Particular clinical presentations of psoriasis in HIV patients

Patients with HIV infection have a higher propensity for infectious, inflammatory, neoplastic and metabolic disorders. The link with psoriasis vulgaris is explained by well-known pathophysiological phenomena and can be observed at any stage of infection. The aim of our study was to characterize the clinical spectrum of psoriasis in a group of 50 patients with HIV. Our findings showed particular clinical presentations of psoriasis in those patients, suggesting a predilection for scalp lesions, palmoplantar keratoderma and flexural involvement, as well as a trend towards severe immunodeficiency. Psoriasis, a frequent reason for consultation, allows earlier suspicion and diagnosis of HIV in the presence of these particular patterns.

Development of a new ionisation chamber, for HP(10) measurement, using Monte-Carlo simulation and experimental methods

An ionisation chamber that directly measures the quantity personal dose equivalent, H(p)(10), is used as a secondary standard in some metrology laboratories. An ionisation chamber of this type was first developed by Ankerhold. Using the Monte-Carlo simulation, the dose in the sensitive volume as a function of the IC dimensions and the effects of the several components of the ionising chamber have been investigated. Based on these results, a new ionising chamber, lighter than the previous ones, is constructed and experimentally tested.

Early syphilitic meningoencephalitis masquerading as postclimacteric endogenous depression--a unique dermatologic presentation

According to WHO, syphilis represents 3% of all sexually transmitted diseases. Additionally, the occurence of this disease has also been increasing in developed countries. The secondary stage of syphilis is characterized by a large variety of symptoms and may mimic many skin diseases. The generalized exanthem of the secondary stage is often confused with a drug eruption. The systemic involvement may also resemble other diseases. It is due to these peculiarities that syphilis, and in particular its secondary stage, is known in literature as the "clinical chameleon" or "great imitator". Nonspecific neurological symptoms like headache, lightheadedness, and slight mental depression appear prior to the skin manifestations characteristic of the second stage of the disease. Subsequently, when the patient begins to develop the characteristic disseminated maculopapular exanthem with palmoplantar involvement, the clinician may have to re-evaluate to exclude an early form of syphilitic meningoencephalitis. We report here the case of a female patient with suspected endogenous depression as part of the post-climacterium syndrome. Shortly after the introduction of antidepressant therapy the patient developed a generalized maculopapular exanthem. She was seen in the Dermatology clinic due to suspicion for a drug eruption. A diagnosis of secondary syphilis with palmoplantar involvement, associated with an early form of syphilitic meningoencephalitis, was established. After systemic antibiotic treatment, complete remission was achieved.

Simulation studies on a prototype ionisation chamber for measurement of personal dose equivalent, Hp(10)

A prototype ionisation chamber for direct measurement of the personal dose equivalent, Hp(10), similar to the one developed by the Physikalisch-Technische Bundesantalt (PTB), was designed and constructed by the Metrological Laboratory of Ionizing Radiation (LMRI) of Nuclear and Technological Institute (ITN). Tests already performed have shown that the behaviour of this chamber is very similar to the PTB chamber, mainly the energy dependence for the X-ray radiation qualities of the ISO 4037-1 narrow series N-30, N-40, N-60, N-80, N-100 and N-120 and also for gamma radiation of 137Cs and 60Co. However, the results obtained also show a dependence on the energy and angles of incident radiation and a low magnitude of the electrical response of the ionisation chamber. In order to optimise the performance of the chamber, the LMRI initiated numerical simulation of this ionisation chamber by Monte Carlo method using the MCNPX code.

Expression and genomic profiling of colorectal cancer

Colorectal cancer still represents a paradigm for the elucidation of the cellular, genetic and molecular mechanisms that underly solid tumor initiation, progression to malignancy, and metastasis to distal organ sites. The relative ease with which pathological specimens can be obtained by either surgery or endoscopy from different stages of tumor progression has facilitated the application of omics technologies to allow the genome-wide analysis both at the RNA (gene expression) and DNA (aneuploidy) levels. Here, we have reviewed the multiplicity of studies appeared to date in the scientific literature on the expression and genomic analysis of colorectal cancer, and attempted an integration of the profiling data generated and made available in the public domain. This approach is likely to pinpoint specific chromosomal loci and the corresponding genes which (i) play rate-limiting roles in colorectal cancer, (ii) represent putative diagnostic and prognostic markers for the accurate prediction of clinical outcome and response to treatment, and (iii) encompass potential therapeutic targets. Moreover, cross-species data mining and integration of the human colorectal cancer profiles with those obtained from mouse models of intestinal tumorigenesis will even more contribute to the elucidation of highly conserved pathways and cellular functions underlying malignancy in the GI tract. Notwithstanding the above promises, tumor heterogeneity, limited cohort sizes, and methodological differences among experimental and bioinformatic approaches still poses main obstacles towards the optimal utilization and integration of omics profiles.

Dosimetry at the Portuguese research reactor using thermoluminescence measurements and Monte Carlo calculations

This work presents an extensive study on Monte Carlo radiation transport simulation and thermoluminescent (TL) dosimetry for characterising mixed radiation fields (neutrons and photons) occurring in nuclear reactors. The feasibility of these methods is investigated for radiation fields at various locations of the Portuguese Research Reactor (RPI). The performance of the approaches developed in this work is compared with dosimetric techniques already existing at RPI. The Monte Carlo MCNP-4C code was used for a detailed modelling of the reactor core, the fast neutron beam and the thermal column of RPI. Simulations using these models allow to reproduce the energy and spatial distributions of the neutron field very well (agreement better than 80%). In the case of the photon field, the agreement improves with decreasing intensity of the component related to fission and activation products. (7)LiF:Mg,Ti, (7)LiF:Mg,Cu,P and Al(2)O(3):Mg,Y TL detectors (TLDs) with low neutron sensitivity are able to determine photon dose and dose profiles with high spatial resolution. On the other hand, (nat)LiF:Mg,Ti TLDs with increased neutron sensitivity show a remarkable loss of sensitivity and a high supralinearity in high-intensity fields hampering their application at nuclear reactors.

Photon and fast neutron dosimetry using aluminium oxide thermoluminescence dosemeters

Al(2)O(3):Mg,Y thermoluminescence (TL) dosemeters were used to measure photon and fast neutron doses in a fast neutron beam recently implemented at the Portuguese Research Reactor, Nuclear and Technological Institute, Portugal. The activation of Al(2)O(3):Mg,Y by fast neutrons provides information about the fast neutron component by measuring the activity of the reaction products and the self-induced TL signal. Additionally, the first TL reading after irradiation determines the photon dose. The elemental composition of the dosemeters was determined by instrumental neutron activation analysis and by particle induced X-ray emission. Results demonstrate that Al(2)O(3):Mg,Y is an adequate material to discriminate photon and fast neutron fields for reactor dosimetry purposes.