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Biomedical subjects

R Belfort

Publications and source records attributed to R Belfort.

At least 19 recordsLinked to original sources
PubMed2006

TGFBI gene mutations in Brazilian patients with corneal dystrophy.

PURPOSE: To investigate the transforming growth factor beta-induced gene (TGFBI) mutations in Brazilian patients with corneal dystrophy and to evaluate the phenotype-genotype correlation in these patients. METHODS: A total of 11 unrelated families were studied. The diagnosis of corneal dystrophy was based on clinical and histopathological findings. Genomic DNA was extracted from peripheral blood leucocytes, and exons 4 and 12 of the TGFBIgene were amplified by polymerase chain reaction followed by direct sequencing on both strands. RESULTS: Five different mutations in the TGFBIgene were found in the probands. We identified the following mutations: lattice corneal dystrophy--R124C and A546T; Reis-Bücklers corneal dystrophy--R555Q and R124L; granular corneal dystrophy--R555W and Avellino dystrophy--R555W. In three of the 11 studied families there was no mutation in exons 4 and 12. CONCLUSIONS: This is the first report of mutations in the TGFBIgene in a series of Brazilian patients with corneal dystrophy. The findings indicate that TGFBIgene screening should be considered in the diagnosis of corneal dystrophy.

Base Sequence↗
PubMed2006

Colour vision defects in asymptomatic carriers of the Leber's hereditary optic neuropathy (LHON) mtDNA 11778 mutation from a large Brazilian LHON pedigree: a case-control study.

AIMS: To determine if asymptomatic carriers from a previously identified large pedigree of the Leber's hereditary optic neuropathy (LHON) 11778 mtDNA mutation have colour vision deficits. METHODS: As part of a comprehensive analysis of over 200 members of a large Brazilian LHON pedigree spanning seven generations, colour vision tests were obtained from 91 members. Colour vision was tested one eye at a time using the Farnsworth-Munsell 100 (FM-100) hue colour vision test. The test was administered under uniform conditions, taking into account: ambient light levels, daylight colour temperature of 6700 kelvin, and neutral uniform background. Tests were scored using the FM-100 MS-Excel computer scoring program. Defects were determined and categorised as tritan, deutan, or protan. Categorisation of each dyschromatopsia was based on review of demonstrated axis computer generated plots and age adjusted error scores which coincided with Verriest 95% confidence intervals. Only the axis with the greatest magnitude error score was used to classify the defect. 55 of the 91 test subjects were LHON mtDNA 11778 J haplotype mutation carriers, proved by mtDNA analysis. The remaining 36 subjects were age matched non-blood relatives (off pedigree), who served as controls. RESULTS: 27 of 55 carriers (49.10%) were shown to have colour vision defects in one or both eyes. 13 of the 27 (48%) abnormal tests in the carrier group were tritan defects and the remaining 14 (52%) were deutan defects. Nine of the 27 (33%) abnormals in the carrier group were identified as having bilateral defects. Six of these were deutan, and the remaining three were tritan dyschromatopsias. Only six of the 36 (16.66%) age matched controls were found to have any type of dyschromatopsia. Five (83.3%) of these were deutan defects. The remaining one was a tritan defect. The difference between the two groups using a chi(2) test with one degree of freedom was statistically significant with a p value less that 0.001. CONCLUSIONS: Until now, LHON has always been characterised by a sudden, devastating vision loss. Asymptomatic carriers, those without vision loss, were considered unaffected by the disease. It now appears that asymptomatic carriers of the LHON mutation are affected by colour vision defects and may manifest other subtle, yet chronic, changes.

Brazil↗
PubMed2004

Adiponectin receptors gene expression and insulin sensitivity in non-diabetic Mexican Americans with or without a family history of Type 2 diabetes.

AIMS/HYPOTHESIS: The recent discovery of two adiponectin receptors (AdipoR1 and AdipoR2) will improve our understanding of the molecular mechanisms underlying the insulin-sensitising effect of adiponectin. The aim of this study was to determine for the first time whether skeletal muscle AdipoR1 and/or AdipoR2 gene expression levels are associated with insulin resistance. METHODS: Using RT-PCR and northern analysis we measured AdipoR1 and AdipoR2 gene expression in skeletal muscle from healthy Mexican Americans with normal glucose tolerance who had (n=8) or did not have (n=10) a family history of Type 2 diabetes. RESULTS: Gene expression profiling indicated that the AdipoR1 and AdipoR2 isoforms are highly expressed in human skeletal muscle, unlike in mice where AdipoR2 expression was highest in the liver, and AdipoR1 was highest in skeletal muscle. In the study subjects, the expression levels of AdipoR1 (p=0.004) and AdipoR2 (p=0.04), as well as plasma adiponectin concentration (p=0.03) were lower in people with a family history of Type 2 diabetes than in those with no family history of the disease. Importantly, the expression levels of both receptors correlated positively with insulin sensitivity (r=0.64, p=0.004 and r=0.47, p=0.048 respectively). CONCLUSIONS/INTERPRETATION: Collectively, these data indicate that both isoforms of the adiponectin receptor play a role in the insulin-sensitising effect of adiponectin.

Adiponectin↗
PubMed2002

Ocular toxoplasmosis: more than just what meets the eye.

Toxoplasma gondii is an intracellular parasite whose life cycle may include the man as an intermediate host. Close to a billion people are infected with this parasite worldwide. Ocular lesions may occur in up to 25% of those individuals infected. The infection may occur intra-uterus, through the placenta when the mother is infected during pregnancy. The parasite may also infect adults after the ingestion of contaminated food products, most notably meats or water. We have shown that although congenital and post-natal (acquired) infection results in similar ocular lesions, the immunological mechanisms behind the development of disease are different. On the other hand, contrary to published data obtained in mice, we were unable to find evidence that the T. gondii express superantigen activity for human lymphocytes. Our findings are important because they suggest that superantigen activity is not important as a pathological mechanism in human disease. Our data also suggest that, whereas the ocular lesion caused by infection after birth is the result of an excessive or dysfunctional immune response, the lesions caused by congenital infection may be due to a lack of an appropriate response to the parasite.

Animals↗
PubMed2001

Resolution of microsporidial keratoconjunctivitis in an AIDS patient treated with highly active antiretroviral therapy.

PURPOSE: To report the outcome of microsporidial keratoconjunctivitis in a patient with acquired immunodeficiency syndrome (AIDS) after highly active antiretroviral therapy without any specific treatment for microsporidiosis. METHODS: Case report. A 42-year-old woman diagnosed with AIDS and severe immunodepression (CD4+ of 9 cells/mm(3) and viral load of 460,000/mm(3)), antiretroviral naive, presented with cerebral toxoplasmosis and microsporidial keratoconjunctivitis in the right eye documented by conjunctival scraping and electron microscopy. RESULTS: The patient was treated with a combination of indinavir, stavudine, and lamivudine, besides sulfadiazine and pyrimethamine. No specific treatment for the microsporidial keratoconjunctivitis was attempted. One month later, the keratoconjunctivitis had disappeared. CONCLUSION: This case suggests that microsporidial keratoconjunctivitis in the setting of AIDS and severe immunodepression can be effectively managed with highly active antiretroviral therapy alone.

AIDS-Related Opportunistic Infections↗
PubMed2001

A follow-up study of Toxoplasma gondii infection in southern Brazil.

PURPOSE: To understand better the natural history of ocular toxoplasmosis by reexamining a well-characterized population in Southern Brazil. METHODS: Ophthalmological examination and serologic tests for Toxoplasma gondii infection were performed in 1997 on 383 individuals who had undergone the same evaluation in 1990. RESULTS: Of 109 seronegative subjects in 1990, 21 (19.3%) became seropositive by 1997, and 2 (1.5% of previously seronegative patients; 9.5% of those known to have seroconverted) developed ocular toxoplasmosis. Seroconversion occurred more frequently in individuals under 17 years of age (16 of 46 patients, 34.8%) than in those greater than 17 years of age (5 of 63 patients, 7.9%; p = 0.002). Of 131 seropositive individuals who did not have ocular lesions in 1990, 11 (8.3%) had typical toxoplasmic lesions in 1997. Of the 13 individuals with non-specific hyperpigmented small retinal lesions in 1990, 3 (23%) presented with typical lesions in 1997. CONCLUSIONS: Acquired T. gondii infection can result in late development of ocular lesions. Small, non-specific hyperpigmented retinal lesions may represent sites of T. gondii infection in seropositive individuals.

Adolescent↗
PubMed2001

Anterior chamber intraocular lens for high myopia: five year results.

PURPOSE: To evaluate the effectiveness of the surgical correction of high myopia 5 years after anterior chamber intraocular lens (IOL) implantation and to analyze the lens position and related complications. SETTING: Federal University of São Paulo-Escola Paulista de Medicina, São Paulo, Brazil. METHODS: This prospective study comprised 26 eyes that were implanted with an anterior chamber IOL (model ZB5M) and had a minimum follow-up of 5 years. Before and after surgery, manifest and cycloplegic refractions were done; slitlamp examination was performed; anterior chamber depth was measured; and keratometry, ophthalmoscopy, and central corneal endothelial cell count were performed. At the last follow-up, computerized biomicroscopy of the anterior segment was also done. RESULTS: The spherical equivalent decreased from -16.5 diopters (D) +/- 4.1 (SD) preoperatively to -0.9 +/- 0.9 D postoperatively. At the last examination, 57.7% of eyes had a spherical equivalent refraction within +/-1.0 D of emmetropia. Of eyes with a preoperative best spectacle-corrected visual acuity of 20/40 or better, 73.3% had an uncorrected visual acuity of 20/40 or better postoperatively. The mean tilt caused by the IOL was 4.4 +/- 2.7 degrees (range 0.5 to 12.2 degrees) and the mean IOL decentration, 0.3 +/- 0.2 mm (range 0.02 to 0.8 mm). The mean decrease in the endothelial cell count was 1.5%, with a mean cell density of 2808 +/- 305 cells/mm2 preoperatively and 2765 +/- 242 cells/mm2 postoperatively. Pupillary ovalization was observed in 12 eyes (46.1%). CONCLUSIONS: The anterior chamber IOL safely and effectively corrected high myopia.

Adult↗
PubMed2001

Photodynamic therapy with indocyanine green for occult subfoveal choroidal neovascularization caused by age-related macular degeneration.

PURPOSE: To report two cases of occult subfoveal choroidal neovascularization (CNV) due to age-related macular degeneration (AMD) that were successfully treated utilizing large spot, low irradiance 810-nm light and intravenous injection of small-volume, high-concentration indocyanine green (ICG) bolus, termed ICG-mediated photodynamic therapy (i-PDT). METHODS: Case report. Two patients with occult subfoveal CNV (two eyes) due to AMD were treated with i-PDT and were prospectively followed with fluorescein and indocyanine green angiography as well as optical coherence tomography (OCT). RESULTS: Both patients presented a 3-line increase in visual acuity by twelve months of follow-up. A significant regression of the CNV was demonstrated by fluorescein angiography within one week following treatment. OCT revealed diminishing of the subretinal fluid. There were no complications related to the procedure. CONCLUSION: i-PDT induced CNV regression and improved the visual acuity in these particular cases, suggesting a new and promising way to treat neovascular AMD. The partial anatomical restoration associated to the improvement of the visual function observed in both patients suggests that a selective therapeutic effect was achieved. Further studies are required not only to assess the clinical value of this treatment but also to better understand the major mechanism of action involving this novel treatment modality.

Aged↗
PubMed2001

Lack of evidence for superantigen activity of Toxoplasma gondii towards human T cells.

Toxoplasma gondii is an obligatory intracellular parasite whose life cycle may include man as an intermediate host. More than 500 million people are infected with this parasite worldwide. It has been previously reported that T. gondii contains a superantigen activity. The purpose of the present study was to determine if the putative superantigen activity of T. gondii would manifest towards human T cells. Peripheral blood mononuclear cells (PBMC) from individuals with no previous contact with the parasite were evaluated for proliferation as well as specific Vbeta expansion after exposure to Toxoplasma antigens. Likewise, PBMC from individuals with the congenital infection were evaluated for putative Vbeta family deletions in their T cell repertoire. We also evaluated, over a period of one year, the PBMC proliferation pattern in response to Toxoplasma antigens in patients with recently acquired infection. Some degree of proliferation in response to T. gondii was observed in the PBMC from individuals never exposed to the parasite, accompanied by specific Vbeta expansion, suggesting a superantigen effect. However, we found no specific deletion of Vbeta (or Valpha) families in the blood of congenitally infected individuals. Furthermore, PBMC from recently infected individuals followed up over a period of one year did not present a reduction of the Vbeta families that were originally expanded in response to the parasite antigens. Taken together, our data suggest that T. gondii does not have a strong superantigen activity on human T cells.

Adult↗
PubMed2000

Discrimination between patients with acquired toxoplasmosis and congenital toxoplasmosis on the basis of the immune response to parasite antigens.

Many persons infected with Toxoplasma gondii develop ocular lesions. Immunologic parameters in the response to T. gondii were evaluated in infected persons with and without ocular lesions and in noninfected controls. Subjects were divided into groups on the basis of presence of serum antibodies to T. gondii, presence of ocular lesions, and clinical history. Production of interleukin-2 and interferon-gamma by peripheral blood mononuclear cells from patients with probable congenital toxoplasmosis was decreased, compared with that in persons with presumed acquired infection. Cell proliferation and delayed-type skin reaction induced by soluble toxoplasma tachyzoite antigen followed the same pattern. Asymptomatic persons showed high levels of interleukin-12 and interferon-gamma, whereas persons with ocular lesions had high interleukin-1 and tumor necrosis factor-alpha responses toward soluble toxoplasma tachyzoite antigen. These data suggest that patients with ocular disease due to congenital infection show tolerance toward the parasite. Furthermore, susceptibility to ocular lesions after acquired toxoplasmosis is associated with high levels of interleukin-1 and tumor necrosis factor-alpha, whereas resistance is associated with high levels of interleukin-12 and interferon-gamma.

Adolescent↗
PubMed2000

Epidemiological study of 134 subjects with allergic conjunctivitis.

At times it is difficult to distinguish among the subtypes of chronic allergic conjunctivitis. A prospective study with 134 patients was carried out. Patients were diagnosed with vernal keratoconjunctivitis (VKC), atopic keratoconjunctivitis (AKC) or perennial allergic conjunctivitis (PAC). Demographic information was also collected including, age at symptom onset, sex, history of non-ocular allergy, and history of family allergy. Forty-six percent were diagnosed with VKC, 40% with AKC, 8% with PAC, and 6% were not specifically diagnosed. This distribution information as well as the demographic information collected demonstrates that there are patterns within each subgroup of chronic ocular allergy sufferers. These findings will be helpful in the diagnosing and proper classification of ocular allergic conditions.

Brazil↗
PubMed2000

Treatment of cytomegalovirus retinitis with an intraocular sustained-release ganciclovir implant.

The objective of this prospective study was to evaluate the efficacy and complications of the use of an intraocular sustained-release ganciclovir implant for the treatment of active cytomegalovirus (CMV) retinitis in AIDS patients. Thirty-nine eyes of 26 patients were submitted to ocular surgery. All patients underwent complete ocular examination before and after surgery. The surgical procedure was always done under local anesthesia using the same technique. The mean time for the surgical procedure was 20 min (range, 15 to 30 min). The average follow-up period was 3.7 months. Of all patient, only 4 presented recurrence of retinitis after 8, 8, 9 and 2 months, respectively. Three of them received a successful second implant. All 39 eyes of the 26 patients presented healing of retinitis as shown by clinical improvement evaluated by indirect binocular ophthalmoscopy and retinography. Retinitis healed within a period of 4 to 6 weeks in all patients, with clinical regression signs from the third week on. Six (15.4%) eyes developed retinal detachment. None of the patients developed CMV retinitis in the contralateral eye. The intraocular implant proved to be effective in controlling the progression of retinitis for a period of up to 8 months even in patients for whom systemic therapy with either ganciclovir or foscarnet or both had failed. The intraocular sustained-release ganciclovir implant proved to be a safe new procedure for the treatment of CMV retinitis, avoiding the systemic side effects caused by the intravenous medications and improving the quality of life of the patients.

AIDS-Related Opportunistic Infections↗
PubMed2000

Hypopyon in a patient with presumptive diffuse unilateral subacute neuroretinitis.

PURPOSE: To report a case of diffuse unilateral subacute neuroretinitis (DUSN) that developed an acute iridocyclitis with hypopyon. METHODS: Case report. We describe a 21-year-old male with clinical diagnosis of DUSN who developed a sudden and severe acute iridocyclitis with hypopyon after one year of follow-up that resolved after treatment with systemic corticosteroids. RESULTS: Anterior chamber paracentesis was performed and cultures were negative. Cytologic studies disclosed the presence of eosinophils. CONCLUSIONS: This unusual ocular finding may be related to the death of the nematode in the course of the disease.

Acute Disease↗
PubMed1999

Exophiala jeanselmei causing late endophthalmitis after cataract surgery.

PURPOSE: To report two cases of late endophthalmitis caused by Exophiala jeanselmei after cataract surgery. METHODS: Case reports, including clinical evaluation, direct examination, and culture of the aqueous humor. RESULTS: In each case, samples from the anterior chamber had positive growth of yeasts with toruloid hyphae and pseudohyphae. Intravitreal and anterior chamber amphotericin B were used in both cases. Apparent clinical resolution was achieved, but after 3 months in one case and 6 months in the other the infection recurred more aggressively, with severe endophthalmitis leading to ocular atrophy. CONCLUSION: E. jeanselmei causes a severe intraocular infection and isolation, and identification of the agent ensures proper diagnosis and treatment. After clinical resolution of the infection, careful and long-term follow-up is recommended to promptly detect relapse and immediately reintroduce treatment.

Aged↗