scholarly journals Resistance of Aspergillus niger Tiegh. to the effect of amide anesthetics

2021 ◽  
Vol 10 (1) ◽  
pp. 86-91
Author(s):  
Vadim Aleksandrovich Isaichkin ◽  
Ekaterina Sergeevna Selezneva ◽  
Evgeniy Sergeevich Korchikov
Keyword(s):  
Aspergillus Niger ◽  
Adaptive Response ◽  
Genetic Information ◽  
Low Dose ◽  
Wide Distribution ◽  
High Dose ◽  
Mycelium Growth ◽  
Direct Exposure ◽  
Anesthetic Solution ◽  
Series Of Experiments

The wide distribution of Aspergillus in nature is determined by their ability to adapt in the conditions of development of anthropogenic biocoenoses. Micromycetes survive due to rapid growth, intensive reproduction and labile metabolism, causing various kinds of damage to the substrates on which they were due to certain circumstances. However, it is noted that in the process of adaptation, many Aspergillus change physiologically, i.e. without changing the genetic information and heredity of this organism. These features of Aspergillus make them indispensable in model experiments allowing to assess the effects of xenobiotics even in micro doses and the ability to adapt to them. In this regard, it is interesting to investigate anesthetics widely used in surgery. Some of them have shown antibacterial activity, but their antifungal activity remains unknown. The authors investigated the ability of Aspergillus niger Tiegh. to adapt to the effects of certain amide anesthetics: lidocaine, ropivacaine and bupivacaine. Two series of experiments were carried out. In the first one the effect of anesthetics was investigated at concentrations of 0,001; 0,01 and 0,1 mg/ml per growth, number of colonies and sizes of spores and conidiophores; in the second one A. niger Tiegh. spores from a culture grown in a environment containing an anesthetic solution at a concentration of 0,001 mg/ml were germinated on nutrient medium with anesthetics at a concentration of 1 mg/ml. It was discovered that anesthetics affect differently the germination of spores and the formation of colonies of A. niger Tiegh. The maximum toxicity was shown by ropivacaine, significantly reducing the number of colonies, the minimum by bupivacaine. It was discovered that ropivacaine and bupivacaine inhibit mycelium growth more than lidocaine. All investigated anesthetics at selected concentrations do not affect reliably the size of spores and conidiophores. The study of preadaptation caused by a low dose of anesthetics showed that the number of colonies in preadapted cultures after exposure at a high dose of 1 mg/ml significantly increased compared to direct exposure at a dose of 1 mg/ml. It can be argued that the observed changes in the number of colonies are an adaptive response of A. niger Tiegh. to the action of anesthetics. The diameter of colonies after preadaptation was significantly less than with direct exposure at a dose of 1 mg/ml (p 0,05), that is we observe the effect of cumulation. Possible mechanisms of the observed effect, including hormesis, are discussed.

Lack of High-Dose Radiation Mediated Prostate Cancer Promotion and Low-Dose Radiation Adaptive Response in the TRAMP Mouse Model

2013 ◽  
Vol 180 (4) ◽  
pp. 376 ◽  
Author(s):  
M. D. Lawrence ◽  
R. J. Ormsby ◽  
B. J. Blyth ◽  
E. Bezak ◽  
G. England ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Mouse Model ◽  
Adaptive Response ◽  
Low Dose ◽  
High Dose ◽  
Low Dose Radiation ◽  
Tramp Mouse ◽  
Dose Radiation

scholarly journals Protection of mice by living Vi and O vaccines against death caused by Salmonella paratyphi C

1957 ◽  
Vol 55 (4) ◽  
pp. 513-526 ◽  
Author(s):  
G. T. L. Archer ◽  
J. L. Whitby
Keyword(s):  
Low Dose ◽  
Positive Culture ◽  
Acute Intoxication ◽  
High Dose ◽  
Single Experiment ◽  
Series Of Experiments ◽  
Set Up ◽  
True Infection ◽  
Relationship Of ◽  
Dose Levels

In seeking a more satisfactory test than the conventional mouse-protection tests for the assessment of typhoid-paratyphoid vaccines in relation to their O and Vi antigens, it was decided to undertake a series of experiments with vaccines containing the somatic antigens of Salmonella paratyphi C and to use this organism to challenge mice thus immunized. Salm. paratyphi C contains the same Vi antigen as Salm. typhi and moreover it is capable of giving rise to a true infection in mice in contrast to the acute intoxication which follows a fatal dose of Salm. typhi.Large doses, of the order of 100 × 106, of this paratyphoid organism injected intraperitoneally into mice resulted in acute intoxication with death in 24–72 hr., similar in every way to the picture with typhoid bacilli, but when the dose was reduced 100-fold or more an infective illness was set up which after an interval of 5–10 days or more, during which the organisms multiply freely in the tissues, terminated fatally. Typhoid bacilli do not produce a true infection in mice.Living vaccines were prepared of Salm. typhi Ty6S (an almost pure Vi strain) and Salm. cholerae-suis (contains the same O-antigen complex as Salm.paratyphi C). These were used separately, and in combination, to immunize different batches of mice by the subcutaneous route against a subsequent intraperitoneal challenge with a Vi-positive culture of Salm. paratyphi C at both high- and low-dose levels. The different challenge doses were to assess the relative values of the 0 and Vi components in protecting against intoxication (high dose) and infection (low dose), respectively.Against intoxication pure Vi vaccines were almost as effective as Vi + O vaccines, whereas pure O vaccines gave little or no protection.Against fatal infection the combined Vi + O vaccine offered good protection and the pure O vaccine was but little inferior, whereas the pure Vi vaccine appeared to be without significant effect.Quite small doses of Salm. paratyphi C administered by the intra-gastric route can give rise to a general infection in mice, but in order to obtain consistent results much larger doses were found necessary (about 300 x 106 organisms). Mice immunized with the same three vaccines and subsequently challenged by the intragastric route with this large dose showed significant protection throughout. The combined, O + Vi, vaccine did not appear to have any advantage over the pure O vaccine, but both were markedly superior to the pure Vi vaccine. Further experiments on the same lines are however necessary to see if the results obtained in this single experiment are reproducible.The relationship of the above findings to the evaluation of agents employed in man for the prophylaxis of enteric fever and the need for further experimental work of a similar nature are discussed.We wish to thank Dr F. Kauffmann for strains of Salm. paratyphi C, Lt-Col. T. E. Field, whose results we have freely quoted, and Dr S. Peto for advice on statistical evaluation of our results.

Hormesis, resveratrol and plant-derived polyphenols: some comments

2011 ◽  
Vol 30 (12) ◽  
pp. 2027-2030 ◽  
Author(s):  
Salvatore Chirumbolo
Keyword(s):  
Risk Assessment ◽  
Dose Response ◽  
Adaptive Response ◽  
Low Dose ◽  
High Dose ◽  
Low Doses ◽  
General Behaviour

Hormesis is a dose–response phenomenon, usually present in plants and animals, characterized by a low-dose stimulation and high-dose inhibition, often resulting in typical U-shaped or J-shaped curves. Hormesis has become an interesting model for toxicology and risk assessment, as it has been described for several nature-derived phytochemicals but also because this adaptive response to stressors might hide an underlying more general behaviour of cell towards low doses.

Acetaminophen: Neonatal hepatotoxicity due to late pregnancy exposure

1987 ◽  
Vol 45 ◽  
pp. 718-719
Author(s):  
G.A. Miranda ◽  
M.A. Arroyo ◽  
C.A. Lucio ◽  
M. Mongeotti ◽  
S.S. Poolsawat
Keyword(s):  
Low Dose ◽  
Fetal Liver ◽  
Late Pregnancy ◽  
Toxic Chemicals ◽  
Control Group ◽  
High Dose ◽  
Over The Counter ◽  
Liver And Kidney ◽  
Neonatal Liver ◽  
Childbearing Women

Exposure to drugs and toxic chemicals, during late pregnancy, is a common occurrence in childbearing women. Some studies have reported that more than 90% of pregnant women use at least 1 prescription; of this, 60% used more than one. Another study indicated that 80% of the consumed drugs were not prescribed, and of this figure, 95% were “over-the-counter” drugs. Acetaminophen, the safest of all over-the-counter drugs, has been reported to induce fetal liver necrosis in man and animals and to have abortifacient and embryocidal action in mice. This study examines the degree to which acetaminophen affects the neonatal liver and kidney, when a fatty diet is simultaneously fed to the mother during late pregnancy.Timed Swiss Webster female mice were gavaged during late pregnancy (days 16-19) with fat suspended acetaminophen at a high dose, HD = 84.50 mg/kg, and a low dose, LD = 42.25 mg/kg; a control group received fat alone.

Evaluation of hippocampus in rhesus monkeys after chronic (1-year) inhalation exposure to marijuana: I. Electron microscopy

1990 ◽  
Vol 48 (3) ◽  
pp. 398-399
Author(s):  
A.M. Andrews ◽  
S.W. Wilson ◽  
A.C. Scallet ◽  
S.F. Ali ◽  
J. Bailey ◽  
...  
Keyword(s):  
Synaptic Vesicles ◽  
Rhesus Monkeys ◽  
Low Dose ◽  
Inhalation Exposure ◽  
Synaptic Cleft ◽  
High Dose ◽  
Withdrawal Time ◽  
Treatment Groups ◽  
Ultrastructural Evidence ◽  
Male Rhesus

Exposure of rhesus monkeys (Macaca mulatta) to marijuana via inhalation or to intravenous delta-9-tetrahydrocannabinol (THC), reportedly caused ultrastructural evidence of increased synaptic width. Chronic marijuana smoke in a single rhesus monkey examined after a six month withdrawal time caused ultrastructure changes in the septal, hippocampal and amygdala regions; the synaptic cleft was widened, electron opaque material was found in the cleft and in the pre- and postsynaptic regions, with some clumping of the synaptic vesicles. The objective of our study was to assess neuropathological alterations produced by chronic inhalation of marijuana smoke.Nineteen male rhesus monkeys, 3-5 years of age and weighing 3-8 kg, were divided into four treatment groups: a) sham control, b) placebo smoke (7 days/ week) c) low dose marijuana (2 times/week with 5 days/week sham) and d) high dose marijuana (7 times/week). A smoke exposure consisted of smoke from one cigarette (2.6% THC) burned down to 10 mm butt length. Smoke was administered via smoke generator (ADL II, Arthur D. Little, Inc. Cambridge, MA) and nose-mouth only masks (local production) equipped with one-way valves.

Benefit/Risk Profile of Combined Antiplatelet Therapy with Ticlopidine and Aspirin

1991 ◽  
Vol 65 (05) ◽  
pp. 504-510 ◽  
Author(s):  
Raffaele De Caterina ◽  
Rosa Sicari ◽  
Walter Bernini ◽  
Guido Lazzerini ◽  
Giuliana Buti Strata ◽  
...  
Keyword(s):  
Platelet Function ◽  
Low Dose ◽  
Bleeding Time ◽  
Ex Vivo ◽  
Stable Coronary Artery Disease ◽  
High Dose ◽  
Single Drug ◽  
Before And After ◽  
Serum Thromboxane ◽  
Artery Disease

SummaryTiclopidine (T) and aspirin (ASA) are two antiplatelet drugs both capable of prolonging bleeding time (BT), with a different mechanism of action. A synergism in BT prolongation has been reported and is currently considered an argument for not recommending their combination. However, a profound suppression of platelet function might be a desirable counterpart of a marked prolongation of BT, with a possible use in selected clinical situations. We therefore studied ex vivo platelet function (aggregation by ADP 0.5-1-2.5 μM; adrenaline 0.75-2.5 μM; collagen 1.5-150 μg/ml; arachidonic acid 1 mM; PAF 1 μM; adrenaline 0.17 μM + ADP 0.62 μM; serum thromboxane ([TX]B2 generation) and BT (Mielke) in 6 patients with stable coronary artery disease receiving such combination. Patients underwent sequential laboratory evaluations at baseline, after 7 days of T 250 mg b.i.d., before and after the intravenous administration of ASA 500 mg, respectively, and, finally, after a minimum of 7 days of sole ASA oral administration (50 mg/day). The experimental design, therefore, allowed a comparison of T and ASA effects (2nd and 4th evaluation), and an assessment of the combination effect (3rd evaluation). Platelet aggregation in response to all doses of ADP was depressed more by T than by ASA. Conversely, responses to adrenaline, and arachidonate were affected more by ASA than by T. For all other agents, differences were not significant. T + ASA combination was more effective (p <0.05) than either treatment alone in depressing responses to high-dose collagen (% over control, mean ± SEM: T: 95 ± 3; ASA: 96 ± 5; T + ASA: 89 ± 4). Serum TXB2 (basal, ng/ml: 380 ± 54) did not change with T (372 ± 36), dropped to <1 ng/ml on ASA injection and slightly re-increased to 9.1 ± 3.1 ng/ml on oral low-dose ASA. BT (basal 7.4 ± 0.6 min) was affected similarly by T (9.2 ± 0.8) or ASA (9.7 ± 0.9) alone, but increased to 15.0 ± 0.7 min on combination treatment (106% increase over control). Thus, the strong synergism in BT prolongation by ASA-T combination has a counterpart in the inhibition of platelet function in response to strong stimuli such as high-dose collagen, not otherwise affected significantly by single-drug treatment. This effect is a possible rationale for the clinical evaluation of T + ASA combination.

Intensive Initial Oral Anticoagulation and Shorter Heparin Treatment in Deep Vein Thrombosis

1984 ◽  
Vol 52 (03) ◽  
pp. 276-280 ◽  
Author(s):  
Sam Schulman ◽  
Dieter Lockner ◽  
Kurt Bergström ◽  
Margareta Blombäck
Keyword(s):  
Deep Vein Thrombosis ◽  
Oral Anticoagulation ◽  
Dose Group ◽  
Low Dose ◽  
Clinical Signs ◽  
Coagulation Factor ◽  
High Dose ◽  
Vein Thrombosis ◽  
Heparin Treatment ◽  
Deep Vein

SummaryIn order to investigate whether a more intensive initial oral anticoagulation still would be safe and effective, we performed a prospective randomized study in patients with deep vein thrombosis. They received either the conventional regimen of oral anticoagulation (“low-dose”) and heparin or a more intense oral anticoagulation (“high-dose”) with a shorter period of heparin treatment.In the first part of the study 129 patients were randomized. The “low-dose” group reached a stable therapeutic prothrombin complex (PT)-level after 4.3 and the “high-dose” group after 3.3 days. Heparin was discontinued after 6.0 and 5.0 days respectively. There was no difference in significant hemorrhage between the groups, and no clinical signs of progression of the thrombosis.In the second part of the study another 40 patients were randomized, followed with coagulation factor II, VII, IX and X and with repeated venograms. A stable therapeutic PT-level was achieved after 4.4 (“low-dose”) and 3.7 (“high-dose”) days, and heparin was discontinued after 5.4 and 4.4 days respectively. There were no clinical hemorrhages, the activity of the coagulation factors had dropped to the same level in both groups at the time when heparin was discontinued and no thromboembolic complications occurred.Our oral anticoagulation regimen with heparin treatment for an average of 4.4-5 days seems safe and reduces in-patient costs.

Effects of Aspirin and Sulfinpyrazone on Thromboxane and Prostacyclin Synthesis in Rabbits

1979 ◽  
Author(s):  
J McDonald ◽  
A Cerskus ◽  
M Ali
Keyword(s):  
Arachidonic Acid ◽  
Platelet Aggregation ◽  
Low Dose ◽  
High Dose ◽  
Prostacyclin Synthesis

Arachidonic acid (AA) or collagen were infused into rabbits causing intravascular platelet aggregation with thrombocytopenia, hypotension and death. Thromboxane and prostacyclin synthesis were measured by radioimmunoassay of plasma TXB2 and 6-keto-PGF1α. The effects of pretreatement with aspirin (ASA) or sulfinpyrazone(SPZ) were assessed.Death in drug-treated rabbits was always associated with elevations of plasma TXB2(1-40 ng/ml) and of 6-keto-PGF1α(1-20 ng/ml). Collagen produced only small elevations of plasma TXB2 compared to AA but protection by ASA correlated better with inhibition of TXB2 and 6-keto-PGF1α synthesis than with inhibition of aggregation. Low dose ASA produced less inhibition of prostacyclin synthesis than high dose ASA but was less effective in preventing thromboxane synthesis and death.

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