For the purpose of monitoring spinal cord function, evoked spinal cord potential was observed by recording electrodes in the subarachnoid space at the level of the conus medullaris and stimuli delivered to the rostral spinal cord from the epidural space. A specially designed, flexible tube-type electrode was used for both recording and stimulating. The spinal cord evoked potential consisted of an initial spike followed by polyphasic waves. The peak amplitude change was considered to be the main indicator of events that would potentially be hazardous to spinal cord function. Two hundred and twenty-nine operations were monitored by the recording electrode. Six of the patients experienced postoperative neurologic complications. During operation, the peak amplitudes of the evoked potentials diminished to less than 50% of the control values. Simultaneous monitoring of evoked potential revealed that this method was more sensitive than the wake-up test. No complications resulted from the application of this method. Thus, monitoring is a sufficiently sensitive, safe, and reliable method to be useful during aggressive surgery in the spine and spinal cord.

Electrodes↗

PubMed1983

High-performance liquid chromatography and fluorometric detection of biologically important thiols, derivatized with ammonium 7-fluorobenzo-2-oxa-1,3-diazole-4-sulphonate (SBD-F).

Thiol compounds which are derivatized with a fluorogenic reagent, ammonium 7-fluorobenzo-2-oxa-1,3-diazole-4-sulphonate (SBD-F), are separated on a high-performance liquid chromatography column (muBondapak C18) and detected fluorometrically at 515 nm with excitation at 385 nm. Two kinds of gradient elution system were adopted for the separation of SBD cysteine, homocysteine, cysteamine, glutathione and N-acetylcysteine. The detection limits were in the range 0.07-1.4 pmole. Utilizing the proposed method, only a reduced form of glutathione was found in human whole blood at the level of 1.6 +/- 0.4 mM. However, in the plasma, both the reduced and oxidized (tri-n-butylphosphine-treated) L-cysteine, glutathione and an unknown substance were detected. The amounts of L-cysteine and total L-cysteine (reduced plus oxidized) in plasma were 27 +/- 2 and 72 +/- 7 microM, respectively.

Chromatography, High Pressure Liquid↗

PubMed1983

Determination of catecholamine sulfoconjugate isomers in normal human urine by use of high-performance liquid chromatography with a photochemical detector.

A method for the determination of catecholamine sulfoconjugate isomers (CA-S) in urine was developed. The photo-induced fluorogenic reaction of CA-S with ethylenediamine reported previously was applied to the postcolumn labeling of HPLC for sensitive and selective detection. Special equipment for the reaction was made with a uv-irradiation lamp and a reaction coil of Teflon tubing inside a temperature-controlled reaction box. Lower determination limits of this system were 1 to 2 pmol. Urine samples pretreated with small ion-exchange resin columns were subjected to HPLC. Peaks corresponding to CA-S were identified quantitatively by two different separation methods. Thus, all six CA-S were first detected in the urine of normal individuals. The excretion rates of dopamine 3-sulfate, dopamine 4-sulfate, norepinephrine 3-sulfate, norepinephrine 4-sulfate, epinephrine 3-sulfate, and epinephrine 4-sulfate were 420 +/- 240, 98 +/- 55, 86 +/- 95, 15 +/- 14, 18 +/- 7, and 3 +/- 1 ng/min (+/- SD), respectively (n = 5).

Catecholamines↗

PubMed1983

The Monod-Wyman-Changeux allosteric model describes haemoglobin oxygenation with only one adjustable parameter.

The Monod-Wyman-Changeux allosteric model describes the oxygen equilibrium of haemoglobin in terms of three parameters: the oxygen association constant for the T state, KT, that for the R state, KR, and the allosteric constant, L0, where Li = [Ti]/[Ri] and Ti and Ri are the T and R states, respectively, combined with i oxygen molecules (i = 0 to 4). This model predicts that heterotropic effects exerted by various non-haem ligands are due exclusively to displacement of the allosteric equilibrium (T0 in equilibrium R0) and neither the KT nor the KR values depend upon the concentration of non-haem ligands (solution conditions), whereas the experimental data indicated that not only L0, but also KT, varies significantly with changes in solution conditions. On the basis of accurate oxygen equilibrium data, which were obtained recently under a variety of solution conditions, I examined correlations between the Monod-Wyman-Changeux parameters and found the following: as long as the constraints imposed on the haemoglobin molecule are not very strong, both KR and L4 are essentially constant and, further, log L0 + 4 log KT = log L4 + 4 log KR is constant, irrespective of solution conditions. As a consequence, the haemoglobin oxygenation can virtually be described in terms of only one parameter, either KT or L0. Implications of this phenomenon are also described.

Adult↗

PubMed1983

O-methylation of dopamine-o-sulfates with catechol-0-methyltransferase.

[2H2]-dopamine-3-0-sulfate (DM-3-0-S) and [2H2]-dopamine-4-0-sulfate (DM-4-0-S) were synthesized to investigate the possibility of their being substrates for catechol-0-methyltransferase (COMT). [2H5]-3-0-methyldopamine (3-0-Me-DM) and [2H5]-4-0-methyldopamine (4-0-Me-DM) were also synthesized as internal standards for the determination of enzymatic products by gas chromatography-mass spectrometry (GC-MS). [2H2]-DM-3-0-S or [2H2]-DM-4-0-S was incubated at 37 degrees for 60 min in the presence of S-adenosyl-L-methionine with a crude enzyme preparation obtained from rat liver homogenate. The incubation mixture was treated with 0.5N HCl at 100 degrees C for 1h to hydrolyze the remaining sulfate moiety. The reaction products were extracted with an Amberlite XAD-4, derivatized with pentafluoropropionic anhydride and determined by GC-MS. When [2H2]-DM-3-0-S was used as a substrate, [2H2]-3-0-Me-DM was found to be a major product accompanied by [2H2]-4-0-Me-DM as a minor product. The ratio of [2H2]-3-0-Me-DM to [2H2]-4-0-Me-DM was found to be 26:1, while the ratio was 5.4:1 when [2H2]-dopamine was used as a substrate. When [2H2]-DM-4-0-S served as a substrate, [2H2]-3-0-Me-DM was preferentially produced without detectable formation of [2H2]-4-0-Me-DM.

Animals↗

PubMed1983

Hemoglobin Kariya [alpha 40 (C5) Lys leads to Glu]: a new hemoglobin variant with an increased oxygen affinity.

A new abnormal hemoglobin, Hb Kariya [alpha 40 (C5) Lys leads to Glu], with an amino acid substitution at the alpha 1 beta 2 contact was discovered in a young Japanese man. This variant migrated to the anode faster than Hb A, being nearly the same as Hb I in electrophoretic mobility. It amounted to about 6% of the total hemoglobin of the hemolysate. This hemoglobin showed an increased oxygen affinity, decreased heme-heme interaction and a lowered 2,3-DPG effect.

Adult↗

PubMed1983

A novel fluorogenic reagent for thiols: ammonium 7-fluorobenzo-2-oxa-1,3-diazole-4-sulfonate.

Ammonium 7-fluorobenzo-2-oxa-1,3-diazole-4-sulfonate (SBD-F) was newly synthesized as a fluorogenic reagent for thiol compounds. Its reactivity to glutathione is superior to its 7-chloro analog, SBD-Cl. The optimal reaction condition was selected at 60 degrees C and pH 9.5 for 1 h. The detection limits for glutathione, coenzyme A, cysteamine, homocysteine, N-acetylcysteine, cysteine, and D-3-mercaptomethylpropanoyl-L-proline (captopril) were 100, 120, 160, 330, 390, 3600, and 150 pmol/ml, respectively. Proline and alanine did not give fluorescence under this condition.

Chromatography, High Pressure Liquid↗

PubMed1983

Selective in vitro toxicity of purothionin conjugated to the monoclonal antibody 225.28S to a human high-molecular-weight melanoma-associated antigen.

The toxic agent purothionin was conjugated to the monoclonal antibody 225.28S to a human high-molecular-weight melanoma-accociated antigen. The toxic conjugate displayed in vitro toxicity to cultured human Colo 38 melanoma cells as indicated by reduced uptake of 3H-thymidine following a 24-h incubation and loss of cell viability following a 7-day incubation. The effect is dose-dependent and is specific since addition of the toxic conjugate to a cultured Raji B lymphoid cells did not affect their 3H-thymidine uptake or their viability.

Antibodies, Monoclonal↗

PubMed1983

Dynamic response of preoptic and hypothalamic neurons to scrotal thermal stimulation in rats.

Activities of preoptic and anterior hypothalamic (POAH) neurons were recorded in anesthetized rats in response to scrotal thermal stimulation. Thirteen out of 54 neurons responsive to changes of scrotal temperature (Tscr) showed dynamic responses. Four of these neurons increased and 3 neurons decreased their firing rates responding dynamically to warming but not to cooling. Six other neurons were inhibited by scrotal cooling only. These dynamic responses were produced even by temperature changes as slow as 2 degrees C/min and only when the scrotum was warmed or cooled in the Tscr range above 35 degrees C. These dynamic responses are suggested to be a result of signal processing in supraspinal structures including POAH itself.

Animals↗

PubMed1983

Liquid chromatographic determination of amino and imino acids and thiols by postcolumn derivatization with 4-fluoro-7-nitrobenzo-2,1,3-oxadiazole.

Explore the source record for details and available documents.

4-Chloro-7-nitrobenzofurazan↗

PubMed1983

Ischaemia-induced changes in canine cardiac sarcoplasmic reticulum.

Effects of myocardial ischaemia on sarcoplasmic reticulum (SR) of dog hearts were investigated. Regional ischaemia was produced by occlusion of the left circumflex artery, and a microsomal fraction enriched in vesicles of SR was isolated from subendocardium (Endo) and subepicardium (Epi) of control and ischaemic areas of the heart. No significant changes occurred in ischaemic Epi. A loss of in vitro activities (ie calcium transport and ATPase) was found for SR from ischaemic Endo which paralleled the changes in the histology of the tissue. At 5 min of coronary occlusion, Ca2+ binding and Ca2+-ATPase activities of SR from ischaemic Endo were normal. A decrease in the activities of SR was first evident at 15 min after the occlusion, decreased further at about 30 min and remained at that level at 60 min of ischaemia. The maximal rate of Ca2+ uptake did not parallel the Ca2+-binding and Ca2+-ATPase activities. The degree of cAMP-dependent phosphorylation by endogenous and exogenous protein kinase was not different between SR from control and ischaemic areas. A participatory role of SR in the ischaemic impairment of left ventricular systolic and diastolic performance is discussed.

Animals↗

PubMed1983

Purification and properties of rat brain dipeptidyl aminopeptidase.

Dipeptidyl aminopeptidase, which hydrolyzes the 7-(Gly-Pro)-4-methylcoumarinamide, has been purified from the brains of 3 week-old rats. It was purified about 2,600-fold by column chromatography on CM-cellulose, hydroxyapatite and Gly-Pro AH-Sepharose. This enzyme hydrolyzed Lys-Ala-beta-naphthylamide well with an optimum pH of 5.5. It was inhibited by diisopropyl fluorophosphate, phenyl-methanesulfonyl fluoride, some cations, and puromycin, but was not inhibited by p-chloromercuribenzoate, N-ethylmaleimide, dithiothreitol, EDTA, iodoacetic acid, and bacitracin, indicating that rat brain dipeptidyl aminopeptidase is a serine protease. This enzyme showed a molecular weight of 220,000 by gel filtration and of 51,000 by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The properties of purified rat brain dipeptidyl aminopeptidase were similar to those of bovine pituitary dipeptidyl peptidase II, but the molecular weight and substrate specificity of these enzymes were different.

Animals↗