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Biomedical subjects

I Miranda

Publications and source records attributed to I Miranda.

15 recordsLinked to original sources
PubMed2005

Interaction between surgical procedure for repairing retinal detachment and clinical risk factors for proliferative vitreoretinopathy.

PURPOSE: To asses risk factors of proliferative vitreoretinopathy (PVR) and a model for predicting it. METHODS: Observational, case-control. 335 patients with non-complicated retinal detachment (RD) were included: 134 developed PVR (Cases); 201 patients did not (Controls). Risk factors for PVR were identified by multivariate analysis. Influence of variables was assayed according to the surgical approach. By logistic regression analysis a model to predict the risk of developing PVR and odds ratio (OR) values for each clinical factor were estimated. RESULTS: Risk was higher in patients > 70 years and with intraocular pressure lower than 14 (OR: 3.84; CI 95%: 2.04-7.30) and in retinal breaks larger than "1 clock hour" (OR: 2.54; CI: 1.28-5.05), extended retinal detachments (OR: 4.01; CI: 1.98-8.10) and reinterventions (OR: 1.55; CI: 1.14-9.22). Scleral surgery also was a risk factor (OR: 3.89; CI: 2.12-7.14) and aphakia/pseudophakia when scleral surgery is performed (OR: 3.33; CI: 1.54-7.22). A model to predict PVR was proposed with these results. CONCLUSIONS: Surgical approach modifies risk factors of PVR, and should be taken into account to improve the models for predicting it.

Adolescent↗
PubMed2003

[Clinical risk factors for postoperative proliferative vitreoretinopathy (PVR). A prospective study].

PURPOSE: To identify clinical risk factors for development of postoperative PVR, to determine the incidence of this complication and its time of onset by a prospective multicentric study. METHODS: A multicentric and prospective study of 223 patients with rhegmatogenous retinal detachment (RD) was conducted. Logistic regression analysis was used to identify risk factors for PVR among 83 variables related to preoperative, intraoperative and postoperative characteristics. RESULTS: 22 out of 223 RD developed PVR (incidence 9.9%, confidence interval 95%: 5.9-13.9). After logistic regression analysis, four variables showed an odds ratio higher than 1.0 (RD affecting 4 quadrants, cryopexy, aphakia/pseudophakia and those RD in which an encircling band was implanted). None of these factors showed a < > value lower than 0.05. Most of postoperative PVR (77.2%) appeared in the first month after surgery. CONCLUSIONS: This study establishes the incidence of PVR, and its time of onset, but it was not effective to identify clinical risk factors with a high level of confidence.

Adolescent↗
PubMed2001

Frequency and determinants of microalbuminuria in mild hypertension: a primary-care-based study.

OBJECTIVE: To evaluate the frequency of microalbuminuria and its relationship with several risk factors and left ventricular mass in a population of mildly hypertensive subjects attended in a primary-care setting. DESIGN: Cross-sectional study. SETTING: Eight primary-care centres. PATIENTS: Two hundred and twenty-three non-diabetic patients recently diagnosed with mild hypertension were included in the study. None of them had clinical evidence of target-organ damage or had received prior antihypertensive treatment. INTERVENTIONS: Subjects included in the study underwent clinical interview, measurement of blood pressure (BP) on three visits, blood analysis, measurement of albumin by immunonephelometry in three overnight urine collections, 24 h BP monitoring and M-mode and Doppler echocardiography. MAIN OUTCOME MEASURES: Tobacco habit, clinic BP, body mass index, serum lipids and uric acid, glycaemia, urinary albumin excretion (UAE), ambulatory BP and left ventricular mass index. RESULTS: The frequency of microalbuminuria was 7.2%. Microalbuminuric patients were more likely to be men and to be characterized by higher ambulatory BP, body mass index and uric acid levels. Regression analysis demonstrated that male sex and 24 h systolic BP were determinants of UAE. Patients with white-coat hypertension showed lower UAE than did subjects with sustained hypertension. Although a certain relationship between UAE and left ventricular mass index was found, these variables were not significantly correlated. CONCLUSIONS: A low proportion of mildly hypertensive patients attended in a primary care setting are microalbuminuric. In this population, UAE is an expression of BP values over 24 h and correlates with several risk factors.

Adult↗
PubMed2001

[Comparison of different techniques for cytologic analysis of vitreous specimens].

PURPOSE: To assess the efficacy of four methods to study the cytology of vitreous samples, and to evaluate the most efficient for routine analysis and immunocytochemical staining. METHODS: Diluted and undiluted vitreous samples of 87 consecutive patients suffering vitreoretinal surgery for different diseases were analysed. The specimens were centrifugated and then processed through four different procedures: agar sandwich (29 cases), direct paraffin embedding (33 cases), cytospin preparations (82 cases) and cytoblock (8 cases). RESULTS: Evaluable material was obtained in: agar sandwich 18 out of 29 cases (62%), direct paraffin embedding 32 out of 33 cases (96.9%), cytospin 72 out of 82 cases (87.8%) and cytoblock 1 out of 8 cases (12.5%). CONCLUSIONS: Direct paraffin embedding and cytospin are the most efficient procedures for routine purposes. Agar sandwich technique seems to be useful for studying small pieces of tissue. Direct paraffin embedding and agar sandwich technique seems to be valuable for immunocytochemistry. After 8 cases processed with cytoblock, our experience did not show valuable results for processing vitreous samples.

Cytological Techniques↗
PubMed1999

Cholinergic modulation of neostriatal output: a functional antagonism between different types of muscarinic receptors.

It is demonstrated that acetylcholine released from cholinergic interneurons modulates the excitability of neostriatal projection neurons. Physostigmine and neostigmine increase input resistance (RN) and enhance evoked discharge of spiny projection neurons in a manner similar to muscarine. Muscarinic RN increase occurs in the whole subthreshold voltage range (-100 to -45 mV), remains in the presence of TTX and Cd2+, and can be blocked by the relatively selective M1,4 muscarinic receptor antagonist pirenzepine but not by M2 or M3 selective antagonists. Cs+ occludes muscarinic effects at potentials more negative than -80 mV. A Na+ reduction in the bath occludes muscarinic effects at potentials more positive than -70 mV. Thus, muscarinic effects involve different ionic conductances: inward rectifying and cationic. The relatively selective M2 receptor antagonist AF-DX 116 does not block muscarinic effects on the projection neuron but, surprisingly, has the ability to mimic agonistic actions increasing RN and firing. Both effects are blocked by pirenzepine. HPLC measurements of acetylcholine demonstrate that AF-DX 116 but not pirenzepine greatly increases endogenous acetylcholine release in brain slices. Therefore, the effects of the M2 antagonist on the projection neurons were attributable to autoreceptor block on cholinergic interneurons. These experiments show distinct opposite functions of muscarinic M1- and M2-type receptors in neostriatal output, i.e., the firing of projection neurons. The results suggest that the use of more selective antimuscarinics may be more profitable for the treatment of motor deficits.

Acetylcholine↗
PubMed1993

Effects of aging in retinal image quality.

The retinal image quality characterized by the modulation-transfer function of the eye was measured for two groups of subjects aged in the late twenties and mid sixties, respectively. In both groups, we obtained modulation transfer functions by using a double-pass method under the same experimental conditions: 4-mm artificial pupil, paralyzed accommodation, and objective control of the refractive state and centering. Results showed lower values of modulation in the retinal image for older subjects compared with the younger subjects. The modulation transfer function ratio is similar to that previously found for contrast-sensitivity measurements with subjects in the same age groups. These results suggest that a significant fraction of the loss in spatial vision with age has an optical origin. Apart from the well-known increase in intraocular scattering, there also appears to be an increment in ocular aberration that causes an additional reduction in the contrast of retinal images.

Adult↗
PubMed1991

[Keratitis caused by Pseudomonas aeruginosa and secondary endophthalmitis].

We report three patients with Pseudomonas aeruginosa keratitis. Two patients in the Intense Care Unit had exogenous bacterial endophthalmitis assessed by histopathology; the infection had probably a nosocomial origin and the outcome was fatal. The third case was associated with the use of soft contact lenses and even though clinically endophthalmitis was suspected there was a favourable response to treatment. We review diagnostic aspects and discuss the management of bacterial keratitis and endophthalmitis.

Adult↗
PubMed1990

Cutis marmorata telangiectatica congenita and glaucoma.

A case of cutis marmorata telangiectatica congenita (CMTC) is described in association with congenital glaucoma. Approximately 68 cases of CMTC and only four cases associated with glaucoma have been reported. The type of glaucoma seems to be related to an abnormality of the filtration in the anterior angle, due to increased pressure in the episcleral vessels. The surgical treatment is trabeculectomy, and opening an alternative drainage pathway.

Glaucoma↗
PubMedDate not supplied

Ebstein's anomaly. Clinical profile in 174 patients.

The study population consisted of 148 patients who did not undergo surgical treatment and 26 who were operated, most of them diagnosed after the age of 2, with a follow-up from 6 months to 25.3 years. Patients were divided in three groups of clinical deterioration according to their functional class and cardiothoracic index (CTR) long-term follow-up in 148 nonoperated patients showed significant differences for mortality between groups I and III (p < 0.001), and between groups II and III (p < 0.02). Predictors of death included the association among functional class III or IV CTR > or = 65% with either cyanosis or arrhythmias (p < 0.05). The multivariate analysis showed that clinical deterioration (p < 0.0001), CTR (p < 0.0002) and functional class (p < 0.001), were significant for mortality. Kaplan-Meier analysis showed a survival rate of 81% in the overall patients free from surgical treatment. According to Kaplan-Meier analysis, the rate of survival was lower in patients with CTR > or = 65% (63.5%), in patients who had functional class IV (52.5%) and in patients included in group III of clinical deterioration (38.2%). Despite the fact that the association of functional class III or IV plus CTR > or = 65% with either cyanosis or arrhythmias is a good predictor for death, the mortality in patients who had only one of these variables was lower. Patients included in group II of clinical deterioration in stable condition presented long survival with medical treatment. Due to the high mortality rate found in group III, surgical treatment of Ebstein's anomaly must be done before deteriorating into group III. Surgical indication must be done considering the surgical risk of each group according to the experience of the Institution and comparing the rate of surgical mortality with the rate of survival without surgery.

Adolescent↗
PubMedDate not supplied

[Chromosome 22 (22q.11.2) deletion. Etiology of conotruncal heart abnormalities].

Important advances in the diagnosis and treatment of congenital heart disease (CHD) have been made in the past 50 years. Nowadays echocardiogram plays an important role in the diagnosis. This procedure is able to identify a wide range of malformations. Cardiac catheterization is mainly a therapeutic tool, surgery is now performed much earlier because CHDS are diagnosed sometimes before birth or very early in life. All this advances in the diagnosis and treatment of this group of patients, allows them not only a better quality of life but also the possibility of reaching adulthood and having children. The study of the etiology of CHD is a field that has not evolved as fast as the assessment and treatment. Nowadays we have a larger population of adults with CHD. The discovery of a microdeletion of chromosome 22 q11.2 associated with conotruncal cardiac defects, proves a common etiology for clinical phenotypes and conotruncal malformations. In order to identify, which of these patients share the same etiology and presented with this syndrome, we collected a group that shared not only heart defects of the conotruncal type but also specific phenotypic alterations such as broad nasal bridge, nasal dimple, high palate, and digitalization of the first finger among others. The first two patients studied with FISH technique were positive to monosomy of a locus on chromosome 22. Those patients with CHD of conotruncal type should undergo microdeletion testing so genetic counseling can be offered as well as appropriate treatment in areas such as cardiology and developmental psychology.

Child↗
PubMedDate not supplied

[Corrected transposition of the great arteries].

Sixty-nine patients with Corrected Transposition of the Great Arteries were studied, with a mean age of 8.3 years. Forty-nine had atrial situs solitus (SS) and 20 atrial situs inversus (SI). The diagnosis was proved by echocardiography in 28 cases and in all by angiocardiography. In cases with SS, 29 presented ventricular septal defect (VSD), 20 had subvalvular pulmonary stenosis (SVPS), 13 tricuspid regurgitation (TR), 13 atrio-ventricular block (AVB), and seven without associated defects. In cases with SI, 13 had VSD, 14 SVPS, five IT, three AVB, and two without associated defects. The long-term follow-up of the atrioventricular (AV) conduction in 53 cases, ranging between 2 and 37 years (mean 8.3) showed at the beginning of the evaluation 37 cases with normal AV conduction, 14 with first degree AVB, and two with complete AVB. At the end of the follow-up 24 cases had normal AV conduction, 13 first degree, two second degree, four intermittent and 10 complete AVB. The contingency table showed that the possibility of developing changes of the AV conduction was greater in those cases who had an abnormality at the beginning with a relative risk of 2.27 (p = 0.03). Twenty-three cases had SVPS associated with VSD without significant symptoms. During a follow-up ranging from 1 to 20 years (mean 6.5 +/- 5.9), five of these patients were surgically corrected at ages from 6 to 11 years. The remaining cases have had a stable course. At the beginning of the study, 18 cases had TR, and it developed in five more patients during the same follow-up period.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

[Comparative study of 2 mechanical mitral valves].

We present the long term follow-up of two groups of patients under 16 years of age in whom two different types of mitral valve prostheses were used for the treatment of mitral valve disease. Group I was formed by 74 patients with Starr-Edwards (6120) prosthesis and group II by 36 cases with Bjork-Shiley prosthesis. Group I was followed for a mean period of 11 years and group II for a mean period of 7.5 years. The clinical evolution of both groups assessed according to the New York Heart Association criteria showed improvement of the functional class (p less than 0.006). Twenty seven cases of group I and 21 of group II underwent cardiac catheterization for the evaluation of surgical results. In group I, the mean pulmonary arterial systolic pressure (PASP) decreased from 57 mmHg to 33 mmHg (p less than 0.001) and the mean pulmonary arterial wedge pressure (PAWP) from 20.8 mmHg to 12.1 mmHg (p less than 0.05). In group II, the mean PASP decreased from 59.2 mmHg to 28.5 mmHg (p less than 0.001) and the mean PAWP from 24.6 mmHg to 8.5 mmHg (p less than 0.001). There was statistically significant difference for a greater incidence of thromboembolism in group I (p = 0.037). No differences were found for bacterial endocarditis, dysfunction and death.

Adolescent↗
PubMedDate not supplied

[Truncus arteriosus communis and interrupted aortic arch].

The association between persistent truncus arteriosus and interrupted aortic arch is a rare but important condition since it has special clinical and therapeutic implications. In this article we present three cases with this malformation. The clinical characteristics are similar to patients with isolated truncus such as heart failure and cyanosis since birth, a protosystolic click, an ejection murmur over the left parasternal line, heart enlargement, increased pulmonary vascular markings and biventricular hypertrophy. The clinical suspicion of interrupted aortic arch is bases on the presence of asymmetric pulses in the upper and lower limbs, but this difference is present only when the arterial duct is restrictive. Because of that, the echocardiographic analysis, mainly, and the angiocardiogram, secondarily, are very important diagnostic tools. We analyze the echocardiographic diagnostic findings, as well as the angiocardiographic anatomy. Also, some important pathophysiological aspects are discussed.

Aorta, Thoracic↗