scholarly journals Short-term radiorespirometry of cell suspensions

1974 ◽  
Vol 144 (3) ◽  
pp. 487-496 ◽  
Author(s):  
W G Duncombe
Keyword(s):  
Detailed Analysis ◽  
Glucose Oxidation ◽  
Specific Radioactivity ◽  
Cell Types ◽  
Cell Suspensions ◽  
Short Term ◽  
Low Concentration ◽  
High Specific Radioactivity

1. An apparatus and method are described with which the oxidation of labelled substrates to14CO2 by cell suspensions may be examined. 2. The use of high-specific-radioactivity substrates at low concentration together with frequent quantitative collection of CO2 permit a more detailed analysis of the appearance of various substrate carbon atoms as CO2 than is possible by existing techniques. 3. Typical experiments with various cell types are reported, in which pathways of glucose oxidation are examined.

scholarly journals Fibrillar organization of fibronectin is expressed coordinately with cell surface gangliosides in a variant murine fibroblast.

1986 ◽  
Vol 102 (5) ◽  
pp. 1898-1906 ◽  
Author(s):  
S Spiegel ◽  
K M Yamada ◽  
B E Hom ◽  
J Moss ◽  
P H Fishman
Keyword(s):  
Cell Surface ◽  
Cholera Toxin ◽  
Cell Attachment ◽  
Specific Radioactivity ◽  
Cell Types ◽  
Concomitant Treatment ◽  
Matrix Assembly ◽  
Surface Receptors ◽  
High Specific Radioactivity ◽  
Fibrillar Network

NCTC 2071A cells, a line of transformed murine fibroblasts, grow in serum-free medium, are deficient in gangliosides, synthesize fibronectin, but do not retain and organize it on the cell surface. When the cells are exposed to exogenous gangliosides, fibrillar strands of fibronectin become attached to the cell surface. A morphologically distinct variant of NCTC 2071A cells was observed to both retain cell surface fibronectin and organize it into a fibrillar network when the cells were stained with anti-fibronectin antibodies and a fluorescent second antibody. A revertant cell type appeared to resemble the parental NCTC 2071A cells in terms of morphology and fibronectin organization. All three cell types were subjected to mild NaIO4 oxidation and reduction with KB3H4 of very high specific radioactivity in order to label the sialic acid residues of surface gangliosides. The variant had much more surface gangliosides than the parental, particularly more complex gangliosides corresponding to GM1 and GD1a. The surface gangliosides of the revertant were intermediate between the parental and the variant. By using sialidase, which hydrolyzes GD1a to GM1, and 125I-labeled cholera toxin, which binds specifically to GM1, the identity and levels of these gangliosides were confirmed in the three cell types. When variant cells were exposed to sialidase for 2 d, there appeared to be little change in fibronectin organization. Concomitant treatment of the cells with the B subunit of cholera toxin, which bound to all the surface GM1 including that generated by the sialidase, however, eliminated the fibrillar network of fibronectin. In addition, exposure of the variant cells to a 70,000-mol-wt fragment of fibronectin, which lacks the cell attachment domain but contains a matrix assembly domain, inhibited the formation of fibers. Finally, all three cell types were assayed for their ability to attach to and spread on fibronectin-coated surfaces; no significant differences were found. Our results further establish that the ability of a cell to organize fibronectin into an extracellular matrix is dependent on certain gangliosides, but they also indicate that cell adhesion to fibronectin is independent of these gangliosides. We suggest that matrix organization and cell attachment and spreading are based on separate mechanisms and that these functions are associated with different cell surface "receptors."

scholarly journals A Minimal Model for G Protein–Mediated Synaptic Facilitation and Depression

2003 ◽  
Vol 90 (3) ◽  
pp. 1643-1653 ◽  
Author(s):  
Richard Bertram ◽  
Jessica Swanson ◽  
Mohammad Yousef ◽  
Zhong-Ping Feng ◽  
Gerald W. Zamponi
Keyword(s):  
G Protein ◽  
Cell Types ◽  
G Protein Coupled Receptors ◽  
Β Subunit ◽  
Short Term ◽  
Paired Pulse ◽  
Synaptic Facilitation ◽  
Protein Inhibition ◽  
G Protein Coupled ◽  
High Pass

G protein–coupled receptors are ubiquitous in neurons, as well as other cell types. Activation of receptors by hormones or neurotransmitters splits the G protein heterotrimer into Gα and Gβγ subunits. It is now clear that Gβγ directly inhibits Ca2+ channels, putting them into a reluctant state. The effects of Gβγ depend on the specific β and γ subunits present, as well as the β subunit isoform of the N-type Ca2+ channel. We describe a minimal mathematical model for the effects of G protein action on the dynamics of synaptic transmission. The model is calibrated by data obtained by transfecting G protein and Ca2+ channel subunits into tsA-201 cells. We demonstrate with numerical simulations that G protein action can provide a mechanism for either short-term synaptic facilitation or depression, depending on the manner in which G protein–coupled receptors are activated. The G protein action performs high-pass filtering of the presynaptic signal, with a filter cutoff that depends on the combination of G protein and Ca2+ channel subunits present. At stimulus frequencies above the cutoff, trains of single spikes are transmitted, while only doublets are transmitted at frequencies below the cutoff. Finally, we demonstrate that relief of G protein inhibition can contribute to paired-pulse facilitation.

Synthesis of high-specific-radioactivity 4- and 6-[18F]fluorometaraminol- PET tracers for the adrenergic nervous system of the heart

2001 ◽  
Vol 9 (3) ◽  
pp. 677-694 ◽  
Author(s):  
Oliver Langer ◽  
Frédéric Dollé ◽  
Héric Valette ◽  
Christer Halldin ◽  
Françoise Vaufrey ◽  
...  
Keyword(s):  
Nervous System ◽  
Specific Radioactivity ◽  
Pet Tracers ◽  
High Specific Radioactivity ◽  
Adrenergic Nervous System

scholarly journals Weather data errors analysis in solar power stations generation forecasting

2018 ◽  
Vol 51 ◽  
pp. 02002 ◽  
Author(s):  
Stanislav Eroshenko ◽  
Alexandra Khalyasmaa
Keyword(s):  
Detailed Analysis ◽  
Solar Power ◽  
Weather Data ◽  
Forecasting Model ◽  
Short Term ◽  
Data Errors ◽  
Power Stations ◽  
Software Product ◽  
Short Term Forecasting ◽  
Errors Analysis

The paper presents a short-term forecasting model for solar power stations (SPS) generation developed by the authors. This model is based on weather data and built into the existing software product as a separate short-term forecasting module for the SPS generation. The main problems associated with forecasting the SPS generation on cloudy days were revealed in the framework of authors' research, which is due not to the error of the developed model but to the use of the same learning sample for both solar and cloudy days. This paper contains analysis of the main problems related to the learning sampling, samples pattern, quality and representativeness for forecasting the SPS generation on cloudy days. Besides, the paper includes a calculation example performed for the existing SPS and a detailed analysis of the forecast generation on cloudy days based on the actual weather provider data.

scholarly journals Interactions of Nereistoxin and Its Analogs with Vertebrate Nicotinic Acetylcholine Receptors and Molluscan ACh Binding Proteins

Marine Drugs ◽  
2022 ◽  
Vol 20 (1) ◽  
pp. 49
Author(s):  
William Kem ◽  
Kristin Andrud ◽  
Galen Bruno ◽  
Hong Xing ◽  
Ferenc Soti ◽  
...  
Keyword(s):  
Disulfide Bond ◽  
Nicotinic Acetylcholine Receptors ◽  
Acetylcholine Receptors ◽  
Specific Radioactivity ◽  
Electric Organ ◽  
Binding Affinities ◽  
Nicotinic Acetylcholine ◽  
High Affinity ◽  
High Specific Radioactivity ◽  
Alpha Bungarotoxin

Nereistoxin (NTX) is a marine toxin isolated from an annelid worm that lives along the coasts of Japan. Its insecticidal properties were discovered decades ago and this stimulated the development of a variety of insecticides such as Cartap that are readily transformed into NTX. One unusual feature of NTX is that it is a small cyclic molecule that contains a disulfide bond. In spite of its size, it acts as an antagonist at insect and mammalian nicotinic acetylcholine receptors (nAChRs). The functional importance of the disulfide bond was assessed by determining the effects of inserting a methylene group between the two sulfur atoms, creating dimethylaminodithiane (DMA-DT). We also assessed the effect of methylating the NTX and DMA-DT dimethylamino groups on binding to three vertebrate nAChRs. Radioligand receptor binding experiments were carried out using washed membranes from rat brain and fish (Torpedo) electric organ; [3H]-cytisine displacement was used to assess binding to the predominantly high affinity alpha4beta2 nAChRs and [125I]-alpha-bungarotoxin displacement was used to measure binding of NTX and analogs to the alpha7 and skeletal muscle type nAChRs. While the two quaternary nitrogen analogs, relative to their respective tertiary amines, displayed lower α4β2 nAChR binding affinities, both displayed much higher affinities for the Torpedo muscle nAChR and rat alpha7 brain receptors than their respective tertiary amine forms. The binding affinities of DMA-DT for the three nAChRs were lower than those of NTX and MeNTX. An AChBP mutant lacking the C loop disulfide bond that would potentially react with the NTX disulfide bond displayed an NTX affinity very similar to the parent AChBP. Inhibition of [3H]-epibatidine binding to the AChBPs was not affected by exposure to NTX or MeNTX for up to 24 hr prior to addition of the radioligand. Thus, the disulfide bond of NTX is not required to react with the vicinal disulfide in the AChBP C loop for inhibition of [3H]-epibatidine binding. However, a reversible disulfide interchange reaction of NTX with nAChRs might still occur, especially under reducing conditions. Labeled MeNTX, because it can be readily prepared with high specific radioactivity and possesses relatively high affinity for the nAChR-rich Torpedo nAChR, would be a useful probe to detect and identify any nereistoxin adducts.

scholarly journals Selective cytotoxicity of 125I-labeled monoclonal antibody T101 in human malignant T cell lines

Blood ◽  
1986 ◽  
Vol 67 (2) ◽  
pp. 429-435
Author(s):  
E Boven ◽  
T Lindmo ◽  
JB Mitchell ◽  
PA Jr Bunn
Keyword(s):  
T Cell ◽  
Cell Lines ◽  
Specific Activity ◽  
Specific Radioactivity ◽  
High Specific Activity ◽  
Tumor Localization ◽  
Cytotoxic Effects ◽  
High Specific Radioactivity ◽  
T Cell Lines

The radiolabeled anti-T cell antibody T101 can be used for specific tumor localization, but unlabeled T101 produces limited cytotoxicity in patients. We thus studied the in vitro cytotoxic effects of T101 labeled with 125I, a radionuclide known for its short-range, high- linear-energy electrons. We showed that 125I-T101 could be readily prepared at high specific activity with high immunoreactivity. Human malignant T cell lines HUT 102, MOLT-4, and HUT 78 were found to differ in the number of T65 determinants (the antigen recognized by T101) and the sensitivity to external x-ray radiation, which were of significance for the cytotoxicity of 125I-T101 in vitro. The cytotoxic effects of 125I-T101 were also found to be dose dependent and increased with exposure time under frozen conditions. As controls, unlabeled T101 had no cytotoxic effect, while free Na 125I or the 125I-labeled irrelevant antibody 9.2.27 exerted minor cytotoxicity. In HUT 102 and MOLT-4, more than 3 logs' cell killing was achieved within four weeks. Because considerable cytotoxicity was demonstrated in vitro by 125I-T101 on T65- positive malignant cells, and because low-dose 111In-T101 can be used successfully for tumor localization, future trials using 125I-T101 at high specific radioactivity may improve therapeutic results in patients with T65-positive malignancies.

scholarly journals Concise Review: Considering Optimal Temperature for Short-Term Storage of Epithelial Cells

2021 ◽  
Vol 8 ◽  
Author(s):  
Ayyad Zartasht Khan ◽  
Tor Paaske Utheim ◽  
Catherine Joan Jackson ◽  
Kim Alexander Tønseth ◽  
Jon Roger Eidet
Keyword(s):  
Epithelial Cells ◽  
Storage Temperature ◽  
Freezing Point ◽  
Retinal Pigment ◽  
Cell Types ◽  
Retinal Pigment Epithelial Cells ◽  
Storage Medium ◽  
Short Term ◽  
Short Term Storage ◽  
Term Storage

Transplantation of novel tissue-engineered products using cultured epithelial cells is gaining significant interest. While such treatments can readily be provided at centralized medical centers, delivery to patients at geographically remote locations requires the establishment of suitable storage protocols. One important aspect of storage technology is temperature. This paper reviews storage temperature for above-freezing point storage of human epithelial cells for regenerative medicine purposes. The literature search uncovered publications on epidermal cells, retinal pigment epithelial cells, conjunctival epithelial cells, corneal/limbal epithelial cells, oral keratinocytes, and seminiferous epithelial cells. The following general patterns were noted: (1) Several studies across different cell types inclined toward 4 and 16°C being suitable short-term storage temperatures. Correspondingly, almost all studies investigating 37°C concluded that this storage temperature was suboptimal. (2) Cell death typically escalates rapidly following 7–10 days of storage. (3) The importance of the type of storage medium and its composition was highlighted by some of the studies; however, the relative importance of storage medium vs. storage temperature has not been investigated systematically. Although a direct comparison between the included investigations is not reasonable due to differences in cell types, storage media, and storage duration, this review provides an overview, summarizing the work carried out on each cell type during the past two decades.

Rebuilding Finance’s “Action Man” through CNBC’sThe Closing Bell

2018 ◽  
Vol 20 (7) ◽  
pp. 702-719
Author(s):  
Diane L. Cormany
Keyword(s):  
Twentieth Century ◽  
Financial Crisis ◽  
Detailed Analysis ◽  
Global Financial Crisis ◽  
Structural Reform ◽  
Short Term ◽  
Market Change ◽  
Finance Capital ◽  
Late Twentieth ◽  
Late Twentieth Century

CNBC’s The Closing Bell contributed to the expansion of finance capital in the late twentieth century through its televisual emphasis on incremental market change that functions affectively to call for action. Such emphasis on short-term stock movement was called into question during the 2008 global financial crisis. However, detailed analysis demonstrates that The Closing Bell did not alter course. I argue that its ongoing focus on incremental movement has worked affectively to shore up a masculinized culture of finance during a period that demanded structural reform.

scholarly journals Role of TRIB3 in regulation of insulin sensitivity and nutrient metabolism during short-term fasting and nutrient excess

2012 ◽  
Vol 303 (7) ◽  
pp. E908-E916 ◽  
Author(s):  
Jiarong Liu ◽  
Wei Zhang ◽  
Gin C. Chuang ◽  
Helliner S. Hill ◽  
Ling Tian ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Oxygen Consumption ◽  
Insulin Sensitivity ◽  
Glucose Uptake ◽  
Glucose Transport ◽  
Oxygen Consumption Rate ◽  
Glucose Oxidation ◽  
Consumption Rate ◽  
Negative Regulator ◽  
Short Term

We have suggested previously that Tribbles homolog 3 (TRIB3), a negative regulator of Akt activity in insulin-sensitive tissues, could mediate glucose-induced insulin resistance in muscle under conditions of chronic hyperglycemia (Liu J, Wu X, Franklin JL, Messina JL, Hill HS, Moellering DR, Walton RG, Martin M, Garvey WT. Am J Physiol Endocrinol Metab 298: E565–E576, 2010). In the current study, we have assessed short-term physiological regulation of TRIB3 in skeletal muscle and adipose tissues by nutrient excess and fasting as well as TRIB3's ability to modulate glucose transport and mitochondrial oxidation. In Sprague-Dawley rats, we found that short-term fasting enhanced insulin sensitivity concomitantly with decrements in TRIB3 mRNA (66%, P < 0.05) and protein (81%, P < 0.05) in muscle and increments in TRIB3 mRNA (96%, P < 0.05) and protein (∼10-fold, P < 0.05) in adipose tissue compared with nonfasted controls. On the other hand, rats fed a Western diet for 7 days became insulin resistant concomitantly with increments in TRIB3 mRNA (155%, P < 0.05) and protein (69%, P = 0.0567) in muscle and a decrease in the mRNA (76%, P < 0.05) and protein (70%, P < 0.05) in adipose. In glucose transport and mitochondria oxidation studies using skeletal muscle cells, we found that stable TRIB3 overexpression impaired insulin-stimulated glucose uptake without affecting basal glucose transport and increased both basal glucose oxidation and the maximal uncoupled oxygen consumption rate. With stable knockdown of TRIB3, basal and insulin-stimulated glucose transport rates were increased, whereas basal glucose oxidation and the maximal uncoupled oxygen consumption rate were decreased. In conclusion, TRIB3 impacts glucose uptake and oxidation oppositely in muscle and fat according to levels of nutrient availability. The above data for the first time implicate TRIB3 as a potent physiological regulator of insulin sensitivity and mitochondrial glucose oxidation under conditions of nutrient deprivation and excess.

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