Constraints on Dark Matter Properties from Observations of Milky Way Satellite Galaxies

We perform a comprehensive study of Milky Way (MW) satellite galaxies to constrain the fundamental properties of dark matter (DM). This analysis fully incorporates inhomogeneities in the spatial distribution and detectability of MW satellites and marginalizes over uncertainties in the mapping between galaxies and DM halos, the properties of the MW system, and the disruption of subhalos by the MW disk. Our results are consistent with the cold, collisionless DM paradigm and yield the strongest cosmological constraints to date on particle models of warm, interacting, and fuzzy dark matter. At 95% confidence, we report limits on (i) the mass of thermal relic warm DM, m_{WDM}>6.5  keV (free-streaming length, λ_{fs}≲10h^{-1}  kpc), (ii) the velocity-independent DM-proton scattering cross section, σ_{0}<8.8×10^{-29}  cm^{2} for a 100 MeV DM particle mass [DM-proton coupling, c_{p}≲(0.3  GeV)^{-2}], and (iii) the mass of fuzzy DM, m_{ϕ}>2.9×10^{-21}  eV (de Broglie wavelength, λ_{dB}≲0.5  kpc). These constraints are complementary to other observational and laboratory constraints on DM properties.

Widespread methane seepage along the continental margin off Svalbard - from Bjørnøya to Kongsfjorden

Numerous articles have recently reported on gas seepage offshore Svalbard, because the gas emission from these Arctic sediments was thought to result from gas hydrate dissociation, possibly triggered by anthropogenic ocean warming. We report on findings of a much broader seepage area, extending from 74° to 79°, where more than a thousand gas discharge sites were imaged as acoustic flares. The gas discharge occurs in water depths at and shallower than the upper edge of the gas hydrate stability zone and generates a dissolved methane plume that is hundreds of kilometer in length. Data collected in the summer of 2015 revealed that 0.02-7.7% of the dissolved methane was aerobically oxidized by microbes and a minor fraction (0.07%) was transferred to the atmosphere during periods of low wind speeds. Most flares were detected in the vicinity of the Hornsund Fracture Zone, leading us to postulate that the gas ascends along this fracture zone. The methane discharges on bathymetric highs characterized by sonic hard grounds, whereas glaciomarine and Holocene sediments in the troughs apparently limit seepage. The large scale seepage reported here is not caused by anthropogenic warming.

Methane excess in Arctic surface water-triggered by sea ice formation and melting

Arctic amplification of global warming has led to increased summer sea ice retreat, which influences gas exchange between the Arctic Ocean and the atmosphere where sea ice previously acted as a physical barrier. Indeed, recently observed enhanced atmospheric methane concentrations in Arctic regions with fractional sea-ice cover point to unexpected feedbacks in cycling of methane. We report on methane excess in sea ice-influenced water masses in the interior Arctic Ocean and provide evidence that sea ice is a potential source. We show that methane release from sea ice into the ocean occurs via brine drainage during freezing and melting i.e. in winter and spring. In summer under a fractional sea ice cover, reduced turbulence restricts gas transfer, then seawater acts as buffer in which methane remains entrained. However, in autumn and winter surface convection initiates pronounced efflux of methane from the ice covered ocean to the atmosphere. Our results demonstrate that sea ice-sourced methane cycles seasonally between sea ice, sea-ice-influenced seawater and the atmosphere, while the deeper ocean remains decoupled. Freshening due to summer sea ice retreat will enhance this decoupling, which restricts the capacity of the deeper Arctic Ocean to act as a sink for this greenhouse gas.

ICP is lower during propofol anaesthesia compared to isoflurane and sevoflurane

OBJECTIVES

Propofol is a cerebral vasoconstrictor while inhalation anaesthetics like isoflurane and sevoflurane act as cerebral vasodilators in both animal and human studies. This difference of action upon cerebral vessels might implicate a lower ICP during propofol anaesthesia. Cerebral metabolism is decreased by all three anaesthetics. In a prospective, randomised multicenter study ICP was compared during anaesthesia with propofol, isoflurane and sevoflurane.

METHODS

117 patients subjected to elective craniotomy for supratentorial tumour. Propofol: N = 41; isoflurane: N = 38; sevoflurane: N = 38. Nitrous oxide was omitted and all anaesthetics were supplemented with a continuous infusion of fentanyl. ICP was measured subdurally after removal of the bone flap. MABP, CPP, PCO2, AVDO2, rectal temperature, tumour size and midline shift were registered too.

STATISTICS

Kruskal-Wallis Variance on Ranks. All values in medians with range. P < 0.05 was considered significant.

RESULTS

ICP (mmHg): propofol 7 (-1-20), isoflurane 12 (1-29), sevoflurane 11 (2-32). ICP was significantly lower in the propofol group compared to the isofluane and sevoflurane groups. CPP (mmHg): propofol 80 (45-104), isoflurane 60 (32-84), sevoflurane 63 (44-77). CPP was significantly higher in the propofol group compared to the isoflurane and sevoflurane groups. AVDO2 (mmol/l): propofol 3.1 (0.9-5.1), isoflurane 2.5 (1.1-4.5), sevoflurane 2.6 (0.8-4.1). AVDO2 was significantly higher in the propofol group compared to the isoflurane and sevoflurane groups. No significant differences in PCO2, rectal temperature, tumour size and midline shift were found.

CONCLUSIONS

Subdural ICP is significantly lower during propofol anaesthesia compared to isoflurane and sevoflurane anaesthesia. CPP and AVDO2 are significantly higher during propofol anaesthesia compared to isoflurane and sevoflurane anaesthesia.

Activation of protein kinase C in permeabilized human neuroblastoma SH-SY5Y cells

The activation of protein kinase C was investigated in digitonin-permeabilized human neuroblastoma SH-SY5Y cells by measuring the phosphorylation of the specific protein kinase C substrate myelin basic protein4-14. The phosphorylation was inhibited by the protein kinase C inhibitory peptide PKC19-36 and was associated to a translocation of the enzyme to the membrane fractions of the SH-SY5Y cells. 1,2-Dioctanoyl-sn-glycerol had no effect on protein kinase C activity unless the calcium concentration was raised to concentrations found in stimulated cells (above 100 nM). Calcium in the absence of other activators did not stimulate protein kinase C. Phorbol 12-myristate 13-acetate was not dependent on calcium for the activation or the translocation of protein kinase C. The induced activation was sustained for 10 min, and thereafter only a small net phosphorylation of the substrate could be detected. Calcium or dioctanoylglycerol, when applied alone, only caused a minor translocation, whereas in combination a marked translocation was observed. Arachidonic acid (10 microM) enhanced protein kinase C activity in the presence of submaximal concentrations of calcium and dioctanoylglycerol. Quinacrine and p-bromophenacyl bromide did not inhibit calcium- and dioctanoylglycerol-induced protein kinase C activity at concentrations which are considered to be sufficient for phospholipase A2 inhibition.

Binding and internalization of a iodinated substance P analog by cultured anterior pituitary cells

Substance P binding to cultured anterior pituitary cells was characterized using Bolton-Hunter iodinated substance P as a ligand. At 0 degrees C, the interaction of the ligand and the cellular surface binding sites was found to be specific, rapid and reversible. Scatchard and Hill analysis of specific binding revealed a single class of non-interacting binding sites with a high affinity (KD = 0.48 nM) and a moderate density of binding sites (Bmax = 1187 binding sites/cell). At 37 degrees C a NaOH-soluble intracellular ligand pool was observed in addition to a surface-bound ligand pool released by a low pH buffer. Thus, substance P seems to be internalized after binding to cellular surface binding sites by means of receptor-mediated endocytosis. The internalization was rapid and could be blocked by colchicine (20 microM), an inhibitor of microtubuli assembly. Following internalization, intracellular degradation of the ligand could be demonstrated. Leupeptin (100 microM), an inhibitor of certain lysosomal enzymes could inhibit the cellular degradation of the added ligand, but had only a moderate influence on internalization. These results demonstrate that substance P after binding to a surface-localized receptor on its pituitary target cells is internalized and subsequently degraded by lysosomal enzymes.

[High-voltage therapy of prostate cancer]

High-voltage therapy is becoming increasingly important as a form of individual differential therapy of carcinoma of the prostate. Around 40% of all patients with a diagnosis of carcinoma of the prostate can be treated with high-voltage therapy. The precondition is the absence of bone and soft-tissue metastases and of juxtaregional lymph-node metastases. Individual carcinoma therapy is based on pre-therapeutic tumor classification according to the TNM system. The 5-year survival rates are presented from a retrospective study carried out using primary radiation monotherapy and a combined hormone and radiation therapy; these figures were calculated by the life-table method. The study revealed no significant differences between the two forms of therapy as regards 5-year survival rates. The 5-year survival rates of all patients of the classifications T0-T3Nx-N2M0 irradiated (n: 198) (72% +/- 11% for hormone plus radiation therapy and 74% +/- 11% for radiation monotherapy) did not differ greatly from those of a normal male population of the same age (77%). High-voltage therapy of carcinoma of the prostate can thus be classified as a curative method of treatment.

[Suppression of testicular testosterone production by irradiation of the testis in prostatic cancer]

Irradiation of the tests of 11 patients with carcinoma of the prostate in the age from 68 to 78 years with 20 Gy (5 X 2 Gy per week) decreased the plasma testosterone levels to an average of 70,3% of the initial values. After operative orchidectomy, however, a decrease of the plasma testosterone level to only 5% the values before operation was observed. Therefore, the operative orchidectomy cannot be replaced by the irradiation of the testes. Higher irradiation doses may cause skin injuries and there is the possibility of being a real carcinogen noxe for the irradiation region too.