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Biomedical subjects

A Berta

Publications and source records attributed to A Berta.

54 records · Page 3Linked to original sources
PubMed1991

Plasminogen activator inhibitors in human tears.

Plasminogen activator inhibitor activity was demonstrated in tears of patients suffering from various corneal and conjunctival diseases. Active plasminogen activator inhibitor was also detected by reverse fibrin zymography in tears of a patient suffering from Sjögren's syndrome and in those who underwent eye surgery. Immunoblotting revealed that both type 1 and type 2 plasminogen activator inhibitors may be present in human tears when the epithelial cells of the cornea and conjunctiva are affected and/or the permeability of the conjunctival blood vessels is increased. The molecular weight of inhibitors suggested the simultaneous presence of both free and activator-complexed inhibitors. However, no plasminogen activator inhibitor was detectable in normal human tears, suggesting that the presence of plasminogen activator inhibitors in tears may be associated with the pathological events at the ocular surface.

Conjunctival Diseases↗
PubMed1990

Urokinase-type plasminogen activator in rabbit tears. Comparison with human tears.

Plasminogen activator activity was determined in stimulated normal rabbit tears, and was identified as being due to urokinase using specific antibodies. The activator activity is about 100-fold higher in rabbit tears than in human tears. The molecular weight of the activator was determined by fibrin zymography to be 40-50 kDa. However, a multiband pattern of urokinase-type antigen ranging in molecular weight from 60-70 kDa to 200 kDa was detected by immunoblotting. The 60-70 kDa protein was resistant to reduction. The antigen concentration is more than 100-fold higher than the concentration expected from the activity measurement, indicating that most of the urokinase in rabbit tears is in inactive form, such as in inhibitor or receptor complexes.

Animals↗
PubMed1990

Determination of plasminogen activator activities in normal and pathological human tears. The significance of tear plasminogen activators in the inflammatory and traumatic lesions of the cornea and the conjunctiva.

Plasminogen activator activity in normal human tears was found to be 0.03 +/- 0.02 IU/ml with casein plate, and 0.06 +/- 0.04 IU/ml with a spectrophotometric method. Elevated levels of plasminogen activator activity (range 0.11-2.05 IU/ml) were detected in the tear fluid of patients suffering from various corneal and conjunctival diseases including corneal ulcers, superficial keratitis, persistent epithelial defects, recurrent erosions, bullous keratopathy, contact lens associated erosions, alkali burns of the cornea, Mooren's ulcer, conjunctival pemphigoid, acute keratoconus, and corneal melanoma. Plasminogen activator activity, determined in the absence of fibrin in tear samples collected by capillary tubes at low flow rates, is considered to be the result of the presence of urokinase-type plasminogen activator (uPA) deriving from the epithelial cells of the cornea and the conjunctiva. It is suggested that an increase in the level of uPA in tears plays an important role not only in ulceration (the formation and repair of epithelial and stromal defects), but also in the development and healing of a number of other inflammatory processes, infections, immunological processes, chemical burns, contact lens associated lesions; in the invasion of microorganisms and leukocytes, in edema formation, in neovascularization, and in the invasive growth of tumors in the cornea and the conjunctiva.

Conjunctival Diseases↗
PubMed1990

Hemodynamic changes after ruthenium irradiation of Hippel's angiomatosis.

The authors report a case of Hippel's angiomatosis successfully treated with contact beta irradiation. The area of the multiplex retinal angioma and the accompanying retinal detachment was irradiated with a 106Ru/106Rh radioactive applicator. Hemodynamic changes due to irradiation were followed up in the ipsilateral ophthalmic artery with transcranial Doppler sonography. Scarring was also demonstrated by fluorescein angiography and A- and B-scan ultrasonography. Irradiation caused the narrowing and later the occlusion of the precapillaries and capillaries (i.e. the resistance vessels) and that of the shunts inside the angioma; consequently, vascular resistance increased. Transcranial Doppler sonographic recordings showed a decrease in blood flow velocity as compared to pathologically increased blood flow velocity in angiomas, and a gradual increase in vascular resistance which was lower before treatment.

Adult↗
PubMed1989

Plasminogen activator activity and plasminogen independent amidolytic activity in tear fluid from healthy persons and patients with anterior segment inflammation.

Plasminogen activator activity and plasminogen independent amidolytic activity were measured in human tears by a spectrophotometric method using human plasminogen and chromogenic peptide substrate S-2251. This assay is sensitive predominantly to urokinase-like plasminogen activator. Tears were collected with glass capillaries. The activator activity in normal tears was found to be low, 0.06 +/- 0.04 (SD) IU/ml. Elevated levels were measured in the tears of patients with various types of conjunctival and corneal disorders. The affected epithelial cells of the cornea and conjunctiva were suggested to be responsible for the elevated activity. Plasminogen independent amidolytic activity was usually very low except in cases of increased permeability of the conjunctival blood vessels. The procedure is recommended as a useful tool for the study of the pathological changes in the epithelial cells of the cornea and conjunctiva.

Conjunctival Diseases↗
PubMed1989

[A new method for semi-quantitative alpha 1-antitrypsin determination in human tear fluid].

We developed a simple and rapid semiquantitative method for the determination of alpha-1-antitrypsin (alpha-1-AT) in human tears. It is a modification of Endre's method (1974) which was originally developed for the determination of serum alpha-1-AT. A filter paper disc saturated with trypsin was placed on the light-sensitive side of a color slide that had been developed unexposed. The trypsin digested the gelatine layers containing different stains and the film under the filter paper showed various colors depending on the trypsin content of the filter paper and the duration of digestion. If the filter paper discs saturated with trypsin had been treated with 5 microliters of tears before film digestion, the trypsin inhibitors in the tears partially or totally inhibited the digestion of the layers with different stains. Four grades of tear trypsin inhibitor capacity were differentiated on the basis of the inhibition of film digestion. These grades correspond to four alpha-1-AT concentration ranges: I greater than 150 micrograms/ml; II = 50-150 micrograms/ml; III = 15-50 micrograms/ml; IV less than 15 micrograms/ml. The concentration ranges were determined by radial immune diffusion. Alpha-1-AT was determined in the tears of 14 normal and 36 pathological eyes using the film digestion method. This method has been found to be suitable for rapid clinical and screening examinations and for the diagnosis of different types of keratitis.

Conjunctivitis↗
PubMed1988

Combined surgical procedure for the prevention of blindness caused by progressive high myopia.

A combined prophylactic procedure consisting of the strengthening of the sclera by fascia lata implants and the laser photocoagulation of peripheral retinal degenerations has been developed for the prevention of blindness caused by progressive high myopia. More than 7 years of experience gained with over 400 patients showed that none of the treated eyes developed retinal detachment or other severe complications of high myopia. Moreover, the degree of myopia decreased by a mean value of 3.0 D in 90%, and the visual acuity improved by a mean value of 0.15 in 70% of the patients treated. The authors suggest that their combined prophylactic procedure should be tried out and introduced to general ophthalmological practice.

Adult↗
PubMed1986

[Sjögren syndrome in childhood].

The authors report on the case of a 7-year-old girl with keratoconjunctivitis sicca. The diagnostic difficulties are discussed and the literary data on Sjögren's syndrome in childhood are summarized.

Child↗
PubMed1986

Tear glycoprotein determinations in the diagnosis and differential diagnosis of dry eyes.

Lacrimal, conjunctival and serum glycoproteins were detected by tear glycoprotein electrophoresis in normal tears, and in tears of patients suffering from acute and chronic conjunctivitis, caustic injuries, aqueous tear deficient dry eyes (keratoconjunctivitis sicca and Sjögren's syndrome), and mucus deficiencies (ocular pemphigoid, and Stevens Johnson syndrome). The use of tear protein and glycoprotein electrophoresis is discussed in the diagnosis and differential diagnosis of dry eyes in different forms and stages of the diseases. The possible physiological role of different glycoproteins and the significance of glycoprotein determinations in the selection of various therapeutic procedures is discussed.

Diagnosis, Differential↗
PubMed1985

IgM paraprotein in the subretinal fluid of a patient with recurrent retinal detachment and Waldenström's macroglobulinaemia.

IgM paraprotein was detected by immunoelectrophoresis and polyacrylamide-gel electrophoresis in the subretinal fluid (SRF) of a patient suffering from recurrent retinal detachment and Waldenström's macroglobulinaemia. Paraproteins in large quantities may inhibit fibrin formation which in turn may be an important agent in retinal reattachment and the starting point of scar formation in the subretinal space. By this case report the authors wanted to support the assumption that changes in the protein composition of SRF might explain the unsuccessful outcome in certain cases of retinal detachment when reattachment could not be achieved though the diagnosis was correct and the surgery performed correctly.

Electrophoresis↗
PubMed1982

A polyacrylamide-gel electrophoretic study of human tear proteins.

The protein composition of normal and pathological tears was studied by polyacrylamide-gel (disc) electrophoresis. Polyacrylamide-gel electrophoresis was shown to detect at least 14 fractions in 2-10 microliters of native tears. A comparison was made between the protein composition of normal tears and serum. The most characteristic bands in the tear-protein pattern were identified by parallel electrophoresis of tears, serum, human milk and purified egg-white lysozyme. The identified fractions were specific tear prealbumin, serum albumin, transferrin, lactoferrin and lysozyme. An unidentified major tear-protein component was also described. The tear-protein pattern was divided into six zones: (1) prealbumin zone; (2) post-albumin zone; (3) post-transferrin zone; (4) macroglobulin zone; (5) basic globulin zone; (6) prelactoferrin zone. A significant rise in the level of serum albumin and transferrin was demonstrated in tears from cases of acute catarrhal conjunctivitis. The optimal circumstances were discussed under which major and minor tear components and basic and acidic tear proteins can be determined simultaneously. Polyacrylamide-gel electrophoresis is recommended as a useful method to study the various diseases of the anterior segment of the eye.

Electrophoresis, Polyacrylamide Gel↗
PubMedDate not supplied

Progesterone administration fails to protect albino male rats against photostress-induced retinal degeneration.

PURPOSE: Female patients show better recovery after brain injury and lower incidence of vascular diseases before menopause. The aim of this study was to test the protective effect of female sexual hormones against photostress-induced photoreceptor apoptosis. METHODS: Five week old male albino Sprague-Dawley rats were injected intraperitoneally with progesterone (60 mg/kg body weight) for 4 days. The control group was injected with the vehicle only (benzyl alcohol). Both groups were halved and one was stressed with light (2700 lux for 24 hours) and the other remained under the original dim cyclic light condition. For functional evaluation, baseline electroretinograms (ERGs) were recorded 7 days before light stress, with follow-up ERGs 5 days after the cessation of light exposure. Animals were sacrificed and their eyes enucleated for histology. RESULTS: Light exposure caused pronounced decrease in the ERG a- and b-wave amplitudes compared to controls. However, in the light-stressed group, the difference in retinal function between progesterone-treated and nontreated animals was not statistically significant. The thickness of the outer nuclear layer and the length of rod outer and inner segments were significantly reduced in the light-stressed group, indicating loss of rod photoreceptor cells. Progesterone had no neuroprotective effect on rod cell structure. CONCLUSIONS: The administration of progesterone did not prove to be protective against excessive light-caused retinal degeneration on male albino rats. The role of other sexual steroids and their interaction need to be clarified.

Animals↗
PubMedDate not supplied

The efficacy and safety of timolol maleate versus brinzolamide each given twice daily added to travoprost in patients with ocular hypertension or primary open-angle glaucoma.

PURPOSE: To compare the efficacy and safety of timolol maleate 0.5% versus brinzolamide 1% when added to travoprost 0.004% in patients with ocular hypertension or primary open-angle glaucoma. DESIGN: A prospective, double-masked, randomized, active-controlled, parallel comparison. METHODS: Qualified patients at Visit 1 were placed on travoprost dosed every evening for 4 weeks and then were randomized at baseline (Visit 2) to the addition of timolol maleate or brinzolamide each given twice daily. Patients returned to clinic at Week 4 (Visit 3) for a safety visit and Week 12 (Visit 4) for an efficacy visit. At Visits 2 and 4 the intraocular pressure (IOP) was measured at 08:00, 12:00, and 16:00 hours. RESULTS: Ninety-seven patients on brinzolamide had a baseline diurnal IOP of 21.5+/-2.2 mmHg and 95 on timolol maleate had 21.3+/-2.5 mmHg, each added to travoprost. The diurnal mean IOP at Week 12 was 18.1+/-2.7 mmHg for brinzolamide and 18.1+/-3.0 mmHg for timolol maleate (p=0.96). There was no statistical difference found between treatment groups in the absolute level of pressure, or in the reduction in IOP from baseline, at each time point or for the diurnal curve (p>0.05). There was no significant difference for any adverse event between groups (p>0.05), with the most common side effect being conjunctival hyperemia in 15/97 (16%) brinzolamide and 6/95 (6%) timolol treated patients (p=0.06). CONCLUSIONS: This study showed that brinzolamide provides similar safety and efficacy compared to timolol maleate when added to travoprost.

Antihypertensive Agents↗
PubMedDate not supplied

Antiproliferative effect of 4-thiouridylate on OCM-1 uveal melanoma cells.

PURPOSE: Brachytherapy is a well-established, effective treatment for uveal melanoma with a failure rate of 15%. The fatal consequence of unsuccessful treatments offers reason for improvement of the method. The authors propose using an apoptosis inducing agent locally, concomitantly with the well-established therapy, to sensitize the tumor cells. The authors propose a new nontoxic moderately active apoptosis inducing agent, 4-thio-uridylate (s4UMP), for this purpose. METHODS: OCM-1 uveal melanoma cells were treated with various concentrations of s4UMP and its effect was monitored by measuring the cell viability (MTT assay). The following apoptosis detecting methods were performed to reveal the mechanism of decreased cell viability: light microscopy, DNA fragmentation assay, determination of caspase 9 activity, and FACS analysis. RESULTS: The viability of uveal melanoma cells was decreased by 32%, 40%, and 9% after 24, 48, and 72 hours of treatment with 10 microg/mL (30 microM) s4UMP. The effect was not dose dependent; it rather followed a saturation-type inhibition and the cells at lower drug concentration recovered after 72 hours. Characteristic apoptotic cell morphology and DNA fragmentation was detected in treated cells. The caspase-9 was activated upon treatment showing maximal activity at 48 hours suggesting the induction of apoptosis. The annexin binding activity further verified the apoptogenic activity of s4UMP. CONCLUSIONS: Uveal melanoma, more than other solid tumors, is resistant to most of the chemotherapeutic protocols as indicated by the high mortality rate of metastatic disease. The authors showed that s4UMP, a naturally occurring nucleotide, could induce apoptosis in uveal melanoma cells, suggesting a potential supplementary therapeutic application of the compound.

Antimetabolites↗