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H S Dua

Publications and source records attributed to H S Dua.

At least 19 recordsLinked to original sources
PubMed2002

S antigen specific effector T cell activation detected by cytokine flow cytometry.

BACKGROUND/AIMS: Effector T cell activation is particularly important in the initiation of autoimmune uveitis. This pilot study seeks to demonstrate activation of human peripheral effector T cells in response to the uveitis candidate autoantigen, retinal S antigen (SAg), using cytokine flow cytometry (CFC). METHODS: Peripheral blood mononuclear cell (PBMC) suspensions from uveitis patients and controls were stimulated with bovine SAg. Activation responses were detected by CFC. RESULTS: Electronic gating enabled analysis of CD69+, IFN-gamma+ CD4+ lymphocytes. An SAg specific response was detectable in four of 13 patients and four of eight controls. CONCLUSION: SAg specific, peripheral, effector T cell activation can be detected by CFC. Similar levels of responsiveness were seen in patient and control groups. More detailed cytokine profiling may demonstrate functional differences between the groups.

Arrestin↗
PubMed2001

Tacrolimus (FK506) in the management of high-risk corneal and limbal grafts.

OBJECTIVE: To assess the efficacy and side effects of tacrolimus in the management of patients with high-risk corneal and limbal grafts. DESIGN: Noncomparative case series. PARTICIPANTS: Seventeen patients (23 grafts) were treated with tacrolimus; 15 patients (20 host corneas) had two or more quadrants of stromal vascularization, 6 patients had stem cell deficiency, and 6 patients had glaucoma. Seven patients had received one previous graft, six patients had two previous grafts, and four patients had three previous grafts. INTERVENTION: Patients with high-risk corneal and limbal grafts were treated with systemic tacrolimus at a mean optimum dosage of 4.4 mg daily (range, 2-12 mg daily). MAIN OUTCOME MEASURES: Graft survival, visual acuity. RESULTS: No patient has had irreversible graft rejection while receiving tacrolimus. The follow-up period ranges from 12 to 46 months, with a mean of 24 months. Three patients have had reversible graft rejection associated with low tacrolimus levels. Nine patients have stopped treatment; two had reversible rejection within 2 months of stopping, and five grafts remain clear. The other four patients stopped treatment because of graft failure, which was not considered to be rejection related. Eight patients remain on treatment, and all have clear grafts. CONCLUSIONS: Tacrolimus (FK506) is effective in prevention of rejection in patients with high-risk corneal and limbal grafts.

Epithelial Cells↗
PubMed2001

Ocular surface reconstruction in LOGIC syndrome by amniotic membrane transplantation.

PURPOSE: To determine whether preserved amniotic membrane can be used to reconstruct the ocular surface after excision of the invading granulation material typical of LOGIC syndrome (laryngeal and ocular granulation tissue in children from the Indian subcontinent). METHODS: Granulation tissue was dissected and excised from both eyes of a 10-year-old boy with LOGIC syndrome. This procedure was followed by coverage of the corneal, scleral, and subtarsal regions of each eye with amniotic membrane, which had been stored for 6 months at -70 degrees C. RESULTS: Initial 2.5-month follow up demonstrated complete disappearance of granulation tissue. The fornices were patent, there was no recurrence of symblepharon, ocular inflammation was suppressed, and the patient reported markedly increased comfort. Both eyelids remained ptotic because of levator muscle atrophy secondary to many years of inability to open either eye. No residual scarring or evidence of granulation tissue was observed in that period. The 10-month follow up demonstrated limited recurrence, particularly where there was an intraoperative break in the amniotic membrane. CONCLUSIONS: After 24 operations to treat the ocular complications induced by LOGIC syndrome, amniotic membrane transplantation was the first effective treatment. In the early follow up period (2-3 months), there was complete cessation of the proliferation of granulation tissue and reepithelialization of the corneal surface. Longer follow up (10 months) demonstrated limited recurrence, which will require retreatment.

Amnion↗
PubMed2001

The epithelial flap for photorefractive keratectomy.

BACKGROUND/AIMS: Epithelial debridement for photorefractive keratectomy (PRK) is associated with pain, slower visual recovery, and may be aetiological in haze production. The aim of this study was to assess the clinical results of a new technique involving raising and replacing of an epithelial flap in photorefractive keratectomy. METHODS: A prospective, non-randomised, comparative, paired eye trial was performed in 72 eyes of 36 patients who underwent PRK with a Nidek EC-5000 excimer laser. For epithelial debridement before PRK, the eyes were divided into two groups. The first eye of each patient was treated with 20% ethanol debridement and the second eye with an epithelial flap which was replaced after treatment. PRK was carried out with the same laser and nomogram in both groups by the same surgeon. Visual and refractive outcome of PRK treatment was compared in both groups. RESULTS: The mean (SD) preoperative mean spherical equivalent (MSE) was -3.61 (1.38) dioptres (D) (range -1.00 D to -7.88 D) with no significant difference between the two groups. After a mean follow up period of 62.6 weeks (range 52-70) the final MSE was +0.07 (0.61) D (range -5.50 D to +4.50 D) in the debridement group and -0.24 (0.43) D in the epithelial flap group. There was no statistically significant difference between the two groups in postoperative MSE. The best corrected visual acuity was better in the epithelial flap group at all visits; this difference was statistically significant (p<0.05). The corneal haze was less in the epithelial flap group and this difference was also statistically significant (p<0.05). CONCLUSIONS: Managing the corneal epithelium as a hinged flap with 20% ethanol is a safe technique with faster visual rehabilitation and reduced haze compared with debridement of the epithelium with alcohol. Further studies need to be performed to compare pain levels postoperatively with the epithelial flap and epithelial debridement.

Adult↗
PubMed2001

Intravitreal invading cells contribute to vitreal cytokine milieu in proliferative vitreoretinopathy.

AIM: To examine the contribution of infiltrating cells in the local production of cytokines within the vitreous of patients with proliferative vitreoretinopathy (PVR). METHODS: The presence of mRNA coding for IL-6, IL-8, IL-1beta, IL-1alpha, TNFalpha, IFNgamma, IL-12, and HPRT was investigated in 25 vitreous samples from patients with PVR, 11 vitreous samples from patients with retinal detachment (RD) not complicated by PVR, and 10 vitreous samples from patients with macular hole (MH). A quantitative reverse transcriptase polymerase chain reaction (RT-PCR) using an internal competitor was used to investigate these samples. From these samples, 15 PVR, 8 RD, and 8 MH were analysed for the protein levels of the same cytokines using enzyme linked immunosorbent assay (ELISA). Spearman correlation was used to test any association between mRNA and cytokine protein levels, as an indicator of the contribution these cells make to the intravitreal cytokine milieu. RESULTS: A strong correlation was found between mRNA and their respective cytokine levels (protein products) for IL-6, IL-8, IL-1beta, IL-1alpha, TNFalpha, IFNgamma (Spearman r = 0.83, 0.73, 0.67, 0.91, 0.73, and 0.73 respectively), but not for IL-12. The median levels of IL-6, IL-8, IL-1beta, and IFNgamma mRNA and their respective cytokines were significantly higher (p <0.05) in patients with PVR than in those with macular hole. There was no statistically significant difference in the median levels of IL-1alpha mRNA between PVR and MH but the cytokine IL-1alpha was detected at a significantly higher level in PVR compared with MH patients. Between PVR and RD patients, there was no statistically significant difference in mRNA levels for all the investigated cytokines (p >0.05) except for IL-6 where there was a statistical significance (p= 0.038). In contrast, the median levels of IL-6, IL-8, and IL-1beta cytokines were significantly higher (p <0.05) in patients with PVR than in those with RD, whereas for IL-1alpha and IFNgamma no significant statistical difference was detected between PVR and RD patients (p >0.05). When results of RD and MH patients were compared, a statistical difference was only detected in mRNA levels of INFgamma (p = 0.008). However, no difference was detected for INFgamma (protein product) or for any of the other cytokines between RD and MH patients. CONCLUSION: Levels of both protein and mRNA encoding IL-6, IL-8, IL-1beta, and IFNgamma is significantly increased in vitreous samples from patients with PVR. The strong correlation between ELISA detectable cytokines (protein products) and their respective mRNA levels suggest that intravitreal, invasive cells are the major source of these cytokines, with the exception of IL-12. Cells invading the vitreous do not appear to locally produce IL-12 mRNA. This would appear to implicate cells peripheral to the vitreal mass as the major source of this cytokine.

Adult↗
PubMed2001

Meta-analysis of randomised controlled trials comparing latanoprost with timolol in the treatment of patients with open angle glaucoma or ocular hypertension.

AIM: To evaluate the comparative efficacy and tolerance of latanoprost versus timolol through a meta-analysis of randomised controlled trials (RCTs). METHODS: Systematic retrieval of RCTs of latanoprost versus timolol to allow pooling of results from head to head comparison studies. Quality of trials was assessed based on randomisation, masking, and withdrawal. Sensitivity analyses were used to estimate the effects of quality of study on outcomes. The data sources were Medline, Embase, Scientific Citation Index, Merck Glaucoma, and Pharmacia and Upjohn ophthalmology databases. There were 1256 patients with open angle glaucoma or ocular hypertension reported in 11 trials of latanoprost versus timolol. The main outcome measures were (i) percentage intraocular pressure (IOP) reduction for efficacy; (ii) relative risk, risk difference, and number needed to harm for side effects such as hyperaemia, conjunctivitis, increased pigmentation, hypotension, and bradycardia expressed as dichotomous outcomes; and (iii) reduction in systemic blood pressure and heart rate as side effects. RESULTS: Both 0.005% latanoprost once daily and 0.5% timolol twice daily reduced IOP. The percentage reductions in IOP from baseline (mean (SE)) produced by latanoprost and timolol were 30.2 (2.3) and 26.9 (3.4) at 3 months. The difference in IOP reduction between the two treatments were 5.0 (95% confidence intervals 2.8, 7.3). However, latanoprost caused iris pigmentation in more patients than timolol (relative risk = 8.01, 95% confidence intervals 1.87, 34.30). The 2 year risk with latanoprost reached 18% (51/277). Hyperaemia was also more often observed with latanoprost (relative risk =2.20, 95% confidence intervals 1.33, 3.64). Timolol caused a significant reduction in heart rate of 4 beats/minute (95% confidence interval 2, 6). CONCLUSION: This meta-analysis suggests that latanoprost is more effective than timolol in lowering IOP. However, it often causes iris pigmentation. While current evidence suggests that this pigmentation is benign, careful lifetime evaluation of patients is still justified.

Adrenergic beta-Antagonists↗
PubMed2001

Failure of amniotic membrane transplantation in the treatment of acute ocular burns.

AIM: To report the failure of amniotic membrane transplantation (AMT) for ocular surface reconstruction in patients with severe acute chemical and thermal burns. METHODS: Four eyes of three patients who suffered severe chemical (n=3) and thermal (n=1) burns were studied. The aim of AMT was to prevent symblepharon formation, promote conjunctival regeneration, inhibit corneal melting by promoting epithelialisation, and to protect the ocular surface while associated lid burns were treated. AMT was used to cover the entire ocular surface of all the severely burnt and ischaemic eyes, 2-3 weeks after the injury. Where indicated, AMT was repeated by itself or in combination with other procedures in all patients. RESULTS: Three of the four eyes developed symblepharon and progressive corneal melt requiring urgent tectonic keratoplasty. All four eyes had persistent epithelial defects. Less than 25% of conjunctival regeneration occurred in three eyes. Two eyes autoeviscerated, one patient underwent lid sparing exenteration for a painful blind eye and one eye became phthysical. CONCLUSIONS: AMT did not help to restore the ocular surface or preserve the integrity of the eye in all our patients with severe acute burns, when used by itself or in combination with other surgical procedures. This reflects the extreme severity of the ocular burns in these patients and, in turn, draws attention to the fact that the current classification system does not adequately reflect such severity. In the current system such burns would be grouped under grade IV injuries to the eye (more than 50% limbal ischaemia). The prognosis of patients with 100% limbal ischaemia is much worse than patients with just over 50% limbal ischaemia. This inadequacy of the classification system probably also explains the difference between outcomes of management of grade IV burns (with AMT) in this series, compared with others.

Acute Disease↗
PubMed2001

Effect of ABO blood group mismatching on corneal epithelial cells: an in vitro study.

AIM: To determine, in vitro, the effects of blood group ABO mismatching on corneal epithelial cells. METHODS: Corneal epithelial cell cultures were established from 32 human cadaver donor eyes. Epithelial cells (100 microl of 4 x 10(2) cells per microl) were incubated for 4 hours with antibodies against blood group antigens A, B, and AB, with and without complement. Cell lysis was assayed by a chemiluminescent assay using Cytolite reagent. Live cells, remaining after incubation, were counted in a scintillation counter. The blood group of the donors was determined retrospectively, in a blinded manner. RESULTS: Retrospective tracing of donor blood groups was possible for 20 donors. In all cases the blood group corresponded with that suggested by the cell lysis assay. Significant cell lysis was observed when known A group cells were incubated with anti-A and anti-AB antibody, B group cells were incubated with anti-B and AB antibody, and AB group cells were incubated with anti-AB antibody. Lysis occurred only in the presence of complement. No lysis of O group cells was observed with any of the antibodies. In all cases, lysis was observed only with neat (serum) antibody concentrations. CONCLUSIONS: Blood group ABO mismatching results in significant lysis of corneal epithelial cells. The antibody concentration required for lysis equals that found in serum. Such levels of antibody are unlikely to be achieved in tears and/or aqueous. This may offer an explanation for the conflicting reports of the studies on the effect of blood group matching on corneal grafts. The variability in the outcome may reflect the levels of antibodies gaining access to the corneal cells and not the mismatching alone.

ABO Blood-Group System↗
PubMed2001

In vitro model of infectious crystalline keratopathy: tissue architecture determines pattern of microbial spread.

PURPOSE: To develop an in vitro model of infectious crystalline keratopathy using human corneal buttons and to test the hypothesis that the compactness of the corneal stroma determines the pattern of microbial spread. METHODS: Twenty human corneal buttons obtained after penetrating keratoplasty for keratoconus (KC) and eight human corneal buttons obtained from eye bank (EB) donor eyes were maintained in organ culture. Fourteen buttons (10 KC and 4 EB donors) were maintained in a turgid state (swollen, edematous) and 14 in a nonturgid state (compact, normal state of deturgescence) by the omission or addition of 5% dextran to the culture medium. Eight KC and four EB nonturgid buttons and eight KC and four EB turgid buttons were inoculated with Streptococcus viridans (Lancefield group G, gram-positive) organisms. Two KC nonturgid and two KC turgid buttons were inoculated with Klebsiella oxytoca (gram-negative) organisms. Bacterial migration and spread in the tissue were observed by light and electron microscopy. RESULTS: Of the nonturgid buttons, six KC buttons and all four EB buttons inoculated with S. viridans and both KC buttons inoculated with K. oxytoca demonstrated an arborizing, crystallike pattern of bacterial spread. In the turgid buttons, five KC and all four EB buttons inoculated with S. viridans and both KC buttons inoculated with K. oxytoca demonstrated globular, amorphous colonies. This was in complete contrast to the needlelike branching appearance seen in nonturgid corneal buttons. Electron microscopy confirmed an interlamellar spread of the bacterial colonies. CONCLUSIONS: This is the first in vitro model of bacterial keratitis. It demonstrates that the pattern of spread of bacteria within corneal tissue is largely determined by the compactness of the corneal stroma. Altering tissue architecture changed the pattern of bacterial migration and spread. This model has considerable potential in further understanding host-microbe interactions and microbial spread that occurs during infection.

Adult↗
PubMed2000

Protection of corneal endothelium from irrigation damage: a comparison of sodium hyaluronate and hydroxypropylmethylcellulose.

PURPOSE: To compare the endothelial protection of sodium hyaluronate and hydroxypropylmethylcellulose against endothelial damage induced by irrigation. METHODS: An in vitro assay with freshly excised porcine eyes was developed using the Janus green photometry technique. Irrigation and aspiration technique was standardised. Forty pairs of porcine eyes were used. One randomly chosen eye was filled with sodium hyaluronate (SH) and the other with hydroxypropylmethylcellulose (HPMC). Irrigation and aspiration was carried out with balanced salt solution for 5 min. Twenty additional pairs of porcine eyes served as controls. Student's t-test was used for statistical analysis. RESULTS: Both viscoelastic agents protected the endothelium as compared with controls. The endothelial protection, determined with the Janus green photometric technique, was significantly greater with HPMC than with SH. CONCLUSIONS: Viscoelastic agents are effective in protecting the endothelium from irrigation damage in porcine eyes in vitro. HPMC provided greater protection than SH in this particular model.

Animals↗
PubMed2000

Clinical and pathologic findings in human keratolimbal allograft rejection.

OBJECTIVE: To characterize the clinical and pathologic features of cadaveric keratolimbal allograft (KLAL) rejection. DESIGN: The study design is descriptive. PARTICIPANTS: Four patients (five eyes) with KLAL rejection are reported. INTERVENTION: All patients were subjected to slit-lamp biomicroscopy, treatment of rejection, and ultimately required repeat KLAL surgery. In three patients (four eyes), specimens obtained at the time of repeat surgery were subjected to immunohistochemical staining against the following immune and surface human antigens: CD4, CD8, CD19, CD3, DR, CK19, CK3, and vimentin. RESULTS: Signs of allograft rejection included intense sectoral injection, diffuse or perilimbal conjunctival injection, edema, and infiltration of the KLAL grafts, leading to punctate epithelial erosions, epithelial defects, and surface keratinization. Rejected specimens revealed T-lymphocyte infiltration (CD4:CD8, 2:1) with strong HLA-DR (MHC class II) expression. The epithelium stain results were positive for cytokeratin 19 and weakly positive to absent for cytokeratin 3. The epithelial stain results were weakly positive for vimentin in only one specimen. CONCLUSIONS: KLAL rejection is a newly recognized entity. Pathologic findings of rejected specimens indicate that this is a T-cell mediated rejection phenomenon. The pattern of cytokeratin staining provided little evidence that the epithelium covering KLALs had a corneal phenotype. The scarcity of vimentin-positive epithelial cells suggests that the stem-cell/transient-cell pool was probably depleted. Early recognition of clinical rejection is important, as treatment with immunosuppressive therapy may reverse the process.

Adult↗