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H Moreira

Publications and source records attributed to H Moreira.

At least 19 recordsLinked to original sources
PubMed2001

Laser in situ keratomileusis to correct myopia, hypermetropia and astigmatism after penetrating keratoplasty for keratoconus: a series of 27 cases.

BACKGROUND: Excimer laser treatment has been shown to be effective and safe in correcting anisometropia following penetrating keratoplasty (PKP). In this report we review our experience with excimer laser in situ keratomileusis (LASIK) to correct refractive myopia, hypermetropia and astigmatism in patients who had undergone PKP for keratoconus. METHODS: We reviewed the records of 22 patients (27 eyes) who had undergone LASIK to correct myopia, hypermetropia or astigmatism, in simple or combined forms, following corneal transplantation for keratoconus. LASIK was performed at a hospital in Curitiba, Brazil, between September 1998 and February 2000. The eyes were classified into two groups: those with a negative spherical equivalent and those with a positive spherical equivalent. LASIK was performed using the Moria LSK microkeratome and the Nidek EC-5000 excimer laser. RESULTS: The mean length of follow-up was 9.52 months for the 23 eyes with myopia and 5.75 months for the 4 eyes with hypermetropia. The mean refractive spherical equivalent in the myopic eyes was -5.27 (standard deviation [SD] 1.91) dioptres before LASIK and -0.45 D (SD 1.68 D) at the last follow-up visit. The corresponding values in the eyes with hypermetropia were +5.18 D (SD 1.46 D) and + 1.18 D (SD 0.94 D). The rate of regression of astigmatism in the myopic eyes was 76%. After surgery 18 (78%) of the myopic eyes and all the hypermetropic eyes had an uncorrected visual acuity of 20/40 or better. The best spectacle-corrected visual acuity was better than 20/25 in 22 (95.7%) of the myopic eyes and all the hypermetropic eyes. One eye lost 1 line of best spectacle-corrected Snellen visual acuity, and one eye lost 6 lines secondary to epithelial ingrowth. Wound dehiscence, intraoperative flap complications, graft rejection or other complications did not develop in this series. INTERPRETATION: In this series, LASIK proved to be relatively safe and effective in correcting refractive errors after PKP for keratoconus.

Adult↗
PubMed2001

Towards a model to predict macular dichromats' naming errors: effects of CIE saturation and dichromatism type.

Thirty macular dichromat children (12 protanopes + 18 deuteranopes) and 29 controls, between 5 and 9 years old, participated in a monolexemic denomination task. Their clinical status was determined after a repeated application of a chromatic test set (Ishihara, CUCVT, and TIDA). The stimuli to be named were 12 tiles from the Color-Aid set belonging to the green, blue, and purple basic categories. Results showed that: (a) Dichromats made more naming errors when low saturation stimuli were used; (b) protanopes made more errors that deuteranopes; and (c) pseudoisochromatic lines predicted accurately the type of most frequent naming errors but they underestimated macular dichromats' functional capacity to name colors. Results are consistent with a model of macular dichromats' vision that hypothesizes a residual third type of cone in the periphery of the retina. Implications of this fact for everyday use of colors by macular dichromats' and for the validity of standard clinical diagnoses are discussed.

Child↗
PubMed2001

Chronic Trypanosoma cruzi infection associated with low incidence of 1,2-dimethylhydrazine-induced colon cancer in rats.

Experimental data have demonstrated that chronic infection with intracellular parasites may enhance resistance against some types of tumour. This phenomenon has not yet been demonstrated for experimental Trypanosoma cruzi chronic infection. This study investigated the effect of a specific colon cancer inducing drug, 1,2-dimethylhydrazine (DMH), on chronically T.cruzi infected Wistar rats. Infection was obtained by inoculation of 10(5) tripomastigote forms by subcutaneous (s.c.) route. Acute phase of the infection was monitored every other day by examination of a blood smear from each animal until negativation. In the early chronic phase of the infection, colon adenocarcinoma was induced by weekly s.c. injections of DMH at a dose of 20 mg/kg body weight for 12 weeks. 102 animals were divided in four test groups: 39 infected rats received DMH (group 1); 32 non-infected rats received DMH (group 2); 16 infected rats and 15 non-infected animals were used as control groups. Animals were killed 6 months after the first dose of DMH. The whole colon was removed and prepared for light microscopic examination. Twelve animals from group 1 and 22 from group 2 had colon adenocarcinomas, the proportion of cancer being 30.7 and 68.7%, respectively (chi(2) = 10.16; P < 0.05). The relative risk of having a colon tumor in infected animals (group 1) was 0.45 (IC 95% 0.26-0.76), which is a protective risk compared with non-infected animals. These findings show that chronic infection with T.cruzi is associated with a lower incidence of DMH-induced colon cancer in rats.

1,2-Dimethylhydrazine↗
PubMed2001

Effect of pneumoperitoneal pressure on tumor dissemination and tumor recurrence at port-site and midline incisions.

Over the past several years numerous cases of port site tumor recurrence after laparoscopic resection of a cancerous tissue have been reported. Possible mechanisms for tumor seeding include tumor removal, contaminated instruments, pneumoperitoneum, and aerosolization of tumor cells. This experiment examined the relationship among trocar contamination, aerosolization, and tumor recurrence with increasing pneumoperitoneal pressure using a hamster model. Increased pneumoperitoneal pressure significantly increased both instrument contamination and tumor recurrence at midline and port site incisions. Interestingly, increasing pneumoperitoneal pressure had no significant effect on the number of aerosolized tumor cells. The results reaffirm that the use of a reduced pneumoperitoneum or gasless laparoscopy may significantly lower port site tumor recurrence.

Animals↗
PubMed2000

Consultation.

Explore the source record for details and available documents.

Journal Article↗
PubMed2000

Use of bioresorbable membrane (sodium hyaluronate + carboxymethylcellulose) after controlled bowel injuries in a rabbit model.

PURPOSE: Patients in whom enterolysis is performed are at high risk for recurrence of adhesions and for injury during adhesiolysis. Therefore, the aim of this study was to assess the safety of sodium hyaluronate-based bioresorbable membrane (Seprafilm) after myotomy and enterotomy. METHODS: A total of 60 rabbits underwent laparotomy with equal distribution to one of three groups: creation of either three repaired, or three unrepaired myotomies, or three repaired enterotomies. Thus, a total of 180 defects were created in the same anatomic positions. One-half of the animals in each group had the surface of the myotomies or enterotomies covered by Seprafilm. Fourteen days later, after complete absorption of Seprafilm, the presence of intra-abdominal abscess, adhesions, and the integrity of the suture line were evaluated by a surgeon blinded to the use of Seprafilm and by a standard radiographic isobaric contrast study. Statistical analysis was done by use of Fisher's exact test; significance was set at P < 0.05. RESULTS: The incidence of adhesions in the repaired myotomy group were 2 (6.6 percent) and 9 (30 percent) in the Seprafilm and control (nonSeprafilm) groups, respectively (P < 0.05); in the unrepaired myotomy group, 2 (6.6 percent) and 10 (33 percent) in the Seprafilm and control groups, respectively (P < 0.05); and in the enterotomy group, 28 (94 percent) and 29 (97 percent) in the Seprafilm and control groups, respectively (P = not significant). A single phlegmon occurred in the myotomy group at a Seprafilm site (1.6 (1/60) vs. 0 percent, P = not significant). There were no leaks in this group. In the enterotomy group, the incidence of phlegmons was 33 percent (10/30) in the Seprafilm group, whereas it was 27 percent (8/30) in the nonSeprafilm group (P = not significant). The incidence of leaks was 6.6 (2/30) and 10 percent (3/30) in the Seprafilm and nonSeprafilm group, respectively (P = not significant). CONCLUSION: The use of Seprafilm at the sites of myotomies significantly reduced the incidence of adhesions. Effectiveness at the enterotomy site may have been attenuated by a greater inflammatory response. Importantly, Seprafilm did not increase septic mortality in any group.

Absorbable Implants↗
PubMed2000

Probability of occurrence of life-threatening ventricular arrhythmias in Chagas' disease versus non-Chagas' disease.

The implantable cardioverter defibrillator (ICD) is highly effective in the treatment of ventricular arrhythmias (VA) responsible for sudden cardiac death. However, the probability of occurrence of these arrhythmic events in presence of cardiomyopathy remains uncertain. The aim of this study was to compare the probability of nonoccurrence of life-threatening VA in ICD recipients with Chagas' versus non-Chagas' heart disease. Over a mean follow-up of 10.5 months, 53 ICD recipients (mean age = 50.1 years, 48 male) were evaluated. Eleven patients had Chagas' heart disease, 19 had idiopathic dilated cardiomyopathy and 23 had ischemic cardiomyopathy. Ventricular tachyarrhythmias with a cycle length < 315 ms were considered life-threatening. The cumulative probability of nonoccurrence of life-threatening VA was examined by Kaplan-Meyer method and the outcomes were submitted to the log rank test. At 2 years, the cumulative probability of life-threatening VA nonoccurrence was 0 in the Chagas' heart disease group versus 40% up to 55 months of follow-up in the non-Chagas' disease group (P = 0.0097). Among patients with cardiomyopathies of different etiologies, those with Chagas' heart disease had the lowest cumulative probability of nonoccurrence of life-threatening VA, confirming its unfavorable prognosis and the importance of preventive measures against sudden death in this disease.

Adult↗
PubMed1998

Pudendal neuropathy is predictive of failure following anterior overlapping sphincteroplasty.

PURPOSE: This study assessed the efficacy of anterior overlapping sphincteroplasty and parameters predictive of a successful outcome. METHODS: Clinical findings and physiologic investigations of female patients who underwent anterior overlapping sphincteroplasty for fecal incontinence between 1988 and 1996 were reviewed. The extent of sphincter damage was assessed at needle electromyography as the number of quadrants exhibiting decreased motor unit potentials. Prolonged pudendal nerve terminal motor latencies were those of greater than 2.2 ms. The size of the endoanal ultrasound defect was assessed as degrees circumference of the external sphincter in which viable muscle was absent. Patients were reviewed by telephone questionnaire and were asked to grade the outcome of their surgery as excellent or good (success) or fair or poor (failure). Incontinence was graded using a scoring system of 0 (perfect continence) to 20 (complete incontinence). RESULTS: There were 100 patients who had an overlapping sphincteroplasty; complete follow-tip information was obtained for 77 patients at a median of 24 (range, 2-96) months. The median age was 47 (range, 25-80) years and they had a median duration of incontinence of four (range, 0.1-39) years. Prior sphincteroplasty had been performed in 30 patients with a median of one (range, 1-7) operations. Investigations performed included electromyography (n = 49), pudendal nerve terminal motor latency (n = 71), endoanal ultrasound (n = 49), and manometry (n = 67). Sixty percent of patients had improved continence and 42 (55 percent) considered their surgery to have been successful as attested to by a significant decrease in their incontinence score (from 15.1 +/- 4.5 to 4.3 +/- 4.2; P < 0.0001). Neither patient age, parity, prior sphincteroplasty, cause or duration of incontinence, extent of electromyography damage, size of the endoanal ultrasound defect, nor any manometric parameter correlated with outcome. However, 62 percent of 59 patients with bilaterally normal pudendal nerve terminal motor latencies had a successful outcome compared with only 16.7 percent of 12 patients with unilateral or bilateral prolonged pudendal nerve terminal motor latencies (P < 0.01). CONCLUSION: Bilateral normal pudendal nerve terminal motor latencies are the only factors predictive of long-term success after overlapping sphincteroplasty.

Adult↗
PubMed1997

Chagasic megacolon associated with colon cancer.

Two cases of chagasic megacolon associated with colon cancer are reported. This is the first communication with complete clinical details of this association. Our two cases presented tumors (adenocarcinomas) in a nondilated segment of the transverse colon. The associated tumor lesions were diagnosed by a barium enema. Both patients had a typical clinical epidemiology and history of chagasic megacolon.

Adenocarcinoma↗
PubMed1993

Holmium laser thermokeratoplasty.

PURPOSE: Corneal curvature can be altered by shrinking stromal collagen with a pulsed solid-state holmium: YAG laser in a procedure termed laser thermokeratoplasty. METHODS: The authors performed laser thermokeratoplasty in 40 human cadaver eyes using a ring pattern of 32 spots, each spot having a diameter of 300 microns. RESULTS: The amount of induced corneal steepening decreased as ring diameter was increased in 1 mm increments, with 22.2 +/- 3.3 and 3.7 +/- 2.0 diopters (D) of central steepening with diameters of 3 and 7 mm, respectively. Results of histologic examination showed a cone-shaped zone of increased stromal hematoxylin uptake extending posteriorly for 90% of stromal thickness. Energy levels greater than those needed to induce topographic changes produced limited endothelial injury in rabbit corneas and, in some cases, intraocular inflammation. A computerized, finite element model of the globe demonstrated central corneal steepening as a result of heat-induced stromal contraction to a depth of 75% corneal thickness. CONCLUSIONS: These data support previous studies indicating that central corneal topography can be modified by heating corneal stroma in a controlled fashion with the mid-infrared holmium:YAG laser.

Animals↗
PubMed1992

Multifocal corneal topographic changes with excimer laser photorefractive keratectomy.

Excimer laser photorefractive keratectomy can flatten the central cornea, thereby eliminating myopic refractive errors; in older patients, however, presbyopia limits satisfaction. Computer-assisted topographic analysis of corneas after refractive surgery indicates that a minority of patients achieve a multifocal lens effect, such that they maintain reasonable acuity over a range of defocus. We have purposefully attempted to create a multifocal refractive effect and have analyzed the subsequent topographies quantitatively to determine if multifocality was achieved. In corneas not operated on and plastic hemispheres, a fairly small range of corneal powers is observed; the range of powers is increased after a monofocal ablation. After multifocal ablations, a greater spread of surface powers is observed, often with a bimodal distribution, indicative of an apparent multifocal effect. These observations suggest that in some patients undergoing photorefractive keratectomy for myopia, it may be possible to reduce symptoms of presbyopia, although a decrease in image contrast or monocular diplopia may complicate this approach.

Animals↗
PubMed1992

In situ collagen gel mold as an aid in excimer laser superficial keratectomy.

PURPOSE: The aim of this study is to evaluate the potential use of bovine type I collagen as an adjuvant to excimer laser keratectomy. METHOD: A suspension of collagen with the capability to polymerize into a gel was applied to the anterior corneal surface of freshly enucleated porcine eyes, using 35.0 diopter (D), 45.5 D, or 52.0 D contact lenses as molds. Keratometry, photokeratoscopy, slit-lamp photography, scanning electron microscopy, and light microscopy were performed on the new surfaces. Furthermore, an irregular corneal surface was created and a suspension of collagen was applied to mask protruding irregularities, therefore creating a smooth surface that was subjected to excimer laser keratectomy. Ablation rates for both collagen and cornea were measured. RESULTS: Collagen suspension placed on a cornea and molded with contact lenses created a smooth-surfaced gel that conformed to the shape of the contact lens and adhered to the anterior cornea; it was optically smooth and regular as shown by photokeratoscopy, keratometry, and scanning electron microscopy. The corneal curvature was altered in accordance with the base curvature of the contact lens used. Results of keratometry showed resolution of pre-existing astigmatism without induction of new astigmatism. The ablation rate of the gel was not measurably different than that of cornea; hence, when applied to an irregular corneal surface, a smooth surface was created after excimer laser ablation. CONCLUSION: This study supports the potential value of collagen gel as an adjuvant to excimer laser keratectomy for removal of corneal irregularities as well as for correction of myopia or hyperopia with or without astigmatism.

Animals↗
PubMed1992

Quantitative analysis of wound healing after cylindrical and spherical excimer laser ablations.

PURPOSE: Superficial corneal ablation using the 193 nm excimer laser for the correction of myopia and astigmatism produces histologic changes in the corneal profile that can be quantitatively analyzed. METHODS: Using the excimer laser, spherical and cylindrical corneal ablations were performed on rabbit eyes at depths of 2, 4, 6, and 8 diopters. After 12 weeks, the corneas were examined histologically using a dichlorotriazinyl aminofluorescein stain for collagen, and the results were quantified using a digital video image analysis system. RESULTS: Epithelial thickness and thickness of new collagen were positively correlated with the depth of ablation after spherical ablations. With astigmatic ablations, epithelial thickness and new collagen production were correlated with ablation depth in one axis only. CONCLUSION: These results suggest that during cylindrical corneal ablations with the excimer laser, radially asymmetrical stromal ablations produce quantitatively asymmetrical wound healing.

Animals↗
PubMed1992

Corneal toxicity study of two perfluorocarbon liquids in rabbit eyes.

Perfluorocarbon liquids are fully fluorinated, synthetic, transparent compounds with a high specific gravity. These compounds are being increasingly used as an intraoperative tool for repair of complicated retinal detachments. A potential complication of their use, however, is liquid entering the anterior chamber in aphakic patients. In the study described herein we evaluated the effects of two of these liquids when placed in the anterior chamber of the rabbit eye. Sixteen rabbit eyes underwent anterior chamber injection of 0.05 ml of either perfluoroctane, perfluoropolyether, or balanced salt solution (control eyes). Animals were monitored clinically by biomicroscopy and external photography for up to 14 days, after which they were sacrificed and the corneas processed for light and for scanning electron microscopy. The animals injected with perfluoropolyether showed more intense stromal inflammation and corneal vascularization (p less than 0.02) than did those that received perfluoroctane. However, the perfluoroctane group showed more of the "fish-egging" phenomenon (p less than 0.03). Loss of endothelial cells was similar in the two groups, as determined by light and scanning electron microscopy. These results suggest that the corneal toxicity of these two perfluorocarbon liquids is such that their use as vitreous substitutes should be limited to short-term replacement.

Animals↗
PubMed1992

Anti-inflammatory therapy and outcome in a guinea pig model of Pseudomonas keratitis.

Corneal scarring as a consequence of bacterial keratitis is an important cause of visual loss and a major indication for penetrating keratoplasty. Anti-inflammatory agents might be useful in this condition for limiting corneal damage, but benefit from adjunctive anti-inflammatory therapy has never been demonstrated. In this limited pilot study, we compared the effect on clinical outcome of treating Pseudomonas keratitis in guinea pigs with prednisolone (a corticosteroid), flurbiprofen (a cyclo-oxygenase inhibitor), nordihydroguaiaretic acid (a lipoxygenase inhibitor), and a leukotriene antagonist, SKF104353 [R-(R*, S*)]-beta-[(2-carboxyethyl) thio-alpha-hydroxy-2-(8-phenyloctyl) benzenepropanoic acid, zinc salt]. None of the anti-inflammatory agents prevented sterilization of ulcers with antibiotic (ofloxacin) therapy. Therapy with the leukotriene antagonist appeared to reduce infiltrate size more quickly and produce a more rapid reduction in lesion size, but the differences were not statistically significant. Sample size calculations suggest that very large numbers of animals would be required to prove efficacy. The role of anti-inflammatory agents in reducing the stromal destruction caused by bacterial keratitis remains controversial.

Analysis of Variance↗
PubMed1992

Corneal topographic changes over time after radial keratotomy.

Radial keratotomy flattens the cornea, but in a nonuniform fashion. We used computer-assisted topographic analysis to examine curvature changes in different regions of the cornea. Within 45 days after surgery in human eyes, the central and midperipheral cornea flattens and the periphery steepens. Shortly after surgery, the central cornea (within 1-1.5 mm of the corneal light reflex) is steeper than the adjacent midperipheral cornea (1.5-3 mm peripheral to the light reflex). With time, however, the central cornea flattens more than the midperiphery, such that it is no longer relatively steeper. This regional variability in corneal curvature after radial keratotomy helps explain phenomena such as multifocal lens effect after radial keratotomy, and the changes with time account for the conflicting results observed clinically in human corneas and experimentally in human eye bank eyes.

Adult↗
PubMed1992

Multifocal corneal topographic changes after radial keratotomy.

Quantitative analysis of the central corneal refractive powers of both eyes of three patients demonstrated that, after radial keratotomy, the corneas tended to have a greater range of refractive powers than preoperatively, and that the corneas with a multifocal effect had a wider distribution of refractive powers than the corneas of eyes without this effect. It may be possible to intentionally achieve a multifocal lens effect by designing a refractive procedure to predictably widen the distribution of central corneal refractive powers.

Cornea↗