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C T Ferreira

Publications and source records attributed to C T Ferreira.

14 recordsLinked to original sources
PubMed2000

[Liver transplantation]

OBJECTIVE: To review the clinical aspects and the theoretical basis of liver transplantation in children, focusing mainly pre and post surgical periods. METHODS: References were obtained from computerized search in the National Library of Medicine (Medline), recent review articles, and personal files. RESULTS: Great development has occurred in surgical techniques, in organ preservation, in postoperative care, and in immunosuppression methods after the first liver transplantation surgery took place in a child with biliary atresia in 1963. Liver transplantation has become an efficient therapy, widely accepted and used in all age groups. It is a very complex procedure, with many professionals involved and with several legal, ethical and economical implications. We review in this article the clinical aspects before transplantation, including indications, contraindications, clinical and laboratory evaluations, as well as postsurgical aspects, both in the immediate period, after the 1st week, and the long-term outcome, discussing the complications and the treatment of each. CONCLUSIONS: Liver transplantation has dramatically improved the survival of pediatric patients with chronic hepatic diseases. Patients of liver transplantation in the pediatric age group present today survival rates of 90% in the different transplantation centers.

Journal Article↗
PubMed1999

Category specificity in object agnosia: preservation of sensorimotor experiences related to objects.

We report a case of semantic agnosia, characterized by category specificity. Object recognition, mainly involving visual representation, was severely impaired, whereas object recognition involving both visual and sensorimotor representations, was relatively well preserved. His ability to recognize gestures and produce appropriate gestural responses to objects was remarkable. These two factors lead the authors to form a hypothesis, in an attempt to explain the mechanisms involved in object recognition. It has been argued that manipulation of an object may give access to a certain amount of knowledge about it, and that preservation of sensorimotor experiences of objects might be important in recognizing some of them. This could account for the category specificity, described in object agnosia.

Agnosia↗
PubMed1998

Spatio-temporal working memory and frontal lesions in man.

The delayed-response paradigm is thought to be a marker of the activity of the dorsolateral convexity of primates' prefrontal cortex, as this procedure requires the activation of working memory processes. Although the role of the dorsolateral prefrontal cortex (DLPC) in working memory seems to be well established, much remains to be understood about the processes this structure actually controls: encoding domain-specific information, its retention in short-term memory, its monitoring in working memory, or its selection and retrieval when a specific response program is required. To clarify the role of the DLPC in delayed-response tasks in humans, a set of sequencing paradigms was designed which incorporates the dissociation of (1) spatial and temporal parameters, (2) recall and recognition processes, and (3) the presence or absence of a delay. Performance of a group of patients with DLPC lesions (n = 8) was compared to that of age-matched normal subjects (n = 8). To verify the specificity of the results obtained for the DLPC lesioned patients, the performance of patients with a temporal lobotomy was also studied (n = 10). A significant effect of the delay was observed only in patients with DLPC lesions, affecting both their spatial and spatio-temporal recall, whereas their spatio-temporal recognition was normal. These findings suggest that the DLPC plays a role in the retrieval of visuospatial information for guiding a response program.

Brain Injuries↗
PubMed1998

Optic aphasia with pure alexia: a mild form of visual associative agnosia? A case study.

A single-case study is reported of a naming disorder selective to the visual modality. The patient showed intact access to structural knowledge of objects and letters, but impaired access to complete semantic knowledge of objects and alphabetical knowledge of letters from visual input. The impairment was most striking when the patient had to discriminate between semantically similar objects or within a given symbolic repertoire, i.e. letters. The co-occurrence of a partial deficit of visual recognition for objects and for letters indicated features of optic aphasia and pure alexia. This symmetric performance between object and letter processing may also constitute a mild form of visual associative agnosia.

Aged↗
PubMed1998

Separate visual pathways for perception of actions and objects: evidence from a case of apperceptive agnosia.

Recognition of different kinds of visual stimuli was studied in a patient who acquired apperceptive visual agnosia after a bilateral occipitotemporal lesion which partially spared the primary visual cortex. Impairment in recognising static objects perceived visually sharply contrasts with the relatively well preserved ability to recognise objects from gestures illustrating their use, and to recognise actions shown in line drawings. It is suggested that the occipitoparieto-frontal pathway is involved in the recognition of actions, and in the recognition of objects when sensorimotor experience is evoked.

Aged↗
PubMed1997

Category-specific anomia: implication of different neural networks in naming.

The occurrence of anomia specifically affecting the ability to name animals is described in three patients. This deficit is contrasted with their capacity to name actions and tools. It is suggested that it is easier to access the names of 'operative' items, which were learned through both visual and sensorimotor experience, than the names of 'figurative' items, which were primarily learned through the visual modality. This hypothesis is consistent with the infero-temporal location of brain damage in these patients. Their ability to retrieve knowledge about operative items is assumed to be due to the sparing of the occipito-parietal area. Because the impairment also involves the recognition of animals, the likely locus of damage is the semantic component of the processing system.

Aged↗
PubMed1997

Optic aphasia: evidence of the contribution of different neural systems to object and action naming.

Visual stimulus naming was studied in a 66-year-old male patient with optic aphasia subsequent to left occipito-temporal infarction. While having difficulty in naming objects perceived visually, he was able to name objects by viewing gestures illustrating their use, and to name actions shown in pictures. These results suggest that naming performance depends on the kind of stimulus that is visually presented (object vs. action). The present findings lend support to congnitive models which postulate the existence of visual and functional semantic systems.

Aged↗
PubMed1992

Effects of canatoxin on the Ca(2+)-ATPase of sarcoplasmic reticulum membranes.

Canatoxin, a toxic protein isolated from the seeds of Canavalia ensiformis, was studied for its effects on the sarcoplasmic reticulum vesicles obtained from rabbit skeletal muscle. Canatoxin inhibited Ca2+ accumulation catalysed by the Ca(2+)-ATPase, without affecting the hydrolytic activity of this enzyme or membrane permeability to Ca2+. The effects of canatoxin were dose dependent, but not time dependent. It is concluded that canatoxin interacts with the Ca2+ pump and uncouples Ca2+ uptake from Ca(2+)-dependent ATP hydrolysis.

Adenosine Triphosphate↗
PubMed1992

Difference in the sensitivity of junctional and longitudinal sarcoplasmic reticulum Ca(2+)-ATPase to ADP.

The Ca2+ release mechanism that triggers muscle contraction is still not completely understood. We compared Ca2+ accumulation and acetyl phosphate hydrolysis by the Ca(2+)-ATPases present in the longitudinal and junctional membrane of the sarcoplasmic reticulum of rabbit skeletal muscle and found that Ca(2+)-ATPase is more sensitive to ADP inhibition when the enzyme is located on the junctional membrane than when the enzyme is located on the longitudinal membrane (K0.5 = 144 microM for the junctional enzyme vs K0.5 = 415 microM for the longitudinal enzyme). When the enzyme was solubilized in non-ionic detergent (2% v/v Triton X-100) and tested again using 2 mM AcP as substrate, the difference in ADP sensitivity observed with native preparations disappeared. We conclude that the enzyme is regulated differently depending on its localization on the membrane of the sarcoplasmic reticulum.

Adenosine Diphosphate↗
PubMedDate not supplied

[Pseudomembranous colitis]

OBJECTIVE: To alert about the pseudomembranous colitis in children, a consequence of the use of antibiotics. METHODS: This report is the result of the clinical follow-up of a patient with chronic diarrhea after the use of several antibiotics. The bibliography was obtained through Medline system. RESULTS: Case report of a girl two years and seven months old, previously healthy, with a clinical picture of chronic diarrhea with dysenteric characteristics after the use of antibiotics, associated with important weight lost and hypoproteinemia. The diagnosis of pseudomembranous was established clinically and was confirmed by colonoscopy and the presence of Clostridium difficile toxin A in the stools. CONCLUSIONS: It is necessary to consider the C. difficile infection in any child with diarrhea associated to the use of antibiotics. The antibiotics in pediatric patients should always be prescribed with caution and precise indications.

Journal Article↗
PubMedDate not supplied

[Upper gastrointestinal endoscopy in children: indications and results]

OBJECTIVE: To present and discuss the indications, the endoscopic and histologic findings and the complications of upper digestive endoscopies carried out in children and adolescents.METHODS: We have done 228 endoscopies in pediatric patients with ages between 3 months to 19 years (x=5.7 y) during a period of 8 months. General anesthesia was used in 80% of patients (182). Biopsies were done in 210 patients and the Helicobacter pylori was searched for in 130 patients by antral biopsies with Hematoxylin-Eosin coloration.RESULTS: The endoscopy indication was diagnostic in all patients, and in 18 cases there was some therapeutic procedure. Fifty-eight percent of examinations presented endoscopic alteration and 84% had abnormal histologic findings. The most frequent endoscopic findings were esophagitis in 50 patients, gastritis in 44 and duodenitis in 29. Ten peptic ulcers were diagnosed. Between the histologic findings the most frequent ones were gastritis in 87 patients, esophagitis in 50 and atrophy of duodenal mucosa in 9. The H. pylori was positive in 25 (19.2%) patients.CONCLUSION: The upper digestive endoscopy has become an essential procedure to the pediatric gastroenterology practice, amplifying the available diagnostic means and enabling therapeutic endoscopy in the presence of upper digestive lesions. In the present report, 58% of the studied population presented some endoscopic lesion.

Journal Article↗
PubMedDate not supplied

[Follow-up of pediatric patients evaluated for liver transplantation].

OBJECTIVE: To analyze the evolution of pediatric patients chosen for hepatic transplantation. METHODS: A review was made of the clinical charts of the first 65 children and adolescents with chronic liver disease, aged 5 months to 19 years (X = 6.8%), chosen for liver transplantation during the period of August 1994 to March 1996. Data refer to the patients' demographic characteristics, etiology of their liver disease, their psychosocial situation and of their parents, and their clinical and laboratorial evaluation. According to the severity of the disease, patients were classified as active (waiting for a donor), in evaluation, inactive (compensated liver disease), and excluded for psychosocial or medical conditions, or because of bad indication. RESULTS: Eight patients (12%) received transplantation, and one of them died. Seven (11%) died when in evaluation or waiting for a donor. Ten patients (15%) were excluded from the waiting list: 6 for social problems, and 4 for medical problems. No patient was excluded for bad indication. Six patients are in the active list, waiting for donor. The other 23 patients (35%) are in evaluation, and 11 (17%) are classified as inactive in the waiting list. CONCLUSIONS: Eleven patients (17%) were not operated on due to the advanced stage of the liver disease. We emphasize the necessity of organ donation, and the early contact of the patients with a reference center.

English Abstract↗
PubMedDate not supplied

[Viral hepatitis: update].

OBJECTIVE: The authors present an update related to different types of viral hepatitis in infancy. The clinic-laboratorial and special outcome aspects are presented. METHODS: The most important articles about viral hepatitis were selected through Medline. The epidemiologic and clinical characteristics related to the subject are reported with emphasis on Brazilian data. RESULTS: This review analyzes the diseases caused by agents that have in common the viral origin and the hepatotropism, but the hepatitis are different particularly in those aspects related to outcome and prognosis. The B virus, for example, may be related to healthy asymptomatic carrier to acute hepatitis, chronic disease, cirrhosis and hepatocellular carcinoma. To date the known viruses are six: A, B, C, D, E and G. CONCLUSIONS: Viral hepatitis is a disease caused by one of the 6 different hepatotropic viruses which originate a wide range of clinical presentations. The viral distribution in Brazil is irregular; in some regions the B virus is prevalent, in others it is rare. The viral infections are the most important and the most frequent causes of liver disease in Brazilian children. The present review is to update viral hepatitis in infancy.

English Abstract↗