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J A Gomes

Publications and source records attributed to J A Gomes.

At least 37 records · Page 2Linked to original sources
PubMed1998

IFN-gamma in human Chagas' disease: protection or pathology?

An apparently paradoxical role for IFN-gamma in human Chagas' disease was observed when studying the pattern of cytokine production by peripheral blood mononuclear cells (PBMC) obtained from two groups of chagasic patients after specific stimulation with Trypanosoma cruzi-derived antigens. The groups studied were 1) patients treated with benznidazole during the acute phase of Trypanosoma cruzi infection and 2) chronically infected untreated patients. In the treated group, higher levels of IFN-gamma were produced by PBMC from individuals cured after treatment when compared to non-cured patients. In contrast, in the chronically infected group (not treated) higher levels of IFN-gamma were produced by PBMC from cardiac patients in comparison with asymptomatic (indeterminate) patients. This apparently paradoxical role for IFN-gamma in human Chagas' disease is discussed in terms of the possibility of a temporal difference in IFN-gamma production during the initial stages of the infection (acute phase) in the presence or absence of chemotherapy. The maintenance of an immune response with high levels of IFN-gamma production during the chronic phase of the infection may favor cure or influence the development of the cardiac form of the disease.

Chagas Disease↗
PubMed1997

Predictors of long-term survival in patients with malignant ventricular arrhythmias.

The study consisted of 369 patients (age 62 +/- 13 years) who presented to our institution from April 1984 to April 1994 for malignant ventricular arrhythmias presenting as sustained ventricular tachycardia (VT) in 57% of patients, ventricular fibrillation in 25% of patients, and syncope due to VT in 17% of patients. Coronary artery disease was present in 74% of patients, cardiomyopathy in 19% of patients, and no evident heart disease in 7% of patients. Two hundred twenty-one patients were given drug, therapy, 47 patients underwent arrhythmia surgery, and 75 patients had an implantable cardioverter-defibrillator (ICD). During a mean follow-up of 30 months (range 1 to 101), 66 patients (18%) died from a cardiac death of which 26 (39%) were sudden. Cox regression analysis was conducted utilizing a total of 19 variables (clinical and therapeutic) in the entire population and separately in patients with coronary artery disease and cardiomyopathy. The most significant variables (multivariate analysis) of survival from cardiac mortality in the entire population were: congestive heart failure (CHF) class (p = 0.0003), ejection fraction (p = 0.02), and the use of drug therapy (p = 0.03); in patients with coronary artery disease, CHF class (p = 0.0001) and ejection fraction (p = 0.0006); and in patients with cardiomyopathy, CHF class (p = 0.009) and sustained VT on Holter monitoring (p = 0.007). Kaplan-Meier survival rates from cardiac death were: significantly lower (p = 0.005) in patients with CHF class III and IV compared with CHF class I and II (25% vs 58%, p = 0.005) with drug therapy; marginally significant (47% vs 88%, p = 0.06) from 20 to 40 months in patients with an ICD; and nonsignificant in patients who underwent arrhythmia surgery (63% vs 71%). Patients with an ICD had a better expected survival (82%) than patients who had arrhythmia surgery (69%) and drug therapy (65%). Thus, in patients with malignant ventricular arrhythmias, CHF class was the most significant independent predictor of survival from cardiac mortality over all disease substrates, and therapy influenced survival depending on the CHF class. Patients in CHF class III and IV who underwent arrhythmia surgery or had an ICD had a better expected survival than those taking drug therapy, and the negative impact of antiarrhythmic therapy was most prominent in patients with CHF class III and IV.

Aged↗
PubMed1997

Phenotypic analysis of resident lymphoid cells in the conjunctiva and adnexal tissues of rat.

The conjunctival associated lymphoid tissue is considered to be an integral part of the mucosal immune system. Under normal circumstances immune mechanisms in mucosal associated lymphoid tissue of the gut and bronchus can selectively suppress, rather than enhance, immune responsiveness to encountered antigens, inducing a state of tolerance. It is possible that conjunctival associated lymphoid tissue can also induce a state of tolerance to encountered antigens. Such a response may be exploited to modulate immune mediated ocular disease. Enhanced tolerance may protect the host against foreign antigen. Alternatively, under certain circumstances when the normal immune system is altered or disrupted the mucosal tissue may act to induce sensitisation and trigger immune mediated disease. The rat is frequently used as an animal model of immune mediated eye disease, but the normal profile of immune cells in the rat conjunctiva has not been studied. This information is essential for meaningful interpretation in the experimental situation. In this study we examined the immunophenotype of lymphoid tissue associated with the conjunctiva, lacrimal gland and Harderian gland of the Lewis rat. CD4+, Ia+ and the monocyte/macrophage population of cells were found predominantly in the substantia propria of the conjuctiva and interstitial connective tissue of the glands. CD8+ cells were distributed mainly in relation to the conjunctival and glandular epithelium. Goblet cells stained strongly with the monoclonal antibody (MAb) MRC OX-39, which is a marker for IL-2 receptors. The overall pattern of distribution of immunocompetent cells in the rat was found to be similar to that reported in humans.

Animals↗
PubMed1997

Corneal transplantation in children with Peters anomaly and mesenchymal dysgenesis. Multicenter Pediatric Keratoplasty Study.

OBJECTIVE: The purpose of the study is to describe graft and visual outcomes of penetrating keratoplasty among young children with Peters anomaly and associated mesenchymal dysgeneses. DESIGN: The design was a multicenter retrospective analysis of the indications and outcome in pediatric keratoplasty. PARTICIPANTS: The records of all children aged 12 years and younger who underwent penetrating keratoplasty for mesenchymal dysgenesis between January 1975 and May 1993 at the participating centers were reviewed. MEASURES: The data were analyzed regarding graft survival and postoperative visual acuity. RESULTS: Forty-seven corneal transplants in 36 eyes of 29 patients with mesenchymal dysgenesis were studied. The majority of eyes operated on (30) had Peters anomaly (83%). Patients' mean age at the time of keratoplasty was 7 months. After a mean follow-up period of 38 months, 61% of eyes retained full graft clarity. One and 3-year survival rates were 79% (95% confidence interval [CI] = 65%-93%) and 62% (95% CI = 45%-79%), respectively. Postoperative corneal ulcers/nonhealing epithelial defects (P = 0.03), and additional noncorneal surgical procedures at the time of transplantation (P = 0.05) were associated with graft failure. Provision of postoperative optical aids (P = 0.01) was associated with better postoperative visual acuity levels. CONCLUSIONS: Penetrating keratoplasty for Peters anomaly and related mesenchymal dysgeneses in young children has a reasonable chance of success during the critical years of visual maturation and is associated with satisfactory visual results in one third to half the cases. The data suggest that complicated cases requiring additional surgical procedures have a worse prognosis.

Child↗
PubMed1997

Effect of topical anti-transforming growth factor-beta on corneal stromal haze after photorefractive keratectomy in rabbits.

PURPOSE: To determine the relationship between anti-transforming growth factor-beta (anti-TGF-beta) antibodies and the amount of corneal stromal haze after excimer laser photorefractive keratectomy (PRK). SETTING: Wills Eye Hospital, Philadelphia, Pennsylvania, USA. METHODS: Nineteen rabbits had bilateral PRK. Dichlorotriazinyl fluorescein was used to stain the exposed stroma; all rabbits were then treated with antibiotic ointment for 4 days. Ten rabbits were randomized to treatment with topical anti-TGF-beta1, -beta2, and -beta3 antibody 50 microg three times a day for 4 days; the others received diluent three times a day for 4 days. Stromal haze was graded weekly for 8 weeks on a 0 to 4+ scale. At the end of the study, all corneas were examined histopathologically. RESULTS: All treated eyes developed appreciable haze. Seven control rabbits and one antibody-treated rabbit had an epithelial erosion (P = .00001). Antibody-treated rabbits had significantly less haze at 3, 4, and 5 weeks (right eyes) and 3, 4, 5, 7 and 8 weeks (left eyes) (P < .05). Histopathology and fluorescence microscopy showed subepithelial collagen deposition consistent with clinical haze. CONCLUSIONS: Topical anti-TGF-beta antibody reduced stromal haze after PRK in the rabbit model and may be clinically beneficial in humans.

Administration, Topical↗
PubMed1997

A pitfall in using far-field bipolar electrograms in arrhythmia discrimination in a patient with an implantable cardioverter defibrillator.

Analysis of stored electrograms from bipolar far-field electrodes is considered to be useful in differentiating supraventricular from ventricular arrhythmias. A case of inappropriate ICD shocks for sinus tachycardia is presented whereby successive shocks caused marked widening of the ventricular electrograms. Analysis of these stored electrograms, recorded from far-field bipolar electrodes, gave the false impression of ventricular tachycardia. The widening was due to the current of injury effects, probably a consequence of the large amount of intervening myocardium between the bipoles. While analyzing recordings from far-field bipolar electrodes is generally useful, it is not always reliable, for changes in electrogram morphology, relative to baseline rhythm, may result from other factors like current of injury.

Adult↗
PubMed1997

Syncope: the diagnostic value of head-up tilt testing.

To determine the usefulness of prolonged head-up tilt in the diagnosis of neurally mediated syncope, 201 patients with history of syncope of unknown cause and 102 age and gender matched control subjects underwent a 40 minute 60 degrees head-up tilt test. Head-up tilt elicited syncope (i.e., was positive) in 74 of the 201 patients (37%) with a history of unexplained syncope and in only 6 of the 102 controls (6%). The specificity of the test was 100% in patients 60 years of age and older. Symptoms during tilt-induced syncope were identified by the patients as similar to those they had suffered during their spontaneous episodes. All 80 subjects who had tilt-induced syncope recovered without sequelae. The positive predictive value of a positive responses to head-up tilt was 93% and the negative predictive value was 43%. The results indicate that the prolonged head-up tilt test is a very specific procedure of high diagnostic value in patients with a history of unexplained syncope. It is particularly useful in the elderly age groups who have a high incidence of syncope.

Female↗
PubMed1997

Conjunctival autograft for pterygium surgery: how well does it prevent recurrence?

BACKGROUND AND OBJECTIVE: The efficacy of the surgical management of pterygium with conjunctival autograft was evaluated. PATIENTS AND METHODS: In a retrospective survey, the records of 94 consecutive patients who underwent surgery for pterygium between 1984 and 1993 were reviewed. Only the first pterygium procedure for each patient performed at Wills Eye Hospital was included. The statistical technique of survival curve analysis by the Kaplan-Meier product limit was used to analyze the results separately after the removal of primary and recurrent pterygia. RESULTS: Thirty-one patients with primary pterygium underwent simple excision. Forty patients had conjunctival autografts. The recurrence rates estimated at 1 year were 40% and 16%, respectively (P= .031). In both groups, patients who were 50 years old or younger were more likely to have a recurrence (P = .029). All 23 patients with recurrent pterygium had conjunctival grafts, and the estimation of recurrence at 1 year was 25%. No serious complications occurred in any group. * CONCLUSION: Conjunctival autograft decreases the recurrence rate for primary pterygium compared with simple excision.

Conjunctiva↗
PubMed1997

Corneal topography after selective suture removal for astigmatism following keratoplasty.

BACKGROUND AND OBJECTIVE: The authors sought to determine whether the immediate corneal topographic changes induced by selective suture removal for astigmatism after keratoplasty were stable over time. PATIENTS AND METHODS: Computerized videokeratoscopic images were obtained prior to and immediately following suture removal in 14 patients, and then again at the next postoperative visit 4 to 6 weeks later. These images were analyzed and statistically compared for central corneal power and vector of the central 3-mm corneal astigmatism. RESULTS: Most of the topographic changes induced by suture removal occurred immediately. However, continued shifting in corneal curvature did take place over the subsequent 4 to 6 weeks. Unpredictable shifts were more pronounced in patients whose surgery had been performed more than 20 months prior to suture removal. CONCLUSION: Computerized videokeratoscopy graphically elucidates continued shifts in corneal topography following the removal of sutures for the control of astigmatism after keratoplasty.

Aged↗
PubMed1996

Value of quantitative measurement of signal-averaged electrocardiographic variables in arrhythmogenic right ventricular dysplasia: correlation with echocardiographic right ventricular cavity dimensions.

OBJECTIVES: We sought to investigate the relation between signal-averaged electrocardiographic (ECG) variables and the extent of right ventricular disease, as estimated by right ventricular enlargement during detailed echocardiography, in patients with arrhythmogenic right ventricular dysplasia. BACKGROUND: In patients with ventricular tachycardia of right ventricular origin, a normal signal-averaged ECG is indicative of "idiopathic" ventricular tachycardia, whereas an abnormal signal-averaged ECG is a specific marker for right ventricular disease, especially dysplasia. Signal-averaged ECGs in these patients are mildly to grossly abnormal. METHODS: Ten patients with the clinical diagnosis of arrhythmogenic right ventricular dysplasia were included. All patients had documented, sustained ventricular tachycardia, no coronary artery disease and a normal QRS duration of < or = 110 ms on routine 12-lead electrocardiography. Signal-averaged ECGs were recorded using time-domain analysis. Right ventricular cavity dimensions recorded during two-dimensional echocardiography were measured at the level of the inflow tract, midcavity and outflow tract. Signal-averaged ECG variables and echocardiographic measurements were correlated using linear regression analysis. RESULTS: Nine of 10 patients had abnormal signal-averaged ECGs. There was a consistent correlation between all signal-averaged ECG variables and the right ventricular cavity dimensions at the level of the midcavity. The correlation was most significant with the duration of the filtered QRS complex (p < 0.001 for QRS duration, p < 0.01 for late potential duration and p < 0.05 for root-mean-square voltage of the last 40 ms). There was no consistent correlation between the signal-averaged ECG variables and right ventricular dimensions at the level of the inflow and outflow tracts. CONCLUSIONS: The majority of patients with arrhythmogenic right ventricular dysplasia have abnormal signal-averaged ECGs. In the absence of bundle branch block, the extent of abnormality of signal-averaged ECG variables is in proportion to right ventricular cavity enlargement, and thus is indicative of the severity of right ventricular dysfunction.

Adult↗
PubMed1996

The effect of topical cyclosporin on conjunctiva-associated lymphoid tissue (CALT).

Topical cyclosporin A is increasingly being used in the treatment of ocular surface immune-mediated disorders. The availability of the drug in oil-based vehicles or collagen shields has restricted its use because of ocular irritation or blurring of vision. Although topical cyclosporin is being used more frequently, its effect on the immunocompetent cells of the conjunctiva is not known. Our aim was to study the effect of cyclosporin instillation on the immunocomponent cells of conjunctiva-associated lymphoid tissue (CALT) of Lewis rat, using a novel method of topical drug delivery. A suspension of collagen bits impregnated with cyclosporin A was instilled into eyes of Lewis rats for 4 days (group 1) or 8 days (group 2). Control rats (group 3) received the suspension without cyclosporin. Frozen sections of eyelids and conjunctiva were immunostained with the following monoclonal antibody markers: W3/13 (CD3), W3/25 (CD4, macrophages), OX-8 (CD8), MARD-3 (B cells), ED1, ED2 (macro/monocytes), OX-6 (class II MHC, Ia) and OX-39 (CD25, IL-2 receptor). Intraepithelial (IE) and substantia propria cells for each subset were counted and expressed as numbers per section. By day 8, intraepithelial and substantia propria cells for all the above markers, except B cells, showed a significant reduction in numbers. The p values were < 0.02 for W3/13 (CD3), W3/25 (CD4), OX-8 (CD8), OX-39 (CD25) (IE only), ED1, ED2 and OX-6 positive cells. Goblet cells of control animals showed strong positive reaction with OX-39 (CD25) antibody. This was completely abolished following 8 days of topical cyclosporin. This study demonstrated that topical cyclosporin A induces a marked reduction in numbers of all subtypes of immunocompetent cells in the conjunctival epithelium and substantia propria.

Administration, Topical↗
PubMed1996

Vortex or whorl formation of cultured human corneal epithelial cells induced by magnetic fields.

The terms 'vortex keratopathy' and 'hurricane keratopathy' describe two similar conditions affecting the corneal surface. In the former, a vortex or whorl pattern is seen on the corneal surface and is due to the deposition of substances such as pigment, iron or drugs in the epithelial cells. In the latter, a similar pattern is presented by migrating epithelial cells but, unlike the former, the pattern is rendered more visible by fluorescein staining. Both represent the migratory pattern of normal epithelial cells which is otherwise not visible due to the slow rate of epithelial turnover and migration. The whorl pattern has a clockwise predisposition in the majority of cases and is hypothesised to be due to the influence of ocular electro-magnetic fields on the migrating epithelial cells. In this study we tested in vitro the effect of static magnetic fields on corneal epithelial cells. We were able to reproduce dramatic vortex or whorl patterns in response to magnetic fields, but without preferential migration towards the North or South Pole.

Adult↗
PubMed1996

Topographic stability and safety of contact lens use after penetrating keratoplasty.

PURPOSE: We evaluated long-term corneal topographic stability and the safety of contact lens use after penetrating keratoplasty (PK). METHODS: Over a period of 3 years, we followed 18 patients who had been fit with rigid gas permeable (RGP) contact lenses after PK on the basis of computerized topographic measurements 1.5 mm superior to the visual axis. Computerized corneal topography, keratometry, refraction, visual acuity, slit-lamp examination, and contact lens parameters were recorded at the time of lens fitting and at 3 years follow-up. Comparison between the two times was performed using the paired Student's t test. The ten patients (55.5%) that did not undergo suture removal after initial contact lens fitting and who did not change contact lens type during the follow-up period were considered eligible for topographic and keratometric evaluation. RESULTS: Absolute keratometric astigmatism, average keratometric values, computerized corneal topography measurements 1.5 mm superior to the visual axis, and inferior minus superior measurements did not reveal significant differences over time. Keratometric vector analysis showed a significant change in astigmatism during the study period. Complications observed in the 18 patients included suture infiltrates (two patients), corneal neovascularization (six patients), graft rejection (five patients), transitory punctate epithelial keratitis (eight patients), and giant papillary conjunctivitis (three patients). All were successfully treated topically and with temporary cessation of contact lens wear. CONCLUSIONS: RGP contact lens use after PK is safe provided patients are properly fit and followed by the ophthalmologist. Although corneal topographic changes occur, stability remains acceptable.

Adult↗
PubMed1996

Recurrent keratopathy after penetrating keratoplasty for aniridia.

Corneal lesions in aniridia include peripheral pannus and epithelial abnormalities that may advance centrally, resulting in the need for penetrating keratoplasty. Three patients with aniridia who underwent repeated corneal surgical procedures (one keratectomy and six penetrating keratoplasties) are described herein. A clinicopathological correlation was performed. In all three patients there was evidence of recurrent pannus and epitheliopathy on histopathological examination, which correlates with the clinical findings. These findings suggest that the pathophysiology of recurrent aniridia keratopathy may be related to a primary abnormality in the stem cells of the recipient corneal limbus. Aniridic pannus and epitheliopathy recur in grafts after penetrating keratoplasty and threaten the transplanted cornea. The risk of recurrent keratopathy should be considered when recommending a surgical procedure to patients with aniridia.

Adolescent↗
PubMed1995

Outcome of penetrating keratoplasty after ocular trauma in children.

OBJECTIVE: To characterize the outcome of penetrating keratoplasty in children for the visual rehabilitation of corneal injury. DESIGN: Multicenter retrospective study of the outcome of penetrating keratoplasty for ocular trauma in children. PATIENTS: All children aged 12 years and younger who underwent penetrating keratoplasty between January 1975 and May 1993 for penetrating corneal (n = 18) or corneoscleral (n = 3) trauma and nonpenetrating corneal trauma (n = 1). MAIN OUTCOME MEASURES: Graft survival and postoperative visual acuity improvement. RESULTS: Twenty-two children underwent 25 penetrating keratoplasties during the study period. Graft survival was 84% at 1 year and 70% at 2 years after surgery. Visual acuity improved in 15 (83%) of the 18 children with measurable preoperative and postoperative vision. Children with posterior segment injury before keratoplasty were less likely to maintain a clear graft (P = .04) and less likely to have improved vision postoperatively (P = .06). Children who received amblyopia treatment and appropriate optical correction postoperatively were more likely to have visual improvement than those who did not (P = .02). CONCLUSIONS: Penetrating keratoplasty for corneal trauma is generally a successful operation in the pediatric age group, with visual improvement seen in more than four fifths of cases. Graft survival and visual outcome are best in patients with trauma limited to the anterior segment. Aggressive postoperative refractive correction and amblyopia management also appear to contribute to a better visual outcome in pediatric keratoplasty.

Child↗
PubMed1995

The indications for and outcome in pediatric keratoplasty. A multicenter study.

PURPOSE: A multicenter study was undertaken to delineate the indications for and outcome of pediatric keratoplasty. METHODS: The authors retrospectively studied 164 grafts in 131 eyes of 108 children younger than 12 years of age, with an average follow-up of 45 months. Multivariate linear and logistic regression was performed to evaluate potential risk factors for poor visual outcome and graft failure. Graft survival was depicted in terms of the Kaplan-Meier survival curve. RESULTS: Corneal opacities were grouped into three diagnostic categories: congenital (64%), traumatic (17%), and acquired nontraumatic (19%) opacities. Overall graft survival was 80% at 12 months and 67% at 24 months postoperatively. There was no significant difference in retention of clarity among diagnostic groups. Vitrectomy-lensectomy, regrafts, and postoperative complications were associated significantly with poor allograft survival. Eighteen percent of all eyes had worse vision at the time of the last visit than preoperatively. Amblyopia treatment was the only independently significant prognosticator for visual improvement after surgery. Timing of keratoplasty was not demonstrated to be associated with visual outcome. Visual acuity in 33% of eyes that could be quantified was better than 20/200 at the last visit, whereas 62% of eyes retained full graft clarity. CONCLUSION: The authors conclude that keratoplasty can be successful in most children, especially when combined with appropriate amblyopia management.

Amblyopia↗