Luiz Cesar Peres

Multipotent mesenchymal stromal cells obtained from diverse human tissues share functional properties and gene-expression profile with CD146+ perivascular cells and fibroblasts.

OBJECTIVE The relationship of multipotent mesenchymal stromal cells (MSC) with pericytes and fibroblasts has not been established thus far, although they share many markers of primitive marrow stromal cells and the osteogenic, adipogenic, and chondrogenic differentiation potentials. MATERIALS AND METHODS We compared MSCs from adult or fetal tissues, MSC differentiated in vitro, fibroblasts and cultures of retinal pericytes obtained either by separation with anti-CD146 or adhesion. The characterizations included morphological, immunophenotypic, gene-expression profile, and differentiation potential. RESULTS Osteogenic, adipocytic, and chondrocytic differentiation was demonstrated for MSC, retinal perivascular cells, and fibroblasts. Cell morphology and the phenotypes defined by 22 markers were very similar. Analysis of the global gene expression obtained by serial analysis of gene expression for 17 libraries and by reverse transcription polymerase chain reaction of 39 selected genes from 31 different cell cultures, revealed similarities among MSC, retinal perivascular cells, and hepatic stellate cells. Despite this overall similarity, there was a heterogeneous expression of genes related to angiogenesis, in MSC derived from veins, artery, perivascular cells, and fibroblasts. Evaluation of typical pericyte and MSC transcripts, such as NG2, CD146, CD271, and CD140B on CD146 selected perivascular cells and MSC by real-time polymerase chain reaction confirm the relationship between these two cell types. Furthermore, the inverse correlation between fibroblast-specific protein-1 and CD146 transcripts observed on pericytes, MSC, and fibroblasts highlight their potential use as markers of this differentiation pathway. CONCLUSION Our results indicate that human MSC and pericytes are similar cells located in the wall of the vasculature, where they function as cell sources for repair and tissue maintenance, whereas fibroblasts are more differentiated cells with more restricted differentiation potential.

Prevalence and Demographic Characteristics of Celiac Disease Among Blood Donors in Ribeirão Preto, State of São Paulo, Brazil

Celiac disease (CD) is an underdiagnosed disease occurring in different clinical forms. This study aimed to determine the prevalence of CD among blood donors from Ribeirão Preto, Brazil, and to study some demographic characteristics of celiac patients. Blood samples from 3000 blood donors were tested for the presence of tissue transglutaminase antibody and positive samples were tested for endomysial antibody. Donors positive to both tests were referred for clinical evaluation and for a jejunal biopsy. Twenty-four samples were moderately/strongly positive for transglutaminase, with 9 of them being endomysial negative and 15 positive. Of the 13 biopsies obtained from 12 females and 1 male, 1 was classified as Marsh grade IV, 4 as grade III, 2 as grade II, 4 as grade I, and 2 as grade 0. Estimated prevalence was therefore 1:273 (0.33%; 95% CI, 0.127 to 0.539). The 1:273 estimated prevalence of CD detected indicates that the disease is not rare in Brazil. The frequency was higher among females and among individuals of European descent, with a significantly higher frequency for a family history of digestive tract cancer or epilepsy.

Caudal dysplasia sequence: severe phenotype presenting in offspring of patients with gestational and pregestational diabetes.

The association of maternal diabetes mellitus and congenital anomalies is well established. Children of insulin-dependent diabetic women have an increased risk of congenital malformations, especially major multiorgan defects. The cardiovascular, central nervous, gastrointestinal, genitourinary and musculoskeletal are the most affected body systems. Studies also show that offspring of women with gestational diabetes (specially those with fasting hyperglycaemia) tend to have higher rates of congenital anomalies. We report two cases of infants born to unrelated mothers: one with diabetes mellitus first detected during pregnancy (gestational diabetes) and the other with pregestational diabetes. Both infants had amelia of the lower limbs (suggestive of caudal dysplasia sequence), together with cardiovascular, skeletal, urinary and gastrointestinal defects. While pregestational diabetes seems to leave no doubt about its teratogenicity, the association of gestational diabetes and fetal/newborn malformations is still under discussion. Complete absence of the lower limbs has not been reported in association with gestational diabetes, but it may represent a spectrum of the caudal dysplasia sequence. The presentation of two cases with the same clinical phenotype of mothers with gestational and pregestational diabetes supports the evidence that gestational diabetes can be responsible for the development of the most severe form of the caudal dysplasia sequence.

Raine dysplasia: a Brazilian case with a mild radiological involvement.

We report a preterm male infant, the first child of a young consanguineous couple, whose physical examination revealed craniofacial disproportion with microcephaly, wide fontanelles, exophthalmos, low nasal root and hypoplastic nose, long philtrum, small mouth, high arched and narrow palate, micrognathia, dysplastic, low-set and rounded ears, short neck and, arthrogryposis. Postmortem findings included hypoplastic lungs. Radiological examinations showed mild and localized increased of bone density in the cranial vault and skull base and facial bones and undermodelled in the long bones. The above findings are characteristics of Raine dysplasia but the case reported here presents a mild bone involvement with only a localized bone sclerosis and absence of prenatal fractures. We discuss the possibility that this case represents an allelic mutation of the Raine gene. The consanguinity of the parents reinforces the hypothesis of autosomal recessive inheritance for this entity.

Teratogenic effect of retinoic acid in swiss mice

PURPOSE To identify the types of malformations resulting from the administration of retinoic acid (RA) to Swiss mice on different days of pregnancy. METHODS Twenty-four pregnant Swiss mice were divided into 4 groups of 6 animals each. The experimental groups received a single intraperitoneal injection of RA (70 mg/kg) on gestational days 7, 8 and 9 (D7, D8 and D9), while control animals (C) received only saline solution. RESULTS Were obtained: exencephaly (C:0; D7:16.1%; D8:25.4%; D9:0), myelomeningocele (C:0; D7:25.8%, D8:30.9%, D9:0), spina bifida occulta (C:0, D7:29%, D8:41.8%, D90), gastroschisis (C:0, D7:6.4% D8:5.4%, D9:0), omphalocele (C:0, D7:6.4%, D8:14.5%, D9:0), lower limb alterations (C:0, D7:74.1%, D8:80%, D9:0), imperforated anus (C:0, D7:100%, D8:100%, D9:100%), and tail agenesis/alteration (C: D7:100%, D8:100%, D9:100%). CONCLUSION The experimental model using Swiss mice proved to be efficient in the induction of the different types of defects, with the eighth gestational day being the one that most favored the induction of neural tube defect, omphalocele, gastroschisis, lower limb defects, imperforated anus and tail agenesis/alteration. On this basis, this is a useful model for future investigation of neural development and of the formation of the appendicular skeleton.

Ischemic myocardial injuries after cardiac malformation repair in infants may be associated with oxidative stress mechanisms

BACKGROUND Despite advances in pediatric cardiac surgery, perioperative myocardial injury can be the major determinant of postoperative dysfunction after cardiac surgery. This study investigated the pathology-related differences in 29 infants with congenital heart disease that led to death. The infants were treated at the University Hospital of Ribeirão Preto, Brazil. METHODS The patients were divided into four groups: Group 1, 16 infants who underwent operations for congenital heart disease on cardiopulmonary bypass; Group 2, four infants who underwent off-cardiopulmonary bypass operations for congenital heart disease; Group 3, nine infants who died from congenital heart disease prior to surgical treatment; and Group 4 (control group), five infants with no congenital heart disease and who died from other causes. The myocardial injuries and oxidative stress mechanisms were assessed by histopathology and immunohistochemistry and were quantified by morphometrical analyses. RESULTS Contraction band necrosis and dystrophic calcification were found primarily in infants of Group 1. Coagulation necrosis and healing were prominent in Group 2, while infants without repair (Group 3) showed mainly colliquative myocytolysis. Apoptotic cells were more prominent in the operative groups. The control group showed no significant myocardial lesions. Lipid peroxidation was the principal mechanism of oxidative stress accounting for the myocardial lesions. CONCLUSION The diversity of the lesions observed in these hearts seemed to indicate a large spectrum of cell damage due to inadequate myocardial perfusion, especially when these infants underwent surgery. Oxidative mechanisms could be a common mediator in the pathogenesis of myocardial injuries, mediated by peroxidation of the membrane phospholipids and resulting in changes in the permeability of the cell membrane, cell death, and intracellular calcium overload. Furthermore, an immature and often hypertrophied myocardium may promote unfavorable conditions, leading to heart failure and a lethal outcome.

Enamel hypoplasia in a litter of rats with alloxan-induced diabetes mellitus

Enamel hypoplasia is an important clinical problem commonly seen in children born to diabetic women. We aimed to characterize the enamel hypoplasia in Wistar rats born to alloxan-induced diabetes mellitus rats. Groups consisted of pregnant rats supplemented (ISDR) or not (NISDR) with insulin and controls, in which sterile saline solution was administered instead of alloxan or insulin. The mandibular incisors of one-month-old rats born to these mothers were analyzed. Whitish defective enamel was found macroscopically in both experimental groups (ISDR = 37.5%, NISDR = 33.3%) but not in the control group. Mild to severe enamel hypoplasia was observed by scanning electron microscopy (ISDR = 93.8%; NISDR = 100%, control = 4.2%). The severity of hypoplasia correlated positively with the maternal level of blood glucose. In conclusion, the intensity of enamel hypoplasia in the teeth of the litter born to alloxan-induced diabetic rats was variable and was dependent on the glycemic level of the pregnant rat.

Detection of parvovirus B19 infection in formalin-fixed and paraffin-embedded placenta and fetal tissues

Parvovirus B19 infection was first discovered in 1975 and it is implicated in fetal death from hydrops fetalis the world over. Diagnosis is usually made through histological identification of the intranuclear inclusion in placenta and fetal organs. However, these cells may be scarce or uncharacteristic, making definitive diagnosis difficult. We analyzed histologically placentas and fetal organs from 34 cases of non-immune hydrops fetalis, stained with Hematoxylin and Eosin (HE) and submitted to immunohistochemistry and polymerase chain reaction (PCR). Of 34 tissue samples, two (5.9%) presented typical intranuclear inclusion in circulating normoblasts seen in Hematoxylin and Eosin stained sections, confirmed by immunohistochemistry and PCR. However, PCR of fetal organs was negative in one case in which the placenta PCR was positive. We concluded that parvovirus B19 infection frequency is similar to the literature and that immunohistochemistry was the best detection method. It is highly specific and sensitive, preserves the morphology and reveals a larger number of positive cells than does HE with the advantage of showing cytoplasmic and nuclear positivity, making it more reliable. Although PCR is more specific and sensitive in fresh or ideally fixed material it is not so in formalin-fixed paraffin-embedded tissues, frequently the only one available in such cases.

An experimental study on the effects of ethanol and folic acid deficiency, alone or in combination, on pregnant Swiss mice.

Introduction: Ethanol is teratogenic, interferes with folic acid and is extensively used by young women. Our objective was to determine the effects of ethanol and/or folate deficiency on mouse fetuses. Method: In Experiment 1, pregnant mice receiving a commercial diet were divided into three groups: control (C), low ethanol dose (LE, 0.4 g/kg), and high ethanol dose (HE, 4.0 g/kg). In Experiment 2, pregnant mice receiving a folate‐free diet (FFD) were divided into three groups: folate deficiency (FD), folate deficiency plus a low ethanol dose (FDLE), and folate deficiency plus a high ethanol dose (FDHE). Groups C and FD received saline and the remaining groups received ethanol administered i.p. from the 7th to the 9th gestational day (GD) and were sacrificed on the 18th GD. Results: In Experiment 1, Group HE presented congenital anomalies, late fetal death (LFD), lower fetal length and weight and placental weight and diameter than Groups C and LE. In Experiment 2, there was a smaller number of live fetuses, a larger number of reabsorptions and LFD, a smaller length and lower fetal weight, placental weight and diameter in Groups FDLE and FDHE than in Group FD. Conclusion: In animals receiving a commercial diet, a high ethanol dose is deleterious to the pregnancy, inducing congenital anomalies, intrauterine growth restriction, reduction of the placenta and increased LFD, events that did not occur with the low dose. However, with a folate free diet, a low ethanol dose is as deleterious as a high dose.

Implantação de um programa de avaliação terminal do desempenho dos graduandos para estimar a eficácia do currículo na Faculdade de Medicina de Ribeirão Preto

PURPOSE To describe the main steps in the implementation of such assessment, as well as to present the measures taken in order to overcome the difficulties that have been found. METHODS The proposed two-step assessment consists of a test of cognitive aspects based on Multiple Choice Questions (MCQ) and practical exams of clinical skills in each of 5 terminal areas. Students enrolled as volunteer for either step or both. The examinations were developed and carried out by faculty members nominated by the involved Departments under the supervision of an institutional work group. The rates of student enrollment for the summative assessment has been recorded and the responses of both students and faculty members were evaluated by means of specific questionnaires. RESULTS In the first two years, adhesion of students to the MCQ test was consistently high, but volunteering to the practical exams was persistently low. Moreover, there was a sharp decrease in faculty involvement, from the first to the second year. To overcome these difficulties, a number of measures were implemented aiming at increasing student adhesion and faculty involvement, as well as to improve assessment methods. As a consequence, a remarkable increase in both student adhesion and faculty involvement was recorded. CONCLUSION The measures taken resulted in sharp increases in both acceptance of the proposed assessment and the quality of the examination methods, which have allowed a more reliable characterization of the strenghts and weaknesses of the local curriculum.PURPOSE. To describe the main steps in the implementation of such assessment, as well as to present the measures taken in order to overcome the difficulties that have been found. METHODS. The proposed two-step assessment consists of a test of cognitive aspects based on Multiple Choice Questions (MCQ) and practical exams of clinical skills in each of 5 terminal areas. Students enrolled as volunteer for either step or both. The examinations were developed and carried out by faculty members nominated by the involved Departments under the supervision of an institutional work group. The rates of student enrollment for the summative assessment has been recorded and the responses of both students and faculty members were evaluated by means of specific questionnaires. RESULTS. In the first two years, adhesion of students to the MCQ test was consistently high, but volunteering to the practical exams was persistently low. Moreover, there was a sharp decrease in faculty involvement, from the first to the second year. To overcome these difficulties, a number of measures were implemented aiming at increasing student adhesion and faculty involvement, as well as to improve assessment methods. As a consequence, a remarkable increase in both student adhesion and faculty involvement was recorded. CONCLUSION. The measures taken resulted in sharp increases in both acceptance of the proposed assessment and the quality of the examination methods, which have allowed a more reliable characterization of the strenghts and weaknesses of the local curriculum.