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Biomedical subjects

D de Wolff-Rouendaal

Publications and source records attributed to D de Wolff-Rouendaal.

At least 37 records · Page 2Linked to original sources
PubMed1989

Effect of beta-irradiation by a 106 ruthenium plaque on the rabbit eye choroid.

Fourteen Chinchilla gray rabbit eyes were treated with a ruthenium plaque, receiving 200, 400, or 800 Gy, to assess the effect of beta-irradiation on the normal rabbit choroid. Radiation effects were evaluated using fundus photography, fluorescein angiography, fluorophotometry, and histology. Fluorophotometry showed a fluorescein leakage into the vitreous 1 day after irradiation. Leakage values returned to normal within 1 month after irradiation. Fluorescein angiography showed nonperfusion of the choroid after beta-irradiation; the time between irradiation and the onset of nonperfusion was found to be dose dependent. Five months after 200 Gy irradiation, choroidal atrophy had developed but some vessels still stained with fluorescein; 400 Gy irradiation induced subtotal choroidal nonperfusion within 3 months and 800 Gy within 1 week.

Animals↗
PubMed1989

Effects of microwave-induced hyperthermia on the anterior segment of healthy rabbit eyes.

Hyperthermia was induced in nine healthy rabbit eyes by means of a microwave 2450 MHz stripline applicator. The anterior segment of each eye was heated to a fixed temperature of between 42 degrees C and 46 degrees C for 30 min. The temperature distribution in the eye was calculated using a thermal model and the actual boundary temperatures and microwave intensity were measured. The effects of treatment were evaluated by daily macroscopic examination, fluorescein angiography and fluorophotometry, as well as by histology. Histological examination of changes induced by this hyperthermic delivery system revealed a sharp transition at 44 degrees-45 degrees C from no permanent damage to the anterior chamber at lower temperatures to serious damage such as local necrosis, pigment disruption and local cataract at high temperatures. A sharp transition in the same temperature range was observed in vivo in the fluorescein leakage of the iris vessels by comparative fluorescein angiography and by anterior segment fluorophotometry.

Animals↗
PubMed1989

In vivo ultrasound backscattering estimation for tumour diagnosis: an animal study.

In this study the efficacy of a quantitative analysis of backscattered ultrasound for the differential diagnosis of intraocular tumours is tested. The data acquisition was performed with an on-line acquisition and processing system for in vivo work. The backscattering spectra were corrected for the beam effects (diffraction and focussing). The measurements were taken from an animal model (rabbit) in which a Greene's amelanotic melanoma was implanted in the anterior chamber of the eye. The special histologic arrangement of this tumour makes it optimally suited to an assessment of the correlation between histology and backscattering cross section. Various backscattering models were considered theoretically and the choice for a practical testing was motivated on the properties of the observed backscattering spectra. We conclude that the backscattering model based on an "inhomogeneous continuum" with a cylindrical Gaussian autocorrelation function fits the data optimally. The relatively low correlation of the backscattering cross-sections to histology cannot yet be fully explained. The range of acoustic scatterer sizes, however, corresponds quite well to the dimension of observed and quantified histologic structures.

Animals↗
PubMed1989

Conjunctival keratinisation, an abnormal reaction to an ocular beta-blocker.

Conjunctival leucoplakia was induced by the local beta-blocker metipranolol in one case. Withdrawal of the drug and application of all-trans retinoic acid ointment resulted in resolving of the keratinisation. A striking pharmacological resemblance is discovered between metipranolol and practolol. Metipranolol seems to be a less toxic phenol derivative of practolol. Nevertheless, it seems able to act as antigen.

Chemical Phenomena↗
PubMed1989

The effects of ultrasonically induced hyperthermia on experimental tumors in the rabbit eye.

Greene's melanomas, implanted in the anterior chamber of 31 eyes of 19 Dutch rabbits, were treated with hyperthermia induced by high intensity focused ultrasound (HIFU). The percentage necrosis 24 hr after treatment (N) as a function of steady-state intratumor temperature (T) could be described with N(T) = -181.5 + 4.7T (P less than 0.05). The most frequent side effect was a local hemorrhagic keratitis. The acoustic absorption coefficient and thermal conductivity of the tumor tissue were 0.08 cm-1 X MHz-1 at 36 degrees C and 0.011 W, cm-1 X degrees C-1, respectively. With these parameters a simple thermal model was established that enabled us to predict the ultrasonic intensity needed to reach a desired intratumor temperature.

Animals↗
PubMed1988

Decreased expression of HLA class II antigens on human uveal melanoma cells after in vivo X-ray irradiation.

In order to determine the presence of HLA antigens on human uveal melanomas, we tested anti-HLA monoclonal antibodies on tissue sections of these tumors. A great variety in expression of HLA class I and II antigens was present. A significantly lower expression of HLA class II antigens was present on uveal melanomas that had been irradiated before enucleation. These tumors lacked a lymphocytic infiltrate in comparison with nonirradiated tumors. These data suggest that radiotherapy affects expression of histocompatibility antigens on tumors.

Adult↗
PubMed1987

Ocular and orbital metastasis of cutaneous melanomas.

Two patients with orbital metastasis from cutaneous melanoma are described. In one patient the metastatic tumour was located in the iris, in the other one it was located in the lateral rectus muscle. Only symptomatic treatment is indicated as the term of survival is short.

Adult↗
PubMed1987

Heterogeneous expression of melanoma-associated antigens in uveal melanomas.

Twenty-five uveal melanomas were stained with seven monoclonal antibodies (MoAbs) recognizing different antigens on cutaneous melanomas. A two step immuno-peroxidase procedure was used. Phenotypic heterogeneity was observed for four MoAbs (M.2.2.4, AMF-7, 225.28S, PAL-M1) while two MoAbs (NKI-beteb, CL203.4) reacted strongly with most (85%) uveal melanomas, and one MoAb (R-24) showed very low reactivity. Despite heterogeneity, co-expression of some antigens was observed. Expression of the antigen recognized by MoAb M.2.2.4. was significantly lowered by pre-enucleation irradiation while the other antigens remained unchanged. Expression of antigens on uveal melanomas differed markedly from primary cutaneous melanomas. The clinical relevance of these findings awaits further study.

Antibodies, Monoclonal↗
PubMed1986

Topical application of 5-fluorouracil in premalignant lesions of cornea, conjunctiva and eyelid.

Local application of 5-Fluorouracil was practised on 5 patients. In 3 patients with multiple premalignant oculo-cutaneous lesions, two of whom had also premalignant epibulbar lesions, local 5% 5-Fu cream and/or 1% 5-Fu eyedrops were applied. In 2 other patients who had only premalignant lesions on the cornea and conjunctiva, 1% 5-Fu eyedrops were used only. In animal experiments 1% 5-Fu was not found to cause any damage to normal corneal and conjunctival epithelium. The frequency of the applications and the duration of the treatment were dependent on the location and extent of the lesions. Except for easily treatable lesions, caused by the separation of the tumour epithelium, no complications of local 5-Fu treatment were seen. The visual acuity improved in all 4 patients in whom the cornea was affected. In these premalignant conditions the diagnosis and assessment of the therapy were based on exfoliative cytology and biopsies.

Aged↗
PubMed1986

Expression of HLA antigens in paraffin sections of uveal melanomas.

Expression of histocompatibility (HLA) antigens on tumor cells may influence the recognition of these tumor cells by the immune system. Immunological recognition may influence tumor growth and patient survival. Although HLA class I and II antigens are known to be present on several tissues in the eye, their presence on ocular tumors had not yet been demonstrated. We studied the expression of these antigens on paraffin preparations of uveal melanomas. Most tumors carried class I and beta 2m antigens on most of their cells while class II antigens were less often expressed. No association with tumor cell type or tumor size was observed. Further studies will be necessary to determine the relevance of different levels of antigen expression with regard to patient survival.

HLA Antigens↗
PubMed1986

Nuclear magnetic resonance imaging of intraocular tumors.

Of 11 patients with intraocular tumors who underwent magnetic resonance imaging, seven had melanoma and one each had lymphoma, metastatic carcinoma, hemangioma, and hemorrhage. All were localized in the choroid. We compared the results of the magnetic resonance imaging examinations with those of ophthalmic ultrasonography, external inspection, and histopathologic studies. Magnetic resonance imaging detected six of the seven choroidal melanomas. Demarcation between the tumor and the sclera was excellent. Extrascleral tumor extension could be excluded. Hemorrhage in and beside the choroidal melanoma could be seen separately. Magnetic resonance imaging differentiates choroidal tumors from the surrounding intraocular and extraocular tissues better than computed tomography does, making it an important new diagnostic procedure.

Carcinoma↗
PubMed1986

CT-scan and intraocular tumours: detection and assessment of size and extrascleral growth of uveal melanomas.

Twenty-two patients, who were suspected of an intraocular tumour, were examined with the high resolution thin slice CT-scan (1.5 or 3 mm slices). The final diagnosis in 14 cases was an uveal melanoma, and in 3 cases in which an uveal melanoma was suspected a chorioretinal haemorrhage, an exudative macular degeneration type Junius Kuhnt and an intrascleral foreign body were respectively found. In 2 cases intraocular metastases were demonstrated, and in 2 other cases malignant lymphomata. One patient had a haemangioma. In 10 of the 14 patients with uveal melanomata enucleation was performed and 4 were treated by ruthenium application. The CT-scan was compared with ultrasonographic, operative and histological findings. From the study it appears that the CT-scan is useful for screening uveal melanomas. It is however difficult to distinguish the uveal melanoma from a secondary retinal detachment; differentiation from an exudative macular degeneration was not possible. The size of the tumour was only represented correctly on the CT-scan in half the cases. CT examination fails to demonstrate or exclude epi- and extrascleral growth. The multiple metastases and the haemangioma could only be seen with difficulty on the CT-scan; the latter was however clearly visible after the injection of contrast. The foreign body could be clearly seen without contrast.

Eye Neoplasms↗
PubMed1986

Scintimetric detection of choroidal malignant melanoma with [123I]-5-iodo-2-thiouracil.

[123I]-5-iodo-2-thiouracil (123I-ITU) was evaluated as a radiopharmaceutical for tumor detection in 10 patients with proven choroidal melanoma. Uptake of 123I-ITU was measured with a specially designed single eye probe collimator, 24 h after administration of 123I-ITU. Increased uptake in the tumor-bearing eye as compared to the fellow nontumor bearing eye was found in 7 out of 10 cases when the probe was located 3.5 cm in front of the eye (p less than 0.01). By using a double pinhole collimator tests were positive in 3 out of 10 123I-ITU studies only. Tests with 123I-ITU were compared with 67Ga tests in the same patients. The 67Ga tests with the single eye probe collimator were positive in 6 out 10 cases when the probe was located 6 cm in front of the eye. With the double pinhole collimator tests were positive in 7 out of 10 67Ga studies. It is concluded that 123I-labeled thiouracil is at least as useful as a radiopharmaceutical for ocular melanoma diagnosis as 67Ga-citrate, provided measurements are performed with a single eye probe.

Choroid Neoplasms↗
PubMed1986

Effect of indomethacin on immunogenic keratitis.

The effect of topically administrated indomethacin was studied in rabbits on an experimentally provoked inflammatory keratitis. Intrastromal injection with horse serum induced in the cornea a ring-shaped infiltration with leukocytes and neovascularization. Indomethacin was given as eye drops three times daily during the experiment. In the indomethacin treated eyes leukocyte infiltration was prolonged but not the concomitant neovascularization. The potentiation of the leukocyte response may be due to a facilitation of chemotactic lipoxygenase products.

Animals↗
PubMed1985

Bilateral diffuse benign melanocytic tumours of the uveal tract. A clinicopathological study.

In a patient treated for gall-bladder carcinoma bilateral choroidal tumours were clinically interpreted as intraocular metastases. Post mortem histological examination of both eyes revealed a bilateral diffuse benign melanocytic tumour of the uveal tract. The association of bilateral uveal naevi with terminal carcinomas has been reported in seven other cases; it may be a new ophthalmological syndrome.

Adenocarcinoma↗
PubMed1985

Hematoporphyrin derivative photoradiation treatment of experimental malignant melanoma in the anterior chamber of the rabbit.

The effects of Hematoporphyrin Derivative Photoradiation Therapy (HpD-PRT) on Greene's amelanotic melanoma implanted into the anterior chamber of rabbits have been examined by biomicroscopy, fluorescein angiography and histopathology. The tumors were irradiated 24 hours after injection of HpD when both the porphyrin concentration and the porphyrin ratio tumor/iris were highest. Blanching and shrinkage of tumors were the first signs of tumor destruction. Fluorescein angiography as soon as 20 minutes after irradiation found non-perfusion of blood vessels at the tumor surface. Histopathological observation of vessel wall destruction is in agreement with this finding. Subtotal tumor necrosis was demonstrated in 12 out of 13 experiments. Necrosis was complete in only one experiment. Clusters of viable tumor cells were found when shielded behind pigment, at the tumor periphery and around some blood vessels. Lens damage was observed after irradiation when the iris pigment epithelium was disorganized by the tumor. The iris contained high concentrations of porphyrin and PRT resulted in depigmentation, non-perfusion of the capillary bed, damage to larger iris vessels and finally atrophy. Light intensity measurements were performed in vivo during PRT. The average effective attenuation coefficient at 630 nm was 0.56 mm-1 at the beginning of irradiation and 0.87 nm-1 at the end. Results indicate that as a treatment HpD-PRT in itself might be insufficient but may prove to be an effective modality in combination with other tumor destructive therapies.

Animals↗
PubMed1983

Conjunctival melanomas in The Netherlands: a follow-up study.

In a follow-up study of 45 conjunctival melanoma patients the recurrence rate after local excision was 80% but the mortality rate due to metastasis was low, only 2 out of 25 cases in which the recurrences could be controlled by repeated local excisions. In the 18 cases in which exenteration was required, because of the unfavorable localization of the melanoma or repeated recurrences, the mortality rate due to metastatic disease (7 out of 18) was high.

Aged↗