Effects of a xanthine derivative, propentofylline, on local cerebral blood flow and glucose utilization in the rat.

The effects of the xanthine derivative propentofylline [3-methyl-1-(5'-oxohexyl)-7-propylxanthine] were measured on local cerebral blood flow and glucose utilization in the rat using quantitative autoradiographic techniques. A dose of 0.5 mg/kg/min i.

Sulphoevernan, a polyanionic polysaccharide, and the narcissus lectin potently inhibit human immunodeficiency virus infection by binding to viral envelope protein.

Sulphoevernan is a sulphated alpha-1----3, 1----4 polyglucan (Mr 20,000) with a helical structure. This compound effectively inhibits both human immunodeficiency virus type 1 (HIV-1) and type 2 infection of cells in vitro at concentrations around 0.5 micrograms/ml.

Effect of propentofylline on the biochemical lesion of the rat brain in aluminium-induced neurotoxicity.

Acute and chronic administration of Al-gluconate (12.7% Al) at the concentration of 1 mg/kg produces edema in the rat brain, as reflected by the increase in water and Na+ content. The permeability for Evans blue is also increased, which indicates the opening of the blood-brain barrier.

The effect of early postnatal hypoxia on the regional cerebral utilization of glucose in adult rats.

The purpose of this study was to establish if there are any later changes in the local cerebral energy metabolism after exposing 1-day-old rats for 5 days (10 hr daily) to hypobaric hypoxia (pO2 = 10.5 kPa). For this study the 2-[14C]deoxyglucose method for the determination of the regional utilization of glucose in the rat brain was employed.

Age-dependent stimulation of assembly and of membrane-association of polysomes in rat brain after treatment with xanthine derivatives in vivo.

A new pharmacological approach is described to change the structural state of polyribosomes in old rats. It is shown that the ratio of free to membrane-bound polysomes in rat brain increases significantly depending on age (immature animals, 1.40; mature and old rats, 1.

Differential effects of methylxanthines on local cerebral blood flow and glucose utilization in the conscious rat.

The aim of this study was to test the effects of the three "classical" methylxanthines, theophylline, caffeine and theobromine, on local cerebral blood flow and glucose utilization. Equimolar doses (1.6 mumol/kg/min i.

[Energy metabolism in the brain].

In this review of brain energy metabolism, the utilization of glucose as the sole energy source in the normal brain is described and presented in a schematic form. Important reactions concerned with the synthesis and degradation of the energy carrier in the cell, ATP, are also noted. Changes in energy metabolism with acute oxygen deficiency are shown in the example of rat brain energy metabolism during 30 seconds of nitrogen breathing (significant decrease of phosphocreatine, ATP, total adenine nucleotides and adenylate energy charge).

Uptake of adenosine by isolated bovine cortex microvessels.

The uptake of adenosine is studied in microvessels isolated from a bovine cortex. The KM value for adenosine uptake is 1.92 microM and the Vmax is 1.

Effect of theophylline administration on ketone bodies level in rat plasma and brain.

Administration of theophylline (100 mg/kg b.w. p.

The effect of 1-(5'-oxohexyl)-3-methyl-7-propyl-xanthine on the respiratory activity of the rat brain mitochondria.

The effect of 1-(5'-oxohexyl)-3-methyl-7-propyl-xanthine (HWA 285) on the respiration and oxidative phosphorylation in mitochondria isolated from normal (CM), ischemic (IsM) and postischemic (PIsM) rat brain was investigated. After the administration of 10 mg/kg HWA 285 p.o.

Transport of 2-deoxy-D-[3H]glucose in microvessels isolated from bovine cerebral cortex.

Microvessels were isolated from a bovine cortex and the transport of glucose was investigated by using 2-deoxy-D-[3H]glucose (2-DG). The apparent Km for 2-DG transport was 118 microM and therefore indicates a significant high affinity for the substrate. The inhibition of 2-DG uptake by D-glucose showed an apparent Ki of 222 microM.

Cyclic nucleotide phosphodiesterases in normal and malignant human tissues.

Biopsy samples were obtained from tumor tissue and surrounding normal tissue from the same organs of the same patients in 25 patients. Adequate studies could be performed on all parameters in 18 tissue pairs: 12 malignant melanomas, 4 sarcomas, and 2 others. Significantly higher levels of cAMP low affinity phosphodiesterases were found in the tumors as compared to the controls.

[The effect of pentoxifylline on the Ca2+-induced potassium efflux and on the ATPase-activity of erythrocytes (author's transl)].

The efflux of K+ from aged human erythrocytes is regulated by Ca2+: 5--100 mumol/l Ca2+ stimulate and 1--5 mmol/l Ca2+ inhibit K+-efflux. In fresh erythrocytes Ca2+ is virtually without effect on transport of K+. 3,7-Dimethyl-1-(5-oxohexyl)-xanthine (pentoxifylline) (5.

The role of biochemistry in drug research.

The present and the future role of biochemistry in the search for a new therapeutic agent is reviewed. It is stated that the great importance of the various disciplines of biochemistry, including pathobiochemistry and pharmacological biochemistry, is presently recognized, and the involvement of biochemistry in drug research is increasing. Biochemistry at the present time and in the future will utilize the already known basic biological principles for the new development of new and more useful medicines.

Cyclic 3',5'-adenosine monophosphate phosphodiesterase (cAMP PDE) and cyclic 3',5'-guanosine monophosphate phosphodiesterase (cGMP PDE) in microvessels isolated from bovine cortex.

It was established that microvessels of a bovine cortex exhibit significant cyclic 3',5'-adenosine monophosphate phosphodiesterase (cAMP PDE) and cyclic 3',5'-guanosine monophosphate phosphodiesterase (cGMP PDE) activities. These activities are dependent on the presence of Mg2+. Absence of Ca2+ was virtually without effect.

Influence of theophylline on concentrations of cyclic 3',5'-adenosine monophosphate and cyclic 3',5'-guanosine monophosphate of rat brain.

The influence of theophylline (2.5--100 mg/kg p.o.

On the influence of pentoxifylline on the permeability of rat erythrocytes for methyl-O-glucose.

In a series of experiments it was established that in the presence of pentoxifylline (Trental), methyl-O-glucose permeates rat erythrocyte membrane significantly more than in untreated control experiments. Pentoxifylline itself, apparently does not permeate erythrocyte membrane. It is possible that some of the therapeutic effects of pentoxifylline can be related to the facilitation of red blood cell membrane permeability for glucose.

[The influence of pentifylline and theophylline on reaction kinetics on rat brain ATPase stimulatable by catecholamines (author's transl)].

The effects of 1-hexyl-3,7-dimethyl-xanthine (pentifylline, Cosaldon) and theophylline on rat brain Na+-, K+-, Mg2+ ATPase activities were investigated in in vitro experiments. It was established that pentifylline inhibits catecholamine sensitive ATPase in a dose dependent manner. Theophylline was without effect.

On the biochemical mechanism of action of 1-propyl-3-methyl-7-(5-hydroxy-hexyl)-xanthine (HWA 153), a new bronchospasmolytically active methyl xanthine derivative.

1-Propyl-3-methyl-7-(5-hydroxy-hexyl)-xanthine (HWA 153) is a new bronchospasmolytic agent with a significant influence on the cAMP system of lungs and bronchi. In in vitro experiments HWA 153 inhibits cAMP phosphodiesterase (PDE) isolated from bovine bronchi more than does theophylline. HWA 153 is (in conc.

Influence of pentifylline on brain metabolism of normal and anoxic rats.

1-Hexyl-3,7-dimethyl-xanthine (pentifylline) increases significantly (1 h after oral administration of 25 mg/kg) the adenosine triphosphate and the total adenine nucleotide pool in the brain of normal rats and rats subjected to nitrogen breathing for 30 s. An increase in glycogen and in pyridine nucelotides (NAD+ + NADH2) were also noted. The results indicate that pentifylline shows a tendency toward normalizing or "economizing" the brain metabolism.

Effect of anti-inflammatory agent on L-glutamine-D-fructose-6-phosphate transaminase.

The enzyme L-glutamineD-fructose-6-phosphate aminotransferase (EC 2.6.1.