Elevated Hepcidin Is Part of a Complex Relation That Links Mortality with Iron Homeostasis and Anemia in Men and Women with HIV Infection.

BACKGROUND: Early and chronic inflammation is a hallmark of HIV infection, and inflammation is known to increase hepcidin expression. Consequently, hepcidin may be a key determinant of the iron homeostasis and anemia associated with poorer HIV prognoses. OBJECTIVE: The objective of this study was to understand how hepcidin is related to anemia, iron homeostasis, and inflammation at HIV diagnosis and to investigate associations between hepcidin and all-cause mortality in HIV infection. METHODS: In a retrospective cohort, baseline plasma hepcidin was measured by competitive enzyme immunoassay within 3 mo of HIV diagnosis in 196 antiretroviral-naive Gambians. Iron homeostasis [hemoglobin, plasma transferrin, ferritin, iron, soluble transferrin receptor (sTfR)] and inflammation [α1-antichymotrypsin (ACT)] from the same plasma sample were available, as were absolute CD4 cell counts, age, gender, body mass index (BMI), and HIV type. RESULTS: Anemia was common across the spectrum of immunosuppression [CD4 cell counts (prevalence of anemia): >500 cells/μL (68%), 200-500 cells/μL (73%), and <200 cells/μL (89%); P = 0.032] and in men (81%) and women (76%). Increasing hepcidin was associated with iron homeostasis biomarkers (higher ferritin and lower transferrin, hemoglobin, and sTfR), inflammation (higher ACT), and key health indicators (lower CD4 or BMI, advancing age, and male gender; P < 0.001 except for hemoglobin, P = 0.021). Elevated hepcidin was associated with greater all-cause mortality in a dose-dependent manner [intermediate vs. lowest tertile: unadjusted HR (95% CI), 1.95 (1.22, 3.10); upper vs. lowest tertile: 3.02 (1.91, 4.78)]. Principal components analysis identified 2 patterns composed of hepcidin-ferritin-transferrin, with or without ACT, and iron-sTfR-hemoglobin that may distinguish inflammation and erythropoiesis iron functions. CONCLUSIONS: Elevated hepcidin is independently associated with greater mortality in men and women with HIV infection, and hepcidin is also part of a complex relation linking iron homeostasis, anemia, and HIV. Understanding the mechanisms and role of hepcidin modulation may further guide evidence-based interventions needed to counter detrimental iron homeostasis and anemia in HIV infection

Selection of photosensitisers for photodynamic therapy of cancer using time-resolved photothermal spectroscopy

The photosensitisers proper for the application in photodynamic therapy have to be more efficiently introduced into cancerous than into healthy cells, non-toxic in darkness and absorb energy in the region in which cells are possibly transparent, and to destroy cancerous cell as a result of illumination. The triplet states of dyes are usually very active in photoreactions, therefore, the efficiency of triplet state generation, measured by laser induced optoacoustic spectroscopy, can be a criterion for selection of proper sensitizers. The dyes studied are introduced into model systems such as fluid solutions, films, resting (healthy) cells and stimulated cells (being models of cancerous cells). The natural pigments are usually less toxic than synthetic dyes, therefore, besides different merocyanines, also the bacteriochlorophyll $c$ and bacteriopheophytin $c$ have been studied by the photothermal method, absorption, fluorescence emission and fluorescence excitation spectroscopies. It has been found that the optimal sensitizer has to be chosen in a step by step selection procedure based on the investigation of a dye introduced into various (simple and complex) model systems

Radiative and nonradiative deexcitation of pigments from natural oils

The absorption, steady state photoacoustic, fluorescence emission and excitation spectra of unbleached oils obtained by pressing the seeds of: evening primrose, borage, rape and viper`s burgloss have been taken. Results obtained for samples under air and washed by nitrogen have been compared. In order to establish the occurrence of the slow thermal processes usually related to very photochemically active triplet states, the thermal deactivation in the absorption regions of carotenoids and the pheophytins has been observed at various frequencies of acting light modulations. The interactions between oil pigments are discussed. The generation of triplet states of dyes and singlet oxygen production in oils with different content of carotenoids and pheophytins is evaluated

Characterisation of Porphyrin-TiO2TiO_2 Complex Using Raman Spectroscopy and Electron Paramagnetic Resonance

A complex of meso-tetrakis (4-sulphonatophenyl) porphyrin covalently linked to titanium dioxide has been studied. Illumination of the complex with visible light was shown to result in formation of cationic radicals of the porphyrin. Shape and kinetics of the electron spin resonance signals were analysed which permitted calculation of spectroscopic parameters characterising the photoinduced process of the radicals formation. The dye-semiconductor complex was thoroughly characterised to indicate its possible applications

Applications of photothermic methods in photodynamic therapy investigations

The applications of steady state photoacoustic and time resolved photothermal methods are carried out in our laboratory. Based on these methods, the selection of optimal sensitizers for photodynamic therapy and photodynamic diagnosis of cancer were described. Additionally, in order to establish the fate of absorbed energy, the absorption and fluorescence spectra were measured. All spectra were measure using natural and/or linearly polarized light because of polarized spectroscopy delivers information about the sample structures. Spectral and photochemical properties of selected sensitizers (merocyanines, porphyrines and phthalocyanines) were investigated. All dyes were first investigated in model systems (fluid solutions or rigid matrix) and later incorporated into resting or stimulated cells as well as into cancer cells delivered from cell lines. Stimulated cells could serve as models of malignant tissue and the properties of these cells at various procedures of stimulation were compared. It was shown that steady state photoacoustic, which is less perturbed by scattering than absorption, is very useful in the establishment of the efficiency of sensitizer incorporation into cells whereas a time resolved photothermal method (laser induced optoacoustic spectroscopy) enabled the establishment of a yield of dye triplet states generation. The triplet states are very active in photochemical reactions. Therefore, on the basis of their yield, it is possible to predict the efficiency of light induced lesions of malignant cells

Fluorescence anisotropy of cyanobacterial phycobilisomes oriented in polyvinyl alcohol (PVA) films

Polarized absorption (at 296 and 85 K), fluorescence, and photoacoustic (at 296 and 85 K) spectra of antenna complexes-phycobilisomes isolated from cyanobacteriaTolypothrix tenuis andOscillatoria and embedded in isotropic and anisotropic polyvinyl alcohol films-were measured. From the sets of polarized components of emission, the anisotropy of fluorescence for the pools of differently oriented molecules was calculated. On the basis of polarized photoacoustic and emission spectra, the competition between the process of thermal deactivation of excitation and excitation energy transfer in a chain of excitation donor and acceptor chromophores of phycobilisomes is discussed

Structural and Electrical Characterization of Undoped Diamond Layer Grown by HF CVD

The undoped diamond layers were prepared using hot filament chemical vapor deposition technique. The controlled variation of the deposition parameters resulted in the layers with varying amount of nondiamond impurities. Routine characterization of the layers was carried out using scanning electron microscopy, X-ray diffractometry, and the Raman spectroscopy. Detailed measurements of room temperature electrical conductivity (σ₃₀₀), current-voltage characteristics have yielded useful information about the electrical conduction mechanism in this interesting material. The σ₃₀₀ and I-V characteristic measurements were done in sandwiched configuration taking care off the surface effects. The diamond shows room temperature dc conductivity reaching the values in the range of σ₃₀₀ ≈0.1-1 μS/cm. The I-V characteristics in these layers show space charge limited conduction behavior with I ~ V² in high voltage region. The obtained results are explained in terms of chemically adsorbed hydrogen on the surface of diamond layers, which is a source of acceptor states just above the top of valence band