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We have applied femtosecond transient absorption spectroscopy in pump-probe and pump-dump-probe regimes to study energy transfer between fucoxanthin and Chl a in fucoxanthin-Chl a complex from the pennate diatom Phaeodactylum tricornutum. Experiments were carried out at room temperature and 77 K to reveal temperature dependence of energy transfer. At both temperatures, the ultrafast (<100 fs) energy transfer channel from the fucoxanthin S2 state is active and is complemented by the second pathway via the combined S1/ICT state. The S1/ICT-Chl a pathway has two channels, the fast one characterized by sub-picosecond energy transfer, and slow having time constants of 4.5 ps at room temperature and 6.6 ps at 77 K. The overall energy transfer via the S1/ICT is faster at 77 K, because the fast component gains amplitude upon lowering the temperature. The pump-dump-probe regime, with the dump pulse centered in the spectral region of ICT stimulated emission at 950 nm and applied at 2 ps after excitation, proved that the S1 and ICT states of fucoxanthin in FCP are individual, yet coupled entities. Analysis of the pump-dump-probe data suggested that the main energy donor in the slow S1/ICT-Chl a route is the S1 part of the S1/ICT potential surface.
Three monosubstituted 3-phenylselanyl and 3-phenyltellanyl BODIPY derivatives were synthesized and their spectroscopic properties were characterized and compared to those of iodine and chlorine-atoms containing analogues as well as an unsubstituted BODIPY derivative. The fluorescence quantum yields were found to decrease, whereas the intersystem crossing quantum yields (ΦISC), determined by transient spectroscopy, increased in the order of the H → Cl → Se/I → Te substitution. The maximum ΦISC, found for the 3-phenyltellanyl derivative, was 59%. The results are interpreted in terms of the internal heavy-atom effect of the substituents.
BACKGROUND: Combination of platinum derivatives with paclitaxel is currently the standard front line regimen for patients with epithelial ovarian carcinoma, and represents also an active regimen in patients with metastatic breast or unknown primary carcinomas. Measurement of intestinal permeability represents one of the potential methods of noninvasive laboratory assessment of gastrointestinal mucositis induced by chemotherapy, but little is known about intestinal permeability in patients treated with paclitaxel or platinum. METHODS: Intestinal permeability was assessed in 36 breast and ovarian cancer patients treated with paclitaxel/platinum combination by measuring, using capillary gas chromatography, urinary sucrose, lactulose, xylose and mannitol after oral challenge. The significance of differences during the therapy compared to pre-treatment values was studied by Wilcoxon paired test. The differences between groups of patient were studied by Mann-Whitney U test. Fisher exact test was used to compare the frequency in different subgroups. RESULTS: After administration of the first dose, a significant (p < 0.05) decrease in xylose absorption and increased lactulose/mannitol, sucrose/mannitol, lactulose/xylose and sucrose/xylose ratios were observed, but these parameters returned subsequently to pre-treatment levels. Patients who experienced serious (grade 3 or 4) toxicity had at baseline significantly lower percentages of xylose, mannitol and sucrose, and higher lactulose/mannitol ratio. Nine of 13 (69%) patients with baseline lactulose/mannitol ratio 0.070 or above experienced serious toxicity compared to 4 out of 23 patients (17%) with the ratio below 0.070 (p = 0.002). Post-treatment lactulose, lactulose/mannitol, sucrose/mannitol and lactulose/xylose ratios were significantly increased in patients with serious toxicity. CONCLUSION: A transient significant increase in lactulose/monosaccharide and sucrose/monosaccharide ratios was observed in ovarian and breast cancer patients treated with paclitaxel and platinum. Increased lactulose absorption, lactulose/mannitol, sucrose/mannitol and lactulose/xylose ratios were evident in patients with grade 3 or 4 toxicity, and increased baseline lactulose/mannitol ratio predicted serious toxicity.
- MeSH
- adenokarcinom farmakoterapie metabolismus patologie MeSH
- cisplatina aplikace a dávkování MeSH
- dospělí MeSH
- financování organizované MeSH
- gastrointestinální trakt metabolismus MeSH
- intestinální absorpce účinky léků MeSH
- karboplatina aplikace a dávkování MeSH
- laktulosa metabolismus MeSH
- lidé středního věku MeSH
- lidé MeSH
- mannitol metabolismus MeSH
- monoklonální protilátky aplikace a dávkování MeSH
- nádory glandulární a epitelové farmakoterapie metabolismus patologie MeSH
- nádory prsu farmakoterapie metabolismus patologie MeSH
- nádory vaječníků farmakoterapie metabolismus patologie MeSH
- paclitaxel aplikace a dávkování MeSH
- permeabilita buněčné membrány účinky léků MeSH
- protokoly antitumorózní kombinované chemoterapie terapeutické užití MeSH
- sacharasa metabolismus MeSH
- senioři MeSH
- xylosa metabolismus MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- senioři MeSH
- ženské pohlaví MeSH
BACKGROUND: Primary hypomagnesemia with secondary hypocalcemia (HSH) is a rare genetic disorder. Dysfunctional transient receptor potential melastatin 6 causes impaired intestinal absorption of magnesium, leading to low serum levels accompanied by hypocalcemia. Typical signs at initial manifestation are generalized seizures, tetany, and/or muscle spasms. CASE REPORT: We present a 5 w/o female manifesting tonic-clonic seizures. Laboratory tests detected severe hypomagnesemia and hypocalcemia. The molecular genetic analysis revealed two novel mutations within the TRPM6 gene c.3308dupC (p.Pro1104Thrfs*28) (p.P1104Tfs*28) and c.3958C>T (p.Gln1302*) (p.Q1302*) and the patient was successfully treated with Mg supplementation. CONCLUSION: Ion disbalance should be taken into account in the differential diagnosis of infantile seizures. Accurate diagnosis of HSH together with appropriate treatment are crucial to prevent irreversible neurological outcomes.
- MeSH
- hořčík MeSH
- hyperkalciurie MeSH
- hypokalcemie * genetika MeSH
- kationtové kanály TRPM * genetika MeSH
- lidé MeSH
- mutace MeSH
- nedostatek hořčíku * vrozené genetika MeSH
- nefrokalcinóza MeSH
- vrozené poruchy tubulárního transportu MeSH
- záchvaty genetika MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- kazuistiky MeSH
- Klíčová slova
- klinická infrapupilografie, kinematografická metoda, fotoelektrická metoda,
- MeSH
- Adieho syndrom diagnóza MeSH
- amaurosis fugax diagnóza MeSH
- amblyopie diagnóza MeSH
- atrofie optického nervu diagnóza MeSH
- diagnostické techniky oftalmologické * přístrojové vybavení využití MeSH
- farmakokinetika MeSH
- kymografie metody využití MeSH
- lidé MeSH
- meningeom diagnóza MeSH
- nemoci zrakového nervu diagnóza MeSH
- oční nemoci * diagnóza MeSH
- poruchy zornice diagnóza patologie MeSH
- pupila MeSH
- roztroušená skleróza diagnóza MeSH
- testy zrakového pole metody využití MeSH
- výsledky a postupy - zhodnocení (zdravotní péče) metody využití MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- kazuistiky MeSH
Recent chlorophyll-a fluorescence yield measurements, using single-turnover saturating flashes (STSFs), have revealed the involvement of a rate-limiting step in the reactions following the charge separation induced by the first flash. As also shown here, in diuron-inhibited PSII core complexes isolated from Thermosynechococcus vulcanus the fluorescence maximum could only be reached by a train of STSFs. In order to elucidate the origin of the fluorescence yield increments in STSF series, we performed transient absorption measurements at 819 nm, reflecting the photooxidation and re-reduction kinetics of the primary electron donor P680. Upon single flash excitation of the dark-adapted sample, the decay kinetics could be described with lifetimes of 17 ns (∼50%) and 167 ns (∼30%), and a longer-lived component (∼20%). This kinetics are attributed to re-reduction of P680•+ by the donor side of PSII. In contrast, upon second-flash (with Δt between 5 μs and 100 ms) or repetitive excitation, the 819 nm absorption changes decayed with lifetimes of about 2 ns (∼60%) and 10 ns (∼30%), attributed to recombination of the primary radical pair P680•+ Pheo•- , and a small longer-lived component (∼10%). These data confirm that only the first STSF is capable of generating stable charge separation - leading to the reduction of QA ; and thus, the fluorescence yield increments elicited by the consecutive flashes must have a different physical origin. Our double-flash experiments indicate that the rate-limiting steps, detected by chlorophyll-a fluorescence, are not correlated with the turnover of P680.
Primární hypomagnezemie se sekundární hypokalcemií je vzácná genetická porucha, která se objevuje v časném kojeneckém věku. Příčinou této choroby je porušené vstřebávání hořčíku ze střeva vedoucí k jeho nízké hladině v séru a doprovodné hypokalcemii. Typickými příznaky při první manifestaci jsou generalizované křeče, tetanie a/nebo svalové spasmy. Prognóza onemocnění závisí na její včasné a správné diagnóze.
Primary hypomagnesia with secondary hypocalcemia is a rare genetic disorder that appears in early infancy. The cause of this disease is an impaired intestinal absorption of magnesium leading to its low serum level accompanied by hypocalcemia. Typical signs at initial manifestation are generalized seizures, tetany and/or muscle spasms. The prognosis of the disease depends on rapidity and accuracy of the diagnosis.
- Klíčová slova
- primární hypomagnezémie se sekundární hypokalcémií,
- MeSH
- hořčík aplikace a dávkování krev terapeutické užití MeSH
- hypokalcemie * etiologie farmakoterapie MeSH
- kationtové kanály TRPM fyziologie genetika MeSH
- kojenec MeSH
- křeče u dětí etiologie farmakoterapie genetika MeSH
- lidé MeSH
- nedostatek hořčíku * diagnóza genetika terapie MeSH
- novorozenec MeSH
- výsledek terapie MeSH
- Check Tag
- kojenec MeSH
- lidé MeSH
- mužské pohlaví MeSH
- novorozenec MeSH
- Publikační typ
- kazuistiky MeSH
- práce podpořená grantem MeSH
The authors present a study of the fluorescence and absorbance transients occurring in whole cells of purple nonsulfur bacterium Rhodobacter sphaeroides on the millisecond timescale under pulsed actinic illumination. The fluorescence induction curve is interpreted in terms of combination of effects of redox changes in the reaction center and the membrane potential. The results of this study support the view that the membrane potential act predominantly to increase the fluorescence yield. Advantages of the pulsed actinic illumination for study of the operation of the electron transport chain in vivo are discussed.
- MeSH
- absorpce účinky záření MeSH
- fluorescenční spektrometrie MeSH
- karotenoidy metabolismus MeSH
- kinetika MeSH
- membránové potenciály účinky záření MeSH
- oxidace-redukce účinky záření MeSH
- Rhodobacter sphaeroides cytologie metabolismus účinky záření MeSH
- světlo MeSH
- Publikační typ
- časopisecké články MeSH
