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Biomedical subjects

P LeHoang

Publications and source records attributed to P LeHoang.

At least 19 recordsLinked to original sources
PubMed2003

Polymerase chain reaction analysis of aqueous humour samples in necrotising retinitis.

AIM: To evaluate the diagnostic value of polymerase chain reaction (PCR) performed on aqueous humour for the detection of viral DNA in patients with necrotising herpetic retinitis. METHODS: The clinical features and laboratory results of 22 patients (29 eyes) presenting with necrotising herpetic retinitis between March 1999 and June 2001 were reviewed retrospectively. Aqueous humour was obtained after anterior chamber paracentesis and PCR was performed in all cases. RESULTS: Viral DNA was detected in the aqueous humour of 19 patients (86.4%). Epstein-Barr virus (EBV) seroconversion was evidenced in one additional patient. In the acute retinal necrosis (ARN) group (n = 19), varicella zoster virus (VZV) DNA was identified in six patients, herpes simplex virus 1 (HSV-1) DNA in two patients, herpes simplex virus 2 (HSV-2) DNA in four patients, and cytomegalovirus (CMV) genome in four patients. In the progressive outer retinal necrosis (PORN) group (n = 3), VZV DNA was detected in all patients. No sample was positive for more than one virus. CONCLUSIONS: PCR analysis of aqueous humour in patients with clinical features of necrotising viral retinitis can provide specific aetiological orientation and the method appears to be safe and highly sensitive.

Acute Disease↗
PubMed2002

[Intraocular pressure elevation after subtenon injection of triamcinolone acetonide during uveitis].

INTRODUCTION: New therapeutic concepts in the management of ocular inflammation have led to the development of periocular and intravitreal injections. Such treatment modalities can induce intraocular pressure elevation. PATIENTS AND METHODS: Periocular injections have been given to patients suffering from strictly unilateral or bilateral but asymmetrical and noninfectious posterior uveitis. A history of corticosteroid-induced glaucoma was a contraindication to such treatment. A retrospective review of cases who were given subtenon triamcinolone acetonide injection between May and October 2001 was undertaken to evaluate the efficacy of the treatment and the risk of intraocular pressure elevation. Ocular pressure was measured before and after the injection and the efficacy of the treatment was evaluated by measurements of visual acuity and fluorescein angiography. RESULTS: One or several injections were given to 61 patients. Intraocular pressure rose in 13 patients (21.3%). Medical treatment was unsuccessful in three cases and surgical excision of periocular corticosteroid deposit was required. Therefore, intraocular pressure was controlled with no other medication. Treatment was considered effective in 32 patients (52.45%): improvement of visual acuity (more than two lines) or control of inflammation on fluorescein angiography. DISCUSSION: and conclusions: Periocular subtenon injection of triamcinolone acetonide in posterior noninfectious uveitis is a safe procedure. Intraocular pressure elevation is not frequent and can be controlled through medical treatment or surgical excision of a residual deposit, in which pharmacologically active triamcinolone can be present several months after the injection.

Adolescent↗
PubMed2002

[Vision disorders of central origin].

Cortical blindness (or more generally, cerebral blindness) consists of bilateral visual loss with normal ocular examination and normal pupillary function, related to bilateral occipital lesions. Its most frequent cause in adults is hypoperfusion in the vertebral-basilar arteries, although other curable causes are described. Other syndromes, related to lesions of associative cortical areas or occipital-fugal connections may cause poorly defined visual complaints. Their recognition by the ophthalmologist is mandatory, as they may concern a potentially curable underlying disease.

Blindness, Cortical↗
PubMed2001

Value of high-frequency ultrasound biomicroscopy in uveitis.

PURPOSE: To determine the use of high-frequency ultrasound biomicroscopy (UBM) in the assessment of inflammatory lesions of the iris, ciliary body, pars plana and peripheral vitreous, and in particular to determine the proportion of cases for which UBM contributed significant additional, hitherto inaccessible, information. METHODS: Charts of patients seen in the uveitis clinic at University Eye Hospital from November 1994 to September 1999 for whom a UBM investigation had been performed were analysed. UBM was performed in a standard manner, using a Humphrey UBM 840 system. The clinical relevance of the UBM findings was determined for the whole series and for the following six subgroups of patients arbitrarily established according to the type and location of pathology: hypotony, pseudophakic uveitis, iris and ciliary body pathology excluding hypotony, pars plana pathology, scleritis and Toxocara uveitis. Findings were classified as positive when they confirmed a suspected diagnosis of lesional process or when they gave essential information. Findings were classified as essential when they led to the diagnosis or when they modified therapeutic intervention. RESULTS: During the study period 111 eyes of 77 patients were included. UBM findings contributed essential information that allowed a diagnosis to be reached or that influenced treatment in 43% of cases. It yielded positive findings in 91% of cases, enabling assessment of morphological changes in the iris, ciliary body, and retroiridal and peripheral vitreous induced by intraocular inflammatory or pseudo-inflammatory disorders. Specific UBM signs, present in all patients, were identified in Toxocara uveitis. The groups of patients that benefited most from UBM examination were those with hypotony (83% essential findings) and opaque media (100% essential findings). CONCLUSION: For uveitis patients with an inflammatory process situated in the iris/ciliary body/pars plana/retroiridal vitreous areas, UBM was of great clinical value and improved the management in a significant manner.

Adolescent↗
PubMed2000

Rearrangement of immunoglobulin gene in metastatic Waldenström macroglobulinemia to the vitreous.

PURPOSE: To report metastatic Waldenström macroglobulinemia cells with immunoglobulin heavy chain gene rearrangement in the vitreous and the blood. METHODS: A 58-year-old man with Waldenström macroglobulinemia developed bilateral vitreitis. Diagnostic vitrectomy was performed on the left eye. The vitreous cells and the peripheral blood lymphocytes were analyzed using microdissection and polymerase chain reaction amplification. RESULTS: Vitrectomy specimen of the left eye contained a few degenerated cells. Molecular analysis showed immunoglobulin heavy chain gene rearrangement at the third complementary determining region of the vitreal infiltrating cells and peripheral blood lymphocytes. CONCLUSIONS: Waldenström macroglobulinemia rarely metastasizes to the vitreous. Molecular detection of the immunoglobulin heavy chain gene third complementary determining region rearrangement is helpful in the diagnosis of the malignancy. Microdissection combined with polymerase chain reaction is a useful and innovative tool for molecular pathological investigation.

B-Lymphocytes↗
PubMed2000

[Intraocular hypotony: use of ultrasound biomicroscopy (UBM) for differential diagnosis and its schematic representation].

OBJECTIVES: To determine the use of high-frequency ultrasound biomicroscopy (UBM) in the assessment of hypotony and in particular to determine the proportion of cases for which UBM contributed significant additional hitherto unaccessible information. PATIENTS AND METHODS: Ultrasound biomicroscopy was performed in a standard manner, using a Humphrey UBM 840 system (Humphrey Instruments, Inc., San Leandro, CA). UBM findings were analysed and the clinical relevance of UBM information was determined for the whole collective. RESULTS: Twelve patients with hypotony were examined. UBM findings contributed essential information that allowed to reach a diagnosis or that determined the therapeutic attitude in 10 of the 12 hypotonic patients. In two cases the cause of hypotony was tractional ciliary body detachment, in 5 cases it was post-inflammatory atrophy of the ciliary body, in 3 cases it was post-traumatic irido and cyclodialysis, in one case it was supraciliary and suprachoroidal effusion and in the last case it was due to uveal effusion syndrome. Based on these findings we established a schematic approach for hypotony. CONCLUSIONS: This procedure enabled us to assess the morphological changes found in patients with hypotony. In a majority of cases UBM was useful either to orient therapeutic intervention or to establish a diagnosis. On the base of our findings a schematic approach for hypotony, using UBM, was established.

Algorithms↗
PubMed2000

Ocular and central nervous system lymphoma: clinical features and diagnosis.

PURPOSE: To evaluate the clinical, angiographic, and cytopathologic features of ocular and central nervous system (CNS) lymphoma. PATIENTS AND METHODS: Retrospective study of 44 patients over a 10-year period. RESULTS: A total of 36 women and six men, mean age 54 years (range: 36-90 years), were included. The mean time interval between onset of ocular symptoms and diagnosis was 40 months (range: 1-144 months). Ocular involvement was bilateral in 84% of the cases. Laser flare photometry readings averaged 9.6 photons/ms (2.9-78.3 photons/ms). Vitritis was constant. Funduscopy revealed RPE abnormalities in 60.49% of the cases and punctuate retinal infiltrates in 33.5%. The most common findings with fluorescein angiography were window defects and hypofluorescent round lesions. Patients had CNS involvement in 66% of the cases. Cytologic examination of the vitreous samples showed high-grade B lymphoma in 86% of the cases. Interleukin-10 dosage, when performed, showed elevated levels averaging 2352 pg/ml in all vitreous samples. Molecular biology based on PCR confirmed the diagnosis in 12 patients. Treatment included systemic chemotherapy alone or associated with radiotherapy in various regimens. Fourteen patients died during follow-up. Only 12 patients were in complete remission. CONCLUSION: The prognosis of the disease remains poor. However, the new diagnostic tools and therapeutic strategies may improve the diagnostic delay and the survival outcome.

Adult↗
PubMed2000

Efficacy of interferon alfa-2a in severe and refractory uveitis associated with Behçet's disease.

PURPOSE: To evaluate the efficacy of interferon alfa-2a (IFN alfa) in severe uveitis associated with Behçet's disease, that is refractory to steroids and conventional immunosuppressive agents. PATIENTS AND METHODS: Patients with Behçet's disease (according to the International Study Group criteria), who relapsed despite steroids and immunosuppressive agents, were included in this retrospective study. Ophthalmological examination, laser flare photometry, and fluorescein angiography associated with laboratory tests were performed at regular intervals. IFN alfa (3 millions units thrice a week) was injected subcutaneously. RESULTS: Eight patients (sex ratio: 1) were included between May 1995 and January 1999. The mean age was 29.1 years (14-54 years) and the disease was present between 11 and 167 months before the administration of IFN alfa. IFN alfa was efficient in all cases with a mean follow-up of 22 months (10-55 months). Steroids were tapered from a mean dosage of 47 mg/d to a mean dosage of 8.5 mg/d. Ocular inflammation was controlled and visual acuity improved in all cases. Treatment was generally well tolerated despite a constant but transient flu-like syndrome. IFN alfa was tapered in three patients and stopped in one case without any relapse after five months. CONCLUSIONS: Within the limitations of this retrospective study, low-dose IFN alfa seems to be well tolerated, promising in the management of refractory forms of uveitis due to Behçet's disease, and effective in allowing a reduction of steroid dosage. A prospective controlled study is necessary to confirm these preliminary results.

Adolescent↗
PubMed2000

Ocular tuberculosis.

Despite the use of highly sensitive molecular tools, such as polymerase chain reaction, for the detection of Mycobacterium tuberculosis, ocular tuberculosis remains a subject of controversy. The diagnosis is often presumptive in the absence of ocular biopsies. Choroiditis is the most common ocular manifestation in patients with pulmonary and systemic tuberculosis. Indocyanine green angiography seems to be an interesting method to determine choroidal involvement. PCR technology is proposed to evaluate the presence of the tubercule bacillus DNA in ocular fluids and tissues when conventional microbiologic methods fail to confirm a bacterial etiology. Most of the presumed cases of ocular tuberculosis should be treated with associations of antituberculous drug, especially when a systemic steroid regimen is required.

Antitubercular Agents↗
PubMed2000

Intravenous immunoglobulin (IVIg) for the treatment of birdshot retinochoroidopathy.

Intravenous polyclonal immunoglobulin (IVIg) treatment has been successfully used in a number of autoimmune conditions. Birdshot retinochoroidopathy (BRC) is a bilateral autoimmune posterior uveitis which, in its progressive form, frequently requires immunosuppressive therapy. We report a clinical study aimed at determining the tolerance and efficiency of IVIg treatment in patients with active BRC. The study was conducted in an open manner. Eighteen patients were included. The initial visual acuity (VA) was < or =20/30 in 26 eyes, 20/25 in five eyes, and 20/20 in five eyes. IVIg was given as sole treatment at 1.6 g/kg every four weeks for six months, followed by injections of 1.2-1.6 g/kg at six to eight-week intervals. The mean follow-up was 39 months, ranging between 12 and 53 months. The results showed that the final VA of the 26 eyes with an initial VA of < or =20/30 was increased by two lines or more in 14 eyes (53.8%) and decreased in two (7.7%). Of the five eyes with an initial VA of 20/25, four had improved to 20/20 and one remained stable. Of the five eyes with an initial VA of 20/20, four remained stable and one deteriorated to 20/25. When present, macular edema was improved in half of the eyes on fluorescein angiography. Benign side effects were observed in 12 patients: moderate transient arterial hypertension (7), headache (6), eczematous lesions (6), and hyperthermia (4). The results suggest that IVIg may represent a safe alternative therapy for patients with BRC.

Adult↗
PubMed1999

Ultrasound biomicroscopy in peripheral retinovitreal toxocariasis.

PURPOSE: To report ultrasound biomicroscopic features in peripheral retinovitreal Toxocara uveitis. METHODS: Three patients with unilateral vitreitis suspected to be caused by peripheral toxocariasis were referred for ultrasound biomicroscopic examination of the peripheral retina, pars plana, and adjacent vitreous. RESULTS: In two of the three patients, characteristic pseudocystic transformation of the peripheral vitreous was seen. In both patients, Toxocara serology was positive and eosinophilia was present. In the third patient, no pseudocystic transformation of the peripheral vitreous was seen; however, there was the dense thickening adjacent to the pars plana usually seen by ultrasound biomicroscopy in pars planitis and corresponding to clinically visible snowbanks. The third patient had a negative Toxocara serology and later developed bilateral intermediate uveitis of the pars planitis type. In none of 48 patients with diverse inflammatory conditions of the retroiridal space that were examined by ultrasound biomicroscopy were the characteristic Toxocara-associated pseudocystic images seen. CONCLUSIONS: Pseudocystic transformation of the peripheral vitreous appears to be a rather specific and sensitive ultrasound biomicroscopic sign in patients with presumed peripheral toxocariasis that will likely aid diagnosis in difficult cases.

Adult↗
PubMed1999

Indocyanine green angiography in birdshot chorioretinopathy.

OBJECTIVE: Birdshot chorioretinopathy (BC) is an ocular inflammatory disease involving both the retina and the choroid. The study goal was to evaluate indocyanine green angiographic features in BC to assess choroidal involvement. DESIGN: Retrospective, observational case series. PARTICIPANTS: Fifty-two patients with BC documented with at least 1 concomitant fluorescein and indocyanine green angiogram. INTERVENTION: Indocyanine green angiography (ICGA) was performed according to a standard protocol used for inflammatory disorders. MAIN OUTCOME MEASURE: Indocyanine green angiographic signs were correlated with fundus photographs, fluorescein angiography, degree of inflammatory activity, and stage of disease. RESULTS: In active disease, three main features were observed. The principal finding, found in 100% of patients, was the presence of hypofluorescent dark dots during the intermediate phase of angiography; their evolutionary pattern was twofold, becoming either isofluorescent or remaining hypofluorescent at the late phase of angiography. The other two signs were fuzzy, indistinct choroidal vessels and late-diffuse choroidal hyperfluorescence. In chronic longlasting disease, the characteristic finding was the presence of hypofluorescent dark dots that persisted in the late phase of disease and is theorized to correspond either to chorioretinal atrophy (irregular geographic pattern) or to persistent choroidal granulomas (round oval form). CONCLUSIONS: Consistent ICGA findings in 52 patients allowed the authors to establish a fairly precise ICGA semiology for BC. This procedure enabled the authors to assess choroidal involvement, and, in selected cases, it also was found to be of diagnostic help and useful to monitor therapeutic intervention.

Choroid↗
PubMed1999

CMV retinitis in the era of HAART.

Since 1996, major advances in the treatment of AIDS have markedly changed the incidence and the prognosis of CMV retinitis. Highly active antiretroviral therapy (HAART) is a combination of nucleoside reverse transcriptase inhibitors and protease inhibitors. This new therapeutic strategy is highly efficient in reducing the HIV viral load and increasing CD(4)+ T-lymphocyte count. These biological effects are associated with an improvement of immune functions. Clinically, the completely quiescent CMV retinitis and the unusual prolonged relapse-free interval suggest a certain restoration of immune functions, making possible the discontinuation of maintenance therapy. For most authors, the decision to stop anti-CMV maintenance therapy is based on a CD4+ cell count >100 cells/microl with a low HIV viral load for at least four months. The improvement of CMV retinitis on HAART may also be associated with an intraocular inflammation called immune recovery vitritis. For some patients, this vitritis may be associated cystoid macular edema and an epiretinal membrane responsible for visual loss.

AIDS-Related Opportunistic Infections↗
PubMed1999

Cystoid macular oedema and cytomegalovirus retinitis in patients with HIV disease treated with highly active antiretroviral therapy.

BACKGROUND: Although cystoid macular oedema (CMO) is a rare cause of visual loss in AIDS related cytomegalovirus (CMV) retinitis, nine cases are reported of CMO occurring in HIV infected patients with a prior diagnosis of CMV who were receiving highly active antiretroviral therapy (HAART). METHODS: Medical and ophthalmological records of nine AIDS patients with inactive CMV retinitis were retrospectively analysed. Ophthalmic examination data, laboratory findings, and the systemic antiviral treatment were studied. Ophthalmic examination included visual acuity, anterior chamber flare measured with the laser flare cell meter (LCFM), vitreous haze quantification according to the Nussenblatt grading system, and fluorescein angiography. RESULTS: Nine HIV infected patients, eight men and one woman, mean age 39 years (range 29-53 years) presented with inactive CMV retinitis and CMO. On fluorescein angiography, CMO was present only in eyes (14 eyes) with signs of previous CMV retinitis. CMV retinitis was inactive in all of them. Visual acuity ranged from 20/200 to 20/30. In 10 eyes with CMV retinitis, anterior chamber flare measured with the LCFM ranged from 18.5 to 82 photons/ms (mean 35.42 ph/ms). A significant vitreous inflammation (1.5+) was observed in eight eyes. All patients had been treated with anti-CMV drugs for a mean period of 18 months (range 12-36 months). All nine patients received HAART with a combination of two nucleotide analogue reverse transcriptase inhibitors and one protease inhibitor for a mean period of 14 months (range 9-18 months). The HIV viral load was below detectable levels (< 200 copies/ml) in eight patients and low (3215 copies/ml) in one. At the time of CMO, the median CD4+ lymphocyte count was 232 cells x 10(6)/l (range 99-639). CONCLUSION: In AIDS patients, the usual absence of intraocular inflammation in eyes affected by CMV retinitis has been tentatively explained by the profound cellular immunodeficiency. In these patients, treated with HAART, CD4+ counts were increased for several months (mean 14 months). In their eyes, CMV retinitis was associated with significant ocular inflammation and CMO. These findings could be related to the restoration of immune competence after HAART as recently shown.

AIDS-Related Opportunistic Infections↗
PubMed1999

Entry of human cytomegalovirus into retinal pigment epithelial and endothelial cells by endocytosis.

PURPOSE: Human retinal pigment epithelial (RPE) cells and endothelial cells (HUVECs) are targets of human cytomegalovirus (HCMV) infection in vivo with significantly protracted replication in vitro compared with that in fibroblasts. This study analyzes the kinetics and mechanisms of HCMV entry into both cell types. METHODS: RPE cells were obtained from donor eyes. HUVECs were isolated from human umbilical cords. HCMV entrance was followed by electron microscopy and immunofluorescence in the presence of lysosomotropic agents and cytochalasin B. RESULTS: Human cytomegalovirus entered into RPE cells and HUVECs as early as 5 minutes after virus- cell contact. Entry was mediated by endocytosis, whereas HCMV enters fibroblasts through fusion. Most internalized viral particles and dense bodies appeared to be degraded within vacuoles. Viral entry, transport of viral proteins to the nucleus, and onset of viral transcription (immediate early [IE] protein expression) were significantly blocked by cytochalasin B. Lysosomotropic agents did not significantly reduce IE expression in RPE cells or HUVECs. CONCLUSIONS: This study shows that HCMV penetrates these highly specialized relevant cells via endocytosis. The low level of infection and the delay in the onset of HCMV expression seen in these cells compared with fibroblasts may be related to the sequestration and degradation of incoming viral particles in endocytic vacuoles.

Ammonium Chloride↗