scholarly journals Capacitative Ca2+ Entry Is Closely Linked to the Filling State of Internal Ca2+ Stores: A Study Using Simultaneous Measurements of ICRAC and Intraluminal [Ca2+]

1998 ◽  
Vol 140 (2) ◽  
pp. 325-334 ◽  
Author(s):  
Aldebaran M. Hofer ◽  
Cristina Fasolato ◽  
Tullio Pozzan
Keyword(s):  
Intact Cells ◽  
Soluble Factors ◽  
Intrinsic Kinetics ◽  
Simultaneous Measurements ◽  
Store Depletion ◽  
Cell Recording ◽  
Two Parameters ◽  
First Time ◽  
Kinetics Of ◽  
Filling State

ICRAC (the best characterized Ca2+ current activated by store depletion) was monitored concurrently for the first time with [Ca2+] changes in internal stores. To establish the quantitative and kinetic relationship between these two parameters, we have developed a novel means to clamp [Ca2+] within stores of intact cells at any level. The advantage of this approach, which is based on the membrane-permeant low-affinity Ca2+ chelator N,N,N′,N′-tetrakis (2-pyridylmethyl)ethylene diamine (TPEN), is that [Ca2+] within the ER can be lowered and restored to its original level within 10–15 s without modifications of Ca2+ pumps or release channels. Using these new tools, we demonstrate here that Ca2+ release–activated Ca2+ current (ICRAC) is activated (a) solely by reduction of free [Ca2+] within the ER and (b) by any measurable decrease in [Ca2+]ER. We also demonstrate that the intrinsic kinetics of inactivation are relatively slow and possibly dependent on soluble factors that are lost during the whole-cell recording.

Zeolites Fit For A Crown: Probing Host-Guest Interactions with Thermogravimetric Methods

2018 ◽  
Author(s):  
Asel Sartbaeva ◽  
Paul R. Raithby ◽  
Remi Castaing ◽  
Antony Nearchou
Keyword(s):  
Mass Spectrometry ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Petrochemical Industry ◽  
Rational Use ◽  
New Methodologies ◽  
First Time ◽  
Kinetics Of

Through a combination of thermogravimetry, mass spectrometry and differential thermal analysis, we demonstrate for the first time that all four zeolites show experimental differences in their host-guest interactions with 18C6. In addition, we have estimated the kinetics of 18C6 decomposition, which is a technique that has not been applied to zeolites previously. Using these findings as a toolkit, a more rational use of OSDAs can be utilised to prepare designer zeolites. Furthermore, the new methodologies presented herein can be applied to current zeolites, such as MFI-type zeolites used in the petrochemical industry.

scholarly journals Rapid systemic surge of IL-33 after severe human trauma: a prospective observational study

2021 ◽  
Vol 27 (1) ◽  
Author(s):  
Olav Sundnes ◽  
William Ottestad ◽  
Camilla Schjalm ◽  
Peter Lundbäck ◽  
Lars la Cour Poulsen ◽  
...  
Keyword(s):  
High Resolution ◽  
Prospective Observational Study ◽  
Tissue Injury ◽  
Trauma Patients ◽  
Decoy Receptor ◽  
Interleukin 33 ◽  
Injured Patients ◽  
First Time ◽  
Kinetics Of ◽  
Insight Into

Abstract Background Alarmins are considered proximal mediators of the immune response after tissue injury. Understanding their biology could pave the way for development of new therapeutic targets and biomarkers in human disease, including multiple trauma. In this study we explored high-resolution concentration kinetics of the alarmin interleukin-33 (IL-33) early after human trauma. Methods Plasma samples were serially collected from 136 trauma patients immediately after hospital admission, 2, 4, 6, and 8 h thereafter, and every morning in the ICU. Levels of IL-33 and its decoy receptor sST2 were measured by immunoassays. Results We observed a rapid and transient surge of IL-33 in a subset of critically injured patients. These patients had more widespread tissue injuries and a greater degree of early coagulopathy. IL-33 half-life (t1/2) was 1.4 h (95% CI 1.2–1.6). sST2 displayed a distinctly different pattern with low initial levels but massive increase at later time points. Conclusions We describe for the first time early high-resolution IL-33 concentration kinetics in individual patients after trauma and correlate systemic IL-33 release to clinical data. These findings provide insight into a potentially important axis of danger signaling in humans.

A MODIFIED GENERALIZED LORENZ-TYPE SYSTEM AND ITS CANONICAL FORM

2009 ◽  
Vol 19 (06) ◽  
pp. 1931-1949 ◽  
Author(s):  
QIGUI YANG ◽  
KANGMING ZHANG ◽  
GUANRONG CHEN
Keyword(s):  
Special Form ◽  
Topological Structure ◽  
Complex Dynamics ◽  
Type System ◽  
Chaotic Attractors ◽  
Hopf Bifurcations ◽  
Compound Structure ◽  
Two Parameters ◽  
First Time ◽  
New System

In this paper, a modified generalized Lorenz-type system is introduced, which is state-equivalent to a simple and special form, and is parameterized by two parameters useful for chaos turning and system classification. More importantly, based on the parameterized form, two classes of new chaotic attractors are found for the first time in the literature, which are similar but nonequivalent in topological structure. To further understand the complex dynamics of the new system, some basic properties such as Lyapunov exponents, Hopf bifurcations and compound structure of the attractors are analyzed and demonstrated with careful numerical simulations.

The kinetics of the decarboxylation of β-resorcylic acid in catechol

1976 ◽  
Vol 29 (2) ◽  
pp. 443 ◽  
Author(s):  
MA Haleem ◽  
MA Hakeem
Keyword(s):  
Rate Equation ◽  
Kinetic Data ◽  
Reaction Rate ◽  
Complex Mechanism ◽  
First Order ◽  
Absolute Reaction Rate ◽  
First Time ◽  
Kinetics Of ◽  
Absolute Reaction ◽  
Reaction Rate Equation

Kinetic data are reported for the decarboxylation of β-resorcylic acid in resorcinol and catechol for the first time. The reaction is first order. The observation supports the view that the decomposition proceeds through an intermediate complex mechanism. The parameters of the absolute reaction rate equation are calculated.

scholarly journals Membrane-permeable luciferin esters for assay of firefly luciferase in live intact cells

1991 ◽  
Vol 276 (3) ◽  
pp. 637-641 ◽  
Author(s):  
F F Craig ◽  
A C Simmonds ◽  
D Watmore ◽  
F McCapra ◽  
M R H White
Keyword(s):  
Escherichia Coli ◽  
Mammalian Cells ◽  
Firefly Luciferase ◽  
Luciferase Expression ◽  
Intact Cells ◽  
Cos Cells ◽  
Escherichia Coli Cells ◽  
Luminescent Signal ◽  
The Difference ◽  
Kinetics Of

Five esters of luciferin were synthesized and compared with native luciferin as substrates for firefly luciferase expressed in live intact mammalian cells. The esters themselves were not substrates for purified luciferase, but four were substrates for a purified esterase and all appeared to be hydrolysed to luciferin within mammalian cells. At a substrate concentration of 0.01 mM, the peak luminescence from the cos cells expressing luciferase was up to 6-fold greater with the esters than with unmodified luciferin. At 0.1 mM, the difference between luciferin and the esters was decreased. The kinetics of the luminescent signal with the different luciferin esters varied significantly, indicating possible differences in the rates of uptake, breakdown and enzyme inhibition. The esters did not support luminescence from Escherichia coli cells expressing firefly luciferase, suggesting a lack of appropriate esterase activity in this particular strain. The esters could be useful for the assay of luciferase expression in intact mammalian cells when luciferin levels are limiting, for example in tissues, and in plants. Alternative luciferin derivatives may allow further improvements in sensitivity.

The spliceosome assembly pathway in mammalian extracts

1992 ◽  
Vol 12 (10) ◽  
pp. 4279-4287 ◽  
Author(s):  
S F Jamison ◽  
A Crow ◽  
M A Garcia-Blanco
Keyword(s):  
Spliceosome Assembly ◽  
Protein Factor ◽  
Small Nuclear Ribonucleoprotein ◽  
U2 Snrnp ◽  
U1 Snrnp ◽  
U2 Auxiliary Factor ◽  
Nuclear Ribonucleoprotein ◽  
Auxiliary Factor ◽  
First Time ◽  
Kinetics Of

A mammalian splicing commitment complex was functionally defined by using a template commitment assay. This complex was partially purified and shown to be a required intermediate for complex A formation. The productive formation of this commitment complex required both splice sites and the polypyrimidine tract. U1 small nuclear ribonucleoprotein (snRNP) was the only spliceosomal U snRNP required for this formation. A protein factor, very likely U2AF, is probably involved in the formation of the splicing commitment complex. From the kinetics of appearance of complex A and complex B, it was previously postulated that complex A represents a functional intermediate in spliceosome assembly. Complex A was partially purified and shown to be a required intermediate for complex B (spliceosome) formation. Thus, a spliceosome pathway is for the first time supported by direct biochemical evidence: RNA+U1 snRNP+?U2 auxiliary factor+?Y----CC+U2 snRNP+Z----A+U4/6,5 snRNPs+ beta----B.

scholarly journals IMMUNE RESPONSES IN VITRO

1971 ◽  
Vol 134 (2) ◽  
pp. 395-416 ◽  
Author(s):  
Carl W. Pierce ◽  
Barbara M. Johnson ◽  
Harriet E. Gershon ◽  
Richard Asofsky
Keyword(s):  
Culture Conditions ◽  
Antibody Concentration ◽  
Spleen Cells ◽  
Immunoglobulin Class ◽  
Cell Densities ◽  
Erythrocyte Antigen ◽  
First Time ◽  
Kinetics Of

We have demonstrated for the first time that mouse spleen cells stimulated in vitro with heterologous erythrocytes developed immunoglobulin class-specific γM, γ1, γ2a+2b, and γA plaque-forming cell (PFC) responses. A modification of the hemolytic plaque technique, the addition of goat anti-mouse µ-chain antibody to the assay preparation, specifically prevented development of all γM PFC and enabled accurate and reproducible enumeration of immunoglobulin class-specific PFC after treatment with appropriate monospecific anti-globulins and complement. Culture conditions, with regard to medium, atmosphere, agitation, and spleen cell densities, were similar to those previously shown to support only γM PFC responses. Evaluation of the kinetics of appearance of PFC showed that γM PFC reached maximum numbers on days 4–5; the magnitude of this response was 3–10 times greater than γ1 γ2a+2b, or γA PFC which reached maximum numbers on days 5–6. Optimal erythrocyte antigen dose for γM PFC responses was 107/culture, whereas a dose of 106 erythrocytes/culture consistently stimulated optimal γ1 γ2a+2b, or γA PFC responses. Investigations of the effects of anti-erythrocyte antibody on γM and γG PFC responses indicated that antibody suppressed these responses by neutralizing the effective antigenic stimulus at the macrophage-dependent phase of the response. At the same antibody concentration, γG PFC responses were more effectively suppressed than γM PFC responses. Further, γG responses could be almost completely suppressed by antibody as long as 48 hr after initiation of cultures, whereas γM PFC responses could only be completely suppressed during the first 24 hr. These results were discusssed in terms of the role of antigen in the stimulation γM and γG antibody.

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