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Biomedical subjects

M A Viana

Publications and source records attributed to M A Viana.

At least 19 recordsLinked to original sources
PubMed2004

An imbalance of naive and memory/effector subsets and altered expression of CD38 on T lymphocytes in two girls with hyper-IgM syndrome.

In this report we evaluated CD4(+) T, CD8(+) T and natural killer (NK) cell counts, the levels of naive/memory subsets within the CD4(+) T lymphocyte population, expression of CD38 on T lymphocytes, and CD4(+) and CD8(+) T cell cytokine production in two girls with hyper-IgM (HIM) syndrome. Both girls developed recurrent infections early in infancy, presenting a wide spectrum of clinical manifestations, with a strikingly different disease severity between them. CD4(+) T cell counts were low in both children (patient 1: 214 cells/mm(3) and patient 2: 392 cells/mm(3)), and the CD4/CD8 T cell ratio was 0.4 for patient 1, the patient with the more severe disease, and 1.4 for patient 2. NK cell numbers were low in patient 1 (60 cells/mm(3)) and borderline (286 cells/mm(3)) with regard to normal levels in patient 2. An imbalance of naive and memory/effector cell subsets was found in both girls, with the percentage of CD45RA(+) 27(+) (naive) CD4(+) T lymphocytes being 5.8 and 12.4 for patients 1 and 2, respectively. Expression of CD38 on the surface of T lymphocytes was low in patient 1. Detection of intracellular interferon (IFN)-gamma and tumour necrosis factor (TNF)-alpha in CD4(+) and CD8(+) T lymphocytes upon PMA-Io stimulus was preserved in both children. In conclusion, we found low numbers of CD4(+) T lymphocytes and a dramatic redistribution of naive and memory/effector CD4(+) T lymphocytes in two girls with non-X-linked HIM syndrome. Furthermore, we found low expression of CD38 on T lymphocytes and low numbers of NK cells in the patient with the more severe disease, indicating a possible role for these cells in the pathogenesis of this immunodeficiency.

ADP-ribosyl Cyclase↗
PubMed2004

Laryngeal electromyography: technical features.

Laryngeal Electromyography (LEMG) is an auxiliary diagnostic method used for the comprehension and diagnosis of different neurological diseases that compromise laryngeal function. The most common LEMG technique is the percutaneous insertion of needle electrodes guided by surface anatomical references. We describe techniques for inserting needle electrodes into the tireoaritenoideus (TA), cricotireoideus (CT), cricoaritenoideus lateralis (CAL) and cricoaritenoideus posterioris (CAP) muscles; these are used at UNICAMP laryngology ambulatory, we discuss difficulties found and their proposed solutions. All patients were submitted to otorhinolaryngological, phonoaudiological and laryngeal endoscopy before LEMG. The CAP approach, by digital rotation of the thyroid cartilage was found to be the most difficult, followed by the CAL approach. TA and CT approaches gave no major problems, except with some older and obese patients. A significant complication of the TA approach via thyroid cartilage was a hematoma in one patient which partially obstructed the laryngeal lumen.

Adolescent↗
PubMed2004

Laryngeal electromyography in normal Brazilian population.

Quantitative analysis of normal values of motor unit action potentials duration and amplitude of muscles tireoaritenoideus (TA), cricotireoideus (CT), cricoaritenoideus lateralis (CAL), and cricoaritenoideus posterioris (CAP) was performed in 14 adult normal Brazilian volunteers. The recordings were obtained by percutaneously inserted concentric needle electrode. Different motor unit action potentials were manually selected in each muscle for quantitative computerized analysis of duration and amplitude. The mean values for duration and amplitude were respectively 3.8 ms and 413 microV for TA, 4.9 ms and 585 microV for CT 4.1 ms and 388 microV for CAL and 4.5 ms and 475 microV in CAP. There were no similar reports of normal values of motor unit action potentials in Brazilian subjects.

Action Potentials↗
PubMed2004

Laryngeal electromyography: contribution to vocal fold immobility diagnosis.

Laryngeal Electromyography (LEMG) is a diagnostic test commonly used in patients with vocal fold movement disorder. The aim of this study is to describe LEMG in patients with vocal fold immobility. A total of 55 dysphonic patients with vocal fold immobility diagnosed by laryngeal endoscopy were grouped according to probable clinical cause: 1) unknown; 2) traumatic; or 3) tumoral compression. They were submitted to LEMG by percutaneous insertion of concentric needle electrode. LEMG was conclusive in all patients and showed a majority with peripheral nerve injury. LEMG diagnosed peripheral nerve damage in 25 group 1, 12 group 2, and 11 group 3 patients. LEMG was normal in 4 patients, suggesting cricoarytenoid joint fixation. Central nervous system disorders was suggested in 2 and myopathic pattern in 1. As the major cause of vocal fold immobility is peripheral nerve damage, LEMG is an important test to confirm diagnosis.

Adolescent↗
PubMed1999

The effectiveness of protraction face mask therapy: a meta-analysis.

This study examined the effectiveness of maxillary protraction with orthopedic appliances in Class III patients. A meta-analysis of relevant literature was performed to determine whether a consensus exists regarding controversial issues such as the timing of treatment and the use of adjunctive intraoral appliances. An initial search identified 440 articles relating to Class III malocclusion. Among those articles, 11 studies in English and 3 studies in foreign languages met the previously established selection criteria. Data from the selected studies were categorized by age and appliance groups for the meta-analysis. The sample sizes were comparable between the groups. The statistical synthesis of changes before and after treatment in selected cephalometric landmarks showed no distinct difference between the palatal expansion group and nonexpansion group except for 1 variable, upper incisor angulation, which increased to a greater degree in the nonexpansion group. This finding implies that more skeletal effect and less dental change are produced in the expansion appliance group. Examination of the effects of age revealed greater treatment changes in the younger group. Results indicate that protraction face mask therapy is effective in patients who are growing, but to a lesser degree in patients who are older than 10 years of age, and that protraction in combination with an initial period of expansion may provide more significant skeletal effects. Overall mean values and corresponding standard deviations for the studies selected can also be used to estimate mean treatment effects expected from the use of protraction face mask.

Age Factors↗
PubMed1997

Long-term follow-up of initially successful trabeculectomy.

OBJECTIVE: The purpose was to study the long-term outcomes of primary trabeculectomies that were successful at 1 year. DESIGN: A retrospective study of patients with various types of glaucoma who had trabeculectomies that were successful at 1 year and who had a follow-up of at least 10 years. PARTICIPANTS: There were 40 patients (40 eyes) who had primary trabeculectomies that were successful at 1 year and who had a follow-up range of 10 to 21 years. INTERVENTION: Control of intraocular pressure (IOP) and disease progression was evaluated at 5, 10, and 15 years and at the last obtainable follow-up. MAIN OUTCOME MEASURES: Successful control of IOP was defined as IOP less than 21 mmHg or a reduction of 33% if preoperative IOP was less than 21 mmHg. Successful control of disease progression was defined as stable cup-disc ratios determined by examination, or color photographs or both, as well as stable visual fields. RESULTS: If an eye was considered successful by IOP at 1 year, the probability of successful control of IOP was 82% at 5 years and 67% at 10 and 15 years. If an eye was considered successful by IOP at 1 year, the probability of successful control of disease progression at 5 years was 77%, at 10 years 61%, and at 15 years 48%. If an eye did not require further glaucoma surgery at 1 year, the probability that it still would not need further surgery at 5 years was 90%, at 10 years 75%, and at 15 years 67%. Forty percent of eyes had cataract extraction by the time of last follow-up examination. CONCLUSIONS: Loss of IOP control and progression of glaucomatous damage occurs over time despite initial success at 1 year.

Adolescent↗
PubMed1997

The effect of hyperthyroidism on Müller's muscle contractility in rats.

The objective of this study was to determine if hyperthyroidism affects the responses of Müller's muscle to alpha-1 adrenoceptor agonists and consequently, if these responses might explain thyroid eyelid retraction. Sprague-Dawley adult rats (n = 37) were divided into control and treated groups and given either placebo or intraperitoneal triiodothyronine (250 micrograms/kg/d) for 1, 2, or 3 weeks. A suture was passed through their upper eyelid and connected to a force transducer that measured Müller's muscle contractions. Responses to phenylephrine (0.015-0.61 mmol) were compared with respect to peak amplitude and 50% duration of action. Mean maximum force values [+/-1 standard error of the mean (SEM)] in response to phenylephrine were 1.254 +/- 0.071 gr for controls and 0.963 +/- 0.062 gr for thyroid-treated subjects (p = 0.005). Mean 50% duration of response values (+/-1 SEM) were 9.143 +/- 1.108 min for controls and 5.763 +/- 0.973 min for thyroid-treated subjects (p = 0.014). Hyperthyroid rats had a significantly lower Müller's muscle response amplitude than control rats; however, duration of response was not significantly different between the groups. We believe that hyperthyroidism caused intrinsic changes in Müller's muscle that resulted in eyelid retraction. Based on hypotheses discussed in this article, we expect that further studies will localize these changes to the thyroid hormone receptor on Müller's muscle or calcium-triggered intracellular second messengers. Clinical significance would then be the ability to treat hyperthyroid eyelid retraction with drugs. This study provides the first evidence of functional impairment of Müller's muscle due to hyperthyroidism in an animal model.

Adrenergic alpha-Agonists↗
PubMed1997

[De novo absence status: case report].

There are few descriptions about middle-aged patients who have nonconvulsive status epilepticus, absence status. We reported the clinical case of a woman, 52-year-old, diabetic, referred to the emergency room in a confusional state. Initial electroencephalogram showed continuous typical, bilateral, symmetric and synchronous spike-and-wave discharges. Clinical and electroencephalogram normalization occurred immediately following intravenous injection of benzodiazepine. Computerized axial tomography was normal. The recognition of this entity is essential because of its similarity to psychiatric disturbance and its prompt response to proper treatment.

Diabetes Complications↗
PubMed1996

Differential care of corneal ulcers in the community based on apparent severity.

PURPOSE: To describe current practice patterns in treating infectious keratitis. METHODS: A questionnaire was designed that asked ophthalmologists to describe the diagnostic equipment accessible to their practice for performing smears and obtaining scrapings for microbial culture and sensitivity testing. The questionnaire also presented two hypothetical cases of patients with infectious keratitis. Bacterial keratitis was relatively early and less severe in the first patient, and it was more advanced and more severe in the second patient. Recipients were asked about their diagnostic and therapeutic approach. The survey was mailed to 300 ophthalmologists in Florida, Illinois, and New York. RESULTS: One hundred twenty-four completed surveys (45%) were returned. Six surveys were from cornea specialists, who were excluded from the analysis. Only 18 practices (15%) maintained access to Gram stain supplies, and 58 (50%) maintained culture supplies. Whereas 56% of respondents would treat the patient with the less severe bacterial keratitis without obtaining samples for cultures, only 13% would treat the patient with the more severe condition in this manner (P<0.00001). Of the respondents, 82% would treat the patient with the less severe bacterial keratitis with a fluoroquinolone, compared with 62% for the patient with the more severe infection (P=0.002). The mean frequency of fluoroquinolone administration for the patient with more-severe bacterial keratitis was one drop every 0.88 hours, compared with one drop every 1.48 hours for the patient with the less severe infection. CONCLUSIONS: Ophthalmologists appear to treat suspected infectious keratitis differently, depending on perceived severity; they choose different antibiotic regimens; and are more likely to forgo scrapings for Gram staining and cultures for ulcers that appear less severe. The justification for this approach should be established.

Adult↗
PubMed1996

Recovery from induced corneal edema and endothelial morphology after long-term PMMA contact lens wear.

PURPOSE: To study the effect of long-term polymethyl methacrylate (PMMA) contact lens wear (CLW) on corneal endothelial morphology and corneal hydration control (CHC). METHODS: Sixteen long-term PMMA CL wearers (mean duration of wear 20.8 +/- 8.39 SD years; mean age 40.37 years +/- 10.47 SD) served as subjects and 14 age-matched, non-lens wearing subjects (mean age 41.29 years +/- 10.15 SD) served as controls. Corneal function was assessed by measuring the corneal thickness recovery rate (PRPH) after induced edema from a hypoxic stress load. Endothelial morphology was assessed by taking specular microscopy photographs, digitizing the images, and calculating the cell density, size, and coefficient of variation of cell size (CV). RESULTS: Morphologic analysis showed a significant decrease in mean endothelial cell density (2147 vs. 2865, p < 0.01), an increase in mean cell size (582 vs. 381, p = 0.001), and an increase in polymegethism (CV, 0.32 vs. 0.26, p < 0.01) for PMMA lens wearers compared to agematched controls. Corneal function as measured by PRPH was not significantly different for PMMA lens wearers compared to controls when taken as a whole. However, a subgroup of PMMA lens wearers (seven eyes, four subjects) did show a substantial reduction in PRPH. These subjects also showed a strong relation between reduced PRPH, morphology, and years of lens wear (r2 = 0.99). CONCLUSIONS: Longterm PMMA CLW leads to increased polymegethism in most, if not all, cases and results in a substantial decrease in corneal function in some cases.

Adult↗
PubMed1994

Ocular manifestations of leprosy in a noninstitutionalized community in the United States.

OBJECTIVE: Our goal was to delineate the epidemiologic and clinical patterns of ocular leprosy in an outpatient setting in the United States. DESIGN: Examinations were performed in 61 consecutive outpatients seen in a Midwestern leprosy clinic. PATIENTS: Forty-three male and 18 female patients were examined. The patients' origins included Southeast Asia (24 patients [39%]), Latin America (23 patients [38%]), India (nine patients [15%]), Europe or North America (two patients [3%]), Africa (two patients [3%]), and the Middle East (one patient [2%]). RESULTS: Thirty-nine percent of patients were classified as having polar lepromatous leprosy; 18%, borderline lepromatous leprosy; 3%, borderline borderline leprosy; 36%, borderline tuberculoid leprosy; 2%, polar tuberculoid leprosy; and 2%, indeterminate leprosy. Ninety-six percent of patients had a best-corrected visual acuity of 20/40 or better. Ocular findings included madarosis (28 patients [46%]), subconjunctival fibrosis (18 patients [30%]), punctate epithelial keratopathy (17 patients [28%]), posterior subcapsular cataract (10 patients [16%]), corneal hypesthesia (10 patients [16%]), lagophthalmos (seven patients [11%]), corneal pannus (six patients [10%]), entropion (five patients [8%]), prominent or beaded corneal nerves (four patients [7%]), iridocyclitis (four patients [7%]), focal avascular keratitis (three patients [5%]), scleritis (three patients [5%]), interstitial keratitis (two patients [3%]), iris pearls (two patients [3%]), and ocular clofazimine crystals (two patients [3%]). Madarosis, corneal hypesthesia, and posterior subcapsular cataracts were significantly associated with disease duration (P < .05). CONCLUSION: We report herein a relatively low frequency of visual impairment attributable to leprosy in our series compared with that seen among institutionalized leprous patients. However, since 48% of subjects had one or more sight-threatening complications as a result of their disease, a program of regular ophthalmic follow-up is strongly advocated for all patients with leprosy.

Adolescent↗
PubMed1994

Predictors of occult scleral rupture.

PURPOSE: To determine which signs are sensitive and specific in the setting of trauma to establish the diagnosis of an occult scleral rupture. METHODS: The charts of patients with presumed scleral rupture were identified retrospectively. The ocular findings among the patients who had a rupture based on findings at surgery were compared with those patients who were noted to have normal findings at surgery. RESULTS: Visual acuity worse than 20/400, decreased intraocular pressure, intraocular pressure less than that in the nontraumatized eye, and an afferent pupillary defect were all significant indicators of an open globe. CONCLUSION: Determining the likelihood of an occult rupture can be facilitated by noting the presence or absence of those indicators that are significant and carry a high specificity.

Adolescent↗
PubMed1994

Dynamic shifts in corneal topography after radial and transverse keratotomy.

PURPOSE: The authors aimed to quantitate the dynamic patterns of change in corneal topography after multistaged radial and transverse keratotomy using digitized video-keratography. METHODS: Single and paired radial and transverse keratotomies, with videokeratoscopy between each stage and at the end of the procedure, were performed on fresh animal cadaver eyes using an artificial orbit system. RESULTS: All incisions led to central flattening. A single radial keratotomy caused flattening adjacent to the incision, and steepening 180 degrees away. A paired radial keratotomy caused increased flattening in the meridian of the incisions, and less flattening 90 degrees away. A single transverse incision caused steepening adjacent to the incision and diffuse flattening elsewhere. A paired transverse incision caused flattening near the optical center along the meridian bisecting the incisions and steepening 90 degrees away. CONCLUSION: The authors have demonstrated that computerized videokeratography can be used successfully to systematically quantitate dioptric shifts in multiple hemimeridians and measurement zone diameters after refractive surgery.

Animals↗
PubMed1994

Effect of methazolamide on chronic macular edema in patients with retinitis pigmentosa.

PURPOSE: To determine the effectiveness of methazolamide for improving visual acuity and macular edema in patients with retinitis pigmentosa. METHODS: Seventeen subjects with retinitis pigmentosa and chronic macular edema participated in a prospective, placebo-controlled, double-masked, crossover design study in which either methazolamide or a placebo was taken for 3 weeks. Visual acuity, fluorescein angiograms, and subjective impressions were obtained at baseline and after 3 weeks of treatment with each substance. A subgroup of subjects were enrolled in a more extended period of methazolamide treatment for an additional 3 months. RESULTS: Methazolamide resulted in the improvement of angiographic macular edema in 9 of 17 subjects. As a group, visual acuity statistically improved with methazolamide. However, improvement in at least one eye, of between two and four lines more than while taking placebo, occurred in only three (undilated pupils) or four (dilated pupils) subjects. Subjective improvement during treatment with methazolamide but not placebo occurred in only one subject. An extended period of methazolamide treatment for an additional 3 months in a subgroup of patients did not result in additional beneficial effects on visual acuity. In fact, a partial rebound in the extent of macular edema was found. CONCLUSIONS: Although angiographic improvement of macular edema can occur in patients with retinitis pigmentosa treated with methazolamide, notable (between 3 and 4 lines) or even moderate (between 2 and 3 lines) visual acuity improvement was seen in relatively few patients. When methazolamide was administered in a placebo-controlled fashion, subjective improvement in visual function also was not readily apparent. A more substantial subjective improvement in visual function had occurred with the use of acetazolamide in five of six subjects who also had participated in a previous treatment trial with the use of acetazolamide.

Adolescent↗
PubMed1994

Invasive and noninvasive methods to predict the long-term efficacy of amiodarone: a compilation of clinical observations using meta-analysis.

BACKGROUND: The method of choice to predict the long-term efficacy of amiodarone in the treatment of complex ventricular arrhythmias is unknown. Whether electrophysiological testing or Holter monitoring better predicts long-term outcome is controversial. METHODS AND RESULTS: We performed a meta-analysis of trials using electrophysiological testing or electrocardiographic monitoring to predict the efficacy of amiodarone in patients with sustained ventricular tachycardia. Arrhythmia recurrence data were combined after homogeneity testing across trials. Bayesian estimates and 95% credibility intervals were constructed to compare the arrhythmia-free probability among groups. Nine studies using electrophysiological testing (351 patients) and three using Holter monitoring (167 patients) met criteria for inclusion determined a priori. The combined arrhythmia-free probability estimate and credibility intervals were 0.86 (0.78-0.92) for patients rendered noninducible and 0.81 (0.73-0.87) for patients with abolition of ventricular tachycardia during Holter monitoring on amiodarone. With this primary analysis, there was no significant difference between the predictive value of noninducibility during electrophysiological testing and abolition of ventricular tachycardia with Holter. However, if only those electrophysiological studies using at least triple extrastimuli were included, arrhythmia-free probability for patients rendered noninducible increased to 0.96 (0.88-0.99), significantly better than noninvasive testing. CONCLUSIONS: Noninducible ventricular tachycardia during electrophysiological testing and abolition of ventricular tachycardia during electrocardiographic monitoring on amiodarone appear equally predictive of long-term amiodarone success, but this conclusion seems dependent on the stimulation protocol used. Although the yield is lower (compared to Holter monitoring), ventricular tachycardia rendered noninducible with a stimulation protocol using triple extrastimuli is the most highly predictive test of long-term amiodarone efficacy.

Aged↗
PubMed1994

Combined maximum likelihood estimates for the equicorrelation coefficient.

Combined maximum likelihood estimates for equicorrelation covariance matrices are considered. The case of a common equicorrelation rho and possibly different standard deviations sigma 1, ..., sigma k among k experimental groups is examined first, and the estimation of (rho, sigma 1, ..., sigma k) is discussed. Second, under the assumption of a common standard deviation and possibly different equicorrelations, the estimation of (rho 1, ..., rho k, sigma) is considered. In each case, maximum likelihood solutions and corresponding large-sample variances are presented.

Biometry↗
PubMed1993

Spontaneous and traumatic vitreous hemorrhage.

PURPOSE: The authors sought to provide relevant data regarding the demographic and clinical aspects of spontaneous and traumatic vitreous hemorrhages to guide clinicians in better delineating the expected etiologic patterns of these hemorrhages in an urban environment. METHODS: The records of 253 consecutive patients with newly diagnosed vitreous hemorrhage seen in a general eye clinic were selected for retrospective analysis. To minimize selection bias of a tertiary care center, patients who were referred to the clinic by outside ophthalmologists for vitreoretinal consultation or those with a history of recent intraocular surgery, postoperative complications, or loss to follow-up were excluded from study. Demographic, ocular, and general medical variables were tabulated for the 200 patients (230 eyes) who met our inclusion criteria. RESULTS: Fifty percent of the patients were black, 26% were white, 23% were Hispanic, and 1% was Oriental. The causes of vitreous hemorrhage were proliferative diabetic retinopathy (PDR) (35.2%), trauma (18.3%), retinal vein occlusion (7.4%), retinal tear without a detachment (7.0%), posterior vitreous detachment (6.5%), proliferative sickle retinopathy (5.7%), retinal tear with a detachment (4.8%), subretinal neovascularization from macular degeneration (2.2%), hypertensive retinopathy (1.7%), unknown (2.5%), and other causes (8.7%). Among black patients with spontaneous vitreous hemorrhage, sickle cell retinopathy and retinal vein occlusion were major causes, each accounting for more than 15% of the cases. Systemic hypertension was associated with vitreous hemorrhage from retinal vein occlusion. CONCLUSION: The authors propose that despite the wide array of causative factors of vitreous hemorrhage, the evaluation of demographic, ocular, and medical variables can significantly aid clinicians in identifying its etiologic patterns.

Adolescent↗