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Biomedical subjects

J Deschênes

Publications and source records attributed to J Deschênes.

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

Nitric oxide and transforming growth factor-beta levels during experimental uveitis in the rabbit.

OBJECTIVE: To determine changes in the levels of nitric oxide metabolites and transforming growth factor-beta (TGF-beta) in the rabbit aqueous humour during ocular inflammation. DESIGN: Active experimental uveitis was induced by injection of porcine lens protein (PLP) in three rabbits and of human serum albumin (HSA) in three rabbits; three control rabbits received an injection of saline. OUTCOME MEASURES: Degree of inflammation, antibody titres (determined with the enzyme-linked immunosorbent assay), and aqueous humour levels of nitric oxide metabolites and TGF-beta. A modified Griess assay for nitrites and nitrates (NO2- and NO3-) was used as a measure of nitric oxide generation, and a modification of the CCL-64 mink lung epithelial cell bioassay was used to quantify TGF-beta levels. RESULTS: Following the primary immunologic challenge both experimental groups initially showed a two- to fourfold increment in aqueous levels of nitric oxide metabolites and TGF-beta compared with baseline values. At the peak of the clinically observed inflammation there was a significant increase in the mean nitric oxide metabolite level compared with the control value (p < or = 0.005) (432 nmol/mL for the PLP group and 112 nmol/mL for the HSA group) and a significant decrease (p < or = 0.03) in the mean TGF-beta level (3.1 ng/mL and 0.3 ng/mL respectively). CONCLUSIONS: Nitric oxide may be used as a marker for intraocular inflammation. The increased production of nitric oxide may reflect the loss of immunologic privilege of the ocular microenvironment that occurs during inflammation.

Animals↗
PubMed1997

Immunohistochemical expression of S-100 beta in choroidal melanomas.

OBJECTIVE: To investigate the expressivity of S-100 beta antibodies in choroidal melanomas and to compare it with that of S-100 protein and HMB-45. DESIGN: Twenty-seven choroidal melanoma specimens obtained from the McGill University Ophthalmic Pathology Registry were classified as spindle cell, epithelioid cell or mixed-cell type. Immunohistochemistry was performed using the standard peroxidase-antiperoxidase technique with monoclonal HMB-45, polyclonal S-100, polyclonal S-100 beta and monoclonal S-100 alpha beta antibodies in formalin-fixed, paraffin-embedded sections. OUTCOME MEASURE: Intensity of immunoreaction. The result was considered positive when at least five focal areas of stained cells were observed within the tumour. RESULTS: All 27 tumours were positive for HMB-45, 19 (70%) for S-100, 23 (85%) for S-100 beta, and 21 (78%) for S-100 alpha beta. No correlation was found between the intensity of the immunoreaction and cell classification. CONCLUSIONS: HMB-45 is the most reliable marker for choroidal melanomas. S-100 beta is a more sensitive marker than S-100 for choroidal melanomas regardless of cell type. Contrary to previous reports, S-100 beta should not be considered a useful immunomarker to differentiate between primary choroidal melanoma and cutaneous melanoma metastatic to the choroid.

Antibodies, Monoclonal↗
PubMed1996

Once-weekly intraocular injections of ganciclovir for maintenance therapy of cytomegalovirus retinitis: clinical and ocular outcome.

The clinical course and the outcome of treatment were studied in 40 patients with primary cytomegalovirus (CMV) retinitis in 57 eyes. All had received one 14-day course of intravenous ganciclovir and all were free of other end-organ CMV disease. All afficted eyes received weekly intravitreal injections of 400 micrograms of ganciclovir for maintenance therapy. Median survival of patients was at least 13 months. Fifteen patients had 19 new opportunistic infections during the observation period, but none developed new nonocular CMV disease. Active retinitis recurred in 68.4% of the eyes while receiving maintenance therapy, with a median time to progression of 14.7 weeks. CMV retinitis occurred in 30.4% of the previously uninvolved eyes (follow-up, 3.1 years). Bacterial endophthalmitis complicated treatment in 1 eye, and 5 eyes developed a retinal detachment. Thus, the long-term treatment of CMV retinitis with weekly intraocular injections of ganciclovir was associated with survival and ocular outcome similar to those reported with systemic ganciclovir.

AIDS-Related Opportunistic Infections↗
PubMed1996

Analysis of gene expression during experimental uveitis in the rabbit.

OBJECTIVE: To analyse the pattern of gene expression at the messenger RNA level during ocular inflammation in the rabbit. DESIGN: A gene screen assay was used to quantify specific binding over background (expression index) of various activation markers and cytokines in rabbit iris-ciliary body obtained during active experimental uveitis induced by injection of porcine lens protein (two animals) and in a control group (two animals). OUTCOME MEASURES: Expression indices corresponding to the activation markers and cytokines assayed. RESULTS: Compared with the control eyes, analysis of triplicate samples from the inflamed eyes showed a significantly higher expression index corresponding to the proto-oncogenes c-fos, c-jun and Ha-ras, interleukin-2 and heat shock protein Hsp27 and a significantly lower index corresponding to transforming growth factor-beta (TGF-beta) (p < 0.05). CONCLUSIONS: Active experimental lens-induced uveitis is associated with a significant rise in the gene expression of cellular activation factors and a decrease in an immunoprotective factor (TGF-beta) in the iris and ciliary body of the rabbit.

Animals↗
PubMed1995

Increased immunohistochemical expression of neutral metalloendopeptidase (enkephalinase; EC 3.4.24.11) in villi of the human placenta with pre-eclampsia.

The purpose of this study was to identify the presence of placental neutral metalloendopeptidase (NEP; enkephalinase; EC 3.4.24.11) in human normotensive and pre-eclamptic pregnancy. The localization of NEP in placentae from normotensive, chronic hypertensive and pre-eclamptic pregnancies was carried out on fresh frozen tissues by using a monoclonal primary antibody developed against human common acute lymphoblastic leukaemia antigen (CD10) together with the avidin-biotin-peroxidase method. In placentae from normotensive, chronic hypertensive and superimposed pre-eclamptic pregnancies, intense staining was found in the extravillous trophoblast, and also in fibroblasts of the chorionic plate and stem villi. Light to moderate staining was noted in the villous-associated trophoblast and in some cells from the villous core. In cases of pre-eclampsia, very intense staining was detected not only on the surface, but also in the cytoplasm of the villous-associated trophoblast. The increased expression of placental NEP in pre-eclampsia suggests that this enzyme may be involved in the regulation of the local concentration of circulating biologically active peptides at the fetomaternal interface, and thus could be implicated in the pathophysiological changes of this syndrome.

Adult↗
PubMed1993

Shoulder lipoblastoma: magnetic resonance imaging characteristics.

The authors describe the magnetic resonance imaging (MRI) characteristics of lipoblastoma of the shoulder in an infant. The appearance of the lesion in MRI scans correlated well with the pathological observation of lobules of immature adipose tissue surrounding masses of myxoid tissue. However, the MRI study of lipoblastoma is nonspecific, and the results of other radiologic modalities, such as plain radiography, ultrasonography and computed tomography, are essential for a confident diagnosis.

Humans↗
PubMed1992

The immunology of the eye and its systemic interactions.

Advances in immunology have provided us with new insights about the ocular inflammatory response. Still, the etiology and pathophysiology of many uveitides remain unclear. Factors such as the blood-ocular barrier, sequestration of retinal antigens, local immunomodulators in the aqueous humor, and anterior chamber-associated immune deviation (ACAID) interact and render the eye an immunologically "privileged" site. On the other hand, human leukocyte antigen complex (HLA) interactions, the immunopathology of hypersensitivity reactions, T-cell mediated disease, and autoimmunity are associated pathogenic mechanisms of immune-related ocular disease. In this paper, we review some of the immunologic characteristics of the eye and their relationship to intraocular inflammation. Clinocopathologic correlations are presented. Also, perspectives of current and future research, as well as diagnostic and treatment strategies, are discussed.

Animals↗
PubMed1992

Cataract extraction in uveitis: comparison of aphakia and posterior chamber lens implantation.

We reviewed the charts of 39 patients (45 eyes) with uveitis who underwent cataract extraction (intracapsular or extracapsular) with or without implantation of a posterior chamber intraocular lens (IOL) at the Royal Victoria Hospital, Montreal, between 1981 and 1990. The nine eyes with Fuchs' iridocyclitis in which an IOL was implanted had good visual results and few postoperative complications. The 18 eyes with uveitis other than Fuchs' iridocyclitis that received an IOL did not show a greater risk of postoperative complications than those left aphakic (n = 17), and the postoperative visual acuity was comparable to that of the aphakic eyes. Although the numbers are small, we conclude that the presence of uveitis does not automatically exclude posterior chamber pseudophakia.

Adult↗
PubMed1991

Pagetoid carcinomatous involvement of the penile urethra in association with high-grade transitional cell carcinoma of the urinary bladder.

We present a case of pagetoid carcinomatous involvement of the penile urethra and periurethral glands following cystoprostatectomy for high-grade transitional cell carcinoma of the urinary bladder. Previously reported cases with involvement of the urethra are reviewed. This condition is believed to be a rare variant of transitional cell carcinoma in situ.

Adult↗
PubMed1991

Gastric linitis plastica metastatic to the uvea.

A 59-year-old man underwent total gastrectomy for diffuse, poorly differentiated gastric adenocarcinoma diagnosed as linitis plastica. Loss of vision in the right eye 5 months later due to extensive choroidal tumours was the first indication of metastatic disease. Radiologic studies showed multiple bony metastases. The blind, painful eye was enucleated. Pathological examination of the globe showed massive metastatic mucus-secreting adenocarcinoma of the choroid, with positive immunohistochemical staining for carcinoembryonic antigen (CEA) of the foci of the more highly differentiated neoplastic cells. The plasma CEA level had been normal. The patient died 3 months after enucleation from metastatic disease.

Adenocarcinoma↗
PubMed1990

Nucleolar organizer regions (NOR) in hyperplastic and neoplastic prostate disease.

Nucleolar organizer regions (NOR) are DNA loops encoding ribosomal RNA production. Detectable by the argyrophilia (AgNOR) of associated proteins, AgNOR numbers correlate with growth fraction and may have diagnostic and prognostic utility in human tumors. Because nucleolar size is important in the diagnosis of prostate carcinoma, we compared AgNOR counts in benign, atypical, and malignant prostate lesions and correlated them with nucleolar diameter. We counted AgNOR in benign prostatic hyperplasia, atypical adenomatous hyperplasia, intraductal dysplasias, and carcinomas of various Gleason grades. The mean AgNOR count per nucleus for benign prostatic hyperplasia nuclei was 4.51; for atypical adenomatous hyperplasia, 5.64; for intraductal dysplasias, 7.35; for carcinoma of Gleason grades 2 + 3, 8.87; and for carcinoma Gleason grades 4 + 5, 10.42. Counts in the carcinomas and intraductal dysplasias were significantly different from those of benign prostatic hyperplasia. Mean AgNOR counts of the carcinomas and intraductal dysplasias did not overlap with those of benign prostatic hyperplasia, suggesting that intraductal dysplasia shares more with carcinoma than benign prostatic hyperplasia. Nucleolar diameters increased from benign prostatic hyperplasia to atypical adenomatous hyperplasia, intraductal dysplasias, and the carcinomas, correlating with increasing AgNOR counts. Nucleolar diameters in the carcinomas were significantly different than those of benign prostatic hyperplasia; those in intraductal dysplasias were not. Our findings suggest that AgNOR counts are superior to nucleolar diameters alone in separating intraductal dysplasias from benign prostatic hyperplasia but provide no additional information in diagnosing carcinoma.

Cell Nucleus↗
PubMed1990

A clinicopathological study of seven globes enucleated after primary radiation therapy for malignant melanoma of the choroid or ciliary body.

Seven patients with malignant melanoma of the choroid or ciliary body were initially managed with radiation therapy, either teletherapy with proton or cobalt 60 external beam, or brachytherapy with the insertion of an episcleral plaque containing iodine 125, 60Co or gold 198. All seven globes subsequently were enucleated because of progressive growth of the tumours, total retinal detachment, persistent vitreous hemorrhage, or neovascular or angle-closure glaucoma. Six of the patients had severe visual loss at the time of enucleation. The effects of radiation therapy on the neoplasms and the mechanisms for the visual loss are discussed.

Adult↗