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J Almeida

Publications and source records attributed to J Almeida.

108 records · Page 6Linked to original sources
PubMed1984

Viral diagnoses using the rapid immunofluorescence technique and epidemiological implications of acute respiratory infections among children in different European countries.

From November 1978 to October 1981, a total of 7716 specimens of nasopharyngeal secretions were examined by the rapid immunofluorescence technique to determine the frequency of infections caused by the respiratory syncytial virus (RSV), influenza virus A, and parainfluenza viruses 1 and 3. The tests were carried out in six different virus laboratories located in Newcastle upon Tyne (England), Copenhagen, Oslo, Stockholm, Turku (Finland), and Vienna; laboratories in Lisbon and Paris participated in the study for shorter periods. The specimens were collected from infants and children less than 6 years of age who had been admitted to hospital with an acute respiratory infection. Standardized techniques and quality controlled reagents were used. At least one of the above viruses was detected in 1927 (25%) of the specimens: RSV in 1475, influenza virus A in 123, parainfluenza virus 1 in 110, and parainfluenza virus 3 in 237 specimens. Respiratory syncytial virus dominated in all centres, but in some Scandinavian centres distinct outbreaks due to this virus occurred only once or twice during the 3 years' study period. Three outbreaks of RSV were observed in Newcastle, but here an unprecedented delay of the first winter's epidemic occurred. The delay was associated with prolonged school closures in the area, and with a very early outbreak of influenza. Parainfluenza virus 3, which was predominantly a summer virus in Newcastle, was most frequently encountered during the colder months of the year in the other centres.

Acute Disease↗
PubMed1983

A new ECG classification system for myocardial infarction based on receiver operating characteristic curve analysis and information theory.

An optimized three-lead ECG hierarchial decision-tree type of classification system for myocardial infarction is presented. For selection of the best threshold values for each criterion and the best association of features, we developed a procedure based on "receiver operating characteristic" (ROC) curve data analysis and information theory. Optimization was obtained through maximization of information content of the criteria. The classifier is based on nine measurements that can be easily obtained by hand (QX duration, Q/R Y amplitude, R Y amplitude, Q/R Y duration, Q Z amplitude, QRS and T axes in the horizontal plane, Q Z duration and R Z amplitude) and achieved a satisfactory performance in an independent group of patients (true-positive ratio 0.853, false-positive ratio 0.105, average information content 0.308 bits).

Adult↗
PubMed1978

Herpesvirus morphology: visualization of a structural subunit.

The presence of spontaneously disrupted cytomegalovirus capsids has made it possible to visualize a subunit within the herpesvirus capsomere. The pattern resolved agreed well with the theoretical net based on the concept of a structural subunit at each apex of the hexon.

Capsid↗
PubMed1975

Thin layer chromatography and counter-current analysis in porphyrias.

The porphyrin metabolism of 100 patients with porphyria and 351 of their relatives has been studied. Thin layer chromatography of methyl esters of the urinary porphyrin was undertaken in sixty-six patients with different types of porphyria, and forty-five relatives, seventeen patients with hepatic cirrhosis, three patients with lead poisoning and twenty normal control subjects. This investigation was also made on the stools of thirty-six patients with porphyria, and then of their relatives. Countercurrent analysis of the bile of nine selected patients with porphyria was also undertaken. The results provide some evidence that symptomatic hepatic porphyria may be familial. Thin layer chromatography was decisive in the characterization of a new type of porphyria described recently by the authors (hepato-erythrocytic porphyria). The counter-current examination of the bile showed the absence of the 'S 411' porphyrin in all the nine cases investigated.

Bile↗
PubMed1975

[Hepato-erythrocytic porphyria. A new type of porphyria].

A case of porphyria with symptomatology beginning in early infancy with peculiar biochemical features is described. There were crops of blisters, an extraordinary hypertrichosis and scarring of the exposed skin. The porphyrin examination showed an abnormal excretion pattern of urinary porphyrins with large amounts of 5-COOH carboxyle porphyrins and the protoporphyrin level of the red cells was raised. There was fluorescence of the erythrocytes and erythroblasts. The porphyrin excretion pattern of the stools was similar to those of the PCT. This case is closely similar to another published by the authors in 1969 and to 2 published by Schneider and Simon. The authors consider that could represent a new type of porphyria.

Child↗
PubMedDate not supplied

Modeling retrovirus production for gene therapy. 2. Integrated optimization of bioreaction and downstream processing.

In this work a model envisaging the integrated optimization of bioreaction and downstream processing is presented. This model extends the work presented in part 1 of this pair of papers by adding ultrafiltration to process optimization. The new operational parameters include ultrafiltration time, pressure, and stirring rate. For global optimization, the model uses as constraints the final product titer and quality to be achieved after downstream processing. This extended model was validated with the same system used in part 1, i.e., PA317 cells producing a recombinant retrovirus containing the LacZ gene as a marker in stirred tanks using porous supports. Optimization of the extended model led to the conclusion that bioreaction should have two steps, batch and perfusion, similar to what was found in part 1. Ultrafiltration in a stirred cell should be performed at low pressures and stirring rates to reduce the losses of infective retroviruses. Sensitivity analysis performed on the results of the integrated optimization showed that under optimal conditions the productivity is less sensitive to the parameters related to ultrafiltration than to those associated with bioreaction. These results were interpreted as reflecting the high yield of ultrafiltration (90%). The relevance of the model extension to perform integrated optimization was also demonstrated since a restriction in the specific ultrafiltration area in downstream processing conditioned perfusion duration and perfusion rate in bioreaction. This clearly indicates that overall process optimization cannot be achieved without integrated optimization.

Bioreactors↗
PubMedDate not supplied

Photocurrent near-field microscopy of Schottky barriers.

We used a combination of internal photoemission and of near-field optical microscopy (SNOM) to study the lateral variations in solid interface properties such as energy barriers and electron-hole recombination. In particular we investigated the fully formed Pt-GaP, Au-GaAs, Au-SiNx-GaAs and PtSi-Si Schottky barriers. Our approach enabled us to measure large lateral variations in the photocurrent with spatial resolution on the nanometric scale. Due to the ability of SNOM to supply parallel topographic information, we observed photocurrent variations from zone to zone that only correlated in a few cases with local variations in surface morphology. We assigned the uncorrelated fluctuations to local variations in the interface stoichiometry, the presence of interface states induced by the metallic overlayer and to defect states at the junction. Furthermore, by tuning the photon energy and applied bias we were able to measure the surface distribution of the diffusion length.

Journal Article↗
PubMedDate not supplied

The effect of double adhesive application on the shear bond strength to dentin of compomers using three one-bottle adhesive systems.

The development of one-bottle dentin adhesive systems resulted in much optimism about providing simplified predictable esthetic dentistry. However, laboratory testing of these systems continues to provide significant variations between facilities. A potential effect of the number of applications was noted in this author's laboratory. This study evaluated the effect of doubling the manufacturer's recommended number of applications on shear bond strength to dentin. Ninety human molars were divided into groups of 15. The occlusal surfaces were finished to 600 grit SiC to provide a flat dentin bonding surface. Prime & Bond NT-Dyract, Optibond Solo-Elan and One Step-Dyract were evaluated. Each material was tested using: (1) the recommended number of adhesive applications and (2) twice the number of applications recommended. All adhesive applications were accomplished before light curing the adhesive. The specimens were thermocycled after one week of storage and tested in shear after two weeks. Specimens were also fabricated after adding Rhodamine D to the adhesive to allow for visualization using confocal microscopy. These teeth were sectioned and viewed 24 hours after fabrication. A t-test was used to compare differences within product groups. The results showed a significant effect (p < 0.001) when a double application of Prime & Bond NT was used. No difference was seen with Optibond Solo or One Step. All specimens appeared to have a uniform, glossy appearance of adhesive during fabrication. Therefore, the appearance of the adhesive after application may not be a reliable predictor of acceptable bonding. Confocal microscopy showed that single application Prime & Bond NT specimens did not exhibit a uniform thickness of adhesive across the entire interface. Tubule penetration and hybridization was apparent for all specimens.

Bisphenol A-Glycidyl Methacrylate↗
PubMedDate not supplied

Interaction between clonal plasma cells and the immune system in plasma cell dyscrasias.

The term "monoclonal gammopathy" (MG) includes a group of clonal plasma cell disorders, which show heterogeneous clinical behavior. While multiple myeloma (MM) and plasma cell leukemia (PCL) are incurable malignant diseases, most patients with MG of undetermined significance (MGUS) show an indolent/benign clinical course. Evidence has accumulated which supports the role of the bone marrow microenvironment in MG. Accordingly, the survival, drug-resistance and proliferation of MM cells have been shown to be largely dependent on a supportive microenvironment. Among the different environment-associated parameters, those related to the status/activity of the immune system are particularly relevant. This review focuses on the different ways clonal plasma cells (PC) interact with the immune system in different models of MG, to characterize crucial events in the development and progression of MG. These advances may support the design of novel therapeutic approaches in patients with MG.

Bone Marrow↗
PubMedDate not supplied

Reactive phenotypes after acute and chronic NK-cell activation.

Several phenotypic changes have been shown to occur after NK-cell stimulation, involving molecules that have been proved to regulate NK-cell migration into tissues and NK-cell activation and proliferation as well as target cell recognition and killing. Here, we review the reactive phenotypes observed in vivo after acute and chronic NK-cell activation.

CD56 Antigen↗
PubMedDate not supplied

[Aneurysm of the Valsalva sinus. Echocardiographic diagnosis. Apropos of a case of long post-rupture survival].

The authors present a case of aneurysm of the right sinus of Valsalva with rupture and aorto-cardiac shunt to the exit chamber of right ventricle. Based on clinical information, one can assume that it could be a case which has been with few symptoms for a period of seven years or more. The diagnosis was made possible due to the images obtained by M mode and two dimensional echocardiography, which allowed an unmistakable view of an aneurysmatic dilatation and the site of the rupture which was confirmed later by Doppler echocardiography with colour codification and and anatomical assessment at surgery.

Adult↗
PubMedDate not supplied

T and B lymphocytes, total serum IgE and peripheral eosinophils in bronchial asthma.

Absolute T and B lymphocytes, assayed by E and EAC rosette techniques, serum IgE levels, total eosinophil counts and delayed hypersensitivity cutaneous reactions were studied in 39 asthmatic subjects (19 extrinsic asthmas and 20 intrinsic asthmas) and in 15 age-matched control subjects. The mean value of T lymphocytes was 1753 +/- 709 mm.3 in the extrinsic group, 1511 +/- +/- 530 mm.3 in the intrinsic, and 1609 +/- 451 mm.3 in the controls. There was no statistical difference between the two groups of patients and the controls (P > 0.05). There was also no statistical difference of B lymphocytes between the two groups of patients and the controls. Serum IgE was elevated in 8 extrinsic asthmatics (42.1%), in one intrinsic (5%), and in none of the control population. The mean value of eosinophils ws significantly higher (P < 0.01) in the extrinsic group as compared to the controls. The same was true of the intrinsic group, but not so significantly (P congruent to 0.02). No correlation was observed between the number of T lymphocytes and the skin tests, serum IgE and total eosinophil counts.

Adolescent↗
PubMedDate not supplied

Do myelomatous plasma cells really express surface immunoglobulins?

Surface immunoglobulins (sIg) are traditionally considered to be absent in plasma cells (PC). However, it has recently been reported that up to one third of myeloma patients are positive for surface immunoglobulins. Nevertheless, this observation has not been confirmed in other studies. In order to assess whether or not sIg are really expressed by myelomatous PC and to exclude possible staining of either cytophilic or cytoplasmic Igs, simultaneous experiments were carried out with i) incubation at 37 degrees C, ii) blocking with non-conjugated anti-Ig light chains, and iii) cytoplasmic staining after cell membrane fixation and permeabilization. Triple staining for CD38/kappa/lambda was used in all cases and the staining intensity was quantitated in MESF (molecule equivalents of soluble fluorochrome). In addition, 20 B-CLL cases and 10 healthy donors were used as reference controls. Our study shows that 7 out the 20 patients (35%) analyzed expressed sIg and that the surface staining was specific.

Aged↗