With the aim to understand the onset of expression and developmental profile of plasma membrane (PM) content /density of crucial components of GABA(B)-R signaling cascade, GABA(B)-R1a, GABA(B)-R1b, ...GABA(B)-R2, G(i)1/G(i)2alpha, G(i)3alpha, G(o)alpha, G(z)alpha and Gbeta subunit proteins were determined by quantitative immunoblotting and compared in PM isolated from brain cortex of rats of different ages: between postnatal-day-1 (PD1) and 90 (PD90). PM density of GABA(B)-R1a, GABA(B)-R2, G(i)1/G(i)2alpha, G(i)3alpha, G(o)alpha, G(z)alpha and Gbeta was high already at birth and further development was reflected in parallel decrease of both GABA(B)-R1a and GABA(B)-R2 subunits. The major decrease of GABA(B)-R1a and GABA(B)-R2 occurred between the birth and PD15: to 55 % (R1a, **) and 51 % (R2, **), respectively. Contrarily, PM level of the cognate G-proteins G(i)1/G(i)2alpha, G(i)3alpha, G(o)alpha, G(z)alpha and Gbeta was unchanged in the course of the whole postnatal period of brain cortex development. Maturation of GABA(B)-R cascade was substantially different from ontogenetic profile of prototypical plasma membrane marker, Na, K-ATPase, which was low at birth and further development was reflected in continuous increase of PM density of this enzyme. Major change occurred between the birth and PD25. In adult rats, membrane content of Na, K-ATPase was 3-times higher than around the birth.
Purpose
Tension band wiring (TBW) is the most widely accepted method for patella fracture fixation. The purpose of our study was to compare the biomechanical efficacy of a novel cable construct to ...TBW for the fixation of transverse patella fractures. The tensioned cable construct was hypothesized to have less fracture gapping after cyclic flexion–extension loading and greater ultimate load to failure as compared to TBW.
Methods
Transverse patellar osteotomies (AO/OTA 34C1.1) were performed on nine pairs of fresh-frozen human cadaveric whole legs (mean age 82.2 years, range 71–101). Treatment with TBW or tensioned cable construct was randomized within each specimen pair. Fracture site displacement was measured after 5000 flexion–extension cycles from 0° to 90° at 0.5 Hz. In load to failure testing, the knee was fixed at 45° of flexion and the quadriceps tendon was pulled proximally at 0.5 mm/sec until patella fixation failure. Comparisons were made using paired t-tests with alpha values of 0.05.
Results
Eight paired specimens completed the cyclic loading. The tensioned cable construct had significantly less fracture gapping than TBW (2.9 vs 10.9 mm;
p
= 0.020). Seven paired limbs underwent load to failure testing, which revealed no significant difference between the tensioned cable construct and TBW (1551.6 N vs 1664.0 N;
p
= 0.26).
Conclusion
In this study of transverse patella fracture fixation, a tensioned cable construct demonstrated significantly less fracture gapping compared to TBW in response to cyclic loading with no significant difference in load at failure.
Large number of extracellular signals is received by plasma membrane receptors which, upon activation, transduce information into the target cell interior via trimeric G-proteins (GPCRs) and induce ...activation or inhibition of adenylyl cyclase enzyme activity (AC). Receptors for opioid drugs such as morphine (micro-OR, delta-OR and kappa-OR) belong to rhodopsin family of GPCRs. Our recent results indicated a specific up-regulation of AC I (8-fold) and AC II (2.5-fold) in plasma membranes (PM) isolated from rat brain cortex exposed to increasing doses of morphine (10-50 mg/kg) for 10 days. Increase of ACI and ACII represented the specific effect as the amount of ACIII-ACIX, prototypical PM marker Na, K-ATPase and trimeric G-protein alpha and beta subunits was unchanged. The up-regulation of ACI and ACII faded away after 20 days since the last dose of morphine. Proteomic analysis of these PM indicated that the brain cortex of morphine-treated animals cannot be regarded as being adapted to this drug because significant up-regulation of proteins functionally related to oxidative stress and alteration of brain energy metabolism occurred. The number of delta-OR was increased 2-fold and their sensitivity to monovalent cations was altered. Characterization of delta-OR-G-protein coupling in model HEK293 cell line indicated high ability of lithium to support affinity of delta-OR response to agonist stimulation. Our studies of PM structure and function in context with desensitization of GPCRs action were extended by data indicating participation of cholesterol-enriched membrane domains in agonist-specific internalization of delta-OR. In HEK293 cells stably expressing delta-OR-G(i)1alpha fusion protein, depletion of PM cholesterol was associated with the decrease in affinity of G-protein response to agonist stimulation, whereas maximum response was unchanged. Hydrophobic interior of isolated PM became more "fluid", chaotically organized and accessible to water molecules. Validity of this conclusion was supported by the analysis of an immediate PM environment of cholesterol molecules in living delta-OR-G(i)1alpha-HEK293 cells by fluorescent probes 22- and 25-NBD-cholesterol. The alteration of plasma membrane structure by cholesterol depletion made the membrane more hydrated. Understanding of the positive and negative feedback regulatory loops among different OR-initiated signaling cascades (micro-, delta-, and kappa-OR) is crucial for understanding of the long-term mechanisms of drug addiction as the decrease in functional activity of micro-OR may be compensated by increase of delta-OR and/or kappa-OR signaling.
Trimethyltin fluoride (Me3SnF) is a mild and selective reagent for the installation of actinide fluoride bonds as demonstrated by the room temperature synthesis of a variety of organometallic and ...inorganic thorium(IV), uranium(IV), and uranium(V) fluoride complexes {(1,2,4‐tBu3C5H2)2ThF2, (C5Me5)2U(F)(O‐2,6‐iPr2C6H3), U(F)(O‐2,6‐tBu2C6H3)3, U(F)N(SiMe3)23, (C5Me5)2UF2(L) (L = O=PMe3, O=PPh3, O=PCy3), and (C5Me5)2U(F)(=N‐2,6‐iPr2C6H3)} from their corresponding chloride, bromide, and iodide analogues. From these reactions, the new (C5Me5)2UF2(L) (L = O=PPh3, O=PCy3) uranium fluoride complexes were isolated and characterized by NMR spectroscopy and X‐ray crystallography.
Trimethyltin fluoride (Me3SnF) is a mild and selective reagent for the installation of actinide fluoride bonds as demonstrated by the room temperature synthesis of a variety of organometallic and inorganic thorium and uranium from their corresponding chloride, bromide, and iodide analogues.
The reaction of (C
Me
)
AnCl
(An = Th, U) with 2.8 or 4 equivalents of LiNMe
, respectively, affords (C
Me
)
An(NMe
)
in high yields. In addition to improved syntheses, the solid-state structures, ...voltammetric data, and UV-visible-NIR spectra for these classic actinide bis(dimethylamido) complexes are presented for the first time.
The question on the existence of nontrivial pseudocharacters on anomalous products of locally indicable groups is considered. Some generalizations of theorems of R. I. Grigorchuk and V. G. Bardakov ...on the existence of nontrivial pseudocharacters on free products with the amalgamation subgroup are found. It is proved that they exist on an anomalous product 〈
G, x
|
w
= 1〉, where
G
is a locally indicable noncyclic group. We also prove some other propositions on the existence of nontrivial pseudocharacters on anomalous products of groups. Results on the second cohomologies of these products and their nonamenability follow from the propositions on the existence of nontrivial pseudocharacters on these groups.
Invited for the cover of this issue are JaquelineàL. Kiplinger and co‐workers from Los Alamos National Laboratory, New Mexico, USA. The cover image shows the versatility of trimethyltin fluoride ...(Me3SnF) as a reagent for the conversion of actinide halides to actinide fluorides.
This chemistry is a “pot‐of‐gold”, which allowed us to reach the long‐sought‐after, end‐of‐the‐rainbow actinide fluoride complexes…
Read more about the story behind the cover in the Cover Profile and about the research itself in the Full Paper by J. L. Kiplinger et al.
Non-local conserved charges in two-dimensional sigma models with target spaces SO(2n)/SO(n)×SO(n) and Sp(2n)/Sp(n)×Sp(n) are shown to survive quantization, unspoiled by anomalies; these theories are ...therefore integrable at the quantum level. Local, higher-spin, conserved charges are also shown to survive quantization in the SO(2n)/SO(n)×SO(n) models.
PDF
