[ST-segment shift in V1-V3 in patients with inferior wall infarction depend on angiographic localization of right artery occlusion]. / Zmiana polozenia odcinka ST elektrokardiogramu w odprowadzeniach V1 do V3 u chorych z zawalem sciany dolnej w zaleznosci od angiograficznej lokalizacji zamkniecia prawej tetnicy wiencowej.

Two electrocardiographic types of inferior wall infarct were isolated based on angiographic localization of right coronary artery occlusion. In proximal occlusion of RCA before right ventricular branch there is no depression or more rarely elevation of ST segment in V1-V3 especially in V1 (the first morphological type). ST segment depression in V1-V3 (second morphological type) is characteristic for distal segment of RCA occlusion.

NMDA receptor complex blockade by oral administration of magnesium: comparison with MK-801.

The ion channel of the N-methyl-D-aspartate (NMDA) receptor complex is subject to a voltage-dependent regulation by Mg2+ cations. Under physiological conditions, this channel is supposed to be blocked by a high concentration of magnesium in extracellular fluids. A single dose of magnesium organic salts (i.e., aspartate, pyroglutamate, and lactate) given orally to normal mice rapidly increases the plasma Mg2+ level and reveals a significant dose-dependent antagonist effect of magnesium on the latency of NMDA-induced convulsions; this effect is similar to that seen after administration of the dizocilpine (MK-801) channel blocker. An anticonvulsant effect of Mg2+ treatment is also observed with strychnine-induced convulsions but not with bicuculline-, picrotoxin-, or pentylenetetrazol-induced convulsions. In the forced swimming test, Mg2+ salts reduce the immobility time in a way similar to imipramine and thus resemble the antidepressant-like activity of MK-801. This activity is masked at high doses of magnesium by a myorelaxant effect that is comparable to MK-801-induced ataxia. Potentiation of yohimbine fatal toxicity is another test commonly used to evaluate putative antidepressant drugs. Administration of Mg2+ salts, like administration of imipramine strongly potentiates yohimbine lethality in contrast to MK-801, which is only poorly active in this test. Neither Mg2+ nor MK-801 treatment can prevent reserpine-induced hypothermia. These data demonstrate that oral administration of magnesium to normal animals can antagonize NMDA-mediated responses and lead to antidepressant-like effects that are comparable to those of MK-801. This important regulatory role of Mg2+ in the central nervous system needs further investigation to evaluate the potential therapeutic advantages of magnesium supplementation in psychiatric disorders.

Kinking of the aorta: long-term prognosis.

Six medically treated patients with kinking of the aorta (3 with concomitant aortic stenosis) were followed up for a mean of 51 months. Four patients died and in one survivor apparent radiologic progression occurred. The authors conclude that kinking of the aorta has a more serious outcome than commonly appreciated.

L-lactate enzyme electrode obtained with immobilized respiratory chain from Escherichia coli and oxygen probe for specific determination of L-lactate in yogurt, wine and blood.

An enzyme electrode for L-lactate measurements in various biological media was prepared with an immobilized bacterial respiratory chain fixed to a Clark electrode. The enzymatic film, which was easy to prepare, contained bacteria immobilized in gelatin, tanned with glutaraldehyde. This electrode was sensitive to 0.1 mM L-lactate and could be utilized to 10 mM. The apparent K50 was 5 mM. Less than 8% of the respiration rate with L-lactate was measured with D-lactate and succinate. The competitive inhibitors D-lactate and pyruvate had a K50 of 50 mM. They could be quantitatively measured by inhibition in a range between 5 and 50 mM. It was also possible to discriminate between L-lactate and various metabolites of the respiratory chain: L-malate, succinate, 3-glycero-phosphate or NAD(P)H. Growing E. coli on 1% D-L-lactate as the sole carbon source in minimal medium induced L-lactate respiration tenfold. All other respiratory activities remained below 10% of the activity with L-lactate. A computerized instrument allowed successive measurements every 3 min for more than 10 h with the same enzymatic film. Most of the measured samples required dilution but no clarification or purification. This enzyme electrode may have many applications in basic research (metabolism, enzymology) and applied research (blood, yogurt, juices, wine).

Immobilized respiratory chain activities from Escherichia coli utilized to measure D- and L-lactate, succinate, L-malate, 3-glycerophosphate, pyruvate, or NAD(P)H.

The respiratory chain (membranous, multienzymatic system) from Escherichia coli, was coimmobilized with gelatin and insolubilized in film form by tanning with glutaraldehyde. The film was fixed onto an oxygen sensor. The enzyme electrode can be used for measuring NAD(P)H, D- and L-lactate, succinate, L-malate, 3-glycerophosphate, or pyruvate. The range of metabolites concentrations was from 1 to 50 mM. It was possible to discriminate between the different metabolites (if mixed): By inducing during bacterial growth the specific flavoproteins necessary for L-lactate, succinate, L-malate, and 3-glycerophosphate respirations. The constitutive activities are unaltered on glucose or glycerol, namely D-lactate, NAD(P)H, and pyruvate respiration. When intact bacteria were immobilized (with or without induction), D- and L-lactate, succinate, 3-glycerophosphate, and L-malate respiration were measured, no activities of pyruvate and NAD(P)H respiration were obtained. For these last activities, French press breakage (see section on Membrane Preparations) of bacteria prior to immobilization was necessary. Products of reactions can be used as enzyme inhibitors: Pyruvate inhibits D- and L-lactate; fumarate inhibits succinate, and oxaloacetate inhibits L-malate respirations. Heat denaturation of the bacteria at 55 degrees C for 1 h maintains full activity of succinate and pyruvate respiration. On the other hand, no activity of D- and L-lactate, L-malate, or NAD(P)H respiration was measurable. These enzyme electrodes have many applications in basic and applied research.

Recycling of NADP(+) using immobilizedE. coli and glucose-6-phosphate dehydrogenase.

Recycling of NADP(+) using immobilized wholeEscherichia coli cells as source of respiratory chain, glucose-6-phosphate, and soluble yeast glucose-6-phosphate dehydrogenase (1.1.1.49) is described. NADP(+) was recycled more than 10-fold.We demonstrated NADPH respiration at pH 5.8 inE. coli membrane vesicles. The respiratory chain was involved most probably in NADPH oxidation. 1. The respiratory activity is localized at the level of the inner bacterial membrane. The active site for NADPH facing the cytoplasm. 2. NADPH respiration is inhibited by 10 mM cyanide, similar to the conditions of inhibition of NADH respiration. 3. NADPH dehydrogenase activity seems to be the limiting step of the respiratory chain:K M for NADPH respiration and NADPH dehydrogenase activity are similar. The pH optima for these two activities are also comparable (around pH 5.8). Furthermore, the following properties are rather in favor of a common NADH dehydrogenase and NADPH dehydrogenase activity (1.6.99.2). o| li](1)|At saturating concentrations of NADH and NADPH, neither respiration nor dehydrogenase activities were additive. li](2)|Similar heat inactivation kinetics were observed for NADH and NADPH dehydrogenase-activity.Protection against heat inactivation was obtained for the two activities with NAD(+), NADP(+), NADH, and NADPH.All these results suggested the possibility of recycling of NADP(+) under similar conditions to those previously described for NAD(+) (Burstein et al., 1981). It becomes thus possible to use various NAD(+) and NADP(+)-dependent dehydrogenases in enzyme technology.