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At least 37 records · Page 2Linked to original sources
PubMed1979

Evidence for Na-retaining humoral agents and vasoconstrictor humoral agents in hypertension-prone Dahl 'S' rats. Prevention of NaCl-induced hypertension in Dahl 'S' rats with thiazide.

Dahl 'S' rats become hypertensive when fed a high NaCl diet but remain normotensive on a low NaCl diet. Dahl 'R' rats are normotensive on either diet. For a given perfusion pressure, isolated 'S' kidneys excrete 50% less Na than 'R' kidneys. Therefore, we searched for a Na-retaining hormone in 'S' rats. Kidneys were isolated without ischemia from normal rats and were continuously perfused at 125 mm Hg with blood from Dahl 'S' and 'R' rats, all on low NaCl diets. Kidneys and adrenals had been extirpated from the perfusing rats. During 15 min of perfusion, the isolated 'normal' kidneys excreted a mean of 164 micronEq of Na/min/100 g during 26 perfusion experiments with blood from 'R' rats. The 'normal' kidneys excreted a mean of 84 micronEq Na during 24 perfusions with blood from 'S' rats. Thus, the normal kidneys excreted half as much Na when perfused with 'S' blood compared with 'R' blood (p less than 0.02). Seemingly, a Na-retaining humoral agent is present in the blood of 'S' rats on a low Na diet in the absence of renal and adrenal tissue. Moreover, in these normal kidneys, perfusion with 'S' blood induced a 16% higher renal vascular resistance than perfusion with 'R' blood (p less than 0.01), indicating vasoconstricting agents in 'S' blood. However, the Na-retaining humoral effect in 'S' blood could lead to Na retention by 'S' kidneys in vivo, which could partially account for the susceptibility of 'S' rats to NaCl hypertension. Hypertension in Dahl 'S' rats can be almost completely prevented by concomitant treatment with thiazide diuretics which act mainly on the kidney to facilitate Na excretion. This result is in agreement with the hypothesis that a shift in the pressure natriuresis curve, reducing Na excretion for a given arterial pressure, is partially responsible for the great sensitivity to NaCl hypertension in the 'S' rat. The Na-retaining hormone may contribute to this shift.

Animals↗
PubMed1976

[Resistance of the causative agents of European foulbrood to oxidative disinfecting agents].

Test materials and naturally infected materials from beehives were used to check the resistance of the European foulbrood causative agents to the disinfection agents vofasteril, performic acid, and iosan and iosan-CCT. It was that Bac. alvei spores are destroyed by 1.5 per cent solution of vofasteril for less than an hour's time and by 1.62 per cent solution of performic acid and 4 per cent iosan--for 4 hours. Bac. paraalvei are still more sensitive: they are destroyed by performic acid and iosan for 1--2 hours.. Sodium dodecylsulfate at the rate of 1 per cent, added to solutions of vofasteril and performic acid, speed up the disinfection action up to four times.

Animals↗
PubMed1976

[Modification of the immune reaction by antigen-immunosuppressive-agent conjugates. I. Tentative hypothesis for the induction of antigen-specific suppression by antigen-immunosuppressive-agent conjugates].

The most important mechanisms for the specific depression of immune reactions--immuno-tolerance, enhancement, transfer of antibodies, drug induced tolerance, immunological suicide, application of antibody-toxin-complexes--are discussed with regard to their possible application in the clinical practice. A tentative hypothesis for induction of antigen specific suppression is proposed, basing on the use of antigen-immunosuppressive agent-conjugates (AIC). Antigen binding lymphocytes are supposed to bind the AIC and to pick them up through endocytosis. After breakdown of the AIC in the lymphoid cells the free immunosuppressive agent can become effective causing damage to the specific cell clones.

Animals↗
PubMed1976

Studies with prazosin--a new effective hypotensive agent. I. Open clinical study of prazosin in combination with other antihypertensive agents.

The use of prazosin, a new antihypertensive agent, in combination with other conventional antihypertensive agents, in a hospital outpatient clinic setting, was studied in a mixed group of 104 hypertensive patients. Prazosin effectively lowered the lying and standing blood pressure in the majority of patients whose blood pressure was uncontrolled or poorly controlled before the introduction of prazosin. Blood pressure control was adequately maintained in patients who were given prazosin because of the occurrence of side effects of other antihypertensive medication. No significant change in renal function attributable to prazosin was found in patients with normal or impaired renal function.

Adult↗
PubMed1977

Methods for the study of antidiarrheal agents. Study of commonly used protective and adsorbent agents.

Several agents were employed to induce diarrhea in squirrel monkeys: (1) diarrhaogenic diets, (2) various doses of cholera toxin, (3) prostaglandin derivatives, (4) bile, (5) lactulose, (6) phenolphthalein, (7) castor oil. Kaolin, pectin, Kaopectate and placebo were used as antidiarrheal treatment. Evaluation was based on (a) frequency, (b) consistency, (c) total and dry weight of the stools, and (d) electrolyte loss. The spectrum of procedures employed appeared to be suitable for the evaluation of antidiarrheal agents of the protective and adsorbent class.

Animals↗
PubMed1979

Vocalization response to close-arterial injection of bradykinin and other algesic agents in guinea pigs and its application to quantitative assessment of analgesic agents.

A method for determining the vocalization response to algesic agents in conscious guinea pigs is described. Retrograde injection of small amounts of algesic agents into the femoral artery caused transient but obvious vocalization response in a dose-dependent manner. The vocal sound was converted into electrical signals and the envelope of the sound obtained by a peak detector circuit was recorded on an ink-writing oscillograph. The area of the vocalization response circumscribed by a base line and the envelope tracing of the vocal sound was also recorded. Bradykinin, kallidin, acetylcholine (ACh) and nicotine caused the vocalization response, while substance P, histamine, bethanechol, methacholine, serotonin, kallikrein and prostaglandins E1 and E2 caused no or little response. No detectable tachyphylaxis to bradykinin, ACh and nicotine was observed. The pretreatment with hexamethonium abolished the response induced by ACh or nicotine but not the response induced by bradykinin. These results suggest that the paravascular pain receptor of the femoral artery excited by ACh is nicotinic in character. Subcutaneous injection of morphine, pentazocine, diclofenac and aminopyrine inhibited the vocalization response induced by bradykinin in a dose-dependent manner.

Acetylcholine↗
PubMed1978

Antitumor agents XXX: Evaluation of alpha-methylene-gamma-lactone-containing agents for inhibition of tumor growth, respiration, and nucleic acid synthesis.

Evidence is presented that a number of sesquiterpene lactones isolated from plants and synthesized pyrimidines containing the alpha-methylene-gamma-lactone moiety are potent inhibitors of Walker 256 carcinosarcoma and Ehrlich ascites tumor growth and marginal inhibitors of P-388 lymphocytic leukemia and Lewis lung tumor growth. In vitro aerobic basal respiration and oxidative phosphorylation processes of Ehrlich ascites cells were inhibited by these agents as well as deoxyribonucleic acid polymerase and thymidylate synthetase enzymatic activities. These studies indicate that the alpha-methylene-gamma-lactone moiety, the beta-unsubstituted cyclopentenone ring, and the alpha-epoxycyclopentanone system are the essential moieties for inhibition of these biochemical parameters.

Animals↗
PubMed1979

Antimicrobial spectrum of triclosan, a broad-spectrum antimicrobial agent for topical application. II. Comparison with some other antimicrobial agents.

The antimicrobial activity of 5-chloro-2(2,4-dichlorophenoxy) phenol (triclosan, one of the active ingredients of Logamel, Ciba-Geigy) was compared in vitro with that of other antimicrobials exclusively or occasionally used as topical agents in dermatology: hexachlorophene, clioquinol, chlorquinaldol. gentamicin, neomycin, nystatin, econazole, clotrimazole and salicylic acid. Upon determination of the MICs for 53 strains of aerobic and anaerobic bacteria, yeasts and fungi, triclosan was found to display a high degree of activity against most of the test organisms and to have the broadest spectrum of chemotherapeutically significant antimicrobial activity of the substances tested.

Administration, Topical↗
PubMed1976

[Modification of the immune reaction by antigen-immunosuppressive-agent conjugates. II. Immunogenicity of antigen-immunosuppressive-agent conjugates].

The maintenance of specific immunogenicity of carrier proteins is a necessary condition for the successful use of antigen-immunosuppressive agent-conjugates (AIC) for an antigen specific suppression of the immune response. The experimental results indicate that, in spite of the binding of 6-mercaptopurine (6-MP) and toluyl (T) to bovine gamma globulin (BGG) and human serum albumin (HSA), the carrier specific immunogenicity is not significantly altered. The intradermal application of 6-MP-BGG and T-BGG emulsified with complete Freund's adjuvant in guinea pigs results, in all cases, in a well detectable anti BGG hemagglutination and precipitation titer. This kind of immunization leads also to a formation of anti 6-mercaptopurine and anti new antigen determinants (NAD's) antibodies.

Animals↗
PubMed1976

[Modification of the immune reaction by antigen-immunosuppressive-agent conjugates. IV. Studies on the specific suppression of humoral immune response in guinea pigs by antigen-immunosuppressive-agent conjugates].

Bovine gamma globulin (BGG) antigens were modified by the binding of 6-mercaptopurine and toluyl residues, and their influence on the humoral immune response in guinea pigs was investigated. The antigen-immunosuppressive agent-conjugates (AIC) were different, depending on the method used for their preparation and the number of coupled residues per one molecule of BGG. Conjugates denoted as MPI-n-BGG were prepared by special chemical binding of corresponding thioisocyanates. MPII-n-BGG were synthetized by acetylation, and MPIII-n-BGG conjugates, by reductive alkylation. Pretreatment of guinea pigs with MPIII-19-BGG, MPII-16-BGG resulted in a stimulatory effect on the subsequent humoral immune response induced by BGG application. A significant suppressive influence was detectable if the animals had been pretreated with MPII-6-BGG and MPI-26-BGG. MPI-13-BGG and MPI-36-BGG had no effect on the later induced anti-BGG antibody formation. The immune response against a second antigen (human serum albumin) was not influenced by this kind of pretreatment of the animals. Therefore it seems justified to conclude that both stimulatory and suppressive effects seen here were antigen specific and that both the method for chemical modification and the number of coupled 6-MP residues are very important for their effectivity.

Agglutination↗
PubMed1978

Immunological response to infection with human reovirus-like agent: measurement of anti-human reovirus-like agent immunoglobulin G and M levels by the method of enzyme-linked immunosorbent assay.

The report describes the development of an enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies against the human reovirus-like agent of infantile gastroenteritis (HRVLA). This ELISA system proved to be four times as sensitive as the standard anti-HRVLA fluorescent-antibody assay and ten times as sensitive as the standard anti-HRVLA complement fixation assay. In addition, the ELISA was capable of determining immunoglobulin G (IgG) and IgM subclasses of anti-HRVLA antibody using a single dilution os serum. With this assay, it was discovered that 11 of 21 infected children had anti-HRVLA IgM in their acute sera before the appearance of anti-HRVLA IgG. ELISA is a useful tool in the evaluation of immunological response to HRVLA infection.

Adult↗
PubMed1975

[Antiviral chemotherapeutic agents. XVIII. Adamantane derivatives of amphetamine. Their potential interest as autonomic and antiparkinson agents].

Adamantane isologs of amphetamine, methamphetamine and pheniprazine and several derivatives were synthesized in order to study the influence of their more pronounced lipophilic characteristics on their biological properties. A preliminary examination of their toxicity, antiviral, CNS stimulant and antiparkinson activity is described. The adamantyl amphetamine, which proved active, will be further studied.

Adamantane↗
PubMedDate not supplied

Antimicrobial agents from higher plants. Additional alkaloids and antimicrobial agents from Thalictrum rugosum.

Further study of mother-liquors from ethanolic extracts of Thalictrum rugosum resulted in the identification or partial characterization of 10 alkaloids, bringing the total to 17 characterized in our work on this plant. Five of the new alkaloids were active in vitro against microorganisms. Structures, based upon spectroscopic properties and chemical transformations, are proposed for a new bisbenzylisoquinoline alkaloid named thalrugosaminine, and a protopine alkaloid named protothalipine. A phenanthrene base (thaliglucinone), an aporphine (thalphenine), and three protoberberine bases (columbamine, thalifendine and deoxythalidastine) were identified; three very minor bases of unknown identify were partially characterized.

Alkaloids↗