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Biomedical subjects

L Missotten

Publications and source records attributed to L Missotten.

At least 37 records · Page 2Linked to original sources
PubMed1999

How to protect your eyes from solar retinopathy.

On August 11, in Belgium a solar eclipse will occur which will be total in the Southern area of the country. Although the observation of a solar eclipse is an intriguing phenomenon, inappropriate shielding from the sunlight can cause irreversible ocular lesions. Besides good absolute absorption of visible light, a blocking of ultraviolet and infrared light is equally important. In this study, four homemade sun filters were tested: a soot-blackened piece of glass, a black unexposed developed slide film, an audio-CD and a recordable CD-ROM. Also two commercially available filters were investigated: eclipse-shades and mylar foil. The soot-blackened glass and black slide film slip were highly transparent for infrared light, making them dangerous for solar observation. The recordable CD-ROM was too transparent for visible light to serve as solar filter, while the audio-CD tested absorbed enough visible, ultraviolet and infrared light to make it suitable for eclipse viewing. However, many types of audio-CD's are available making it impossible for the observer to know if a given CD is safe to use for solar viewing. Both commercially available solar filters tested had a good absolute visible light absorption, as well as an equally good absorption of ultraviolet and infrared light, making them safe for eclipse observation.

Belgium↗
PubMed1998

Results of treatment of choroidal malignant melanoma with high-dose-rate strontium-90 brachytherapy. A retrospective study of 46 patients treated between 1983 and 1995.

PURPOSE: We review the results of treatment of small to medium-sized choroidal malignant melanomas after high-dose-rate brachytherapy with a strontium-90 applicator. METHODS: The applicator is positioned against the sclera using an afterloading technique. Brachytherapy is completed in a single session lasting 2-4 h with the patient under local anaesthesia. From September 1983 until March 1995, 46 eyes were treated in this way. Most tumours were 7-11 mm in diameter (range from 4.5-15 mm) with a mean height of approximately 3 mm (range from 1.5-7 mm). Follow-up ranged from 6 months to 12 years (mean 49 months). RESULTS: Thirty of the 46 eyes had at the final evaluation a nonevolutive scar (20 of these after a single application, the others with some additional treatment). In 13 eyes the tumours were in involution but their complete destruction was not yet certain, and 3 eyes were enucleated for local recurrence. Three patients developed systemic metastases. No radiogenic complications were noticed. CONCLUSION: Strontium-90 brachytherapy is a valuable and safe treatment technique for small to medium-sized choroidal malignant melanomas. In addition the use of a strontium-90 applicator is inexpensive thanks to this element's long half-life and the short application time.

Adult↗
PubMed1998

Gelatinase B in proliferative vitreoretinal disorders.

PURPOSE: To investigate whether gelatinases A and B are involved in the pathogenesis of proliferative vitreoretinal disorders. METHODS: In a prospective study of 101 consecutive patients, vitreous and paired serum samples were obtained from 38 patients with rhegmatogenous retinal detachment complicated by proliferative vitreoretinopathy, 25 patients with rhegmatogenous retinal detachment with no proliferative vitreoretinopathy, and 38 patients with proliferative diabetic retinopathy. Gelatinase activities were determined by quantitative zymography. RESULTS: All vitreous samples contained comparable levels of the constitutive gelatinase A. Inducible gelatinase B was detected in eight (32%) of 25 vitreous samples from patients with rhegmatogenous retinal detachment with no proliferative vitreoretinopathy (mean +/- SD, 319.5 +/- 521.0 scanning units), in 17 (44.7%) of 38 vitreous samples from patients with proliferative vitreoretinopathy (560.6 +/- 718.9 scanning units), and in 34 (89.5%) of 38 vitreous samples from patients with proliferative diabetic retinopathy (1,707.2 +/- 1,220.3 scanning units). The incidence of detection of gelatinase B in proliferative diabetic retinopathy cases was significantly higher than it was in rhegmatogenous retinal detachment with no proliferative vitreoretinopathy and proliferative vitreoretinopathy cases (P < .001). Gelatinase B levels in the vitreous samples of patients with proliferative diabetic retinopathy were higher than the levels found in patients with rhegmatogenous retinal detachment with no proliferative vitreoretinopathy and in patients with proliferative vitreoretinopathy (P = .0152). Gelatinase A was detected in all the tested sera, whereas none of the tested paired serum samples contained detectable gelatinase B activity. CONCLUSIONS: Gelatinase B may play an important role in extracellular matrix degradation associated with neovascularization in proliferative diabetic retinopathy.

Collagenases↗
PubMed1998

Immunopathogenesis of conjunctival scarring in trachoma.

PURPOSE: Trachoma, a chronic follicular conjunctivitis caused by infection with Chlamydia trachomatis, is the leading cause of preventable blindness. The blinding complications are associated with progressive conjunctival scarring that may result from immunologically mediated responses. We studied the processes involved in the regulation of inflammation and fibrosis in trachoma by investigating the expression of fibrogenic cytokines in the conjunctiva. METHODS: We studied conjunctival biopsy specimens obtained from nine subjects with active trachoma and from four control subjects. We used immunohistochemical techniques and a panel of monoclonal and polyclonal antibodies directed against interleukin-1 alpha (IL-1 alpha), interleukin-1 beta (IL-1 beta), tumour necrosis factor-alpha (TNF-alpha) and platelet-derived growth factor (PDGF). In addition, we characterised the composition of the inflammatory infiltrate by the use of a panel of monoclonal antibodies. Sirius red and Van Gieson stains were used to characterise the extent of fibrous tissue in the substantia propria. RESULTS: Trachoma specimens showed greater numbers of inflammatory cells than control specimens. The expression of cytokines was absent in the normal conjunctiva. Cytoplasmic IL-1 alpha and IL-1 beta expression was noted in the conjunctival epithelium in all trachoma specimens. IL-1 alpha, IL-1 beta, TNF-alpha and PDGF were detected in macrophages infiltrating the substantia propria. B lymphocytes predominated over T lymphocytes in six trachoma biopsies with fibrosis confined to the deep substantia propria, whereas T lymphocytes predominated over B lymphocytes in three biopsies with more extensive fibrosis. In all trachoma biopsies helper/inducer T lymphocytes outnumbered suppressor/cytotoxic T lymphocytes. CONCLUSIONS: The upregulated local production of IL-1 alpha, IL-beta, TNF-alpha and PDGF might contribute to conjunctival damage and scarring in trachoma.

Adolescent↗
PubMed1998

Collagen content and types in trachomatous conjunctivitis.

PURPOSE: To study alterations in conjunctival collagen in the conjunctiva of patients with active trachoma. METHODS: We studied conjunctival biopsy specimens obtained from nine subjects with active trachoma and from four control subjects. We used immunohistochemical techniques and a panel of monoclonal and polyclonal antibodies directed against types I, III, IV and V collagen. RESULTS: In normal conjunctiva, the staining for types I and III collagen was localised to the substantia propria. Type IV collagen was located in the epithelial and capillary endothelial basement membranes. The staining for type V collagen was absent. In trachoma biopsy specimens, staining for types I and III collagen showed collagen fibrils among epithelial cells, patchy increase in staining intensity in the upper stroma, and thicker and irregularly arranged collagen fibrils in the substantia propria. Staining for type IV collagen showed irregularly thickened epithelial basement membrane. Staining for type V collagen showed patchy staining in the upper substantia propria; it was also noted in the cytoplasm of fibroblasts, in the walls of blood vessels in the substantia propria, and in the walls of accessory lacrimal glands. CONCLUSIONS: Our data indicate new type V collagen formation, and increased types I, III and IV collagen content, in the conjunctiva from patients with active trachoma.

Adolescent↗
PubMed1998

An immunohistochemical study of collagens in trachoma and vernal keratoconjunctivitis.

PURPOSE: To analyse the distribution and types of collagen in the conjunctiva of patients with trachoma and vernal keratoconjunctivitis (VKC). METHODS: Conjunctival biopsy specimens were collected from 9 patients with active trachoma, 9 patients with scarred trachoma, 6 patients with active VKC and 9 control subjects. The presence and distribution of collagen was assessed microscopically with immunohistochemical techniques and a panel of monoclonal and polyclonal antibodies directed against types I, III, IV and V collagen. RESULTS: In normal conjunctiva, the staining for types I and III collagen was localised to the substantia propria. Type IV collagen was located in the epithelial, vascular endothelial and accessory lacrimal gland basement membranes. Staining for type V collagen was absent. New type V collagen deposition close to basement membranes was noted in active trachoma, scarred trachoma and VKC. The extent of deposition of type V collagen was markedly increased in scarred trachoma when compared with active trachoma. Staining for type IV collagen showed irregularly thickened epithelial basement membrane in active trachoma, and a marked increase in basement membrane type IV collagen was noted in scarred trachoma. Immunoreactivity of types I and III collagen increased in active trachoma and decreased in scarred trachoma. VKC conjunctiva contained increased amounts of types I, III and IV collagen due to marked increase in the thickness of vascular endothelial basement membrane and very prominent deposition of types I and III collagen around stromal vessels. CONCLUSIONS: Our data indicate new type V collagen formation in the conjunctiva from patients with active trachoma, scarred trachoma and VKC. Increased deposition of types I, III and IV collagen is noted in VKC and active trachoma. Our findings suggest that increased deposition of type IV collagen and new type V collagen formation contributes to the development of conjunctival fibrosis in scarred trachoma.

Adolescent↗
PubMed1998

How to calculate surgically induced astigmatism after cataract surgery?

Corneal astigmatism is a complex entity with a power and an axis. The purpose of this article is to give a summary of the most popular methods to calculate surgically induced astigmatism, and to discuss their differences. Various methods exist, but we will only discuss the most popular ones. The interested surgeon can use these methods on his patients to calculate and compare the surgically induced astigmatism of each of his surgical techniques. Doing so, he will be able to use the ideal technique in each individual case. Astigmatism-neutral as well as astigmatism-inducing techniques should be used. A correct pre- and postoperative keratometry is of course very important.

Astigmatism↗
PubMed1998

Conjunctival squamous cell carcinoma and intraepithelial neoplasia in AIDS patients in Congo Kinshasa.

PURPOSE: To determine the clinical characteristics of conjunctival squamous cell carcinoma and conjunctival intraepithelial neoplasia in AIDS patients. METHODS: A review of AIDS patients with biopsy-confirmed conjunctival squamous cell carcinoma and conjunctival intraepithelial neoplasia seen between 1994 and 1997. RESULTS: Ten patients, aged from 25 to 46 years (average, 37.3 years) were seen. There were three men and seven women. The mean delay of diagnosis was 7 months. Of the 10 patients, three had squamous cell carcinoma of the conjunctiva and seven had conjunctival intraepithelial neoplasia. Both eyes were involved with equal frequency. Lesions involved the corneoscleral limbus and the conjunctiva in eight patients and the conjunctiva in two patients. Localization of lesions was temporal in six patients, nasal in three patients and inferior in one patient. All patients were treated by excision of the lesions. A recurrence was seen in two patients (during the follow-up of 6 months). CONCLUSION: The conjunctival squamous cell carcinoma and intraepithelial neoplasia in AIDS patients in this study showed similar clinical characteristics as those reported in immunocompetent persons, but occurred in a younger age group and were more aggressive.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Chronic uveitis in Kinshasa (D R Congo).

PURPOSE: To determine frequencies of different types of chronic uveitis and the possible associated conditions. METHODS: In the retrospective study a review is made of all 336 consecutive patients with chronic uveitis seen during 1983 through 1993. All patients were evaluated ophthalmologically and most of them medically. Traumatic uveitis was excluded from this study. RESULTS: There were 171 (51%) males and 165 (49%) females. Of 336 patients with chronic uveitis, 194 (58%) had anterior uveitis, 76 (23%) had isolated posterior uveitis, 38 (11%) had panuveitis and 28 (8%) intermediate uveitis. Associated conditions were found in 151 (46%) of 336 patients. AIDS, Herpes Zoster Ophthalmicus, toxoplasmosis, tuberculosis, rheumatoid arthritis and onchocerciasis were the most common associated disease respectively in 12.5%, 6.4%, 6%, 6%, 6% and 4% of cases. CONCLUSION: The findings of this study were different from those of other studies published in Europe and the United States.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Monocyte chemotactic protein-1 in proliferative vitreoretinal disorders.

PURPOSE: To investigate whether the chemokines monocyte chemotactic protein-1 (MCP-1) and interleukin-8 (IL-8) are involved in the pathogenesis of proliferative vitreoretinal disorders and to study their possible interaction with IL-6. METHODS: In a prospective study of 125 consecutive patients (125 eyes), vitreous and paired serum samples were obtained and were assayed for MCP-1 and IL-8. Levels of IL-6 were determined by proliferation of the IL-6-dependent hybridoma cell line 7TD1. RESULTS: Monocyte chemotactic protein-1 was detected in 13 (48%) of 27 vitreous samples from patients with retinal detachment, in five (63%) of eight samples from patients with macular pucker, in 31 (72%) of 43 samples from patients with proliferative vitreoretinopathy, and in 32 (76%) of 42 samples from patients with proliferative diabetic retinopathy, but not in samples from five patients with idiopathic epiretinal membrane. There was a significant (P = .049) correlation between the incidence of MCP-1 detection in retinal detachment, macular pucker, and proliferative vitreoretinopathy groups and the severity of proliferation. Interleukin-8 was detected in two vitreous samples from eyes with retinal detachment, in two samples from eyes with proliferative vitreoretinopathy, and in three samples from eyes with proliferative diabetic retinopathy. Monocyte chemotactic protein-1 levels in the vitreous samples were positively correlated with IL-6 levels (r = .31, P = .01). Interleukin-6 levels were significantly (P = .0097) greater in vitreous samples with than without detectable levels of MCP-1. CONCLUSION: Monocyte chemotactic protein-1 is present in a substantial percent of vitreous samples from eyes with proliferative vitreoretinal disorders and may help in stimulating the infiltration of monocytes and macrophages into eyes with these disorders.

Antibodies, Monoclonal↗
PubMed1997

Adhesion molecules in vernal keratoconjunctivitis.

AIMS/BACKGROUND: Adhesion molecules play a key role in the selective recruitment of different leucocyte population to inflammatory sites. The purpose of the present study was to investigate the presence and distribution of adhesion molecules in the conjunctiva of patients with vernal keratoconjunctivitis (VKC). METHODS: The presence and distribution of adhesion molecules were studied in 14 conjunctival biopsy specimens from seven patients with active VKC and in four normal conjunctival biopsy specimens. We used a panel of specific monoclonal antibodies (mAbs) directed against intercellular adhesion molecule-1 (ICAM-1), intercellular adhesion molecule-3 (ICAM-3), lymphocyte function associated antigen-1 (LFA-1), very late activation antigen-4 (VLA-4), vascular cell adhesion molecule-1 (VCAM-1), and endothelial leucocyte adhesion molecule-1 (ELAM-1) In addition, a panel of mAbs were used to characterise the composition of the inflammatory infiltrate. RESULTS: In the normal conjunctiva, ICAM-1 was expressed on the vascular endothelium only, LFA-1 and ICAM-3 on epithelial and stromal mononuclear cells, and VLA-4 on stromal mononuclear cells. The expression of VCAM-1 and ELAM-1 was absent. The number of cells expressing adhesion molecules was found to be markedly increased in all VKC specimens. This was concurrent with a heavy inflammatory infiltrate. Strong ICAM-1 expression was induced on the basal epithelial cells, and vascular endothelial cells. Furthermore, ICAM-I was expressed on stromal mononuclear cells. LFA-1 and ICAM-3 were expressed on the majority of epithelial and stromal infiltrating mononuclear cells. VLA-4 expression was noted on stromal mononuclear cells. Compared with controls, VKC specimens showed significantly more ICAM-3+, LFA-3+, LFA-1+, and VLA-4+ cells. VCAM-1 and ELAM-1 were induced on the vascular endothelial cells. CONCLUSIONS: Increased expression of adhesion molecules may play an important role in the pathogenesis of VKC.

Adolescent↗
PubMed1997

Choroidal metastasis presenting as a painful red eye: clinicopathologic report.

Metastasis is the most common ocular malignancy. An atypical clinical presentation whoever, can delay the diagnosis, particularly when there is no history of malignant disease. Our patient initially presented with a painful red eye and a subretinal mass, but without signs of intraocular inflammation or glaucoma. The results of the diagnostic work-up were inconclusive. Postmortem histopathologic examination revealed a metastasis to the posterior choroid.

Adenocarcinoma↗
PubMed1997

Results of histo-pathologic examination of three enucleated eyes with a choroidal melanoma after strontium-90 irradiation.

Three patients with a choroidal melanoma, treated with HDR (High Dose Rate) Strontium-90 brachytherapy, underwent an enucleation. Radiation effect was only visible at the irradiation zone with a brisk transition to normal tissue. Tumour was replaced by necrotic and scar tissue. The underlying sclera had a markedly reduced number of fibrocytes, but no structural alteration of the collagen stroma.

Aged↗
PubMed1997

Eye diseases and the causes of blindness in the southwestern Equator (equatorial forest) in Zaire, data from an eye camp in three rural centers.

OBJECTIVE: To determine frequencies of eye diseases and causes of blindness in this rural area. METHOD: During a one month period (February 1996), a study was carried out in three rural centers (Mbandaka, Iboko, Lukolela) in the South Western Equator, in the tropical equatorial forest area. A total of 700 patients were examined and ophthalmological examination included visual acuity, inspection of adnexa, refraction, slit-lamp examination, direct funduscopy and intraocular pressures. RESULTS: Cataract and glaucoma were the major ocular diseases found. Among the patients 1/5 was legally blind, and common causes of blindness were: cataract (54%), glaucoma (30%), uveitis (6%), corneal disorder (5%), retinitis pigmentosa (3%), atrophy of eye (3%). CONCLUSION: Cataract and glaucoma constituted a public health problem in this rural area of Zaïre.

Adolescent↗
PubMed1997

Glaucoma in Congo.

OBJECTIVE: To determine frequencies of various types of glaucoma in an urban community of Congo. METHODS: The records of 176 patients with the diagnosis of glaucoma examined between 1991 and 1995 at a non-university center were reviewed. A complete ophthalmological examination was performed in each patient including best visual acuity, refraction, slit-lamp examination, ophthalmology and intraocular pressure measurements. Gonioscopy and visual field examination were performed when needed. RESULTS: The frequency distribution of the various subtypes of glaucoma was: open-angle glaucoma (72.2%), aphakic glaucoma (9%), uveitis glaucoma (6%), exfoliative glaucoma (3%), glaucoma secondary to ocular trauma (2.2%), cataract glaucoma (1.7%), normal tension glaucoma (1.7%), congenital glaucoma (1.7%), neovascular glaucoma (1.3%), pigmentary glaucoma (0.6%), corticosteroid-induced glaucoma (0.6%), and glaucoma associated with retinoblastoma (0.6%); CONCLUSION: Despite the limitations inherent of a retrospective review of records, our study provides an indication of the prevalence of various types of glaucoma in a urban community of Congo. This study confirmed also the rarity of primary angle-closure glaucoma in the black.

Adult↗
PubMed1997

Risk factors for open-angle glaucoma in 260 black subjects in Congo.

OBJECTIVE: To identify possible risk factors for open-angle glaucoma (OAG) among 260 black subjects in Kinshasa (Congo). METHODS: Between May 14, 1996 and June 14, 1996, 260 persons, aged 24-60 years old, working at a factory in Kinshasa, have been examined. Twenty-two patients with OAG and 238 controls were identified. Data were obtained through interviews and clinical examinations. OAG was defined by the presence of both optic disc damage and characteristic visual field defects. RESULTS: The frequency of OAG was 8.5%. Associations were found with intraocular pressure greater than 21 mmHg (Odds ratio (OR) = 119.4, 95% confidence interval (CI), 17.62 to 4960.64), current cigarette smoking (OR = 2.77, 95% CI, 1.04 to 7.34) and Mongo ethnic subgroup (OR = 3.195, 95% CI, 0.93 to 9.57). CONCLUSION: Mongo ethnic subgroup seemed to be another risk factor for OAG in Congo.

Adult↗
PubMed1997

Differences in the trabecular meshwork between Belgian and Congolese patients with open-angle glaucoma.

PURPOSE: To study the alterations of the trabecular meshwork of Belgian and Congolese patients with open angle glaucoma (OAG). METHODS: A trabeculectomy was performed in 27 OAG patients from Belgium and 24 from Congo; the trabecular specimens were fixed, embedded, stained, and studied by light microscopy. These specimens were compared with the trabecular meshworks from 5 Belgian non-glaucomatous eyes. RESULTS: The mean number (+/- standard deviation) of trabecular cells per field was 69 (+/- 10) in Belgian normal eyes, 34 (+/- 17) in Belgian OAG patients, and 10 (+/- 6) in Congolese OAG patients. The trabecular meshwork was collapsed and Schlemm's canal was closed in the cases with a diminished number of cells. Pigmentation was present in 79% of the Congolese and in 35% of the Belgian specimens. CONCLUSION: The trabecular meshwork from OAG patients has a lower cellularity than normal, and the effect is much more pronounced in the trabecular meshwork from Congolese patients. This may be a possible explanation for the racial differences in OAG and the more severe forms of glaucoma in black people.

Aged↗