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Biomedical subjects

G F Lima

Publications and source records attributed to G F Lima.

9 recordsLinked to original sources
PubMed2001

Deterministic walks in random media.

Deterministic walks over a random set of N points in one and two dimensions ( d = 1,2) are considered. Points ("cities") are randomly scattered in R(d) following a uniform distribution. A walker ("tourist"), at each time step, goes to the nearest neighbor city that has not been visited in the past tau steps. Each initial city leads to a different trajectory composed of a transient part and a final p-cycle attractor. Transient times (for d = 1,2) follow an exponential law with a tau-dependent decay time but the density of p cycles can be approximately described by D(p)proportional to p(-alpha(tau)). For tau>>1 and tau/N<<1, the exponent is independent of tau. Some analytical results are given for the d = 1 case.

Journal Article↗
PubMed1997

[Merkel cell tumor. Report of case and treatment with octreotide].

Merkel cell carcinoma is a rare neuroendocrine tumor of the skin. Prognosis is very poor particularly when systemic disease is present. Surgery, chemo and/or radiotherapy treatment are not able to guarantee long survival and quality of life is also very poor. We know that neuroendocrine tumor can be in possession of receptors for somatostatin; during the past years, these receptors have been demonstrated in vivo by octreoscan. We report a case of a patient suffering from metastatic Merkel cell carcinoma; because he was elderly, neither chemotherapy nor radiotherapy were possible as a consequence of the explosion of the disease after surgery. The presence of receptors for somatostatin analogues (octreoscan) allowed treatment with octreotide causing the immediate disappearance of metastasis. After ten months of treatment the patient presents a complete remission of disease. Octreotide, the most important somatostatin analogue, represents a primary role in the neuroendocrine tumor management; the drug also lacks of toxicity.

Aged↗
PubMed1991

Differences in distribution and severity of Helicobacter pylori gastritis in children and adults with duodenal ulcer disease.

The presence of Helicobacter pylori and the gastric mucosa histology were investigated in 15 children and 15 adults with duodenal ulcer. The microorganism was isolated from antral and oxyntic mucosa in 100% of patients, both adults and children. The results of Gram stain and preformed urease test were compared with those of culture and there was no difference in sensitivity among the tests. Antral chronic gastritis was observed in all patients. However, children presented oxyntic gastritis more frequently than adults. It was also observed that the endoscopic aspects were different in the two groups of patients. The results here observed strongly support the idea that, as well as in adults, H. pylori is the causative agent of the gastritis seen in children with duodenal ulceration. On the other hand, the histological findings of oxyntic mucosa of children with duodenal ulcer were different from those of adults.

Adolescent↗
PubMed1991

Helicobacter pylori and gastric histamine concentrations.

An enzyme isotopic assay was used to determine the histamine concentration in the gastric mucosa of patients positive for Helicobacter pylori with (n = 11) and without duodenal ulceration (n = 9) and in negative controls (n = 7). A significant difference was observed when the histamine content of H pylori negative subjects was compared with that of positive patients. On the other hand, there was no significant difference in histamine concentration between H pylori positive patients with duodenal ulceration and those without duodenal ulceration. H pylori positive patients with and without duodenal ulceration had significantly lower gastric histamine concentrations than H pylori negative subjects. The lower gastric histamine concentration observed in H pylori positive patients might be due to increased histamine release which could in turn induce increased gastric acid secretion.

Adult↗
PubMed1988

Distribution of Campylobacter pylori and gastritis in the stomach of patients with and without duodenal ulcer.

The presence of Campylobacter pylori and histological changes of gastric mucosa were studied in 50 consecutive patients with gastric complaints. C. pylori was isolated from the antrum, body, and fundus of 40 patients with (n = 20) and without (n = 20) duodenal ulcer. The incidence of gastritis was not significantly different in the antrum of C. pylori-positive patients with and without ulcer. Otherwise, oxyntic mucosa of both body and fundus regions exhibited gastritis in 64.1% of the C. pylori-positive non-ulcer patients, whereas those with duodenal ulcer presented oxyntic mucosa that was histologically normal or near normal.

Adult↗
PubMed1988

Immunocytochemical identification of Campylobacter pylori in gastritis and correlation with culture.

Endoscopic biopsy specimens of antral mucosa from 25 patients presenting with gastric complaints were obtained for culture and histologic and immunocytochemical studies. The histopathologic study revealed chronic gastritis in 22 patients and borderline chronic gastritis in three patients. The unlabeled-antibody peroxidase-antiperoxidase (PAP) method was applied for the detection of Campylobacter pylori, and its results were compared with those obtained with the culture technique. Strongly positive immunoperoxidase staining was localized in spiral, curved bacteria that were present in the mucus layer adjacent to the gastric epithelial cell surface. The microorganisms were frequently congregated in clumps and were sectioned in several directions. The PAP stains were positive in 19 specimens (76%), and the cultures were positive in 20 (80%). All results negative by culture were also negative by PAP method. Compared with the cultures, the sensitivity and positive predictive value of the PAP method for identification of C pylori in antral mucosa obtained from endoscopic biopsy specimens were 95% and 100%, respectively.

Biopsy↗
PubMed1987

Granular cell tumor of the esophagus: a study of seven cases diagnosed by histologic examination of endoscopic biopsies.

Among the benign tumors of the esophagus, the discovery of a granular cell tumor is exceptional. Although endoscopy permits recognition of this tumor and supports its benign nature, only histologic examination of the endoscopic biopsy specimen permits one to determine its precise nature. The endoscopic appearance of esophageal granular cell tumor ranges from a plaque-like thickening of the mucosa to a polypoid mass. We describe here seven cases of granular cell tumor of the esophagus diagnosed by histologic examination of endoscopic biopsy specimens. We believe the actual incidence of this tumor in this location might be greater if every esophagus were given as much attention at endoscopic examination and at autopsy.

Adult↗
PubMed1983

Gastric cytomegalic inclusion bodies diagnosed by histologic examination of endoscopic biopsies in patients with gastric ulcer.

Gastric cytomegalovirus (CMV) inclusion bodies, indicating CMV infection were detected in three patients with erosions and ulcers in the upper gastrointestinal tract. In all cases, histologic examination of endoscopic biopsies enabled a diagnosis of CMV infection to be made quickly and safely. We emphasize the importance of the histologic examination of gastrointestinal biopsies in the early diagnosis of CMV infection.

Adult↗