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Biomedical subjects

A Almeida

Publications and source records attributed to A Almeida.

At least 109 records · Page 6Linked to original sources
PubMed1983

Post-exercise changes of the Q-Tc interval in coronary heart disease.

A study was made of variations of the Q-Tc interval as a result of exercise on 40 subjects, all submitted to coronary-angiography. The exercise tests were carried out on an ergometric bicycle and the Q-T interval, corrected for heart rate according to Bazett's formula, was measured on the resting ECG before the start of the test, and on the ECG recorded immediately following the end of the exercise. Of the 40 subjects, 29 had coronary heart disease and 11 were considered normal or showed non-significant lesions. In these 11, except for one with left bundle branch block, the Q-Tc showed a shortening on the ECG following exercise. Of the patients with coronary heart disease with or without the presence of contractility disturbances, 20 showed a prolongation of the Q-Tc following exercise, and eight showed no change. The Q-Tc variations were 0.05 sec. +/- 0.03. Analyzing the data as a 2 X 2 contingency table, the value of the alpha 2 corrected for continuity is 30.4, which is highly significant. Our study thus revealed that Q-Tc variations with exercise have a value for the diagnosis of coronary heart disease in exercise tests.

Adult↗
PubMed1982

Experimental Yersinia pestis infection in rodents after intragastric inoculation and ingestion of bacteria.

To clarify the pathogenesis of oral plague infection, we studied the susceptibility of three species of rodents to intragastric inoculation of Yersinia pestis, described the pathology and progression of infection, and measured antibody responses to fraction IA antigen of Y. pestis. The 50% lethal doses of bacteria by intragastric inoculation for Mus musculus, Zygodontomys pixuna, and Rattus rattus were log10 = 6.32, 5.46, and 9.62, respectively, which were at least 1,000-fold higher than the values obtained by subcutaneous inoculation. M. musculus was shown to be susceptible to lethal infection also when bacteria were ingested in drinking water. Microscopic pathology was consistent with heavy systemic infection. Quantitative cultures of tissues at different times after intragastric inoculation revealed that infections of blood, liver, and spleen preceded infections of Peyer's patches and mesenteric lymph nodes. Stool cultures were negative. The strain of Y. pestis used for inoculation was killed when exposed to a buffered solution at pH less than or equal to 3. Antibody responses were observed in some of the surviving rodents after intragastric challenge. These results showed that Y. pestis was an effective oral pathogen that produced fatal systemic infections and self-limited infections with immunity but did not produce enteric pathology or lead to fecal excretion of bacteria.

Animals↗
PubMed1982

The rate pressure product: fact of fallacy?

The product of heart rate and blood pressure, (HR x BP), index of the myocardial oxygen consumption, was evaluated on 37 individuals with ages of between 32 and 65 years; 24 had ischemic heart disease with a disease of 1, 2 or 3 vessels, and 13 had non-significant lesions of 1 vessel (less than 75%) or no coronary heart disease (CHD). From the HR x BP correlation with the study of the angiograms of the coronary arteries, we verified that there was no distinction between patients. with CHD with or without an ejection fraction less than 50% or, with or without disturbances of myocardial contractility, and normal individuals. Thus, we believe that in patients with CHD, an excessive increase in the oxygen requirements of the myocardium is not the sole pathogenic mechanism of ischemia.

Adult↗
PubMed1982

A control and data processing instrument for kidney tubule research.

A microprocess-based instrument has been designed to facilitate research on the electrical properties of isolated renal tubules. Because of the high correlation between the electrical and ionic properties of tubules, this research helps in understanding the mechanisms of reabsorption and secretion along the many functionally different segments of a renal tubule. By replacing manual methods of control, measurement, and calculation, this instrument expedites the experimental procedure and adds accuracy and flexibility not available in the previous arrangement. Based on operational directives entered by the user, the instrument controls the number, frequency, polarity, intensity, and duration of current pulses through the tubule preparation and records the steady-state voltages induced at either end of the tubule. Then, using a transmission line model, it calculates and displays tubule parameters for each current pulse. The diameter of the tubule, as calculated from the model equations, is of immediate interest to the investigator. How well this figure compares with the physical diameter is an indication of the integrity of the preparation and the validity of the other calculations.

Animals↗
PubMedDate not supplied

Possible utility of serum determinations of CA 125 and CA 27.29 in breast cancer management.

The utility of measurement of serum levels of the tumor associated antigens CA 125 and CA 27.29 in detecting the presence of disease and in monitoring changes in disease status was examined in 63 patients with breast cancer. In patients with clinically detectable disease the CA 125 level was elevated in 59%, the CA 27.29 level in 59.5% and one or both markers in 84.6%. Specificity for presence of disease was 83.6% for CA 125, 88% for CA 27.29, and 69.1% for the two markers combined. Changes in marker levels of more than 50% correlated with clinical changes in disease status in 58% of cases for either CA 125 or CA 27.29 alone. In 87.5% of cases with clinically progressive disease one or both marker levels increased by more than 50% from the previous levels. In no case with greater than 50% increase in a marker level was there regression of disease. Thus, the use of these markers in combination might have utility in cases where diagnosis of recurrent disease is difficult or where monitoring of response to treatment is hampered by lack of measurable disease.

Adenocarcinoma↗
PubMedDate not supplied

DNA content by flow cytometry in gastric carcinoma: pathology, ploidy and prognosis.

BACKGROUND/AIMS: The prognostic relevance of histopathologic findings in gastric carcinoma is well established. Studies on DNA-ploidy are still scanty and contradictory. METHODOLOGY: Histopathologic parameters, DNA ploidy and S-phase were evaluated in 78 cancer patients curatively resected, using formalin-fixed paraffin-embedded tissue. RESULTS: Thirty-nine tumors (50%) were aneuploid. No significant correlation was found between histologic data and ploidy, but tumors with nodal involvement were more frequently aneuploid. In univariate analysis, tumor location (p=0.05), tumor size (p=0.01), differentiation grade (p=0.02), Lauren classification (p=0.01), deeper infiltration of gastric wall (p=0.001), nodal affectation (p=0.0000) and number of lymph nodes (p=0.01), TNM stage (p=0.0000), type of gastrectomy performed (p=0.04), and DNA ploidy (p=0.04) significantly influenced survival. S-phase values had no effect on prognosis. In the multiple regression model, factors independently associated with survival were TNM stage (p=0.0009), nodal affectation (p=0.01) and, marginally, ploidy (p=0.08). CONCLUSIONS: In gastric carcinoma curatively resected, the more relevant prognostic factors were stage and nodal involvement. Fifty percent of the tumors were aneuploid. Aneuploidy was significantly associated with poorer prognosis.

Adult↗
PubMedDate not supplied

Illegitimate villin transcripts in normal bone marrow precludes detection of colon cancer micrometastases.

Villin is a specific marker for normal and tumoral colon tissue. We have developed a highly sensitive assay using reverse transcription (RT) and real-time PCR to detect villin transcripts. The sensitivity of detection is one colon cancer cell. However, high levels of illegitimate villin transcripts were observed in normal bone marrow, precluding the use of villin RT-PCR for routine detection of colon cancer cells in bone marrow of patients with colon cancer.

Biomarkers↗
PubMedDate not supplied

[Teleconsulta en neurology in a health unit: preliminary approach].

This paper begins by discussing the influence of neurological diseases in the practice of general practitioners. A thorough review of the literature allows us to conclude that the frequency of neurological complaints in general practice varies between 7% and 15% and that complaints of sleep disorders reach about 26% in those cases. However, general practitioners do not refer all these neurological cases to a neurologist. They screen the cases and refer only 9% of all observed patients. Next, we briefly analyse the impact of telemedicine in general practice. Given this technique's novelty, we present a predictive model for the utility of teleconsultation, which we are currently developing and testing. We then summarise the current status of general practitioners' referrals to our hospital's neurological outpatient clinic, given previous measures that targeted waiting list reduction and adequate referral. After this overview, we present our methodology, which includes the development and implementation of the technologies needed for teleconsultation and the discussion and application of medical protocols for clinical data, benefits and costs. Simultaneously, we investigated the real need for teleconsultation in Neurology according to the literature and to several, more or less optimistic, models of acceptance. Based on this method, teleconsultation began its regular operation in July 1998. We discuss the result of the first 14 weeks of operation. We observed that referral developed according to calculated predictions and that there were clear advantages regarding diagnostics, medication, exam requests, cost avoidance and patient trips to the central hospital. The data collected predicts that this method is useful, efficient and able to substantially reduce costs.

Algorithms↗
PubMedDate not supplied

[Neuroimaging features associated with AIDS].

Due to the nonspecific clinical presentation of Central Nervous System disorders that may come out during the course of Human Immunodeficiency Virus infection, we emphasize the importance of neuroimaging on the differential diagnosis of these situations. Review and illustration of the most typical imaging patterns of the main Central Nervous System disorders in Acquired Immunodeficiency Syndrome.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

[Intravascular therapy of giant cerebral aneurysm].

The endovascular therapy in cerebral aneurysms has met significant technical progress, specially related with new microcatheters and different types of detachable balloons. Reviewing seven cases of giant cerebral aneurysms treated by intra arterial approach, the authors present their results pointing out and discussing the different angiosurgical therapy that can actually be used.

Aged↗
PubMedDate not supplied

[Prevalence of chronic hepatic disease in Portugal. Apropos of a review carried out in a hepatology unit].

UNLABELLED: The chronic elevation of Aminotransferases is one of the most frequent indications for percutaneous Liver Biopsy (LB). From a retrospective study of LB performed in the Hepatology liver Unit of Santa Maria Hospital, between 1989 and 1993, we correlated the histologic diagnosis with the etiology of liver disease, sex, age and the Aspartate aminotransferase/Alanine aminotransferase (AST/ALT) and Gama-Glutamyl transpeptidase (gamma GT) index in patients with chronic liver test abnormalities. 790 LB were reviewed retrospectively, of patients aged between 11 and 78 years, 68% males and 32% females. The most common etiology was Hepatitis C (34.6%), followed by Hepatitis B (20.1%) and alcohol (15.8%). Autoimmune diseases (Primary Biliary Cirrhosis and Autoimmune Hepatitis) were present in 3% of cases, and metabolic liver diseases in 1.4%. The distribution by sex revealed a predominance of Hepatitis C in both, alcoholic liver disease being more frequent in males (21.5% vs 3.9%). The main histological diagnoses were Chronic Active Hepatitis (27.2%), Liver Cirrhosis (19.5%), Steatohepatitis (9.5%) and minor lesions (24.6%). In alcoholic liver disease, 47.2% had Liver Cirrhosis and 16% Steatohepatitis; in Hepatitis B, Liver Cirrhosis was found in 12.6% and in Hepatitis C in 11.4%. Liver Cirrhosis had a prevalence between the 4th and 6th decade of life (82%) with a peak incidence in the 5th, and appeared earlier in Hepatitis B and later in Hepatitis C. The prevalence between sexes was similar. The main etiology of Liver Cirrhosis was alcohol (38.3%). The gamma GT index was greater in alcoholic liver disease (average 4.1) and was nearly twice in Hepatitis C than in Hepatitis B (1.7 vs 0.8). CONCLUSIONS: 1) Hepatitis C in our Hepatology Unit was the main indication for Liver biopsy. 2) The prevalence of alcoholic liver disease is greater in males, being the main etiology of Liver Cirrhosis. 3) The progression to Liver Cirrhosis seems to be similar in Hepatitis B and C. 4) The progression to Liver Cirrhosis is similar in both sexes, being dominant in the 5th decade of life. 5) The progression to Liver Cirrhosis is earlier in Hepatitis B than in Hepatitis C. 6) A gamma GT index elevation, without alcohol abuse, is suggestive of Hepatitis C. 7) Autoimmune and metabolic liver diseases seem to be rare in Portugal.

Adult↗
PubMedDate not supplied

[Localization of brain electric sources in patients with focal epilepsy].

In this paper we discuss a non-invasive method to localize neural electrical sources using EEG data. In this method, the human head is modelled by a set of four concentric spheres with different conductivities which represent the scalp, the skull, the CSF and the brain or by three triangulated surfaces which approximate the exact head shape (in this model we do not consider the CSF layer) using NMR images. In this case the computer effort is very high, since the calculations imply thousands of equations. Therefore, the number of research groups working with this improved model, in the world, is very small. In both models, we assume that the neural source is a current dipole. This makes the model suitable for cases where the active brain areas are limited and localized. We discuss some error factors associated with the method, as the geometry of the head, the conductivity of the different layers and the number of electrodes used in the EEG measurements. Comparing the more realistic head model, with the spherical one we often have differences of 1-2 cm. However, we can reach even more pronounced differences in the frontal areas. Concerning the skull conductivity, we realized that it could introduce errors of 1-2 cm. We observed that at least 50 electrodes should be used only since 21 electrodes could imply errors of about 0.5 cm. The method was applied, both in the spherical version and the realistic one, to clinical cases of focal epileptic patients. The results are discussed in terms of the other clinical information available and they are coherent with the remaining clinical data.

Adolescent↗