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Biomedical subjects

E Barreto

Publications and source records attributed to E Barreto.

18 recordsLinked to original sources
PubMed2001

Enhanced serum glucocorticoid levels mediate the reduction of serosal mast cell numbers in diabetic rats.

Rats turned diabetic by treatment with alloxan exhibit a significant reduction in serosal mast cell numbersin parallel with decreased insulin levels in the plasma. Our aim was to investigate the putative involvement of endogenous glucocorticoid hormone in this phenomenon. The findings indicated that rats treated with alloxan responded with an increase in levels of serum corticosterone concomitantly with decreased mast cell numbers in the pleural space. We found that either surgical bilateral adrenalectomy or pretreatment with the steroid antagonist RU 486 (20 mg/kg, i.p.) impaired the drop in pleural mast cell counts in alloxinated rats. Administration of insulin (15 U/kg) prevented the increase in corticosterone levels and restored pleural mast cell levels in diabetic animals. In addition, treatment of naive rats with corticosterone (0.5 mg/kg, s.c.) or dexamethasone (0.1 mg/kg, s.c.), for 3 consecutive days, led to a reduction in the number of mast cells recovered from the pleural cavity as noted in diabetic animals. In contrast, insulin reduced serum corticosterone levels and induced a significant elevation in pleural mast cell numbers in naive rats. We conclude that there is a causative relationship between increased levels of glucocorticoids and down-regulation of mast cell numbers associated with the diabetic state, both phenomena clearly sensitive to insulin.

Adrenalectomy↗
PubMed2000

Mechanisms for the development of unstable dimension variability and the breakdown of shadowing in coupled chaotic systems.

A chaotic attractor containing unstable periodic orbits with different numbers of unstable directions is said to exhibit unstable dimension variability (UDV). We present general mechanisms for the progressive development of UDV in uni- and bidirectionally coupled systems of chaotic elements. Our results are applicable to systems of dissimilar elements without invariant manifolds. We also quantify the severity of UDV to identify coupling ranges where the shadowability and modelability of such systems are significantly compromised.

Models, Theoretical↗
PubMed2000

From generalized synchrony to topological decoherence: emergent sets in coupled chaotic systems.

We consider the evolution of the unstable periodic orbit structure of coupled chaotic systems. This involves the creation of a complicated set outside of the synchronization manifold (the emergent set). We quantitatively identify a critical transition point in its development (the decoherence transition). For asymmetric systems we also describe a migration of unstable periodic orbits that is of central importance in understanding these systems. Our framework provides an experimentally measurable transition, even in situations where previously described bifurcation structures are inapplicable.

Entropy↗
PubMed1999

Box-counting dimension without boxes: computing D0 from average expansion rates.

We propose an efficient iterative scheme for calculating the box-counting (capacity) dimension of a chaotic attractor in terms of its average expansion rates. Similar to the Kaplan-Yorke conjecture for the information dimension, this scheme provides a connection between a geometric property of a strange set and its underlying dynamical properties. Our conjecture is demonstrated analytically with an exactly solvable two-dimensional hyperbolic map, and numerically with a more complicated higher-dimensional nonhyperbolic map.

Biophysical Phenomena↗
PubMed1993

[Anatomical classification of anterior encephaloceles].

The authors present an anatomical classification of the anterior encephaloceles. The importance of a topographic knowledge of such anomalies in their diagnosis and treatment is emphasized in order to avoid complications during the investigation of a cranio-facial protrusion.

Encephalocele↗
PubMed1987

Pleural biopsy with Cope and Abrams needles.

The object of this study was to compare the diagnostic yield of Abrams and Cope needles. Pleural biopsies were performed in 24 patients with both needles. In two patients, the procedure was repeated within a few days. All patients had pleural effusion. The biopsies were performed at the same time; the biopsy sites were no more than 5 cm distant from each other. Diagnoses were exclusively pathologic. There was no difference between the needles in relation to diagnosis; greater size of the fragment, mesothelial cells, and fibrin were most frequently obtained by Abrams needle, while muscle was better obtained with the Cope needle. The biopsies with both needles were very similar regarding chronic inflammation, granuloma, caseous necrosis, neoplastic tissue, granulation, neutrophils, hemorrhage, vessels, nerves, adipose tissue and epidermis. The advantages of more pleural tissue obtained with the Abrams needle was not translated into better diagnostic yield in the present series.

Biopsy↗
PubMed1985

Cell mediated immunity in American cutaneous and mucosal leishmaniasis.

Cellular immune responses were studied in 35 Brazilian patients with either active cutaneous leishmaniasis (CL), active mucosal leishmaniasis (ML), or healed cutaneous leishmaniasis. The mean age and duration of illness in the two groups were as follows: 14 CL patients, age 28 +/- 13 yr, disease 5 +/- mo; and 16 ML patients, age 34 +/- 15 yr, disease 86 +/- 117 mo. Patients with CL and ML responded well to leishmania antigen in blastogenesis assays. However, the response of ML patients was over three times greater than the response of CL patients. There was a significant correlation between the magnitude of the lymphoproliferative response and the duration of disease activity. There were no significant differences between CL and ML patients in terms of the following parameters: lymphoproliferative responsiveness to mitogens (phytohemagglutinin, concanavalin A, and pokeweed mitogen) and peripheral blood lymphocyte subpopulations (T and B cells, oKT8+ and OKT4+ cells, OKT4:OKT8 ratio). Peripheral blood mononuclear cells from ML patients also generated interferon-gamma containing lymphokine in response to stimulation with leishmania antigen. This lymphokine was capable of inducing macrophages from ML patients to inhibit the intracellular multiplication of leishmania in vitro. These studies have determined that the parameters of lymphocyte and macrophage functions evaluated in ML and CL patients are comparable, except for an enhanced lymphoproliferative response, with leishmania antigen in ML patients. This later finding may be a function of the long duration of active disease in this population and unrelated to the pathogenesis of their mucosal lesions.

Adolescent↗
PubMed1983

[Rhinoentomophthoramycoses. Report of 4 cases].

Four cases of rhynoentomophthoramycosis are reported from urban areas of the states of Bahia and Maranhão, Brazil. The lesions presented with infiltration, redness and heat of the skin of the nose and infraorbital areas and accompanying nasal stuffiness. In on case the infiltration also involved the lips and mandibular area causing severe facial deformity. Microscopically, granulomatous reactions with small abcesses, fibrosis and a dense infiltration of eosinophils were found. Hyphae were seen frequently, always associated with the Splendore phenomenon. Three cases were treated completely with iodine. The one case resistant to iodine was cured with prolonged administration of sulphona. In two cases, plastic surgery was performed for facial reconstruction and nasal-unblocking respectively. Including the cases presented here, only 8 cases of rhynoentomophthoramycosis have been reported in Brazil, but the authors believe that this pathology muta occur more frequently. The lack of knowledge of its clinico-pathological aspects may be responsible for the delay or lack of diagnosis of this entity which occurred in two of the cases reported here.

Adolescent↗
PubMedDate not supplied

[Computer-assisted image processing for quantifying histopathologic variables in the healing of colonic anastomosis in dogs].

BACKGROUND: The authors present the experimental results of the computerized quantifying of tissular structures involved in the reparative process of colonic anastomosis performed by manual suture and biofragmentable ring. The quantified variables in this study were: oedema fluid, myofiber tissue, blood vessel and cellular nuclei. MATERIAL AND METHODS: An image processing software developed at Laboratório de Informática Dedicado à Odontologia (LIDO) was utilized to quantifying the pathognomonic alterations in the inflammatory process in colonic anastomosis performed in 14 dogs. The results were compared to those obtained through traditional way diagnosis by two pathologists in view of counterproof measures. The criteria for these diagnoses were defined in levels represented by absent, light, moderate and intensive which were compared to analysis performed by the computer. RESULTS: There was significant statistical difference between two techniques: the biofragmentable ring technique exhibited low oedema fluid, organized myofiber tissue and higher number of alongated cellular nuclei in relation to manual suture technique. CONCLUSION: The analysis of histometric variables through computational image processing was considered efficient and powerful to quantify the main tissular inflammatory and reparative changing.

Anastomosis, Surgical↗
PubMedDate not supplied

[Colorectal lipomas: anatomoclinical study of 29 cases].

OBJECT: To evaluate the incidence of colorectal lipomas, its diagnostic methodology and therapeutic management. CASUISTIC AND METHODS: The reviewed necropsies performed in a six years period and the patients' records from colorectal lipomas cases treated up to 1965 until 1993 were studied enhancing the clinical presentation, their diagnosis and therapy. The 29 cases of submucosal intestinal lipomas were disposed in three groups. The first group with ten patients lipomas were detected at necropsies. The second group with 11 symptomatic patients and group three with 8 asymptomatic patients which lipomas were discovered accidentally in surgical specimens resected due to neoplasm or in the course of diagnostical procedure. RESULTS: 0.56% of patients who were submitted to necropsy disclosed colorectal lipomas situated preferentially in right colon and in female. Enterourhage was the most often symptom (54.5%) in the group two, followed by cramp abdominal pain. Intussusception appeared in three patients (27.3%). Contrary to the medical literature, the symptomatic lipomas were preferentially situated in left colon and its mean size was 6.1 cm. The diagnosis were performed through opaque enema and more recently by colofibroscopy and CT scan. Resections were performed in all patients: five were enlarged, three were local and other three were endoscopic resections. Multiple lipomas were detected in 30% of patients who were submitted to necropsy and in 25% of asymptomatic group. In both groups no tumor was larger than 2.0 cm of diameter. CONCLUSIONS: Colorectal lipomas are rare in both clinical presentation and necropsy. Before the advent of CT scan and colofibroscopy the majority of the patients were submitted to wide resections, in the assumption of malignancy. Afterwards the endoscopic polipectomy and local resection became our preferential management.

Adult↗
PubMedDate not supplied

Prognostic value of the histopathologic private characteristics of breast cancer in patients with no axillary lymph node involvement.

The biological behavior of breast cancer supports the impression that it is often a systemic disease which can recur many years after the treatment of the local lesion. Since 35% of patients without axillary nodal metastasis will have recurrence of the disease after mastectomy, prognostic indicators are necessary to identify the high-risk patients to allow a more rational adjuvant therapy. We studied the prognostic value of fatty tissue invasion, perineural involvement and lymphatic and venous peritumoral embolization in T2NOMO primary breast carcinomas. Fifty-three patients were studied after initial treatment (only Halsted mastectomy). They were divided into two groups: A (control), with 25 patients with 15 years of survival without clinical and laboratory evidence of metastasis, and group B, with 28 patients who developed metastasis after initial treatment. The results were analysed by the chi-square test (p < 0.05). The fatty tissue invasion was identified in 56.0% and 78.5% in the A and B groups respectively, while venous embolization was only detected in 8.0% of the group A tumors and in 10.7% of those in group B. Neither showed significant variation when analyzed according to the chi-square test. Lymphatic embolization and perineural involvement were found respectively in 36.0% and 40.0% in the group A tumors and in 67.8% and 71.4% of those in group B, exhibiting a significant statistical variation. When analysing the histopathological characteristics in the pre- and post-menopausal patients, the chi-square test disclosed that lymphatic embolization and perineural involvement had a significantly higher incidence only in premenopausal patients in group B.

Axilla↗
PubMedDate not supplied

Cytology by capillarity and anatomopathological diagnosis of solid breast tumors.

A study was conducted on material obtained by capillarity puncture (74 punctures) from 71 patients with breast tumors. The material was fixed in absolute alcohol and stained by the Papanicolaou method and the result was classified as insufficient material, or as negative, suspect or positive cytology. After tumor exeresis, the anatomopathological results of each patient were compared to the cytology data. A single false-positive case was obtained among 44 patients (97% specificity) and 9 false-negative cases were obtained among 16 patients (56% sensitivity).

Adult↗