Biomedical subjects

L Fonseca

Publications and source records attributed to L Fonseca.

At least 19 recordsLinked to original sources

PubMed2004

Thermal AFM: a thermopile case study.

In this work, an atomic force microscope (AFM) with an integrated thermal sensor has been used to obtain the local spatial distribution of temperatures in a micromachined thermopile with submicron resolution. In this communication, we will show how the dimensional, structural and functional characteristics of a thermopile suits well with the requirements for AFM thermal imaging, and how a deeper insight of the thermopile operation can be gained with the aid of these advanced scanning probe-based tools.

Diagnostic Imaging↗

PubMed2002

Novel allelic variants of Mycobacteria isolated in Brazil as determined by PCR-restriction enzyme analysis of hsp65.

Human isolates of Mycobacterium collected in 16 different states of Brazil were submitted to PCR-restriction analysis (PRA) of a 439-bp fragment of the hsp65 gene with HaeIII and BstEII. Fourteen allelic variants not described in clinical isolates so far were observed among 36 (10%) of 356 Brazilian strains, including a new pattern for Mycobacterium scrofulaceum, M. intracellulare, and M. flavescens, two new patterns for M. fortuitum, three new patterns each for M. gordonae and M. terrae, and one new pattern for M. avium complex-like strains. Two unidentified strains each also presented a new pattern, strongly suggesting that Mycobacterium genotypes are distributed biogeographically. The PRA procedure was also performed with 43 reference isolates belonging to 34 species, adding a further six new patterns to the identification algorithm. A database containing the normalized restriction patterns of both enzymes was constructed. Patterns available on the Internet can be introduced into this database, which will make possible the comparison of genotypes from isolates from different parts of the world.

Alleles↗

PubMed2001

Appropriateness of emergency department visits in a Portuguese university hospital.

STUDY OBJECTIVE: There are no studies in Portugal supporting a common claim that most emergency department visits are inappropriate. The aim of this study was to determine the prevalence of and to evaluate factors associated with an appropriate ED visit in a major public hospital. METHODS: A cross-sectional prospective study was performed at a public university hospital ED. Data for demographic variables, duration of complaint, transfer from other medical sources, and previous medical care for the same complaints were collected by interviewing all patients who arrived at the ED within a consecutive period of at least 24 hours. Data for diagnostic tests, treatment performed, and final patient destination were collected by triage records review. An appropriate ED visit was defined by explicit criteria: interhospital transfer, patient death at the ED, hospitalization, and diagnostic tests or treatments performed. RESULTS: The study included 5,818 adult patients. The prevalence of an appropriate ED visit, by use of our criteria, was 68.7%. Sex was an effect modifier. According to this study, determinants of an appropriate visit for men and women were age 60 years or older and complaints of 24 hours or less and in women but not in men, retired from work and with arrival between midnight and 8 AM. CONCLUSIONS: In a university hospital in Oporto, the majority of ED visits were appropriate according to explicit criteria. Some variables may be associated with appropriateness of ED visits. A duration of the complaint 24 hours or less along with an arrival between midnight and 8 AM in women and age 60 years or older in men were the most important determinants.

Adult↗

PubMed2000

Involvement of IFN-gamma receptor-medicated signaling in pathology and anti-malarial immunity induced by Plasmodium berghei infection.

IFN-gamma has been implicated in the pathogenesis of experimental cerebral malaria (ECM). We have used mice lacking the alpha chain of the IFN-gamma receptor (KO mice) to define its role in the pathogenesis of ECM. Infected KO mice did not develop ECM and showed no leukocyte or parasite sequestration in the brain, and no hemorrhages. The resistance of KO mice to ECM was associated with the absence of any increases of TNF-alpha and ICAM-1 proteins in the brain, which are both essential for ECM. Wild-type (WT) mice which do not develop ECM, despite increased local production of TNF-alpha protein, showed no leukocyte accumulation in the brain and this was correlated with the absence of ICAM-1 protein from brain microvessels. KO mice infected with 106 parasitized erythrocytes (PE) of Plasmodium berghei ANKA (PbA) did not develop ECM, but they had high parasitemia and died earlier than WT mice which did not develop ECM. However, KO mice did not develop higher parasitemia than WT mice when both groups were infected with a lower dose (5x10(5) PE) of PbA-infected red blood cells. This indicates that different doses of PE may trigger different IFN-gamma responses and that there may be a threshold concentration for protection against parasitemia.

Animals↗

PubMed2000

Mapping cancer, cardiovascular and malaria research in Brazil.

This paper presents performance indicators for the Brazilian cancer, cardiovascular and malaria research areas from 1981 to 1995. The data show an increasing number of papers since 1981 and author numbers indicate a continuous growth of the scientific community and suggest an expected impact of scientific activity on biomedical education. The data also characterize cardiovascular research as a well-established area and cancer research as a faster growing consolidating field. The 1989-1994 share of Brazilian articles among world publications shows a growing trend for the cancer (1.61) and cardiovascular (1.59) areas, and a decrease for the malaria area (0. 89). The burden of the three diseases on society is contrasted by the small number of consolidated Brazilian research groups, and a questionable balance of thematic activity, especially with regard to malaria. Brazilian periodicals play an important role in increasing the international visibility of science produced in the country. Cancer and cardiovascular research is strongly concentrated in the Southeastern and in Southern regions of Brazil, especially in São Paulo (at least one address from São Paulo in 64.5% of the 962 cancer articles and in 66.9% of the 2250 cardiovascular articles, the second state being Rio de Janeiro with at least one address in 14.1 and 11% of those articles, respectively). Malaria research (468 articles) is more evenly distributed across the country, following the pattern of the endemic distribution of the disease. Surveying these national indicator trends can be useful to establish policies in the decision process about health sciences, medical education and public health.

Abstracting and Indexing↗

PubMed2000

Esophageal reconstruction surgery in oncologic patients: determination of gastric emptying time.

All parts of the gastrointestinal tract are accessible for study using nuclear medicine techniques. We have studied the effect of esophageal reconstruction surgery, in different periods of time, after surgical procedure. Oncologic patients (19) were evaluated after esophageal reconstruction surgery with gastric (group II - 14 patients) or colonic tube (group III - 5 patients) and they were compared with 15 healthy volunteers (group I). Gastric emptying was performed in the same subjects using solid food (egg sandwich) labeled with 99mTc-phytate. In emptying gastric studies, the mean (T1/2) of the patients was much faster than those of the control (p<0.05) when 1/3 distal tube was considered as stomach. However, there was no difference between the T1/2 of group II and group III. We concluded that this nuclear medicine method could be useful in the monitoring the surgical reconstruction of the esophagus.

Adenocarcinoma↗

PubMed1999

Teleconsultation for cooperative acquisition, analysis and reporting of ultrasound studies.

We have developed a teleconsultation system to support cooperation between doctors at different institutions in the acquisition, analysis and reporting of ultrasound studies. All the relevant activities were supported by the application. The system enabled remote supervision of the ultrasound study as it was being performed, cooperative static image acquisition and analysis, as well as report writing. Cooperative analysis of previously acquired studies was also possible. The system is undergoing evaluation in five hospitals in Portugal.

Computer Systems↗

PubMed1998

[Advances in the diagnosis and treatment of pancreatic carcinoma].

Pancreatic carcinoma has a dismal prognosis. In the last years, great efforts have been made to improve diagnosis and preoperative staging of potentially curable carcinomas. Actually, the diagnosis of fairly small tumours is possible. Chemoradiation therapy protocols prior to pancreatectomy, aiming to improve survival, are currently being held. This therapy allows radiation to be distributed into well oxygenated cells before surgical devascularization. This procedure can be done with acceptable morbidity and mortality rates. In selected cases of irresectable carcinoma, surgical palliation allows a better quality of life. Pancreatoduodenal resection, along with other traditional oncological therapies, will continue to be the therapy of choice for patients with carcinoma of the head of the pancreas, without local or regional metastases. However, an intensive search for new therapeutic strategies, specially in the field of molecular biology, is being carried out.

Carcinoma↗

PubMed1996

[Pancreas divisium as a cause of chronic pancreatitis. Clinical case].

We report a 6 years old girl with chronic pancreatitis, presenting as recurring bouts of abdominal pain and hyperamylasemia, secondary to a lack of communication between the main papilla and pancreatic duct (pancreas divisium). The diagnosis was made during an intraoperative pancreatography and treatment consisted in a sphincteroplasty of the secondary papilla.

Child↗

PubMed1996

[Toxoplasma gondii: the characterization of an anti-P30 monoclonal antibody].

A specific monoclonal antibody was characterized to Toxoplasma gondii. The hybridoma produced IgG immunoglobulins. The western blot analysis showed that the monoclonal antibody was specific for the antigen of an apparent molecular mass of 30 kd, which was present on the antigen surface. The monoclonal antibody was purified starting from mouse's ascitic fluid and it was matched with sepharose 4B. This immunoabsorbent was used to purify the specific parasitic antigen. The monoclonal antibody studied may be useful for those techniques contributing to the toxoplasmosis diagnosis.

Animals↗

PubMed1995

Plasmodium berghei: selection of mefloquine-resistant parasites through drug pressure in mosquitoes.

Mefloquine is an antimalarial drug with schizonticidal activity on blood-stage parasites. Studies of the role of mefloquine on the development of Plasmodium berghei ANKA in anopheles stephensi have been carried out that showed a dose-dependent effect on the sporogonic cycle of these parasites, with changes in the numbers of oocysts and the extent of sporozoite invasion of salivary glands. In this study, we show that mefloquine-resistant P. berghei ANKA blood stage parasites could be selected through drug pressure during continuous cyclical transmission of Anopheles gambiae s.l.

Animals↗

PubMed1995

[Correlation of DNA ploidy, c-erB-2 protein tissue status, level of PCNA expression and clinical outcome in gastric carcinomas].

One-hundred and sixty-four patients with gastric carcinomas, who underwent gastrectomy during 1979-1985, were studied. The nuclear DNA contents were measured by cytofluorometry, and immunohistochemical study on the expression of c-erbB-2 protein was performed using a monoclonal antibody against the c-erbB-2 oncogene product. Furthermore immunohistochemical detection of proliferating cell nuclear antigen (PCNA) was performed using a monoclonal antibody against the PCNA. The patients with aneuploid tumor had a significantly worse prognosis than those with diploid tumor. The group with positive staining for c-erbB-2 had a significantly worse prognosis than negative one. The higher group of PCNA indices had a worse prognosis. The patients with tumor showing both aneuploid and positive staining for c-erbB-2 tissue status and PCNA indices. But no correlation was formed between c-erbB-2 tissue status, PCNA indices and DNA contents. From these results, it can be concluded that DNA ploidy, c-erbB-2 protein, and PCNA may reflect the malignant potential of gastric carcinoma.

Aneuploidy↗

PubMed1995

Lymph node metastasis and surgical management of gastric cancer invading the esophagus.

In 88 resected patients with esophagus-invading gastric cancer, the factors determining the prognosis of this disease were investigated by multivariate analysis. Neither, age, sex, macroscopic type, thoracotomy, nor histological type proved to be independent prognostic factors. The presence or absence of lymph node metastasis, serosal invasion, tumor size, and the extent of esophageal invasion were found to be significant independent prognostic factors. Among lymph node metastases, involvement of para-aortic lymph nodes was especially important. The prognosis was significantly better in cases in which these nodes were carefully dissected (R4 gastrectomy), than in cases in which selected dissection was performed (R2). However, no patient with mediastinal lymph node metastasis survived for any lengthy period, and thus the mediastinal lymph nodes seemed to be nodes, the dissection of which brought little effect. Postoperative results were very poor in cases in which the extent of the esophageal invasion was 3 cm or more. These patients should be treated with multi-modal therapy such as neoadjuvant chemotherapy.

Adenocarcinoma↗

PubMed1995

Leprosy in five human immunodeficiency virus-infected patients.

We present five cases of leprosy in five human immunodeficiency virus-positive individuals. The patients were five men between the ages of 18 and 45 years. The five patients presented with skin lesions; three patients with hypopigmented skin lesions, one with skin macules and a history of leprosy, and one with papular lesions. In one patient, there was bilateral "claw hands." Histologically, two cases were categorized as lepromatous leprosy, two as borderline tuberculoid, and one as borderline lepromatous. Follow-up information obtained in the five patients showed one patient had died, and the remaining four patients were alive and receiving antileprosy treatment.

Acquired Immunodeficiency Syndrome↗

PubMed1994

Surgical results of performing R4 gastrectomy for gastric cancer located in the upper third of the stomach.

Because gastric cancers located in the upper third of the stomach are difficult to detect at an early stage, the surgical results remain poor. We performed R4 gastrectomy as a radical procedure for 25 patients, involving complete resection of the latero-aortic and interaorticovenous lymph modes above and below the left renal vein, in combination with the ordinary R2 or R3 gastrectomy (the R4 group). These patients were compared with 156 others who underwent R2 gastrectomy alone (the R2 group). There were no significant differences in operation time, blood loss, or the incidence of complications between the two groups; however, when the survival rates of the patients with tumors invading beyond the subserosa were compared, the 5-year survival rate was found to be significantly higher in the R4 group than in the R2 group. Furthermore, in patients with para-aortic nodal involvement, a significant survival advantage was observed in the R4 group, as compared with the R2 group. These results suggest that the R4 gastrectomy is a rational approach for patients with advanced gastric cancer located in the upper third of the stomach.

Female↗

PubMed1994

Pancreatic trypsinogen and cathepsin B in human pancreatic carcinomas and associated metastatic lesions.

Expression of pancreatic trypsinogen and cathepsin B in 23 surgically resected pancreatic ductal adenocarcinomas was evaluated immunohistochemically, using a monoclonal antibody against human pancreatic trypsinogen and a polyclonal antibody against human cathepsin B. Fifteen of 20 invasive tubular adenocarcinomas (75%) expressed pancreatic trypsinogen in a coarse granular pattern located in the supranuclear cytoplasm of the carcinoma cells. In addition, metastatic lesions, including those in peripancreatic lymph nodes and neural plexuses, expressed pancreatic trypsinogen. In contrast, three intraductal (non-invasive) papillary adenocarcinomas did not express pancreatic trypsinogen. Cathepsin B expression was recognised in 14 of 20 invasive tubular adenocarcinomas (70%) in a fine granular pattern located diffusely in the cytoplasm of the carcinoma cells, while none of the three intraductal papillary adenocarcinomas had detectable cathepsin B. These findings suggest that pancreatic invasive ductal adenocarcinomas express pancreatic trypsinogen and cathepsin B immunoreactive peptides, raising the possibility that pancreatic trypsinogen and cathepsin B may act independently of each other in the process of carcinoma invasion and metastasis, like other different classes of proteases involved in the proteolytic modification of the matrix barrier.

Adult↗

PubMed1994

Productivity versus promised results: one of the dilemmas of biotechnology in Brazil.

In 1983 a new funding program--PADCT ("Programa de Apoio ao Desenvolvimento Cientifico e Tecnológico")--was created in Brazil to stimulate the development of research projects related to what was established as technological priorities. In this paper 3 features of the Biotechnology/Health subprogram of PADCT were studied: a) to what extent productivity of the leaders of the research projects affected the way they were evaluated by the award panel, b) the conflict of interests that might result from the composition of the award panel, and c) the final impact of the program on science and technology. In our sample of 210 submitted projects, 62 were funded. The data suggest that the selection of projects did not ensure a better funding for the more productive research leaders. The presence on the award panel of at least one member from the same institution of a given project increased the chance of its approval but, after approval, it had no influence on the amount of funds granted. In a subsample of 21 scientists, support to 24 projects did not increase the productivity level and 4 products in a preliminary phase of development were reported. The issue of trying to solve problems in areas where there is no established scientific competence is discussed.

Biotechnology↗

PubMed1994

A new surgical technique (left upper abdominal evisceration) for advanced carcinoma of the gastric stump.

In spite of recent advances in the early diagnosis of gastric cancer by mass screening, gastric stump cancers following gastrectomy are still diagnosed at a highly advanced stage, and the surgical results remain very poor. Involvement of the fourth level lymph node stations, local peritoneal carcinomatosis and tumor growth invading the neighboring organs are frequently observed in advanced stump cancers. With the aim of achieving complete resection of these tumors, left upper abdominal evisceration (LUAE) + R4 gastrectomy was performed in 29 patients (Group B) with stump cancer as a radical surgical procedure. The survival of these patients was compared with that of 74 patients (Group A) who underwent total gastrectomy with or without pancreaticosplenectomy. Duration of surgery blood loss, and incidence of postoperative complications were similar with the two methods. When the survival rates were compared, the 5-year-survival rate in stage IV cases was higher for Group B than for Group A. LUAE + R4 gastrectomy is a rational technique for the surgical treatment of stage IV gastric stump cancer.

Adrenalectomy↗