Protection of energy status of hypoxic cardiomyocytes by mild acidosis.

The question was investigated whether mild acidosis can provide energetic protection on the hypoxic myocardial cell by mechanisms other than negative inotropy. The experimental model used was quiescent ventricular cardiomyocytes isolated from the adult rat. The extracellular pH (pHe) in modified hypoxic Tyrode's solution was varied by changing the concentration of bicarbonate at constant PCO2.

NPY-(18-36) and pertussis toxin distinguish between the negative and positive contractile effects of neuropeptide Y (NPY) in ventricular cardiomyocytes.

The mechanism of action of NPY to produce contractions of adult rat ventricular myocytes was investigated. Positive effects were mediated through an L-type Ca2+ channel. Negative effects, linked through an inhibitory G-protein to a transient outward K+ channel, could be antagonised by NPY-(18-36).

Prevention of the oxygen paradox in the isolated cardiomyocyte and the whole heart.

It was investigated in hypoxic-reoxygenated cardiomyocytes and isolated perfused hearts from rat whether temporary contractile blockade by 2,3-butanedionemonoxime (20 mM: BDM) during the initial phase of reoxygenation could prevent severe reoxygenation-induced cell injury. In isolated rat cardiomyocytes, reoxygenation after 120 minutes substrate-free anoxia caused sudden hypercontracture but not cytolysis. Within 15 minutes, a nearly normal free energy change of ATP hydrolysis and a normal cytosolic Ca2+ control were reestablished, in spite of irreversible hypercontracture.

Positive and negative contractile effects of neuropeptide Y on ventricular cardiomyocytes.

The potency of neuropeptide Y (NPY) to cause negative and positive contractile responses in rat ventricular cardiomyocytes was investigated. In these cells, NPY was found to activate the transient outward K+ current (Ito) and the slow inward Ca2+ current (Isi). As reported before (H.

Nitric oxide production by cultured aortic endothelial cells in response to thiol depletion and replenishment.

The requirements and influence of thiols on the production of nitric oxide (NO) were examined in cultured porcine aortic endothelial cells. NO production was diminished when cells were pretreated with thiol-depleting agents (IC50: N-ethylmaleimide, 30 microM; 1-chloro-2,4-dinitrobenzene, 200 microM; diamide, 1.5 mM; diethyl maleate, 20 mM).

[Temporary vision disorders, accentuated by deficient illness adjustment].

A medical expert's opinion had to be given on five patients complaining about temporary visual disturbances. 1. Haze caused by keratoconjunctivitis sicca; 2.

Prevention of the oxygen paradox in hypoxic-reoxygenated hearts.

Reoxygenation after 60 min substrate-free hypoxic perfusion (modified Tyrode solution, 37 degrees C) caused isolated Langendorff hearts (from rats) to rapidly develop hypercontracture and sarcolemmal disruptions indicated by massive and sudden loss of enzymes ("oxygen paradox"). Reoxygenation (30 min) caused an augmented loss of creatine kinase by 25.8% (lactate dehydrogenase by 40.

Macromolecule permeability of coronary and aortic endothelial monolayers under energy depletion.

The dependence of macromolecule permeability (MP; indicator fluorescein isothiocyanate-labeled albumin) of endothelial cells on their energetic state was investigated using confluent monolayers of rat coronary microvascular endothelial cells and porcine aortic macrovascular endothelial cells. When oxidative and glycolytic energy productions were inhibited (5 mM KCN plus 5 mM 2-deoxy-D-glucose) 90% of the endothelial ATP contents were lost within 15 min, followed by a progressive increase of MP, disintegration of the actin cytoskeleton, and the opening of intercellular gaps. Elution of the blocker and a subsequent 3-h incubation in complete culture medium reversed the effects of 2-h metabolic blockade, completely for MP and partially for ATP levels.

Longevity of adult ventricular rat heart muscle cells in serum-free primary culture.

The study had two aims: first, to improve the longevity of isolated adult cardiomyocytes in serum-free culture, and, second, to investigate whether catecholamines which promote hypertrophy in vivo can prolong survival of isolated adult rat cardiomyocytes in serum-free culture. The basic cell culture medium consists of serum-free medium 199 with 10(-7) M insulin. In this medium 50% of the initially plated cardiomyocytes survive in elongated form for 2 days.

Temporary contractile blockade prevents hypercontracture in anoxic-reoxygenated cardiomyocytes.

Reoxygenation after 120-min substrate-free anoxia causes sudden hypercontracture in isolated rat cardiomyocytes. Reoxygenated-hypercontracted cardiomyocytes maintain their sarcolemmal integrity as indicated by the absence of enzyme release and reestablish a nearly normal free energy change of ATP hydrolysis within 15 min [Siegmund, B., A.

[Complicated oculomotor disorders evaluated by the medical expert].

The association of sensory and motor defects may lead the medical expert to a false estimation of a patient's impairment, especially (1) if he simply adds to the sensory impairment of one eye the motor impairment of the other, without thinking of the eyes as a paired organ; (2) if he underestimates a cumulation of sensory and motor defects in the case of partial adaptation, and (3) if he judges from dyskinetic behavioral characteristics that the patient is blind. Several clinical cases illustrating these problems and allowing the following recommendations are described: (1) Prior to simply summing up the single impairments one should examine if an overlap exists. (2) In the case of cumulative disturbances with incomplete adaptation the estimated impairment should be higher.

Metabolism of exogenous substrates by coronary endothelial cells in culture.

The ability of coronary endothelial cells in 14 day confluent cultures to metabolize glucose, palmitate, lactate and various amino acids was investigated. Under aerobic conditions, 99% of glucose, (5 mM) was degraded to lactate and only 0.04% was oxidized in the Krebs cycle.

Changes in the energy metabolism of cultured lens epithelial cells in comparison with the fresh lens.

Energy metabolism of bovine cultured lens epithelial cells (CLEC) was compared to that of fresh bovine lens. CLEC contained high levels of ATP (44 nmol mg protein-1) and creatine phosphate (13 nmol mg protein-1). An ATP/ADP ratio of ten and a creatine phosphate/creatine ratio of two indicated the cells were in a well-energized state.

Appearance of alpha-smooth muscle actin in human eye lens cells of anterior capsular cataract and in cultured bovine lens-forming cells.

Using light and electron-microscopic immunolocalization techniques, and gel electrophoresis combined with immunoblotting, we have examined the expression of cytoskeletal proteins in normal human fetal, child and adult lenses, in human anterior capsular cataract and in bovine lens cells in vivo and in vitro. In this report, we focus our observations on the pattern of actin-isoform expression during normal and pathological situations in vivo and culture conditions. We have noted that cells of developing and mature human lenses as well as bovine lens cells in situ contain only beta- and gamma-actins.

Energetic response of coronary endothelial cells to hypoxia.

The response of endothelial energy metabolism to oxygen supply was studied in cultured coronary endothelial cells from the rat at defined PO2 levels between 0.1 and 100 Torr. In the presence of glucose (5 mM), endothelial respiration (4 nmol O2.

Sarcolemmal integrity and metabolic competence of cardiomyocytes under anoxia-reoxygenation.

In tissue, mechanical cell-to-cell interactions may contribute to cardiomyocyte injury in anoxia-reoxygenation. In the present study, the disturbance of energy metabolism and cell injury were investigated in isolated cardiomyocytes, free of external mechanical constraints. Cardiomyocytes from adult rat, attached to culture dishes, were exposed to 120 min of anoxia and 15 min of reoxygenation in a substrate-free modified Tyrode solution.

[100 years of the Mikulicz syndrome].

Between 1888 and 1892, Mikulicz as well as Fuchs observed each a case of oculo-salivary glandular syndrome. Ten years later, Heerfordt described uveitis complicated by swelling of the lacrimal and salivary glands. Within 100 years, the interpretation of this disease changed repeatedly and considerably: infection of particularly exposed organs--non-avirulent tuberculosis--salivotropic virus--Boeck's disease--allergic-hyperergic reaction--diencephalic and nervous dystrophy with segmental projection--(auto)immune disease--oculo-salivary complex including Sjøgren's syndrome--all these were discussed as possible aetiologies.

The negative inotropic effect of neuropeptide Y on the ventricular cardiomyocyte.

The effect of neuropeptide Y (NPY) on cell contractions of ventricular myocytes isolated from the adult rat heart was investigated. Maximum changes in cell length (dL) during stimulated (0.5 Hz) contractions were determined in presence of the phosphodiesterase inhibitor Ro 20-1724 (0.

Resistance of endothelial cells to anoxia-reoxygenation in isolated guinea pig hearts.

The release of cytosolic enzymes from myocardial and endothelial cells in the anoxic-reoxygenated guinea pig heart was investigated. Isolated hearts were perfused with Tyrode solution in the Langendorff mode. Sixty-minute anoxic perfusion with or without glucose (5 mM) was followed by 15-min normoxic perfusion with glucose.

Fatty acids are not an important fuel for coronary microvascular endothelial cells.

The metabolism by coronary microvascular endothelial cells (CMEC) of the heart typical substrates palmitate and lactate was compared to that of glucose and glutamine. Confluent cultures of CMEC were used. Palmitate oxidation was saturable and independent of the exogenous albumin concentration.

Energy deficiency, calcium overload or oxidative stress: possible causes of irreversible ischemic myocardial injury.

After prolonged ischemia or hypoxia myocardial injury is not reversed but exacerbated by a resupply of the tissue with oxygen and substrates. The mechanism by which reversible ischemic or hypoxic myocardial injury becomes irreversible is not yet understood. It has been debated whether "reperfusion injury" merely uncovers pre-existing irreversible injury, or is indeed caused by the reperfusion/reoxygenation process.

The use of the creatine kinase reaction to determine free energy change of ATP hydrolysis in anoxic cardiomyocytes.

In isolated cardiomyocytes from adult rat heart the free energy change of ATP hydrolysis (dG) was determined under conditions of substrate-free anoxia. Changes of free cytosolic ADP concentrations, needed for the calculation of dG, were determined by two indirect methods since a direct measurement is not feasible: (i) via the mass action ratio of the creatine kinase reaction (CK) assuming near equilibrium conditions, and (ii) via quantification of the net hydrolysis of ATP to ADP by a detailed balancing of possible contribution to Pi production. Both approaches gave virtually identical results, showing that in anoxia only 6% of the ATP hydrolysed are hydrolysed to ADP and 94% completely to adenosine and further degradation products.

Substrate oxidation by adult cardiomyocytes in long-term primary culture.

In medium 199 plus 20% fetal calf serum adult rat cardiomyocytes establish a long-term culture (25 days). During the first 10 days they change their gross morphology from the typical elongated in vivo shape (day 1), to a smooth spherical intermediate form (days 2 to 5), to a spread cell type beating spontaneously (days 10 to 15). During the first 10 days in culture, protein content per cell increases and the cell population decreases.