Monozygotic twin sisters were afflicted by a chronic progressive neurological disease characterized by slurred speech, nystagmus and oculogyral spasms as well as further extrapyramidal and lower motor neuron abnormalities. At autopsy severe loss of nigral and craniospinal motor neurons was noted. In the nuclei of most nerve cell types of the central and peripheral nervous system, roundish inclusion bodies of 3 to 10 microns in diameter were found. Ocular pathology revealed the presence of identical inclusion bodies in the ganglion cells and ganglion cell loss in the posterior retina. Retinal astrocytosis and loss of myelinated axons of the optic nerve were interpreted as reactive features. No inclusions were found in the retinal pigment epithelium. Careful neuro-ophthalmological studies of the first-degree relatives revealed low b-wave of the ERG with other slight aberrations. These were assumed to represent either a carrier or a subclinical state of this presumably inherited disorder.

Adolescent↗
PubMed1986

S-100 protein in retinoblastoma revisited. An immunohistochemical study.

Fifty formalin-fixed and paraffin-embedded retinoblastoma specimens were studied for the presence of S-100 protein in malignant tumour cells and in reactive glial cells. Its distribution in four normal human eyeglobes enucleated because of an orbital tumour was also studied. The laboratory method was a sensitive immunohistochemical staining procedure, and sections from human brain served as controls. Three anti-S-100 protein antisera were used to determine whether previously reported discrepancies could be related to differences in antibody specificity, but all gave identical results. In morphologically normal human retina, a strong reaction for S-100 protein was seen in astrocytes, and a faint, inconsistent positivity was detected in Müller's cells. All intraocular retinoblastomata studied contained cells positive for S-100 protein, which seemed to be reactive glial cells derived from infiltrated retina. Undifferentiated malignant retinoblastoma cells, as well as differentiated tumour cells in Flexner-Wintersteiner rosettes were negative for S-100 protein. Differentiated tumours appeared to contain more S-100 protein-positive glial cells than undifferentiated tumours, but this may be related to their different growth rates. The results do not support the theory that retinoblastoma cells express glial properties.

Eye Neoplasms↗
PubMed1986

Vasoactive intestinal polypeptide-like immunoreactive nerves to the human eye.

Using immunohistochemical techniques, vasoactive intestinal polypeptide (VIP) is visualized in nerves distributed to the human eye. Immunoreactive nerve fibers occur about limbal blood vessels and within the trabecular meshwork. In the iris, free-running stromal nerves are the most common, but nerves to both dilator and sphincter muscles are present as well. Immunoreactive nerves are seen within the ciliary muscle and occasionally within a ciliary process. Innervation to choroidal blood vessels constitutes a prominent feature; innervation to more anterior uveal blood vessels is seen only irregularly. Immunoreactive to more anterior uveal blood vessels is seen only irregularly. Immunoreactive nerves are apposed to melanocytes throughout the uvea. The present findings extend prior reports in the human eye, indicating a potential role for VIP in ocular physiology. Additional neuroanatomical, biochemical and physiological studies are necessary to define fully the ocular function of VIP and to determine ultimely whether VIP has clinical and pharmacological implications.

Aqueous Humor↗
PubMed1986

Management of purulent postoperative endophthalmitis.

In 1985, postoperative purulent endophthalmitis (PPE) was diagnosed in 8 eyes (severe in 5 and presumed in 3 eyes). All were treated with paraocular injections of cefotaxime, gentamicin and triamcinolone with or without the same antibiotics by intraocular and/or systemic route with or without systemic corticosteroids. The suspect causative organisms were Staphylococcus epidermidis in 2 cases, Staphylococcus aureus in 3 cases, streptococcus in 1 case, in 2 cases the cause remained unknown. Pars plana vitrectomy and anterior chamber lavage were performed on 5 eyes, and anterior chamber and vitreous tap on 1 eye. The intraocular lens implants were not removed at vitrectomy. A useful vision ranging from 0.15 to 0.6 was obtained in all cases. Our present regime for the management of purulent postoperative or posttraumatic endophthalmitis is given.

Aged↗
PubMed1986

Intermediate filaments in the human retina and retinoblastoma. An immunohistochemical study of vimentin, glial fibrillary acidic protein, and neurofilaments.

Fifty-five retinoblastoma specimens were studied by a sensitive immunoperoxidase method to determine the intermediate filament types present in human retina and retinoblastoma. Polyclonal antiserum against vimentin and monoclonal antibodies to glial fibrillary acidic protein (GFAP) and to the 200 kD neurofilament triplet protein were used. In the human retina, Müller's cells coexpressed vimentin and GFAP in most instances, probably as a reactive phenomenon. Surprisingly, the horizontal cells did not stain with any of the antibodies used, and may thus lack intermediate filaments. Also, the meshwork of neural fibers in the inner plexiform layer was unusually sparse. Retinoblastoma cells were found to be devoid of all intermediate filament types studied. The tumors contained, however, vimentin and GFAP in the stromal cells. All neurofilament-positive cells in retinoblastoma apparently derived from infiltrated retina. One retinoblastoma eye was also studied by indirect immunofluorescence microscopy of frozen sections with identical results.

Animals↗
PubMed1985

Vitrectomy. Clinical data and cytologic findings of vitrectomy specimens.

Fifty vitreous specimens obtained by routine pars plana vitrectomies were examined using Millipore filter processing and Papanicolaou staining technique. Cytological findings comprised of macrophages (melanophages, siderophages) and inflammatory cells, mainly lymphocytes. In a few cases, pigmented an nonpigmented epithelial cells of the ciliary body were encountered, retinal sensory cells only in one case. Fibroblasts and fragments of granulation tissue occurred in four of the 14 diabetic cases, in four of the 21 posttraumatic cases, in one case of chronic uveitis as well as in one case of retrolental fibroplasia. Fragments of ciliary body were in three specimens from injured eyes. In one case of chronic uveitis slight suspicion of ciliary body melanoma was aroused on the basis of distinct cellular atypia. There was agreement between clinical and cytological diagnosis in most cases, but particularly in posttraumatic and inflammatory diseases cytologic examination offered new diagnostic data. This is a new method of microscopical verification of the condition in the vitreous body in various diseases. Our experiences are preliminary but we feel that this method has proven its availability.

Diabetic Retinopathy↗