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Biomedical subjects

T Tervo

Publications and source records attributed to T Tervo.

At least 37 records · Page 2Linked to original sources
PubMed1997

Platelet-derived growth factor-BB (PDGF-BB) in tear fluid: a potential modulator of corneal wound healing following photorefractive keratectomy.

PURPOSE: To measure the pre- and postoperative tear fluid platelet-derived growth factor-BB (PDGF-BB) concentrations of patients undergoing excimer laser photorefractive keratectomy (PRK). METHODS: Tear fluid samples from PRK patients were collected with scaled microcapillary tubes preoperatively (Day 0, N = 23), on the second (Day 2, N = 24) and on the seventh (Day 7, N = 14) postoperative days. The PDGF-BB concentration was measured using a sandwich enzyme immunoassay, and the PDGF-BB release was calculated by multiplying the concentration by the tear fluid flow in the collection capillary. RESULTS: The mean tear fluid flow in the capillary was 17.4 microliters/ min (range 1.4-55.0) on Day 0, 62.6 microliters/min (4.3-125.0, p = 0.0000) on Day 2, and 15.5 microliters/min (1.2-50.0, NS) on Day 7. Seventeen percent (4/23) of the Day 0 samples contained detectable concentrations of PDGF-BB (range 95-1330 ng/l). On Day 2 all (24/24) tear samples showed significantly increased concentrations (mean 507 ng/l, range 45-2280 ng, p = 0.0001) and releases (mean 27.6 pg/min, range 1.0-98.0; p = 0.0000). On Day 7 PDGF-B was still measurable in 9/14 samples (mean concentration 194 ng/l, range < 5-925 ng/l, and mean release 1.9 pg/min, range 0.04-6.8 pg/min). CONCLUSIONS: PDGF-BB is an inducible component of tear fluid. In spite of hypersecretion caused by the corneal wound, PDGF-BB concentrations raised significantly during the initial wound healing. Increased PDGF-BB release during the two postoperative days following PRK suggests a role in corneal wound healing.

Adult↗
PubMed1997

Tear fluid plasmin activity of dry eye patients with Sjögren's syndrome.

Thirty-two eyes of 16 patients with verified Sjögren's syndrome were examined for clinical signs of dry eye. Tear fluid samples were collected for plasmin assay. Ophthalmologic examinations included estimation of conjunctival or corneal discharge, filament formation and presence of conjunctival or corneal epithelial defects, assessment of tear meniscus height and measurement of tear fluid break-up time, Schirmer test, and fluorescein and Rose-Bengal staining graded by the van Bijsterveld score. Tear fluid plasmin activity (IU/l) was determined by a fluorometric assay and tear fluid flow (microl/min) was measured for calculation of tear fluid plasmin activity release (microIU/min). All patients had relatively dry eyes; the mean Schirmer test value was 5.7 +/- 0.5 mm/5 min. The mean tear fluid break-up time was also low, 7.7 +/- 0.5 s. The mean Bijsterveld score value was 2.5 +/- 0.5. Because collection of tear fluid by microcapillaries for the plasmin assay was difficult due to the low tear fluid flow rate, it was necessary to drop 20 microl of balanced salt solution topically on the cornea to aspirate a tear fluid sample. Despite this, the mean tear fluid plasmin activity was higher than in control individuals (7.75 +/- 1.51 IU/l vs. 0.73, range 0.64-0.80 IU/l). On the basis of these findings we conclude that elevated tear fluid proteolytic activity may play a role in the pathology of dry eye/ocular surface disease.

Adult↗
PubMed1997

Increased release of tumour necrosis factor-alpha in human tear fluid after excimer laser induced corneal wound.

AIMS: To measure the pre- and postoperative tear fluid tumour necrosis factor-alpha (TNF-alpha) concentration and release in patients undergoing excimer laser photorefractive keratectomy (PRK). METHODS: Tear fluid samples from 18 PRK patients were collected with scaled microcapillary tubes preoperatively (day 0), on the second (day 2), and on the seventh (day 7) postoperative days. The TNF-alpha concentration was measured using a double antibody radioimmunoassay, and the TNF-alpha release was calculated by multiplying the concentration by the tear fluid flow in the collection capillary. RESULTS: The mean tear fluid flow in the capillary was 22.5 microliters/min (range 1.5-93.2) on day 0, 80.7 microliters/min (3.0-219, p = 0.0002) on day 2, and 14.6 microliters/min (1.8-41.7, NS) on day 7. The mean TNF-alpha concentration and release values were: day 0, 358 ng/I (110-680) and 9.5 pg/min (0.2-37.5, NS); day 2, 417 ng/l (< 5-750, NS) and 28.6 pg/min (0.6-81.5; p = 0.003); and day 7, 320 ng/I (< 5-735, NS) and 4.8 pg/min (0-25.4, NS), respectively. CONCLUSION: TNF-alpha appears to be a component of normal tear fluid. In spite of hypersecretion caused by the corneal wound, TNF-alpha concentrations remain constant during wound healing. TNF-alpha release increases significantly during the 2 postoperative days following PRK, suggesting a role in corneal wound healing.

Adult↗
PubMed1997

Epidermal growth factor, transforming growth factor-alpha, and epidermal growth factor receptor in labial salivary glands in Sjögren's syndrome.

OBJECTIVE: Epidermal growth factor (EGF) and transforming growth factor-alpha (TGF-alpha) affect cells through binding to a shared EGF receptor (EGF-R), which is a transmembrane protein with tyrosine kinase activity. They exert trophic effects on vascular endothelial, salivary acinar, and ductal and mucosal epithelial cells. In Sjögren's syndrome (SS) focal sialadenitis leads to salivary gland tissue damage, diminished salivary flow, and changes in the oral epithelium, a complex referred to as xerostomia. We compared the localization of EGF, TGF-alpha, and EGF-R in labial salivary glands in SS and in healthy controls. METHODS: Labial salivary gland tissues of 12 patients with SS and 7 healthy controls were stained with the immunohistochemical peroxidase-antiperoxidase method for EGF, TGF-alpha, and EGF-R. RESULTS: Immunoreactivity for both EGF and TGF-alpha was found in endothelial cells of blood vessels and in some ductal epithelial cells. TGF-alpha, but not EGF, was also found in some acinar cells. EGF-R was found in endothelial, acinar, and salivary duct epithelial cells. There was no difference in the expression of EGF-R between diseased and healthy specimens, but both EGF and TGF-alpha were diminished in SS. CONCLUSION: The interrelated localization of EGF-R and its ligands, EGF and TGF-alpha, suggests an autocrine, juxtacrine, and paracrine mitogenic/trophic role for them and thus a role in the maintenance of the secretory and excretory cells of the normal salivary glands. The trophic effects on acinar cells seem not to be mediated by EGF, but more likely by TGF-alpha. The diminished expression of EGF and TGF-alpha indicates a failure of this trophic system in SS, which may contribute to the acinar atrophy and secondary changes thereof, including atrophy of the oral mucosa.

Adolescent↗
PubMed1996

Distribution of SPARC protein (osteonectin) in normal and wounded feline cornea.

The purpose of this study was to determine the distribution of SPARC protein, also known as osteonectin or BM-40, in normal and wounded cat cornea. Indirect immunohistochemistry was used to study the distribution of SPARC protein. The following types of corneal wounds were performed: -5.0-dioptric excimer laser photorefractive keratectomy, mechanical keratectomy, and epithelial scrape wounds. The cats (n = 9) were killed 1-30 days after the operation and corneas prepared for immunohistochemistry using polyclonal rabbit anti-murine SPARC antibody and avidin-biotin complex. Weak immunoreaction for SPARC protein was observed in the cytoplasm of epithelial and endothelial cells but not in the keratocytes of both normal and wounded corneas. Unwounded extracellular matrix was negative in the control cornea. Following experimental wounding, an intense immunoreaction for SPARC appeared transiently at the basal aspect of the basal epithelial cells of multilayered, recently healed epithelium. The SPARC immunoreaction began from the wound edge but was not observed subjacent to the flattened single-layered epithelial cells of the leading edge. The immunoreaction for SPARC was found on Days 1-6 following wounding and subsequently withdrew. The transient appearance of SPARC under the healing corneal epithelium suggests its involvement in the regulation of epithelial cell migration or shape during the healing process.

Animals↗
PubMed1996

The networking between hospital and health centre.

Health care providers, purchasers, and insurers try to manage the costs while maintaining the quality of the care. In the Hospital District of Central Finland we based our plans on the following values: life worth living, justice, truth, responsibility, equality, relationship, and commitment. Most of these values mean responsibility for the patient. At the same time they tell of the ethical basis of our regional networking between hospitals and health centres.

Computer Communication Networks↗
PubMed1996

Lacrimal plugs as a therapy for contact lens intolerance.

We investigated whether canalicular occlusion with a lacrimal plug could increase objective and/or subjective comfort in contact lens (CL) wearers (n = 9) with both a history of lens intolerance and relative tear fluid deficiency. A modified Schirmer test (MST) was performed with the lids closed and under topical anaesthesia. Patients with values of < or = 10 mm/5 min were included. The plugs were inserted into the inferior canaliculus of the eye with the lower MST result; the contralateral eye served as a control. Conjunctival hyperaemia, Rose-Bengal and fluorescein scores, as well as subjective irritation, decreased significantly in plugged eyes at the 1 month follow-up visit but had returned to the pre-operative level at the 3 month visit. Tear fluid plasmin activity was elevated prior to plug insertion. Plasmin activity of the plugged eye was significantly lower at the 1 month visit but neither tear fluid flow (in the collection capillary) nor plasmin release showed any changes. The mean MST value improved significantly, whereas conjunctival chemosis and limbal hyperaemia showed no improvement at the 1 or 3 month follow-up visits after inferior punctual occlusion. Occlusion of the lower canaliculus with a lacrimal plug seems to induce a relatively short-lasting subjective and objective benefit for CL wearers. Plug escape or adaptive changes in lacrimal fluid secretion/elimination rate probably took place during the follow-up. The association of increased plasmin activity with tear deficiency might lead to enhanced tissue proteolysis, and thus contribute to CL-related ocular surface changes.

Adult↗
PubMed1996

Distribution of alpha 6 and beta 4 integrins following epithelial abrasion in the rabbit cornea.

Integrin complex alpha 6 beta 4 is a component of the hemidesmosome. In the unwounded cornea both the integrin subunits face the laminin-containing basement membrane, but the alpha 6 subunit is also located between the basal cells. While the migrating epithelium is known to be without hemidesmosomes, we investigated the distribution of alpha 6 beta 4 during epithelial healing. Epithelial abrasion 7.5 mm in diameter was mechanically created. The rabbits were killed 1-24 h or 2, 3, or 7 days later. Monoclonal antibodies against alpha 6, beta 4, and laminin A were used to detect their distributions by immunohistochemistry. Positive immunostaining for laminin A on the surface of the unepithelialized stroma indicated that basement membrane was intact after the epithelial abrasion. Three hours after corneal wounding, alpha 6, was detectable around the entire cell up to the leading edge of the migrating epithelium. In the peripheral wound, alpha 6, was also prominently present around the basal and suprabasal cells with only the superficial cell layers being negative. The beta 4 subunit showed a dissimilar distribution; it was not detectable subjacent to the leading edge. After 1 h the immunoreaction for the beta 4 subunit had faded 15 - 20 microns peripheral to the wound margin. Thereafter the subepithelial band was segmentally reassembled, starting from the periphery and progressing toward the central area of the wound. One week after epithelial wounding, immunolabeling for both integrin subunits was indistinguishable from that of the control cornea. Our results indicate that in addition to the beta 4 in the rabbit cornea, the alpha 6 subunit is also complex with another beta subunit during the epithelial healing phase. The results also suggest that basal cells 15 - 20 microns peripheral to the wound margin disassemble their HDs prior to the migration process.

Animals↗
PubMed1996

Effect of photorefractive keratectomy on the accuracy of pneumatonometer readings in rabbits.

PURPOSE: To determine whether measurement of intraocular pressure (IOP) using a pneumatonometer is reliable after myopic 5 or 15 D excimer laser photoablation in rabbits. METHODS: Ten rabbits underwent 5 D myopic photorefractive keratectomy (PRK) of the left eye. Another seven rabbits underwent 15 D PRK: The right eye served as a control. The diameter of each PRK was 5 mm. Rabbits were examined 2.5 to 3 months later under general anesthesia. Eyes were cannulated, and the IOP was maintained at 5 to 40 mm Hg and measured using an intracameral manometer and a pneumatonometer at each pressure level; approximately 50 pressure points were formed. Readings of the two techniques were compared. RESULTS: Linear regression analysis comparing manometric and pneumatonometric readings revealed the following data in eyes with 5 D corrections (n = 10): correlation coefficient (r) = 0.926, slope = 1.058, and intercept = -3.133. The values of the unoperated control eyes were: r = 0.900, slope = 0.962, and intercept = -1.010. The following results were obtained in eyes with 15 D photoablation (n = 7): r = 0.876, slope 1.133, and intercept -3.147. Values for the control eye were: r = 0.885, slope = 1.175, and intercept = -3.497. When the manometer and pneumatonometer readings of all animals were compared, the adjusted squared correlation coefficient was 79%. When the variabilities associated with the animals and the PRK procedure (pooled 5 and 15 D corrections) were taken into account, adjusted squared correlation coefficient increased from 8% to 87%. CONCLUSIONS: Photorefractive keratectomy as high as 15 D/5 mm had only a minor effect on pneumatonometer readings in rabbits, indicating that the elastic properties of the cornea related to the accuracy of pneumatonometry were not significantly altered. Postoperative IOP monitoring with tonometers, based on flattening of the cornea under pressure, is accurate after PRK.

Animals↗
PubMed1995

Cellular fibronectin and tenascin in experimental perforating scleral wounds with incarceration of the vitreous.

BACKGROUND: Posterior perforating eye injury carries a high risk of visual loss due to the formation of intravireal and epiretinal scar tissue. Intraocular scar formation in patients with retinal detachment has been shown to be associated with elevated intravitreal FN levels. The extracellular matrix glycoproteins fibronectin (FN) and tenascin (TN) have been located in epiretinal scar membranes. As both FN and TN are also involved in healing of cutaneous and corneal wounds, we undertook to study their expression in rabbit perforating scleral wounds with vitreous incarceration. METHODS: A perforating scleral wound was produced and sutured without removal of vitreous from the wound in 18 pigmented rabbits. The rabbits were killed at various times (1 h to 21 days) after the operation, and the indirect immunohistochemical method was used for demonstration of FN and TN. Monoclonal mouse hybridoma antibodies 52 DH1 and 100 EB2, recognizing the cellular form of FN (cFN) and TN, respectively, were used. RESULTS: During the first post-operative week immunoreaction for glycoproteins, both the locally produced cFN and TN, were observed at the scar tissue containing the prolabed vitreous and the adjacent sclera. Subsequently, the reaction gradually shifted to the vitreal side of the wound, and 3 weeks after the operation it was almost completely restricted to a separated mass of vitreous beneath the scar. CONCLUSION: The expression of cFN and TN in the scleral scar and vitreous is indicative of their local synthesis. The shift of the expression of those proteins to the vitreal side of the wound with time suggests that the scarring process in the vitreous is delayed compared to the sclera.

Animals↗
PubMed1995

Integrins in human anterior chamber angle.

BACKGROUND: Integrins, which are composed of an alpha and beta subunit, are capable of binding to a number of extracellular matrix proteins and, hence, affect cell adhesion and proliferation. METHODS: The distribution of the integrin beta (beta 1, beta 3-beta 5) and alpha (alpha 1-6 and alpha v) subunits in human anterior chamber angle was studied in eyes from subjects aged 9 months to 81 years using the indirect immunofluorescence technique. RESULTS: Immunoreaction for the beta 1 subunit was found throughout the trabecular meshwork (TM), in the cribriform layer, and in the endothelial lining of Schlemm's canal (SC). Labelling for the alpha 3 subunit was found in the TM and the cribriform layer only. In infant eyes the alpha 5 subunit was present in all three areas with the highest concentration in the cribriform layer, whereas no reaction was observed in adult eyes. The alpha 6 subunit was localized to the endothelium of SC only. Immunoreaction for the alpha v subunit was present in the TM and the cribriform layer of infants and young adults. CONCLUSION: The present results suggest the presence of several integrin heterodimers, acting as potential receptors for laminin, collagen, fibronectin, and vitronectin, in the anterior chamber angle.

Adolescent↗
PubMed1995

Increased release of tenascin in tear fluid after photorefractive keratectomy.

BACKGROUND: Extracellular matrix protein tenascin (TN) is expressed in the anterior stroma during corneal wound healing. In this study we analysed TN release in tear fluid after photorefractive keratectomy (PRK). METHODS: Tear fluid TN concentrations of ten PRK patients were measured with an immunoassay. Tear fluids were collected preoperatively and 1, 2 and 7 days after PRK. The tear fluid collection time and the volume of tears collected were registered. Because tear fluid flow was greatly increased postoperatively, tear fluid flow-corrected release (TN flux) was calculated. RESULTS: The tear fluid flow was 4.50 +/- 0.94 microliters/min (mean +/- SEM) preoperatively, 55.48 +/- 16.70 microliters/min (P < 0.01) on the 1st, 33.91 +/- 7.91 microliters/min (P < 0.01) on the 2nd, and 13.79 +/- 5.49 microliters/min (P > 0.05) on the 7th postoperative day. The preoperative TN concentration was 0.85 +/- 0.20 microgram/ml. On the 1st postoperative day it decreased to 0.37 +/- 0.17 microgram/ml (P > 0.05), most likely due to the dilution effect caused by hypersecretion after PRK. The TN concentration was 0.67 +/- 0.12 microgram/ml (P > 0.05) on the 2nd and 0.78 +/- 0.15 micrograms/ml (P > 0.05) on the 7th postoperative day. The preoperative TN flux was 5.23 +/- 1.88 ng/min. On the 1st and 2nd postoperative days the TN flux was 14.40 +/- 4.99 ng/min (P < 0.05) and 22.66 +/- 6.12 ng/min (P < 0.05), respectively. On the 7th postoperative day a tendency towards decreased flux (14.00 +/- 6.02 ng/min, P > 0.05) was observed. CONCLUSION: Although there is a minor decrease in TN concentration after PRK due to increased tear fluid flow, a significant increase in TN flux was observed. Complete reepithelialization of the ablated area was observed in all eyes at the follow-up visit on postoperative day 7.

Adult↗
PubMed1995

Increased release of immunoreactive calcitonin gene-related peptide (CGRP) in tears after excimer laser keratectomy.

The purpose of the study was to quantify the neuropeptide calcitonin gene-related peptide (CGRP) in normal human tear fluid and to determine the effect of photorefractive excimer laser keratectomy (PRK) on its release in tears. CGRP was assayed in tear fluid samples using an enzyme immunoassay (detection limit 0.2 micrograms ml-1). Tear-fluid samples were collected preoperatively, 1, 2 and 7 days after PRK and analysed for CGRP. The changes in tear-fluid secretion were also monitored. The intra-assay variation was 3.0-7.0%. Despite the marked hypersecretion of tears, the concentration of CGRP did not decrease following PRK indicating a concomitant increase in CGRP release by sensory nerves and/or lacrimal gland(s). Consequently, the release of CGRP in tears increased from 197.9 +/- 36.6 ng min-1 (mean +/- S.E.M.) to 1723.0 +/- 402.4 ng min-1 (P < 0.01) on day 1, and to 2304.2 +/- 561.1 ng min-1 (P < 0.01) on day 2. On day 7, only minor elevation (377.02 +/- 83.24 ng min-1) was observed. It is concluded that CGRP is a component of normal human tear fluid. The ocular irritation response related to the photoablation induces an enhanced release of CGRP in tears. As a compound present in corneal sensory nerves CGRP may have a role in wound-healing.

Adult↗
PubMed1995

Expression of cellular fibronectin and tenascin in the rabbit cornea after excimer laser photorefractive keratectomy: a 12 month study.

An indirect immunohistochemical technique was used to monitor the expression of cellular fibronectin (cFN) and tenascin (TN) in the rabbit cornea after photorefractive keratectomy (PRK) in a 1 year follow up study. Rabbits received a 5.0 D myopic PRK, and were killed 3 days, 1, 3, 6, or 12 months after the operation. In most corneas, secondary epithelial defects appeared after the primary healing (mean 6.3 (SD 1.2) days). Corneal haze appeared a few weeks after PRK and was observed throughout the follow up. Three days after wounding an immunoreaction for cFN was observed as a bright narrow subepithelial line, but no immunoreaction for TN could be seen in the anterior third of the corneal stroma. However, at 1-6 months a similar location of immunoreactions for both cFN and TN was observed. Both were found in the anterior stroma at depths of 30-50 microns. At 12 months, only a trace of cFN immunoreaction but no TN immunoreaction could be discerned. Our results suggest that subepithelial scar tissue contains both cFN and TN up to 12 months.

Animals↗
PubMed1995

Microbiological quality in Finnish public swimming pools and whirlpools with special reference to free living amoebae: a risk factor for contact lens wearers?

To assess the possible risk of microbial keratitis associated with swimming or bathing in public pools, the microbiological quality as well as the presence of free living amoebae in 16 halogenated swimming pools and whirlpools, located in Helsinki, Finland, was determined. Five additional whirlpools situated in the ferries cruising from Finland to Sweden were included in the study. Other parameters investigated were the total bacterial count, identification of Pseudomonas aeruginosa and Staphylococcus aureus, measurement of free residual and combined chlorine, potassium permanganate index, urine, pH, and turbidity. Amoebae were detected in 41% of the pool water samples studied. Seven of 11 whirlpools and four of 10 swimming pools were shown to contain amoebae. An Acanthamoeba species was isolated from only one outdoor swimming pool; the other amoebae belonged to the genera Vexillifera, Flabellula, Hartmannella, and Rugipes. Although not a single verified case of Acanthamoeba keratitis has been found in Finland, the findings show that there is a theoretical risk of amoebic and bacterial keratitis associated with swimming or bathing in properly cleaned public pools. Consequently, we do not recommend swimming or bathing with contact lenses.

Amoeba↗