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PubMed1975

Tetramethylenedisulphotetramine: an inhibitor of gamma-aminobutyric acid induced depolarization of the isolated superior cervical ganglion of the rat.

Tetramethylenedisulphotetramine (TETS), a potent convulsant, antagonized the depolarizing action gamma-aminobutyric acid (GABA) in the isolated superior cervical ganglion of the rat. No antagonism of responses to the cholinomimetic agent carbachol was observed. TETS appeared to act in a non-competitive manner and was reversible. Its activity profile was comparable to that of bicuculline in the same tissue except that the latter appears to act in a competitive manner.

Aminobutyrates↗
PubMed1977

Effects of small-particle aerosols of rimantadine and ribavirin on arterial blood pH and gas tensions and lung water content of A2 influenza-infected mice.

The respiratory pathophysiology of A2 influenza infection was studied in mice treated with small-particle aerosols (SPA) of rimantadine or ribavirin. Untreated infections in mice resulted in survival rates of 15% or less and were characterized by (i) severe hypoventilation (decreased P(O2) and increased P(CO2)), (ii) compensated respiratory acidosis (increased P(CO2) and HCO(3) (-), with normal pH), (iii) pneumonia with increased ratio of wet/dry lung weight, and (iv) hypothermia. Treatment with SPA of rimantadine (21 mg/kg per day for 4 days) beginning 72 h after virus challenge significantly improved survival rate (80%) but failed to alter lung pathology from that found in infected, untreated mice. Rimantadine treatment decreased somewhat the severity of hypoventilation, respiratory acidosis, lung wet weight, hypothermia, and lung virus titers from that observed in infected, untreated mice. SPA of ribavirin (26 mg/kg per day for 4 days) initiated 6 h after SPA exposure of mice to virus significantly improved survival rate (95%) and reduced lung virus titers and lung pathology. Gas exchange and pulmonary edema in ribavirin-treated, infected mice were significantly improved over those of infected, untreated controls. The mechanisms for increased survival rates induced by SPA of rimantadine remain uncertain, since increased survival rates could not be ascribed entirely to improvements in lung functions. In contrast, however, ribavirin treatment appeared to improve survival rates by reducing major lung pathology and pulmonary dysfunction. This was probably mediated through the antiviral effects of ribavirin.

Adamantane↗
PubMed1979

Inhibition of in vitro proliferative responses of human lymphocytes by rimantadine hydrochloride.

Rimantadine hydrochloride (alpha-methyl-1-adamantanemethylamine hydrochloride) inhibits the in vitro proliferative response of human peripheral blood lymphocytes to mitogenic and antigenic stimulation. Addition of drug (25 micrograms/ml) at the initiation of 5-day cultures suppressed the responses to phytohemagglutinin, pokeweed mitogen, and concanavalin A by 25, 65, and 90%, respectively. Similarly, responses to streptokinase-streptodornase, tetanus toxoid, and A2/Aichi influenza vaccine were significantly inhibited at concentrations as low as 10 micrograms of rimantadine per ml. Viability studies on 5-day cultures using trypan blue exclusion showed no significant difference between drug-treated and untreated controls. Furthermore, addition of drug on day 3 of 8-day cultures, at a time when the majority of cells had undergone blastogenesis, greatly suppressed the responses to these mitogens. These studies suggest that, in addition to its antiviral action, rimantadine interferes with the generation of cellular immune responses.

Adamantane↗
PubMed1975

[The effect of 1-adamantyl radicals on curare-like activity].

In the series of polymethylene bis-ammonium salts R(CH3)2N(CH2)NN(CH3)2R . 2I--(R=CH3 or Ad) a study was made of the significance of hydrophobic 1-adamantyle radicals (1--Ad) for curare-like activity. Administration of 1-ad radicals into the cation groups of depolarizing agents (n-9--11) altered their mechanism of action and diminished their activity. Attachmeni of 1-Ad radicals to the both quarternary nitrogen atoms of the antidepolarizing agents (n=5 and 6) sharply increased their curare-like activity. The data obtained pointed to the presence of hydrophobic zones in the cholinoreceptors of skeletal muscles.

Adamantane↗
PubMed1978

[Effect of cross-linking agents on mechanical properties of a fluid resin (author's transl)].

Effect of several cross-linking agents added to MMA on the mechanical properties of self-cured fluid resins was studied. The cross-linking agents were 2,2-bis (4-methacryloxyethoxyphenyl) propane, trimethylolpropane trimethacrylate, neopentylglycol dimethacrylate, hexamethyleneglycol dimethacrylate and 1,2-polybutadiene. Their concentrations in MMA were 1,3,5 and 10 wt%. Measured mechanical properties were Brinell hardness, tensile strength, impact strength and transverse strength. The best composition was 5% neopentylglycol dimethacrylate in MMA among studied samples. Microscopic observation of the surface after tensile test suggested that diffusibility of cross-linking agents into PMMA powder affected the mechanical properties. Mechanical properties of both matrix and powder, and their adhesion at the interface had influence upon the mechanical properties of resins processed by powder-liquid method.

Acrylates↗
PubMedDate not supplied

[Study of the effect of rimantadine on the course of mixed viral-bacterial infection in albino mice].

The results of the study of rimantadine effectiveness in a viral-bacterial infection in white mice caused by a mixture of influenza A2 virus (10 LD50) and hemolytic streptococcus group A (350 million bacteria). The drug showed no prophylactic or therapeutic effect in the mixed infection, whereas in influenza infection in the animals which served as a positive control rimantadine had marked antiviral activity (P less than 0.001). It is assumed that the lack of the drug effectiveness against the mixed infection is due to the formation in the animals of virus-microbe complexes which are conducive to an increase of infectious virus titers and virus resistance to various treatments.

Adamantane↗
PubMedDate not supplied

Metabolic reduction of 1-nitrosoadamantane by rabbit liver microsomes. Properties of a C-nitroso reductase system.

Washed microsomes from rabbit liver reduced 1-nitrosoadamantane to N-hydroxy-1-aminoadamantane in the presence of a cofactor solution under aerobic conditions; no further reduction of the hydroxylamino metabolite to 1-aminoadamantane (amantadine) occurred. Reduced pyridine nucleotide cofactors are needed for the metabolic reduction. The rate of formation of N-hydroxy-1-aminoadamantane depended upon the microsomal protein content, the time of incubation and the concentration of 1-nitrosoadamantane incubated. The metabolic reduction occurred in air as well as under nitrogen or carbon monoxide. Cupric chloride, mercuric chloride, cysteamine, FAD, and FMN decreased significantly the C-nitroso reductase. The properties of the C-nitroso reductase differed from those of other microsomal reductive pathways.

Adamantane↗