The endothelium-dependent relaxation of human middle cerebral artery: Effects of activated neutrophils

Neutrophils, activated by 4-phorbol-12-myristate-13-acetate, decreased acetylcholine-induced relaxation of strips of human middle cerebral artery precontracted with noradrenaline. This effect was prevented by catalase, but not by superoxide dismutase. Nifedipine, propranolol and, less markedly, captopril reduced the decrease in acetylcholine-induced relaxation. Aspirin and dipyridamole did not reduce it.     

Mediation by nitric oxide of neurally-induced human cerebral artery relaxation

Human cerebral artery strips relaxed in response to non-adrenergic, non-cholinergic vasodilator nerve stimulation by electrical pulses or nicotine. The relaxation response was abolished by treatment with N^G-nitro-L-arginine, a nitric oxide synthase inhibitor; the inhibitory effect was reversed by L-, but not D-, arginine. Nitric oxide-induced relaxation was unaffected. These findings support the hypothesis that nitric oxide plays a crucial role, possibly as neurotransmitter, in transmitting information from vasodilator nerve to smooth muscle in human cerebral arteries.     

Volume-dependent regulation of the respiratory burst of activated human neutrophils

The effect of incubation medium osmolality on the respiratory burst of human neutrophils was studied using luminol-dependent chemiluminescence (CL) as an indicator of burst activity. Neutrophils were stimulated with N-formyl-Met-Leu-Phe (FMLP), phorbol-12-myristate-13-acetate (PMA), the calcium ionophore A23187, thermoaggregated IgG (IgG_n), and opsonized zymosan (OZ). It was shown that increasing the osmolality of the incubation medium from 320 up to 420 mosM decreased the A231870 and OZ-induced CL responses by 90%. Under the same conditions PMA-, FMLP- and IgG_n-induced CL responses were decreased by 40–60%. A decrease of osmolality to 200 mosM resulted in a 2–3 fold decrease of the A23187-, PMA- and FMLP-induced CL and in a 60–80% increase of OZ- and IgG_n-induced CL. It is suggested that osmolality-mediated alteration of cell volume is an important mechanism for regulating neutrophil activity.     

A transbasisphenoidal approach for selective occlusion of the middle cerebral artery in rats

Summary The authors report a new model of focal cerebral ischemia following a selective occlusion of the middle cerebral artery in rats, without additional insults of hypoxia, hypotension and handling of carotid and vertebral arteries, as required in previously described models.     

Blood pressure and impairment of endothelium-dependent relaxation in spontaneously hypertensive rats

Correlation between hypertension and impairment of endothelium-dependent relaxation was demonstrated using aortae from certain strains of rats with various levels of spontaneous hypertension. It was also observed that the impairment of endothelium-dependent relaxation is the secondary change due to hypertension, and the level and duration of hypertension is the determinant factor of the impairment.     

Blood pressure and impairment of endothelium-dependent relaxation in spontaneously hypertensive rats

Summary Correlation between hypertension and impairment of endothelium-dependent relaxation was demonstrated using aortae from certain strains of rats with various levels of spontaneous hypertension. It was also observed that the impairment of endothelium-dependent relaxation is the secondary change due to hypertension, and the level and duration of hypertension is the determinant factor of the impairment.     

Chemotaxis of human neutrophils against gravity: A new method

Summary A new method is described in which human neutrophils were made to migrate upward and against gravity. Thus, the possible effect of gravity on cell migration and consequent detachment of cell after migration have been eliminated.Supported in part by N.I.H. grants: No.HL19628-03, No. DE04898, No. CA24215 and No.RR05493).     

The destruction of lymphoma cells by activated human lymphocytes

Résumé Les lymphocytes frais du sang humain, après culture avec des cellules lymphoÏdes de lignées continues exposées aux rayons X, peuvent tuer ces cellules ou celles d'une autre lignée lymphoÏde. Les lymphocytes humains stimulés par culture avec la phytohaemagglutinine n'ont pas cet effet.     

Dense core vesicles in cerebral cortex of the human fetus.

The present study clearly demonstrates that by the 15th week of gestation dense core vesicles appear within the human cerebral cortex. These vesicles can be identified within axon cylinders, axon growth cones, and axon synaptic terminals. The role of these vesicles is speculative, yet, their very presence at this early fetal stage seems to reflect an advanced state of synaptic vesicle development.     

The function of intimal longitudinal smooth muscles of the human coronary artery

Bundles of smooth muscles in the intimal layer of the human coronary artery contracted in a longitudinal direction on the application of vasoactive substances. The data indicate that the human coronary artery contracts not only transversely but also longitudinally.     

Heterogeneous responses of canine basilar and middle cerebral arteries to serotonin at normal and high CO2 tension.

The responses of basilar arteries (BAs) to serotonin were attenuated by high PCO2 (86 +/- 1 mm Hg) and the pH matched acidotic solution (PCO2 37 +/- 1 mm Hg), whereas the responses of middle cerebral arteries (MCAs) were not. High PCO2 decreased the basal tone of both arteries, and the changes in basal tone due to high PCO2 were not influenced by 3 x 10(-7) M imipramine, 10(-5) M pargyline or 10(-4) M aspirin. The responses of BAs to serotonin were attenuated by high PCO2 in the presence of imipramine, pargyline and aspirin. The responses of MCAs to serotonin were not influenced by high PCO2 in the presence of pargyline and aspirin, but attenuated by high PCO2 in the presence of imipramine.     

The effects of two neutral polymers on the geometry and deformability of the human erythrocyte.

Polyvinylpyrrolidone and dextran decrease cellular deformability. Changes in volume do not wholly account for the changes which imply a stiffening of the plasma membrane. The effects differ from those induced by charged macromolecules.     

Hemoglobin causes both endothelium-dependent and endothelium-independent contraction of the pig coronary arteries, independently of an inhibition of EDRF effects

Hemoglobin is widely used as an inhibitor of EDRF effects. Hemoglobin contracts pig coronary arteries in vitro. However, during this contraction, effects of substance P and bradykinin which act via the EDRF are not inhibited. This means that the hemoglobin contraction is not caused by inhibition of the EDRF. This contraction is caused by a substance released from the endothelium, and by eicosano?ds released from the smooth muscles.     

Proposed effects of brain noradrenaline on neuronal activity and cerebral blood flow during REM sleep.

We propose that the observed increases of both neuronal activity and cerebral blood flow seen throughout the brain during REM sleep may be effects of decreased central noradrenaline release.     

The effects of non-thermal radio frequency radiation on human lymphocytes in vitro

Zusammenfassung Hypotonische Streuungen, die in radiobestrahlten Kulturen menschlicher Lymphozyten Chromosomenaberrationen erkennen liessen, traten dort siebenmal häufiger auf als in unbestrahlten Kulturen; offenbar das Ergebnis einer wärmefreien Bestrahlung. Trotz des Fehlens bedeutender Unterschiede in der DNA-Synthese, der Zellvergrösserung und im mitotischen Index zwischen bestrahlten und unbestrahlten Kulturen kam es zu Aberrationen.