The effect of cocaine on gastric mucosal PGE2, LTC4 and ulcerations

The association between cocaine use and acute gastroduodenal perforation is known. The effect of cocaine and stress on gastric mucosal ulceration and the levels of prostaglandin E2 (PGE2) and leukotriene C4 (LTC4) was studied in 40 Sprague–Dawley rats. Controls received intraperitoneal (i.p.) saline, ten received i.p. cocaine (35 mg/kg), ten were stressed by the cold restraint method, and ten had i.p. cocaine and stress. Cocaine alone did not induce ulceration, but decreased PGE2 levels. Stress alone caused ulceration, but was not associated with a change in either PGE2 or LTC4 levels. When combined with stress, however, cocaine caused a three-fold increase in ulceration and a significant increase in PGE2 and LTC4 levels. Stress may predispose the cocaine addict to loss of gastroduodenal mucosal integrity, which is related to an imbalance of PGE2 and LTC4 synthesis

Effects of Thyroxine as Compared with Thyroxine plus Triiodothyronine in Patients with Hypothyroidism

BACKGROUND: Patients with hypothyroidism are usually treated with thyroxine (levothyroxine) only, although both thyroxine and triiodothyronine are secreted by the normal thyroid gland. Whether thyroid secretion of triiodothyronine is physiologically important is unknown. METHODS: We compared the effects of thyroxine alone with those of thyroxine plus triiodothyronine (liothyronine) in 33 patients with hypothyroidism. Each patient was studied for two five-week periods. During one period, the patient received his or her usual dose of thyroxine. During the other, the patient received a regimen in which 50 microg of the usual dose of thyroxine was replaced by 12.5 microg of triiodothyronine. The order in which each patient received the two treatments was randomized. Biochemical, physiologic, and psychological tests were performed at the end of each treatment period. RESULTS: The patients had lower serum free and total thyroxine concentrations and higher serum total triiodothyronine concentrations after treatment with thyroxine plus triiodothyronine than after thyroxine alone, whereas the serum thyrotropin concentrations were similar after both treatments. Among 17 scores on tests of cognitive performance and assessments of mood, 6 were better or closer to normal after treatment with thyroxine plus triiodothyronine. Similarly, among 15 visual-analogue scales used to indicate mood and physical status, the results for 10 were significantly better after treatment with thyroxine plus triiodothyronine. The pulse rate and serum sex hormone-binding globulin concentrations were slightly higher after treatment with thyroxine plus triiodothyronine, but blood pressure, serum lipid concentrations, and the results of neurophysiologic tests were similar after the two treatments. CONCLUSIONS: In patients with hypothyroidism, partial substitution of triiodothyronine for thyroxine may improve mood and neuropsychological function; this finding suggests a specific effect of the triiodothyronine normally secreted by the thyroid gland

Programmable RNA Shredding by the Type III-A CRISPR-Cas System of Streptococcus thermophilus

Immunity against viruses and plasmids provided by CRISPR-Cas systems relies on a ribonucleoprotein effector complex that triggers the degradation of invasive nucleic acids (NA). Effector complexes of type I (Cascade) and II (Cas9-dual RNA) target foreign DNA. Intriguingly, the genetic evidence suggests that the type III-A Csm complex targets DNA, whereas biochemical data show that the type III-B Cmr complex cleaves RNA. Here we aimed to investigate NA specificity and mechanism of CRISPR interference for the Streptococcus thermophilus Csm (III-A) complex (StCsm). When expressed in Escherichia coli, two complexes of different stoichiometry copurified with 40 and 72 nt crRNA species, respectively. Both complexes targeted RNA and generated multiple cuts at 6 nt intervals. The Csm3 protein, present in multiple copies in both Csm complexes, acts as endoribonuclease. In the heterologous E. coli host, StCsm restricts MS2 RNA phage in a Csm3 nuclease-dependent manner. Thus, our results demonstrate that the type III-A StCsm complex guided by crRNA targets RNA and not DNA. Highlights • Streptococcus thermophilus type III-A Csm (StCsm) complex targets RNA •Multiple cuts are introduced in the target RNA at 6 nt intervals •Csm3 protein subunits are responsible for endoribonuclease activity of the complex •StCsm complex offers a programmable tool for RNA degradatio

Generation of recombinant single-chain antibodies neutralizing the cytolytic activity of vaginolysin, the main virulence factor of Gardnerella vaginalis

Generated scFvs is the first example of recombinant single-chain antibodies with VLY-neutralizing activity produced in prokaryote expression system. G. vaginalis caused infections continue to be a world-wide problem, therefore neutralizing recombinant antibodies may provide novel therapeutic agents useful in the treatment of bacterial vaginosis and other diseases caused by G. vaginalis

Protection gaps and restoration opportunities for primary forests in Europe

Aims: Primary forests are critical for forest biodiversity and provide key ecosystem services. In Europe, these forests are particularly scarce and it is unclear whether they are sufficiently protected. Here we aim to: (a) understand whether extant primary forests are representative of the range of naturally occurring forest types, (b) identify forest types which host enough primary forest under strict protection to meet conservation targets and (c) highlight areas where restoration is needed and feasible. Location: Europe. Methods: We combined a unique geodatabase of primary forests with maps of forest cover, potential natural vegetation, biogeographic regions and protected areas to quantify the proportion of extant primary forest across Europe\u27s forest types and to identify gaps in protection. Using spatial predictions of primary forest locations to account for underreporting of primary forests, we then highlighted areas where restoration could complement protection. Results: We found a substantial bias in primary forest distribution across forest types. Of the 54 forest types we assessed, six had no primary forest at all, and in two-thirds of forest types, less than 1% of forest was primary. Even if generally protected, only ten forest types had more than half of their primary forests strictly protected. Protecting all documented primary forests requires expanding the protected area networks by 1,132 km2 (19,194 km2 when including also predicted primary forests). Encouragingly, large areas of non-primary forest existed inside protected areas for most types, thus presenting restoration opportunities. Main conclusion: Europe\u27s primary forests are in a perilous state, as also acknowledged by EU\u27s “Biodiversity Strategy for 2030.” Yet, there are considerable opportunities for ensuring better protection and restoring primary forest structure, composition and functioning, at least partially. We advocate integrated policy reforms that explicitly account for the irreplaceable nature of primary forests and ramp up protection and restoration efforts alike

Spin-dependent transport in nanocomposite C:Co films

The magneto-transport properties of nanocomposite C:Co (15 and 40 at.% Co) thin films are investigated. The films were grown by ion beam co-sputtering on thermally oxidized silicon substrates in the temperature range from 200 to 500 degC. Two major effects are reported: (i) a large anomalous Hall effect amounting to 2 \mu ohm cm, and (ii) a negative magnetoresistance. Both the field-dependent resistivity and Hall resistivity curves coincide with the rescaled magnetization curves, a finding that is consistent with spin-dependent transport. These findings suggest that C:Co nanocomposites are promising candidates for carbon-based Hall sensors and spintronic devices.Comment: 13 pages, 7 figure

DNA synapsis through transient tetramerization triggers cleavage by Ecl18kI restriction enzyme

To cut DNA at their target sites, restriction enzymes assemble into different oligomeric structures. The Ecl18kI endonuclease in the crystal is arranged as a tetramer made of two dimers each bound to a DNA copy. However, free in solution Ecl18kI is a dimer. To find out whether the Ecl18kI dimer or tetramer represents the functionally important assembly, we generated mutants aimed at disrupting the putative dimer–dimer interface and analysed the functional properties of Ecl18kI and mutant variants. We show by atomic force microscopy that on two-site DNA, Ecl18kI loops out an intervening DNA fragment and forms a tetramer. Using the tethered particle motion technique, we demonstrate that in solution DNA looping is highly dynamic and involves a transient interaction between the two DNA-bound dimers. Furthermore, we show that Ecl18kI cleaves DNA in the synaptic complex much faster than when acting on a single recognition site. Contrary to Ecl18kI, the tetramerization interface mutant R174A binds DNA as a dimer, shows no DNA looping and is virtually inactive. We conclude that Ecl18kI follows the association model for the synaptic complex assembly in which it binds to the target site as a dimer and then associates into a transient tetrameric form to accomplish the cleavage reaction