Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The contribution of hepatocytes to liver prostaglandin (PG) synthesis Is not clear. We compared prostaglandin synthesis in homogenates of whole liver, freshly isolated hepatocytes, and mixed non-parenchymal cells from the same rat livers, and optimized the assay. Whole liver homogenates made 27.2 +/- 7.1 mg PGE2/mg protein/5 min (+/- SEM, n = 4 livers). Hepatocyte homogenates made 39 +/- 9% as much PGE2/mg protein as did the matched whole livers. Non-parenchymal cell homogenates made slightly more PGE2 than whole liver, but much more PGD2. Subsequent studies showed that fresh hepatocyte suspensions contain significant contamination with non-parenchymal cells. Homogenates from ricin-purified hepatocyte monolayers made at least half as much PGE2 as did conventional monolayers. However, taking cellular purity into account, hepatocytes must contain much less than a third of liver cyclooxygenase activity.
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PMID:The contribution of hepatocytes to prostaglandin synthesis in rat liver. 748 72

Ricin, a toxic lectin from the castor bean, affects the cardiovascular system. Because calcium is very important in cardiotoxicity and cell intoxication, we studied the effects of ricin pretreatment to rabbits on basal intracellular calcium levels and calcium uptake and release from isolated papillary muscle, microsomes, and mitochondria. An increase in basal intracellular calcium levels was observed. Ricin pretreatment nearly doubled the intracellular-free Ca2+ concentration as measured by fura-2 fluorescence microscopy in isolated myocytes (p = 0.002). Ricin did not alter basal calcium efflux in isolated papillary muscles. However, ricin inhibited the NE-induced calcium efflux (expressed as fractional efflux ratios) in papillary muscles from rabbits receiving the minimum lethal dose of ricin at 25-35 minutes (p = 0.002 and 0.003, respectively). Ricin depressed basal calcium uptake into isolated papillary muscles at 5 minutes (mean +/- SEM, mumol/g wet weight) (control: 3.68 +/- 0.57; ricin: 2.31 +/- 0.28, p = 0.045, n = 6). Ricin pretreatment significantly depressed calcium uptake into microsomes (mean +/- SEM, mumol/g protein) (control: 9.9 +/- 1.9; ricin: 3.1 +/- 1.9, p = 0.025, n = 6). Calcium uptake into mitochondria was increased at the beginning (2 minutes, p = 0.048), but not thereafter. Thus, administration of ricin disturbed calcium homeostasis in the rabbit heart, which may be at least partially responsible for altering cardiac function and myocardial cell death.
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PMID:Ricin disturbs calcium homeostasis in the rabbit heart. 893 35

Molecularly imprinted polymer (MIP) for biological warfare agent (BWA) ricin was synthesized using silanes in order to avoid harsh environments during the synthesis of MIP. The synthesized MIP was utilized for the recognition of ricin. The complete removal of ricin from polymer was confirmed by fluorescence spectrometer and SEM-EDAX. SEM and EDAX studies confirmed the attachment of silane polymer on the surface of silica gel matrix. SEM image of Ricin-MIP exhibited nanopatterns and it was found to be entirely different from the SEM image of non-imprinted polymer (NIP). BET surface area analysis revealed more surface area (227 m(2)/g) for Ricin-MIP than that of NIP (143 m(2)/g). In addition, surface area study also showed more pore volume (0.5010 cm(3)/g) for Ricin-MIP than that of NIP (0.2828 cm(3)/g) at 12 nm pore diameter confirming the presence of imprinted sites for ricin as the reported diameter of ricin is 12 nm. The recognition and rebinding ability of the Ricin-MIP was tested in aqueous solution. Ricin-MIP rebound more ricin when compared to the NIP. Chromatogram obtained with Ricin-MIP exhibited two peaks due to imprinting, however, chromatogram of NIP exhibited only one peak for free ricin. SDS-PAGE result confirmed the second peak observed in chromatogram of Ricin-MIP as ricin peak. Ricin-MIP exhibited an imprinting efficiency of 1.76 and it also showed 10% interference from the structurally similar protein abrin.
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PMID:Molecularly imprinted nanopatterns for the recognition of biological warfare agent ricin. 1939 10

Ricin is a scheduled chemical warfare agent and biological warfare agent. Attempts were made for the detection of ricin in water samples by utilizing amperometric immunosensors. These electrodes were made by mixing Paraffin oil with graphite powder and multiwalled carbon nanotubes. The graphite paste electrode (CPE) and multiwalled carbon nanotubes paste electrode (MWCNTPE) were tested for their ability to detect 1-naphthol. A sandwich enzyme linked immunosorbent assay system was used to detect ricin. The detection limit for both electrodes was compared. It was found that the response of amperometric sensor is proportional to the ricin concentration in both the cases and is linear in the range 0.625-25 ng/ml for MWCNTPE and 2.5-25 ng/ml for CPE. The SEM showed that the MWCNTPE has revealed crevices/voids in which the antibodies may get trapped. Spectroscopic experiments proved that MWCNTPE adsorbs antibodies better than CPE. The high sensitivity of MWCNTPE was attributed to its better electrochemical properties rather than to its efficiency to adsorb antibodies.
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PMID:Amperometric immunosensor for ricin by using on graphite and carbon nanotube paste electrodes. 2018 85