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Biomedical subjects

H Seppä

Publications and source records attributed to H Seppä.

15 recordsLinked to original sources
PubMed1998

Prospective randomized comparison of external dacryocystorhinostomy and endonasal laser dacryocystorhinostomy.

OBJECTIVE AND DESIGN: The introduction of endonasal laser dacryocystorhinostomy (ENL-DCR) in the early 1990s showed great promise of changing dacryocystorhinostomy into an elegant, minimally invasive procedure from the traditional external dacryocystorhinostomy (EXT-DCR). This prospective, randomized study compares these two operations, their success rates, surgical durations, and postoperative symptoms. PARTICIPANTS: A total of 64 cases in 61 patients with primary acquired nasolacrimal sac or duct obstruction were divided into 2 subgroups by symptoms (simple epiphora and chronic dacryocystitis). These patients were randomized within both subgroups into 2 operation groups with 32 cases in each group. INTERVENTION: Altogether, 32 EXT-DCRs and 32 ENL-DCRs were performed. The silicone tube was removed at 6 months after surgery. The final follow-up visit was at 1 year after surgery. The patency of the lacrimal passage was investigated by irrigation, and patients were questioned about their symptoms. MAIN OUTCOME MEASURES: The patency of the lacrimal passage to irrigation and the duration of surgery were measured. RESULTS: The success rate at 1 year after surgery was 91% for EXT-DCR and 63% for ENL-DCR after primary surgery. The difference was statistically significant (P = 0.016). The surgical duration for ENL-DCR was three times shorter than for EXT-DCR, the average duration being 23 minutes and 78 minutes, respectively (P < 0.0001). CONCLUSIONS: The EXT-DCR, when compared with ENL-DCR, seems to provide superior operation results in primary acquired nasolacrimal duct obstruction.

Adult↗
PubMed1998

Prospective randomized comparison of endonasal endoscopic dacryocystorhinostomy and external dacryocystorhinostomy.

OBJECTIVES AND STUDY DESIGN: The advent of the rigid endonasal endoscope and the development of functional endoscopic sinus surgery (FESS) technique have awakened interest in an endonasal endoscopic dacryocystorhinostomy (EESC-DCR) in treating nasolacrimal obstruction. This prospective, randomized study compares EESC-DCR with traditional external dacryocystorhinostomy (EXT-DCR) for their success rates, surgical duration, and postoperative symptoms. PATIENTS AND METHODS: Sixty-four cases in 60 patients with primary acquired nasolacrimal sac or duct obstruction were divided into two subgroups by symptoms (simple epiphora/chronic dacryocystitis). These patients were randomized within both subgroups into two operation groups. Altogether 32 EESC-DCRs and 32 EXT-DCRs were performed. The final follow-up visit was at 1 year. The patency of the lacrimal passage was investigated by irrigation and patients were questioned about their symptoms. RESULTS: The success rate at 1 year after surgery was 75% for EESC-DCR and 91% for EXT-DCR after primary surgery. The difference was not statistically significant (P = .18). The success rate after secondary surgery with a follow-up time of 1 year was 97% in both study groups. The average duration for EESC-DCR was 38 minutes, and 78 minutes for EXT-DCR, (P < .001). CONCLUSIONS: EXT-DCR, when compared with EESC-DCR, appears to give a higher, although not statistically significant, primary success rate, but the secondary success rates are equal, indicating that these two different DCR techniques are acceptable alternatives.

Adult↗
PubMed1996

External DCR.

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Dacryocystorhinostomy↗
PubMed1996

Lacrimal bone thickness at the lacrimal sac fossa.

BACKGROUND AND OBJECTIVE: Because laser dacryocystorhinostomy techniques have become more popular during the past few years, interest has grown concerning the anatomic structures that need to be penetrated in these procedures. The authors therefore studied the thickness and the histologic type of the lacrimal bone at the lacrimal sac fossa. PATIENTS AND METHODS: The thickness of 69 lacrimal bones at the lacrimal sac fossa from 48 patients was measured. RESULTS: The mean thickness was 106 microns. In 67% of the patients the mean thickness of individual lacrimal bone was less than 100 microns and in 4% it was more than 300 microns. The thinnest measured cross section of the lacrimal bone sample was 11 microns and the thickest was 722 microns. The lacrimal bone was composed of a thin plate of lamellar bone. CONCLUSION: In most cases the lacrimal bone at the lacrimal sac fossa is so thin that it can be easily penetrated with most surgical instruments.

Adult↗
PubMed1994

Endonasal CO2-Nd:YAG laser dacryocystorhinostomy.

A preliminary series of endonasal dacryocystorhinostomy was carried out on 12 patients with nasolacrimal obstruction using a recently developed combined CO2-Nd:YAG laser that was guided by a fiberoptic light pipe inserted into the lacrimal sac through lacrimal canaliculi. The lacrimal passages were stented using silicone tubing that was kept in place for 6 months postoperatively. At an average follow-up time of 14.3 months the success rate was 83%. The advantages of the operation include a relatively short operation time, quick rehabilitation, absence of a skin wound, good hemostasis, and preservation of canthal anatomy.

Adult↗
PubMed1986

A study of the mechanism of ocular irritation following YAG laser capsulotomy in rabbits.

The irritative response to Nd:YAG laser capsulotomy was studied in unanaesthetized rabbits. Posterior lens capsulotomy with a total energy of 100 mJ had no effect on the pupil size but increased the intraocular pressure by 5-10 mmHg and caused a breakdown of the blood-aqueous barrier. Anterior lens capsulotomy with a total energy of 20, 60 or 100 mJ caused constriction of the pupil, and an increase in intraocular pressure in a dose-dependent manner, and a breakdown of the blood-aqueous barrier. Indomethacin attenuated all the component parts of the irritative response and (D-arg1, D-pro2, D-trp7,9, leu11)-SP attenuated the miotic response. A combination of indomethacin and the substance P antagonist almost completely abolished the irritative response. This indicates that the acute YAG-laser-induced irritation in the rabbit eye is dependent both on a release of prostaglandins and on substance P, the former probably releasing the latter from sensory nerves.

Animals↗
PubMed1985

A low-Mr chemoattractant for vascular endothelial cells.

The formation of new blood vessels occurs by sprouting from previously existing microvasculature. The process involved directed migration of the vascular endothelial cells towards chemical signals released from the target tissue. We have used the Boyden chemotaxis chamber method to identify chemotactic signals for fetal bovine vascular endothelial cells. Human placenta organ cultures produce a high-Mr chemoattractant for the endothelial cells from which a low-Mr factor can be liberated with trichloroacetic acid treatment and ethanol extraction. This activity was isolated from extracts of human placenta using Sephadex LH-20, Amberlite XAD-2, and silica gel thin-layer chromatography. The Mr of the factor is less than 400, it is lipophilic and resistant to proteolytic enzymes. The factor induces chemotactic migration of both aortic endothelial cells and capillary endothelial cells from the retina, but has no effect on fibroblasts or leukocytes suggesting a specific function of the compound for the vascular endothelial cells.

Animals↗
PubMed1983

Components of subendothelial aorta basement membrane. Immunohistochemical localization and role in cell attachment.

Cryosections of fetal and adult bovine aorta were stained with purified, cross-absorbed antibodies against various connective tissue components. The antibodies to the basement membrane components, laminin, heparan sulfate proteoglycan, and type IV collagen, gave a sharp reaction in the subendothelial layer. Antibodies against type III procollagen showed a broad endothelial staining, and staining was also seen in the media layer. A similar staining reaction was seen with antibodies against fibronectin. Bovine fetal aortic endothelial (BAE) cells were isolated and cultured in vitro. The cells became stained by the indirect immunofluorescence method with antibodies against laminin and heparan sulfate proteoglycan and also with antibodies against types III and IV collagen and type I procollagen, as in previously reported experiments. The attachment properties of endothelial cells to the same extracellular matrix components were also studied. BAE cells became attached most readily to surfaces coated with fibronectin or type III or type IV collagen. Laminin and collagen types I and V served as less effective substrates. Attachment to heparan sulfate proteoglycan was slowest of the tested components. The results of the study demonstrate that the BAE cells are associated with basement membranes in vivo. The BAE cells in culture produced interstitial connective tissue components in addition to basement membrane components and showed no clear specific preference in their attachment to any of these.

Animals↗
PubMed1982

Platelet-derived growth factor in chemotactic for fibroblasts.

Chemotaxis assays in modified Boyden chambers were used to detect fibroblast chemoattractants in materials released from early-stage inflammatory cells, namely, mast cells, platelets, and neutrophils. Strong attractant activity was found in substances released from platelets. This activity was accounted for mainly by the platelet-derived growth factor (PDGF), which is released from the platelets and which was active as a chemoattractant at 0.5-1.0 mitogenic units/ml. The mitogenic activity of purified PDGF, measured by [3H]thymidine incorporation, occurs at a similar concentration range. By varying the gradient of PDGF, we demonstrated that PDGF stimulates chemotaxis rather than random motility. Preincubation of suspensions of fibroblasts in the presence of PDGF decreased the subsequent migration of cells to a gradient of PDGF as well as to a gradient of fibronectin, which is also in attractant for fibroblasts. The chemotactic response of fibroblasts to PDGF was not inhibited by hydroxyurea or azidocytidine but was inhibited by actinomycin D and cycloheximide, suggesting that synthesis of RNA and proteins but not of DNA is required for the chemotactic response to occur. Fibroblast growth factor, epidermal growth factor, nerve growth factor, and insulin were not chemotactic for human skin fibroblasts, suggesting that the chemoattractant activity of PDGF for fibroblasts is not a general property of growth factors and mitogens. These results suggest that PDGF could have two functions in wound healing: to attract fibroblasts to migrate into the clot and then to induce their proliferation.

Blood Platelets↗
PubMed1980

The role of chymotrypsin-like protease of rat mast cells in inflammatory vasopermeability and fibrinolysis.

The isolated chymotrypsin-like protease of rat mast cells was shown to cause an increase of vascular permeability in rat skin. Inactivation of the enzymatic activity of the cationic protease abolished the vasoactivity. The smallest effective dose of the maximally active enzyme was estimated to be 0.5 micrograms per injection site, which is less than the amount of the endogenous mast cell enzyme in areas of skin similar to that of an injection site. The smallest effective dose for bovine trypsin was similarly estimated to be 0.3 micrograms per injection site, which is in good agreement with the values previously reported by others. The results suggest that the mast cell protease may act as a mediator of inflammatory vasopermeability. The effect of the enzyme on two potential biological substrates was tested. The enzyme does not hydrolyze elastin, but degrades fibrin clot.

Animals↗
PubMed1979

Studies on enzymes of collagen biosynthesis and the synthesis of hydroxyproline in macrophages and mast cells.

The activities of four intracellular enzymes of collagen biosynthesis were assayed in freshly isolated rat peritoneal macrophages and mast cells and compared with the same enzymes in freshly isolated chick-embryo tendon cells. The macrophages were found to contain activities of all four enzymes, those of prolyl and lysyl hydroxylase being 7 and 12% respectively of those in the tendon cells when expressed per cell or 3 and 4% when expressed per unit of soluble cell protein. The corresponding values for hydroxylysyl galactosyltransferase and galactosylhydroxylysyl glucosyltransferase activities were about 82 and 68% or 32 and 24% respectively. When the macrophages were incubated in suspension with [(14)C]proline, they synthesized a small but significant amount of non-diffusible hydroxy[(14)C]proline. The synthesis per cell was only about 0.1% of that formed by the tendon cells, and its distribution between the cells and the medium also differed from that in the tendon cells. The hydroxy[(14)C]proline synthesized by the macrophages may be present in the Clq subcomponent of the complement, but its amount was too small to allow any characterization of the protein. All four enzyme activities, and in particular the two hydroxylysyl glycosyltransferase activities, seem to be present in macrophages in a large excess compared with the very low rate of synthesis of hydroxy-proline-containing polypeptide chains. The mast cell extract was found to inhibit all four enzyme activities, but even when corrected for this inhibition, prolyl and lysyl hydroxylase activities in the mast cells were less than 0.08% and the two hydroxylysyl glycosyltransferase activities less than 1% of those in the tendon cells. The intracellular enzyme pattern of collagen biosynthesis in the mast cells is thus completely or virtually completely repressed.

Animals↗
PubMed1979

Effect of mast cell chymase of rat skin on intercellular matrix: a histochemical study.

The effects of purified mast cell chymase of rat skin on intercellular matrix were studied histochemically using cartilage as a model. The enzyme effectively releases proteoglycans from neonatal human costal cartilage. An analysis of the primary site of proteolytic attack by chymase in the matrix was attempted. The results suggest that components containing the more acidic radicals (e.g. sulphates) are hydrolyzed first. After a prolonged attack, the matrix loses most of its staining with Toluidine Blue and Alcian Blue, and staining of collagen is increased. The hydrolyzed regions of cartilage in Alcian Blue-stained sections exhibited a purple interference colour in polarized light. A similar interference colour appeared after incubating sections of rat skin with chymase. The mast cell chymase presumably promotes diffusion of plasma to the site of injury by the direct breakdown of connective tissue ground substance.

Animals↗