Is long-term follow-up solely by imaging tests safe in non-operated pancreatic neuroendocrine tumors?

INTRODUCTION: the diagnosis of asymptomatic sporadic nonfunctioning pancreatic neuroendocrine tumors (NF-PNETs) has increased significantly due to the widespread use of high-resolution imaging tests, which is why the most appropriate management at the time of diagnosis is the subject of debate, as is how to follow-up patients. AIMS: the objective of this study was to analyze the frequency of imaging and endoscopic studies performed during long-term follow-up. METHODS: a retrospective review was performed of a database collected between January 2008 and December 2020 of patients with an incidental diagnosis of small NF-PNETs; follow-up was closed in March 2023. The imaging tests performed at the time of diagnosis and long-term follow-up were recorded. Growing less than 1 mm per year has not been considered as a worrisome feature. Follow-up was performed through imaging tests, considering endoscopic cytology for lesions with a faster grow rate. RESULTS: fifty-eight patients were included; the median age was 69 years. The initial mean size of the lesions studied was 12.79 mm (5-27). Follow-up was carried out only with computed tomography (CT) or magnetic resonance imaging (MRI). The initial size did not influence the behavior of the lesion in a statistically significant manner. Twenty-eight tumors (45 %) increased in size, with a growth equal to or less than 4 mm in 24 cases. The mean follow-up time was 82.41 months (12-164). No patient developed metastasis or died from PNET progression. CONCLUSIONS: the follow-up of neuroendocrine tumors of small size can be performed safely with only imaging tests.

Multidrug-Resistant Bacterial Colonization and Infections in Large Retrospective Cohort of Mechanically Ventilated COVID-19 Patients1.

Few data are available on incidence of multidrug-resistant organism (MDRO) colonization and infections in mechanically ventilated patients, particularly during the COVID-19 pandemic. We retrospectively evaluated all patients admitted to the COVID-19 intensive care unit (ICU) of Hub Hospital in Milan, Italy, during October 2020‒May 2021. Microbiologic surveillance was standardized with active screening at admission and weekly during ICU stay. Of 435 patients, 88 (20.2%) had MDROs isolated ≤48 h after admission. Of the remaining patients, MDRO colonization was diagnosed in 173 (51.2%), MDRO infections in 95 (28.1%), and non-MDRO infections in 212 (62.7%). Non-MDRO infections occurred earlier than MDRO infections (6 days vs. 10 days; p<0.001). Previous exposure to antimicrobial drugs within the ICU was higher in MDRO patients than in non-MDRO patients (116/197 [58.9%] vs. 18/140 [12.9%]; p<0.001). Our findings might serve as warnings for future respiratory viral pandemics and call for increased measures of antimicrobial stewardship and infection control.

Recurrent founder-event speciation across the Mediterranean likely shaped the species diversity and geographic distribution of the freshwater snail genus Mercuria Boeters, 1971 (Caenogastropoda: Hydrobiidae).

Dispersal is known to play an important role in shaping the diversity and geographic range of freshwater gastropods. Here, we used phylogenetic methods to test for the influence of dispersal and other biogeographic processes (such as vicariance) on the speciation and distribution patterns of Mercuria Boeters, 1971, a snail genus widely distributed in the western Palaearctic. The 25 extant species traditionally thought to comprise the genus, which were described mainly on the basis of morphology, have been recorded from lowland waters in both the Mediterranean and Atlantic river basins of Europe and North Africa. Using molecular phylogenies based on three gene fragments (COI, 16S rRNA and 28S rRNA) from 209 individuals, four molecular species delimitation methods and a shell characterization, we identified 14 putative species in our dataset, nine of which correspond to species classified by traditional taxonomy. Furthermore, biogeographical modelling favoured a scenario in which recurrent founder-event speciation since the late Miocene is the most probable process explaining the species diversity and distribution of the Mediterranean clades, whereas episodes of postglacial northward colonization from Iberian refugia by the species M.tachoensis may explain the current presence of the genus in Atlantic lowlands. The dispersal events inferred for Mercuria, probably promoted by multiple factors such as the changing connectivity of drainage basins driven by climate change or better access for avian dispersal vectors in lowlands, may explain the rare case among hydrobiids of a species-rich genus containing individual species with a large distribution area.

Synthesis and Characterization of Solvated Lanthanide Tris(trimethylsilyl)siloxides.

In an effort to develop precursors for the production of lanthanide silicate (LnSiOx) materials, the reactions of [Ln(NR2)3] (R = SiMe3) with three equivalents of tris(trimethylsilyl)silanol (H-OSi(SiMe3)3) or H-SST) in tetrahydrofuran (THF) were undertaken. The products were crystallographically characterized as [Ln(SST)3(THF)2] (where Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu). In general, these compounds are similar to the previously reported [Gd(SST)3(THF)2] complex, where each metal center of the monomeric species is found to adopt a trigonal bipyramidal (TBP; τ = av 0.95) geometry; however, the crystallographic structure solutions for these crystals invoke a much larger unit cell that reveals the complex disorder of the axial THF ligands. Using incompletely washed H-SST, the tetrahedrally (T-4) bound [Ln(SST)3(NEt3)] (Ln-NEt3 = Pr-NEt3, Ho-NEt3; NEt3 = triethylamine) compounds were isolated from the same reaction run in toluene. Rational syntheses of amine derivatives were realized by performing the same reaction with pure H-SST in toluene containing the appropriate amine and [Ln(NR2)3] with the final products identified as [Tm(SST)3(NEt3)] (Tm-NEt3) or [Tm(SST)3(NHPr2i)] (NHPr2i = di-iso-propylamine; Tm-NHPr2i). The products isolated from reactions undertaken in pyridine (py) were identified as [Ln(SST)3(py)2] (Ln-py = Ce-py, Eu-py, and Tm-py). The Ln-py structures exhibit the larger unit cell noted for the THF derivatives with each Ln adopting a TBP (τ = av 0.98) metal center possessing equatorial SST and axial py ligands. The same reaction run in toluene led to the isolation of [(η6-tol)Tm(SST)3] (Tm-tol). Multinuclear NMR (1H and 29Si) data support the retention of the solid-state structures of all of these compounds in solution. Photoluminescent measurements of Tb, Sm, Dy, and Eu were found to display emission and lifetime profiles in the visible range due to f-f transitions, consistent with trivalent lanthanide metal centers.

Organophosphorus-Modified Lanthanide Nitrates as Potential Actinide Oxide Aerosol Surrogates.

In search of suitable simulants for aerosol uranium waste products from Plutonium Uranium Redox Extraction (PUREX) process burns, a series of lanthanide nitrate hydrates ([Ln(κ2-NO3)3·nH2O]) were dissolved in the presence of tributylphosphate (O═P(O(CH2)3CH3)3) referred to as TBP) in kerosene or triphenylphosphate (O═P(O(C6H5) referred to as TPhP) in acetone. The crystal structure of the TPhP derivatives of the lanthanide nitrate series and uranium nitrate were solved as [Ln(κ2-NO3)3(TPhP)3] (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) and [U(O)2(κ2-NO3)2(TPhP)2] (U), respectively. The lanthanide-TBP, Ln, and U were further characterized using FTIR spectroscopy, 31P NMR spectroscopy, thermogravimetric analysis, and X-ray fluorescence spectroscopy. Further, thermal treatment of the lanthanide-TBP, Ln, and U using a box furnace to mimic pyrolysis conditions was found by PXRD analyses to generate a phosphate phase [LnP3O9 or UP2O7) for all systems. The resultant nuclear waste fire contaminant particulates will impact both aerosol transport and toxicity assessments.

Trapped Intermediate of a Meerwein-Pondorf-Verley Reduction of Hydroxy Benzaldehyde to a Dialkoxide by Titanium Alkoxides.

A series of titanium alkoxides ([Ti(OR)4] (OR = OCH(CH3)2 (OPri), OC(CH3)3 (OBut), and OCH2C(CH3)3 (ONep)) were modified with a set of substituted hydroxyl-benzaldehydes [HO-BzA-Lx: x = 1, 2-hydroxybenzaldehyde (L = H), 2-hydroxy-3-methoxybenzaldehyde (OMe-3), 5-bromo-2-hydroxybenzaldehyde (Br-5), 2-hydroxy-5-nitrobenzaldehyde (NO2-5); x = 2, 3,5-di-tert-butyl-2-hydroxybenzaldehyde (But-3,5), 2-hydroxy-3,5-diiodobenzaldehyde (I-3,5)] in pyridine (py). Instead of the expected simple substitution, each of the HO-BzA-Lx modifiers were reduced to their respective diol [(py)(OR)2Ti(κ2(O,µ-O')(OC6H4-x(CH2O)-2)(L)x] (OR = OPri, x = 1, L = H (1a), OMe-3 (2a), Br-5 (3a·py), NO2-5 (4a·4py); x = 2, But-3,5 (5a), I-3,5 (6a), ONep; x = 1, L = H (1b), OMe-3 (2b), Br-5 (3b·py), NO2-5 (4b); x = 2, But-3,5 (5b), I-3,5 (6b·py)), as identified by single crystal X-ray studies. The 1H NMR spectral data were complex at room temperature but simplified at high temperatures (70 °C). Diffusion ordered spectroscopy (DOSY) NMR experiments indicated that 2a maintained the dinuclear structure in a solution independent of the temperature, whereas 2b appears to be monomeric over the same temperature range. On the basis of additional NMR studies, the mechanism of the reduction of the HO-BzA-Lx to the dioxide ligand was thought to occur by a Meerwein-Pondorf-Verley (MPV) mechanism. The structures of 1a-6b appear to be the intermediate dioxide products of the MPV reduction, which became "trapped" by the Lewis basic solvate.

The sawtooth EKG pattern of typical atrial flutter is not related to slow conduction velocity at the cavotricuspid isthmus.

INTRODUCTION: We hypothesized that very high-density mapping of typical atrial flutter (AFL) would facilitate a more complete understanding of its circuit. Such very high-density mapping was performed with the RhythmiaTM (Boston Scientific) mapping system using its 64 electrode basket catheter. METHODS AND RESULTS: Data were acquired from 13 patients in AFL. Functional anatomy of the right atrium (RA) was readily identified during mapping including the Crista Terminalis and Eustachian ridge. The leading edge of the activation wavefront was identified without interruption and its conduction velocity (CV) was calculated. CV was not different at the cavotricuspid isthmus (CTI) compared to the remainder of the RA (1.02 vs. 1.03 m/s, P = 0.93). The sawtooth pattern of the surface electrocardiogram (EKG) flutter waves was compared to the position of the dominant wavefront. The downslope of the surface EKG flutter waves represented on average 73% ± 9% of the total flutter cycle length. During the downslope, the activation wavefront traveled significantly further than during the upslope (182 ± 21 milliseconds vs. 68 ± 29 milliseconds, P < 0.0001) with no change in CV between the two phases (0.88 vs. 0.91 m/s, P = 0.79). CONCLUSION: CV at the CTI is not slower than other RA regions during typical AFL. The gradual downslope of the sawtooth EKG  is not due to slow conduction at the CTI suggesting that success of ablation at this site relates to anatomical properties rather than the presence of a "slow isthmus."

The role of the high potential form of the cytochrome b559: Study of Thermosynechococcus elongatus mutants.

Cytochrome b559 is an essential component of the photosystem II reaction center in photosynthetic oxygen-evolving organisms, but its function still remains unclear. The use of photosystem II preparations from Thermosynechococcus elongatus of high integrity and activity allowed us to measure for the first time the influence of cytochrome b559 mutations on its midpoint redox potential and on the reduction of the cytochrome b559 by the plastoquinone pool (or QB). In this work, five mutants having a mutation in the α-subunit (I14A, I14S, R18S, I27A and I27T) and one in the ß-subunit (F32Y) of cytochrome b559 have been investigated. All the mutations led to a destabilization of the high potential form of the cytochrome b559. The midpoint redox potential of the high potential form was significantly altered in the αR18S and αI27T mutant strains. The αR18S strain also showed a high sensitivity to photoinhibitory illumination and an altered oxidase activity. This was suggested by measurements of light induced oxidation and dark re-reduction of the cytochrome b559 showing that under conditions of a non-functional water oxidation system, once the cytochrome is oxidized by P680(+), the yield of its reduction by QB or the PQ pool was smaller and the kinetic slower in the αR18S mutant than in the wild-type strain. Thus, the extremely positive redox potential of the high potential form of cytochrome b559 could be necessary to ensure efficient oxidation of the PQ pool and to function as an electron reservoir replacing the water oxidation system when it is not operating.

Tandem SUMO fusion vectors for improving soluble protein expression and purification.

Availability of highly purified proteins in quantity is crucial for detailed biochemical and structural investigations. Fusion tags are versatile tools to facilitate efficient protein purification and to improve soluble overexpression of proteins. Various purification and fusion tags have been widely used for overexpression in Escherichia coli. However, these tags might interfere with biological functions and/or structural investigations of the protein of interest. Therefore, an additional purification step to remove fusion tags by proteolytic digestion might be required. Here, we describe a set of new vectors in which yeast SUMO (SMT3) was used as the highly specific recognition sequence of ubiquitin-like protease 1, together with other commonly used solubility enhancing proteins, such as glutathione S-transferase, maltose binding protein, thioredoxin and trigger factor for optimizing soluble expression of protein of interest. This tandem SUMO (T-SUMO) fusion system was tested for soluble expression of the C-terminal domain of TonB from different organisms and for the antiviral protein scytovirin.

Photosynthetic cytochrome c550.

Cytochrome c550 (cyt c550) is a membrane component of the PSII complex in cyanobacteria and some eukaryotic algae, such as red and brown algae. Cyt c550 presents a bis-histidine heme coordination which is very unusual for monoheme c-type cytochromes. In PSII, the cyt c550 with the other extrinsic proteins stabilizes the binding of Cl(-) and Ca(2+) ions to the oxygen evolving complex and protects the Mn(4)Ca cluster from attack by bulk reductants. The role (if there is one) of the heme of the cyt c550 is unknown. The low midpoint redox potential (E(m)) of the purified soluble form (from -250 to -314mV) is incompatible with a redox function in PSII. However, more positive values for the Em have been obtained for the cyt c550 bound to the PSII. A very recent work has shown an E(m) value of +200mV. These data open the possibility of a redox function for this protein in electron transfer in PSII. Despite the long distance (22Å) between cyt c550 and the nearest redox cofactor (Mn(4)Ca cluster), an electron transfer reaction between these components is possible. Some kind of protective cycle involving a soluble redox component in the lumen has also been proposed. The aim of this article is to review previous studies done on cyt c550 and to consider its function in the light of the new results obtained in recent years. The emphasis is on the physical properties of the heme and its redox properties. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial.

Treatment of Calcified Lesions Using a Dedicated Super-High Pressure Balloon: Multicenter Optical Coherence Tomography Registry.

BACKGROUND: Calcified lesions often lead to difficulty achieving optimal stent expansion. OPN non-compliant (NC) is a twin layer balloon with high rated burst pressure that may modify calcium effectively. METHODS: Retrospective, multicenter registry in patients undergoing optical coherence tomography (OCT) guided intervention with OPN NC. Superficial calcification with > 180o arc and > 0.5 mm thickness, and/or nodular calcification with > 90o arc were included. OCT was performed in all cases before and after OPN NC, and after intervention. Primary efficacy endpoints were frequency of expansion (EXP) ≥80 % of the mean reference lumen area and mean final EXP by OCT, and secondary endpoints were calcium fractures (CF), and EXP ≥90 %. RESULTS: 50 cases were included; 25 (50 %) superficial, and 25 (50 %) nodular. Calcium score of 4 in 42 (84 %) cases and 3 in 8 (16 %). OPN NC was used alone, or after other devices if further modification was needed, NC in 27 (54 %), cutting in 29 (58 %), scoring in 1 (2 %), IVL in 2 (4 %); or if non-crossable lesion, rotablation in 5 (10 %) cases. EXP ≥80 % was achieved in 40 (80 %) cases with mean final EXP post intervention of 85.7 % ± 8.9. CF were documented in 49 (98 %) cases; multiple in 37 (74 %). There were 1 flow limiting dissection requiring stent deployment and 3 non-cardiovascular related deaths in 6 months follow-up. No records of perforation, no-reflow or other major adverse events. CONCLUSION: Among patients with heavy calcified lesions undergoing OCT guided intervention with OPN NC, acceptable expansion was achieved in most cases without procedure related complications.

Executive summary of the consensus statement of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC), Spanish Society of Neurology (SEN), Spanish Society of Immunology (SEI), Spanish Society of Pediatric Infectology (SEIP), Spanish Society of Rheumatology (SER), and Spanish Academy of Dermatology and Venereology (AEDV), on the diagnosis, treatment and prevention of Lyme borreliosis.

The diagnosis of Lyme borreliosis (LB) is based on the epidemiological history, clinical manifestations and microbiological findings in the early disseminated and late phases of the disease. Related to this fact, microbiological diagnostic techniques have recently appeared. Far from facilitating the diagnosis and the clinical-therapeutic management of LB patients, they are generating confusion. Herein, experts and representatives of Spanish Scientific Societies [Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC), Spanish Society of Neurology (SEN), Spanish Society of Immunology (SEI), Spanish Society of Pediatric Infectology (SEIP), Spanish Society of Rheumatology (SER), and Spanish Academy of Dermatology and Venereology (AEDV)] exposed the executive summary after reviewing the epidemiology, clinical spectrum, available diagnostic techniques for the diagnosis of Borrelia burgdorferi infection, therapeutic and prevention options of LB. By consensus, recommendations for microbiological diagnosis are offered together with those supporting the therapeutic management and prophylaxis of infection.

A high redox potential form of cytochrome c550 in photosystem II from Thermosynechococcus elongatus.

Cytochrome c(550) (cyt c(550)) is a component of photosystem II (PSII) from cyanobacteria, red algae, and some other eukaryotic algae. Its physiological role remains unclear. In the present work, measurements of the midpoint redox potential (E(m)) were performed using intact PSII core complexes preparations from a histidine-tagged PSII mutant strain of the thermophilic cyanobacterium Thermosynechococcus (T.) elongatus. When redox titrations were done in the absence of redox mediators, an E(m) value of +200 mV was obtained for cyt c(550). This value is ∼300 mV more positive than that previously measured in the presence of mediators (E(m) = -80 mV). The shift from the high potential form (E(m) = +200 mV) to the low potential form (E(m) = -80 mV) of cyt c(550) is attributed to conformational changes, triggered by the reduction of a component of PSII that is sequestered and out of equilibrium with the medium, most likely the Mn(4)Ca cluster. This reduction can occur when reduced low potential redox mediators are present or under highly reducing conditions even in the absence of mediators. Based on these observations, it is suggested that the E(m) of +200 mV obtained without mediators could be the physiological redox potential of the cyt c(550) in PSII. This value opens the possibility of a redox function for cyt c(550) in PSII.

Reconstitution, spectroscopy, and redox properties of the photosynthetic recombinant cytochrome b(559) from higher plants.

A study of the in vitro reconstitution of sugar beet cytochrome b(559) of the photosystem II is described. Both α and ß cytochrome subunits were first cloned and expressed in Escherichia coli. In vitro reconstitution of this cytochrome was carried out with partially purified recombinant subunits from inclusion bodies. Reconstitution with commercial heme of both (αα) and (ßß) homodimers and (αß) heterodimer was possible, the latter being more efficient. The absorption spectra of these reconstituted samples were similar to that of the native heterodimer cytochrome b(559) form. As shown by electron paramagnetic resonance and potentiometry, most of the reconstituted cytochrome corresponded to a low spin form with a midpoint redox potential +36 mV, similar to that from the native purified cytochrome b(559). Furthermore, during the expression of sugar beet and Synechocystis sp. PCC 6803 cytochrome b(559) subunits, part of the protein subunits were incorporated into the host bacterial inner membrane, but only in the case of the ß subunit from the cyanobacterium the formation of a cytochrome b(559)-like structure with the bacterial endogenous heme was observed. The reason for that surprising result is unknown. This in vivo formed (ßß) homodimer cytochrome b(559)-like structure showed similar absorption and electron paramagnetic resonance spectral properties as the native purified cytochrome b(559). A higher midpoint redox potential (+126 mV) was detected in the in vivo formed protein compared to the in vitro reconstituted form, most likely due to a more hydrophobic environment imposed by the lipid membrane surrounding the heme.

Immunosenescence, Immune Fitness and Vaccination Schedule in the Adult Respiratory Patient.

Immunosenescence is the gradual deterioration of the immune system caused by advancing age. It is associated with a reduced ability to respond to infections and develop long-term immune memory. It plays a key role in the development of respiratory diseases that are more common in older people, such as asthma, COPD, diffuse interstitial disease and respiratory infections in the elderly. We call immune fitness the establishment of lifestyle habits that can improve our immune capacity. We now know that good eating habits, good social relationships, not smoking, limiting alcohol consumption, exercising, controlling stress levels and establishing a proper vaccination programme can slow down the process of immunosenescence. Influenza and pneumococcal vaccines (PCV13 and PPSV23 conjugate) are well established in the adult vaccination schedule. The new pneumococcal vaccines PCV15 and PCV20 will help to extend protection against pneumococcal disease in adults. The vaccine against COVID-19 is currently the most useful tool to prevent the disease and reduce its pathogenicity. COPD patients and others with respiratory diseases may benefit from prevention of herpes zoster and Bordetella pertussis through vaccination. Respiratory syncytial virus (RSV) vaccine may be another vaccine to be added to the schedule, pending the results of its studies.

La inmunosenescencia es el deterioro gradual del sistema inmune provocado por el avance de la edad. Se asocia a una menor capacidad para responder a las infecciones y desarrollar memoria inmune a largo plazo. Es parte fundamental en el desarrollo de las enfermedades respiratorias más frecuentes en edades avanzadas, como el asma, la EPOC, la patología intersticial difusa y las infecciones respiratorias del anciano.Llamamos fitness inmunológico al establecimiento de unos hábitos de vida que puedan mejorar nuestra capacidad inmunitaria. Actualmente sabemos que tener buenos hábitos alimentarios, buenas relaciones sociales, no fumar, limitar el consumo de alcohol, hacer ejercicio, controlar los niveles de estrés y establecer un correcto programa de vacunación permiten ralentizar el proceso de inmunosenescencia.Las vacunas de la gripe y las antineumocócicas (la conjugada PCV13 y la PPSV23) están bien establecidas en el calendario vacunal del adulto. Las nuevas vacunas antineumocócicas PCV15 y PCV20 van a servir para ampliar la protección contra la enfermedad neumocócica en el adulto. La vacuna contra la COVID-19 es, en el momento actual, la herramienta más útil para prevenir la enfermedad y disminuir su patogenicidad. Los pacientes con EPOC y otros con enfermedades respiratorias podrían beneficiarse de la prevención del herpes zóster y Bordetella pertussis mediante la vacunación. La vacuna contra el virus respiratorio sincitial (VRS) puede ser otra de las siguientes que formen parte de este calendario, en espera de los resultados de sus estudios.

[SEPAR Recommendations for COVID-19 Vaccination in Patients With Respiratory Diseases]. / Recomendaciones SEPAR sobre la vacuna COVID-19 en las enfermedades respiratorias.

The Spanish Society of Pneumonology and Thoracic Surgery (SEPAR) has elaborated this document of recommendations for COVID-19 vaccination in patients with respiratory diseases aimed to help healthcare personnel make decisions about how to act in case of COVID-19 vaccination in these patients.The recommendations have been developed by a group of experts in this field after reviewing the materials published up to March 7, 2021, the information provided by different scientific societies, drug agencies and the strategies of the governmental bodies up to this date.We can conclude that COVID-19 vaccines are not only safe and effective, but also prior in vulnerable patients with chronic respiratory diseases. In addition, an active involvement of healthcare professionals, who manage these diseases, in the vaccination strategy is the key to achieve good adherence and high vaccination coverage.

Changes in photosynthetic electron transfer and state transitions in an herbicide-resistant D1 mutant from soybean cell cultures.

Anomalies in photosynthetic activity of the soybean cell line STR7, carrying a single mutation (S268P) in the chloroplastic gene psbA that codes for the D1 protein of the photosystem II, have been examined using different spectroscopic techniques. Thermoluminescence emission experiments have shown important differences between STR7 mutant and wild type cells. The afterglow band induced by both white light flashes and far-red continuous illumination was downshifted by about 4 degrees C and the Q band was upshifted by 5 degrees C. High temperature thermoluminescence measurements suggested a higher level of lipid peroxidation in mutant thylakoid membranes. In addition, the reduction rate of P700(+) was significantly accelerated in STR7 suggesting that the mutation led to an activation of the photosystem I cyclic electron flow. Modulated fluorescence measurements performed at room temperature as well as fluorescence emission spectra at 77 K revealed that the STR7 mutant is defective in state transitions. Here, we discuss the hypothesis that activation of the cyclic electron flow in STR7 cells may be a mechanism to compensate the reduced activity of photosystem II caused by the mutation. We also propose that the impaired state transitions in the STR7 cells may be due to alterations in thylakoid membrane properties induced by a low content of unsaturated lipids.

High Density Mapping of Pre-Excitation 3D-Illustration of Anatomical Features.

While ablation of accessory pathways is usually performed without 3D mapping system, we present a case where high-density mapping helps in illustrating the anatomical features of epicardial and oblique AP connections.

Cavotricuspid-Isthmus Dependent Flutter or Left-Sided Atrial Tachycardia?

A 52-year-old man with previous mitral valve replacement, cavotricuspid isthmus, and left-sided roof-line ablation for previous typical atrial flutter and tachycardia presented with recurrence of symptoms with an atrial tachycardia measuring 260 ms cycle length on electrocardiogram. Rhythmia electroanatomical mapping (Boston Scientific) was performed to understand the mechanism of arrhythmia and to guide ablative treatment.