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Biomedical subjects

V T Tran

Publications and source records attributed to V T Tran.

At least 19 recordsLinked to original sources
PubMed2004

Differential inflammatory involvement in retina and choroïd in birdshot chorioretinopathy.

BACKGROUND: Birdshot chorioretinopathy is characterised by dual unrelated inflammatory involvement of the retina and the choroid. Indocyanine green angiography made it possible to assess and follow choroidal disease with the same precision as retinal involvement was followed so far. The aim of this study was to analyse the severity, progression and response to therapy of both retinal involvement using fluorescein angiography and choroidal involvement using indocyanine green angiography. PATIENTS AND METHODS: Patients with birdshot retinochoroidopathy followed at La Source Eye Centre in Lausanne, Switzerland from January 1995 to December 2002 were subdivided into three subgroups according to the duration of evolution of the disease: untreated patients with no more than one year duration of the disease (group 1, n = 6); treated patients with disease duration of 1 - 7 years duration (group 2, n = 5) and patients with disease lasting for more than 7 years (group 3, n = 4). Fluorescein and indocyanine green angiographic signs (angiographic scores given by a masked observer) were analysed in the 3 groups and compared to the "cream-coloured" fundus lesions. RESULTS: Fifteen out of the 742 patients (2.0 %) seen at La Source Eye Centre during the time period considered presented BC and were included in the study. In the "early disease group" fluorescein and ICG angiography showed more severe choroidal than retinal involvement with respective scores of 3 +/- 0.79 (ICG) and 2 +/- 1.17 (FA) while there were few depigmented fundus lesions to be seen (score 1 +/- 0.27). The choroidal involvement responded well to systemic corticosteroids +/- immunosuppressive therapy (scores in groups 2 and 3 = 1.2 and 0.75), while retinal disease was stabilised at best (scores in groups 2 and 3 = 2.2. and 2.4) and depigmented fundus lesions increased (scores in groups 2 and 3 = 2.8 and 3). CONCLUSION: The evolution and response to therapy of retinal and choroidal disease in birdshot chorioretinopathy have a different course with choroidal disease responding well to therapy while retinal disease is more resistant, possibly explaining the slow deterioration of functional parameters despite therapy. The increase of "cream-coloured" fundus lesions despite good choroidal response to therapy could be explained by depigmentation left behind after resolution of choroidal stromal granulomas, a hypothesis recently confirmed by an autopsy case of birdshot chorioretinopathy.

Adrenal Cortex Hormones↗
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

The control of haemolysis during transurethral resection of the prostate when water is used for irrigation: monitoring absorption by the ethanol method.

OBJECTIVE: To determine whether the addition of ethanol to water for irrigation during transurethral resection of the prostate (TURP) and monitoring breath ethanol could be used to detect irrigant absorption and to limit free plasma haemoglobin in cases of absorption. PATIENTS AND METHODS: One hundred patients (46 in Piteå, Sweden and 54 in Uong bi, Vietnam) underwent surgery for benign prostatic hyperplasia (BPH) under an intermittent irrigation technique using water containing 2% ethanol. An expired breath alcohol meter was used to monitor ethanol in the patients' breath every 5 min. Blood samples taken after TURP were assessed for free haemoglobin in 99 patients, and other markers of haemolysis were also evaluated in the Swedish group. RESULTS: Thirty-two patients had detectable ethanol in their breath. There was a close correlation between the maximum ethanol reading during surgery and the level of free plasma haemoglobin after TURP (r = 0.90, P < 0.001). There was no correlation between the duration of TURP and the free haemoglobin level. CONCLUSION: Monitoring breath ethanol during TURP assesses absorption and so can help to keep control of haemolysis. It is suggested that the value on the alcohol meter should not be allowed to exceed 0.15 (corresponding to a blood ethanol level of 0.15 per thousand), which should maintain the free plasma haemoglobin level at < 1.0 g/L after TURP. Restricting the operative duration per se is not a reliable safety measure.

Absorption↗
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↗
PubMed1999

Posterior sub-Tenon's steroid injections for the treatment of posterior ocular inflammation: indications, efficacy and side effects.

PURPOSE: Posterior sub-Tenon's steroid injections (PSTSI) are a standard drug delivery method used for the treatment of chronic uveitis of the posterior segment. The aim of this study was to analyse the indications, efficacy and complications of PSTSI in the treatment of chronic uveitis. METHODS: During the period 1990-1994, 53 (9.5%) of 558 patients (58 eyes) followed up in the uveitis clinic received a total of 162 PSTSI of triamcinolone acetonide 40 mg in the superior quadrants. Indications for treatment were vision inferior or equal to 0.7 and/or intolerable visual disturbance. Only patients in whom PSTSI were the only treatment parameter changed were analysed. Among the main parameters analysed were visual acuity, aqueous laser flare photometry, intraocular pressure (IOP) and complications. RESULTS: Anatomical location of uveitis was as follows: anterior HLA-B27-related uveitis with CME (1 patient/1 eye), intermediate uveitis (28/32), posterior uveitis (10/10) and panuveitis (14/15). Mean duration of follow-up was 448+/-57 days. Visual acuity improved significantly from 0.40+/-0.03 to 0.79+/-0.07, with 59.4% of eyes having a gain of 2-5 Snellen lines and 18.7% a gain of >5 lines. Mean aqueous flare photometry decreased significantly from 29.6+/-3.5 to 13.6+/-2.2 photons/ms. Mean IOP increased significantly from 13.6+/-0.5 to 18.5+/-0.8 mm Hg with a rise of pressure >8 mm Hg in 23 cases (36%), transient in 16 cases, but chronic in 6 cases, needing filtering surgery. Partial superior ptosis was seen in two cases and cataract progressed in seven cases. CONCLUSION: PSTSI are very effective in restoring visual acuity in chronic uveitis of the posterior segment, without systemic complications, but at the expense of intraocular hypertension, a complication that was found more frequently than expected.

Adolescent↗
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↗
PubMed1998

Effect of cataract surgery with intraocular lens implantation on inflammation in chronic uveitis: a longitudinal laser flare photometry study.

BACKGROUND: The precise effect of cataract surgery with implantation of an intraocular lens (IOL) on the course of uveitis is not well known. Laser flare photometry allows quantitative assessment of intraocular inflammation. The aim of this study was to determine the effect of cataract surgery with IOL implantation on the disease course and level of inflammation in chronic uveitis, using laser flare photometry monitoring. METHODS: The charts of all patients who underwent surgery for secondary uveitic cataract between 1990 and 1994 (24/558 [4.3%]) were reviewed. Only eyes that had received standardized perioperative steroid treatment and had systematic laser flare photometry follow-up were included. Cataracts due to Fuchs' heterochromic cyclitis were excluded. Visual acuity, flare values and recurrence of flare episodes were compared before and after cataract surgery, and postoperative data were compared between eyes that received heparin-coated IOLs and those that received uncoated IOLs. RESULTS: Nineteen eyes of 16 patients met the inclusion criteria. The mean length of the pre- and- postoperative follow-up periods was 779 and 444 days respectively. The mean visual acuity increased from 0.2 (standard error of the mean [SEM] 0.2) preoperatively to 0.8 (SEM 0.3) postoperatively (p < or = 0.001). The mean flare value decreased from 58.6 (SEM 18.6) photons/ms during preoperative follow-up to 29.7 (SEM 7.8) photons/ms during postoperative follow-up (p < or = 0.006). The mean number of recurrences per 6 months decreased from 0.27 (SEM 0.03) preoperatively to 0.12 (SEM 0.01) postoperatively (p < or = 0.05). The difference in the postoperative recurrence rate between the eyes that received coated IOLs (0.0) and those that received uncoated IOLs (0.18 [SEM 0.02]) approached statistical significance (p < or = 0.054). INTERPRETATION: Quantitative assessment of inflammation by laser flare photometry in patients undergoing surgery for uveitic cataract showed that there was significantly less inflammation and fewer recurrences postoperatively and that recurrences were less severe.

Chronic Disease↗
PubMed1995

Modeling the electrophoresis of rigid polyions: application to lysozyme.

An algorithm is developed to determine the electrophoretic mobility of a rigid polyion modeled as a low dielectric volume element of arbitrary shape containing an arbitrary charge distribution. The solvent is modeled as a high dielectric continuum with salt distributed according to the linearized Poisson Boltzmann equation. Account is also taken of a Stern layer that separates the molecular surface and the surface of hydrodynamic shear, or Stern surface. Relaxation of the ion atmosphere because of the presence of the external field is ignored. The electrostatic and hydrodynamic problems are both solved by boundary element methods. The procedure is first applied to spherical polyions containing monopolar, dipolar, and quadrupolar charge distributions, and calculated mobilities are found to be in excellent agreement with the theory of Yoon and Kim. It is then applied to lysozyme by using models that account for the detailed shape and charge distribution of the enzyme. For reasonable choices of the molecular and Stern surfaces, calculated and experimental mobilities are found to be in fair agreement with each other. However, if a pH independent Stern layer (or, equivalently, translational diffusion constant, Dt) is assumed, the calculated mobilities exhibit a stronger pH dependence than is observed experimentally. A small increase in Dt with increasing pH could correct this discrepancy.

Algorithms↗
PubMed1995

Need for certainty and interest in genetic testing.

The relation among need for certainty, type of information presented about a genetic test, and level of interest in predictive genetic testing was examined. Participants were randomly assigned to receive 1 of 2 descriptions of the test. The only difference between the descriptions was that one included a paragraph that emphasized the cancer risk remaining for those who test negative for gene mutations. As predicted, a significant interaction between need for certainty and type of information presented was observed. Whereas women high in need for certainty were more interested in genetic testing when provided with the standard description and less interested when provided with the more complete one, women low in need for certainty showed the opposite pattern. The results suggest that interest in genetic testing is determined by the correspondence between an individual's personal goals and her perception of the kind of information provided by the test.

Adolescent↗
PubMed1994

[Uveitis in the elderly].

BACKGROUND: There is only scarce information available in the literature on uveitis of older patients. The aim of this study was to study this age group in greater detail. PATIENTS AND METHODS: 435 patients were seen in the uveitis clinic of the University Eye Hospital Jules Gonin from January 1990 to March 1993. We analysed here the 94 (21.8%) patients that presented a first episode of uveitis after the age of sixty. RESULTS: This collective was characterised by an increased frequency of the anatomic diagnosis of panuveitis (p < 0.0001), and of the specific diagnosis of zoster uveitis (p < 0.0001), sarcoidosis (p < 0.0001), uveitis associated with scleritis (p < 0.05) and granulomatous anterior uveitis (p < 0.01). The frequency of diagnosis of intermediate uveitis was significantly reduced (p < 0.034) as were the specific diagnosis of HLA-B27 positive acute anterior uveitis (p < 0.001), pars planitis (p < 0.08) and non granulomatous anterior uveitis (p < 0.01). Reiter's uveitis, Possner-Schlossmann Syndrome, Behçet's uveitis, Vogt-Koyanagi-Harada disease and Toxoplasmosis retinochoroiditis were never diagnosed in this group of elderly patients. The proportion of defined specific diagnosis (75.5%) was comparable to the group of patients of less than 60 years old. CONCLUSION: As can be seen from our data, epidemiological characteristics of old age uveitis differ markedly from younger patients which should influence the diagnostic approach in these patients.

Aged↗
PubMed1994

[Indications and complications of systemic corticosteroid therapy in treatment of uveitis].

PURPOSE: Systemic steroids is often the first choice of immunosuppressive therapy for severe endogenous uveitis. The aim of this study was to analyse the indications of steroid therapy, complications and side-effects. PATIENTS AND METHODS: Charts from all patients that received oral steroid therapy were reviewed for this purpose and a questionnaire was sent out to all patients to record their subjective complaints. RESULTS: From January 1990 to March 1993, 63 out of the 435 new patients seen at the uveitis clinic received oral prednisone. In 4 cases severe complications occurred that did however not lead to discontinuation of therapy. In 2 cases of intolerance cyclosporine (CsA) had to be added to the treatment regimen to lower the steroid doses and in one case steroids had to be stopped because of intolerance. The questionnaire showed a high rate of subjective side-effects to steroids. CONCLUSIONS: In our collective oral steroids were associated with complications, intolerance and side-effects in a high proportion of cases. It is important to explain the possible side-effects to the patient before starting the therapy. The preventable collateral effects like weight gain and decalcification should be addressed by diet recommendations and modern calcium sparing therapy.

Administration, Oral↗
PubMed1993

Intravenous cefazolin in penetrating eye injuries. Treatment of experimental posttraumatic endophthalmitis.

The use of intravenous antibiotics as prophylaxis in penetrating eye injuries is strictly empiric and not based on scientific data supporting their use. To determine the efficacy of prophylactic intravenous cefazolin in penetrating eye injuries, a rabbit model of posttraumatic endophthalmitis was developed. Forty rabbits received penetrating eye injuries followed immediately by an intravitreal inoculum of live Staphylococcus epidermidis. The rabbits then were randomly divided into four groups: group 1 received three doses of intravenous cefazolin; group 2 received six doses, and group 3 received nine doses; group 4 received no treatment and served as controls. All control rabbits developed 4+ vitreitis; rabbits receiving three doses of the antibiotic developed 2+ vitreitis, and those receiving six or nine doses of cefazolin showed no vitreous inflammation (P < or = 0.0001). Histologic examination of control eyes showed an exuberant reaction with formation of retrolental membranes, vitreous abscess, and retinal detachment. Eyes treated with nine doses of cefazolin were devoid of inflammatory cells. These findings suggest that intravenous cefazolin is effective in preventing the development of posttraumatic endophthalmitis in a rabbit model.

Animals↗
PubMed1993

Defective lens fiber differentiation and pancreatic tumorigenesis caused by ectopic expression of the cellular retinoic acid-binding protein I.

All-trans retinoic acid, a metabolite of retinol, is a possible morphogen in vertebrate development. Two classes of cellular proteins, which specifically bind all-trans retinoic acid, are thought to mediate its action: the nuclear retinoic acid receptors (RAR alpha, beta, gamma), and the cytoplasmic binding proteins known as cellular retinoic acid-binding proteins I and II (CRABP I and II). The function of the retinoic acid receptors is to regulate gene transcription by binding to DNA in conjunction with the nuclear retinoid X receptors (RXR alpha, beta, gamma), which in turn have 9-cis retinoic acid as a ligand. Several lines of evidence suggest that the role of the cellular retinoic acid-binding proteins is to control the concentration of free retinoic acid reaching the nucleus in a given cell. Here, we have addressed the role of the cellular retinoic acid-binding protein I in development by ectopically expressing it in the mouse lens, under the control of the alpha A-crystallin promoter. We show that this ectopic expression interferes with the development of the lens and with the differentiation of the secondary lens fiber cells, causing cataract formation. These results suggest that correct regulation of intracellular retinoic acid concentration is required for normal eye development. In addition, the generated transgenic mice also present expression of the transgene in the pancreas and develop pancreatic carcinomas, suggesting that overexpression of the cellular retinoic acid-binding protein is the cause of the tumors. These results taken together provide evidence for a role of the cellular retinoic acid-binding protein in development and cell differentiation. The relevance of these findings to the possible role of the cellular retinoic acid-binding proteins in the transduction of the retinoic acid signal is discussed.

Animals↗
PubMed1992

Vitrectomy for perforating eye injuries from shotgun pellets.

Pars plana vitrectomy and scleral buckling were performed on 22 eyes of 19 patients for treatment of perforating eye injuries from shotgun pellets. We reviewed the intraoperative findings at the time of vitrectomy to determine what factors might influence final visual acuity. The presence of a total retinal detachment at vitrectomy portended a poor prognosis when compared with eyes without total retinal detachment, as only one of ten eyes with total retinal detachment obtained useful vision (P = .002). Preoperative separation of the posterior vitreous was associated with a favorable outcome when compared with the absence of posterior vitreous detachment (P = .035), as ten of 16 eyes with posterior vitreous detachment at the time of vitrectomy ultimately achieved functional vision. The locations of the exit wounds did not affect visual success in the overall series of patients. However, in the patients who achieved visual success, exit wounds outside the vascular arcades were more likely to be associated with final visual acuities of, or better than, 20/70 than were those within the arcades (P = .022). Other prognostic factors, such as the number of perforations and the use of cryotherapy, were also examined for their effects on final visual outcome. However, these factors did not appear to affect visual outcome statistically.

Adolescent↗
PubMed1992

Postnatal development of the ciliary body and pars plana. A morphometric study in childhood.

The ciliary body of the human eye serves many vital functions and provides important access to the posterior segment of the globe in vitreoretinal surgery. Although embryogenesis and prenatal development of the ciliary body have been well documented, continuing development of the ciliary body during early childhood has not been studied extensively. We determined the lengths of the ciliary body and pars plana in 76 normal eyes of subjects who ranged in age from 1 week to 6 years. The ciliary body was found to be of substantial length soon after birth; it measured a mean of 3.06 mm nasally and 3.31 mm temporally. Three quarters of the final length of the ciliary body at adulthood was achieved by age 24 months. The growth of the ciliary body is discussed in relation to the growth of the eye.

Age Factors↗