A Method to Extract Potentials from the Temperature Dependence of Langmuir Constants for Clathrate-Hydrates

It is shown that the temperature dependence of Langmuir constants contains all the information needed to determine spherically averaged intermolecular potentials. An analytical ``inversion'' method based on the standard statistical model of van der Waals and Platteeuw is presented which extracts cell potentials directly from experimental data. The method is applied to ethane and cyclopropane clathrate-hydrates, and the resulting potentials are much simpler and more meaningful than those obtained by the usual method of numerical fitting with Kihara potentials.Comment: 33 pages, 7 figures, to appear in Physica

PuraStat in gastrointestinal bleeding: results of a prospective multicentre observational pilot study

Background: A recently developed haemostatic peptide gel for endoscopic application has been introduced to improve the management of gastrointestinal bleeding. The aim of this pilot study was to evaluate the feasibility, safety, efficacy and indication profiles of PuraStat in a clinical setting. Methods: In this prospective observational multicentre pilot study, patients with acute non-variceal gastrointestinal bleeding (upper and lower) were included. Primary and secondary application of PuraStat was evaluated. Haemoglobin, prothrombin time, platelets and transfusion behaviour were documented before and after haemostasis. The efficacy of PuraStat was assessed during the procedure, at 3 days and 1 week after application. Results: 111 patients with acute gastrointestinal bleeding were recruited into the study. 70 percent (78/111) of the patients had upper gastrointestinal bleeding and 30% (33/111) had lower gastrointestinal bleeding. After primary application of PuraStat, initial haemostatic success was achieved in 94% of patients (74/79, 95% CI 88-99%), and in 75% of the patients when used as a secondary haemostatic product, following failure of established techniques (24/32, 95% CI 59-91%). The therapeutic success rates (absence of rebleeding) after 3 and 7 days were 91% and 87% after primary use, and 87% and 81% in all study patients. Overall rebleeding rate at 30 day follow-up was 16% (18/111). In the 5 patients who finally required surgery (4.5%), PuraStat allowed temporary haemostasis and stabilisation. Conclusions: PuraStat expanded the therapeutic toolbox available for an effective treatment of gastrointestinal bleeding sources. It could be safely applied and administered without complications as a primary or secondary therapy. PuraStat may additionally serve as a bridge to surgery in order to achieve temporary haemostasis in case of refractory severe bleeding, possibly playing a role in preventing immediate emergency surgery

Identification of tetrahydrocarbazoles as novel multifactorial drug candidates for treatment of Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative brain disorder and the most frequent cause of dementia. To date, there are only a few approved drugs for AD, which show little or no effect on disease progression. Impaired intracellular calcium homeostasis is believed to occur early in the cascade of events leading to AD. Here, we examined the possibility of normalizing the disrupted calcium homeostasis in the endoplasmic reticulum (ER) store as an innovative approach for AD drug discovery. High-throughput screening of a small-molecule compound library led to the identification of tetrahydrocarbazoles, a novel multifactorial class of compounds that can normalize the impaired ER calcium homeostasis. We found that the tetrahydrocarbazole lead structure, first, dampens the enhanced calcium release from ER in HEK293 cells expressing familial Alzheimer's disease (FAD)-linked presenilin 1 mutations. Second, the lead structure also improves mitochondrial function, measured by increased mitochondrial membrane potential. Third, the same lead structure also attenuates the production of amyloid-beta (A beta) peptides by decreasing the cleavage of amyloid precursor protein (APP) by beta-secretase, without notably affecting alpha- and gamma-secretase cleavage activities. Considering the beneficial effects of tetrahydrocarbazoles addressing three key pathological aspects of AD, these compounds hold promise for the development of potentially effective AD drug candidates

Calcium Ions Promote Formation of Amyloid β-Peptide (1–40) Oligomers Causally Implicated in Neuronal Toxicity of Alzheimer's Disease

Amyloid β-peptide (Aβ) is directly linked to Alzheimer's disease (AD). In its monomeric form, Aβ aggregates to produce fibrils and a range of oligomers, the latter being the most neurotoxic. Dysregulation of Ca2+ homeostasis in aging brains and in neurodegenerative disorders plays a crucial role in numerous processes and contributes to cell dysfunction and death. Here we postulated that calcium may enable or accelerate the aggregation of Aβ. We compared the aggregation pattern of Aβ(1–40) and that of Aβ(1–40)E22G, an amyloid peptide carrying the Arctic mutation that causes early onset of the disease. We found that in the presence of Ca2+, Aβ(1–40) preferentially formed oligomers similar to those formed by Aβ(1–40)E22G with or without added Ca2+, whereas in the absence of added Ca2+ the Aβ(1–40) aggregated to form fibrils. Morphological similarities of the oligomers were confirmed by contact mode atomic force microscopy imaging. The distribution of oligomeric and fibrillar species in different samples was detected by gel electrophoresis and Western blot analysis, the results of which were further supported by thioflavin T fluorescence experiments. In the samples without Ca2+, Fourier transform infrared spectroscopy revealed conversion of oligomers from an anti-parallel β-sheet to the parallel β-sheet conformation characteristic of fibrils. Overall, these results led us to conclude that calcium ions stimulate the formation of oligomers of Aβ(1–40), that have been implicated in the pathogenesis of AD

Właściwości gleb oraz parametry dendrologiczne drzew po dwudziestoletniej reforestacji pożarzyska Potrzebowice (Środkowa Polska)

The paper presents results of the research on the assessment of technical parameters of forest stands on a post-fire area which has been reclaimed for 20 years, based on various methods of soil preparation. An attempt was made to determine the potential influence of soil properties on them. The following variants were tested: digging furrows with a forest plough, shallow tillage with a disc plough, dimples dug with a shovel, natural succession, forest complex intact by fire (zero area). Planting was done with: Quercus rubra, Pinus sylvestris, Betula pendula, Quercus petraea, Larix decidua, Alnus incana. The examined area is dominated by Brunic arenosols and podzols. The following technical parameters were determined: height, diameter at breast height (DBH), relascopic number of trees and forest cover. Such properties were marked as: texture, solid phase density, soil density, porosity, moisture, pH, hydrolytic acidity, cation exchange capacity, the content of exchangeable cations and available forms, organic carbon and total nitrogen content. No relations were observed between the variations of soil properties and technical parameters of the investigated forest stands. It suggests that soil preparation methods were the most important factor which influenced the examined parameters. According to the obtained results, planting into dimples is a good method for post-fire soil preparation. It is difficult to determine unambiguously which reclamation method is the best for a post-fire area in order to obtain better technical parameters, however, the observations may be helpful in determining more effective ways of post-fire forest stands’ reconstruction.Praca zawiera wyniki badań dotyczące właściwości gleb na pożarzysku restytuowanym od 20. lat, w oparciu o różne sposoby przygotowania gleby oraz odmienne nasadzenia. Scharakteryzowano również podstawowe parametry dendrologiczne drzew, stanowiących odnowienia na poszczególnych – w różny sposób przygotowanych – płaszczyznach. Testowano następujące warianty: wyoranie bruzd pługiem dwuodkładnicowym, płytka orka pługiem talerzowym, jamki wykopane łopatą, sukcesja naturalna, kompleks leśny nienaruszony przez pożar (powierzchnia zerowa). Do nasadzeń użyto: Quercus rubra, Pinus sylvestris, Betula pendula, Quercus petraea, Larix decidua, Alnus incana. Określono następujące parametry techniczne: wysokość, pierśnicę, relaskopową liczbę drzew, zadrzewienie. Na badanym obszarze dominującymi typami gleb były gleby rdzawe oraz bielice. Oznaczono takie właściwości gleby, jak: skład granulometryczny, gęstość fazy stałej, gęstość gleby, porowatość, wilgotność, odczyn, kwasowość hydrolityczną, kationową pojemność sorpcyjną, zawartość wymiennych oraz przyswajalnych form, węgiel organiczny, azot ogólny. W odniesieniu do gleb siedliska leśnego, nienaruszonego przez pożar, w glebach reforestowanego obszaru, wystąpiło znaczne zmniejszenie się zawartości węgla organicznego oraz wzrost zawartości azotu ogólnego. Zawężeniu uległ stosunek C:N; nieznacznie podniosło się pH. Większość kationów wymiennych uległa wymyciu. Właściwości fizyczne gleb poszczególnych płaszczyzn badawczych były zróżnicowane w bardzo małym stopniu. Przeprowadzone badania wskazują, że dość dobrym sposobem przygotowania gleby popożarowej jest nasadzenie w jamki. Na obecnym etapie badań trudno jest jednoznacznie określić wybór najlepszej metody rekultywacji pożarzyska w celu osiągania lepszych parametrów technicznych, jednakże dokonane obserwacje mogą być pomocne w typowaniu efektywniejszych metod odbudowy drzewostanów dotkniętych klęską pożaru

Ehkhikokokk mozga

Following a general review of the relatively rare cases of hydat'dosis of the braln a description is given of the authors' case,. operated at the Neurological Clinic in Łódź. In the course of 5 months following this successful operation and by the consequent general well feeling of the patient there developed in the operated area an abscess caused by Staphylococcus aureus infection, which in spite of the respeated surgical treatment and cure with antlbiotics brought about a fatal termination