scholarly journals Perioperative Prophylactic Chemotherapy of Echinococcus granulosus: Determination of Minimum Effective Length of Albendazole Therapy in In Vitro Protoscolex Culture

HPB Surgery ◽  
1990 ◽  
Vol 2 (3) ◽  
pp. 159-164 ◽  
Author(s):  
D. H. Taylor ◽  
D. L. Morris ◽  
K. S. Richards
Keyword(s):  
Continuous Culture ◽  
Echinococcus Granulosus ◽  
Effective Length ◽  
Culture Period ◽  
Free Medium ◽  
Continuous Therapy ◽  
Prophylactic Chemotherapy ◽  
Drug Free

Protoscoleces of Echinococcus granulosus were cultured in vitro in 500, 250 or 100 μg/1 albendazole sulphoxide for 1, 3, 7, 10, 14d and then ‘recued’ (R) into drug-free medium for the remainder ofthe culture period. Successful minimum lengths of therapy were much longer than for praziquantel, and only at 500μg/1 was the 10dR treatment as effective as continuous therapy for 28d. Treatment with 100 μg/1 both in continuous culture and in the ‘R’ experiments was ineffective over a 35d period. The results are compared with those from similar experiments using praziquantel.

Determination of the minimum time of praziquantel therapy required for the in vitro treatment of protoscoleces of Echinococcus granulosus

1988 ◽  
Vol 62 (1) ◽  
pp. 10-14 ◽  
Author(s):  
D. L. Morris ◽  
D. H. Taylor ◽  
D. Daniels ◽  
E. M. Riley ◽  
K. S. Richards
Keyword(s):  
Drug Treatment ◽  
Echinococcus Granulosus ◽  
Drug Concentration ◽  
Drug Efficacy ◽  
Free Medium ◽  
Drug Concentrations ◽  
Drug Free ◽  
In Vitro Treatment

ABSTRACTOvine and equine protoscoleces of Echinococcus granulosus were cultured for 26 days with our without praziquantel and viability assessed, by eosin exclusion, for cultures in various drug concentrations (50, 250 and 500 μg/l) and periods of exposure (1, 3 or 7 days (d)) before removing/‘rescuing’ to drug-free medium. Drug efficacy was proportional to drug concentration and to length of exposure. At higher drug concentrations shorter exposures were required to produce the effect of continuous drug treatment, 1d therapy at 500 μg/l killing 96% ovine protoscoleces by day 14 whereas 7d therapy at 50 μg/l was required to produce a similar effect. Equine protoscoleces appeared marginally less susceptible than those of ovine origin. The relevance of the results in the need for peri-operative prophylaxis against spilled protoscoleces in man is discussed.

Effect of praziquantel on the strobilar development of Mesocestoides corti in vitro

2000 ◽  
Vol 74 (4) ◽  
pp. 295-299 ◽  
Author(s):  
L. Britos ◽  
L. Domínguez ◽  
R. Ehrlich ◽  
M. Marín
Keyword(s):  
Adult Worm ◽  
Quantitative Data ◽  
Experimental Approach ◽  
Developmental Process ◽  
Adult Stage ◽  
Mechanisms Of Action ◽  
Early Event ◽  
Free Medium ◽  
Drug Free

AbstractThe effect of praziquantel (PZQ) on the strobilar development of the cyclophyllidean cestode Mesocestoides corti was explored. Mesocestoides corti larvae were cultivated under conditions reported to favour their differentiation to the adult stage. Parasites were exposed to 0.1 μg ml-1 PZQ for 16 h and subsequently transferred to drug-free medium. The ocurrence of segmentation — an early event of the larval somatic differentiation to the adult worm — was considered as quantitative data. This phenomenon was evidenced earlier in worms transiently exposed to PZQ with respect to control cultures. Moreover, the rate of segmentation of drug-treated worms at the end of the experiment almost doubled that of control worms. To date, no similar effect on any cestode developmental process has been reported for an anthelmintic drug. In the light of the existing knowledge and understanding of PZQ mechanisms of action, the proposed experimental approach could contribute to the elucidation of pathways and mechanisms involved in cestode strobilar development.

scholarly journals Reduction of the incidence of polyspermic penetration into porcine oocytes by pretreatment of fresh spermatozoa with adenosine and a transient co-incubation of the gametes with caffeine

Reproduction ◽  
2004 ◽  
Vol 128 (6) ◽  
pp. 789-800 ◽  
Author(s):  
Hiroaki Funahashi ◽  
Raquel Romar
Keyword(s):  
Incubation Period ◽  
Culture Period ◽  
Sperm Cells ◽  
Free Medium ◽  
Exposure Treatment ◽  
Pretreatment Effect ◽  
The Mean ◽  
Sperm Nuclei

To reduce the incidence of polyspermic penetration, the effects of transient exposure of washed fresh spermatozoa to caffeine in a brief co-culture in vitro fertilization (IVF) system were examined. A pretreatment effect of spermatozoa with adenosine was also examined. When 5 mmol caffeine/l was supplemented during periods of co-culture and additional culture periods until 8 h after insemination, a shortened co-incubation period of gametes (30 denuded oocytes in 100 μl modified Medium 199-suspended spermatozoa at 2.5 ×105 sperm/ml) from 30 to 5 min increased the monospermy rate in total mature oocytes examined. The number of spermatozoa binding to the zona surface was significantly lower in oocytes co-cultured for 5 min (33.1 ± 2.2) than 8 h (207.6 ± 13.7). A limited exposure of gametes to 5 mmol caffeine/l only during a transient co-culture period for 5 or 30 min significantly reduced the mean number of sperm cells that penetrated into the oocyte. Transient exposure of spermatozoa to caffeine for only 5 min increased the percentage of capacitated cells but not acrosome-reacted cells, as compared with a whole exposure treatment. Furthermore, preincubation of spermatozoa with 10 μmol adenosine/l for 90 min increased both the incidence of capacitated cells and the monospermy rate and consequently decreased the number of sperm cells that penetrated into the oocyte. In conclusion, these results have demonstrated that a new transient co-incubation IVF system, in which denuded oocytes are co-cultured with spermatozoa in medium containing caffeine for 5 to 30 min and then continuing the culture in caffeine-free medium, will reduce the incidence of polyspermic penetration. Preincubation of fresh spermatozoa with adenosine before the transient co-incubation IVF can also improve the monospermy rate. Furthermore, asynchrony in the morphology of sperm nuclei in polyspermic oocytes was reduced by the pretreatment with adenosine and a brief exposure to caffeine.

scholarly journals Serial Daptomycin Selection Generates Daptomycin-Nonsusceptible Staphylococcus aureus Strains with a Heterogeneous Vancomycin-Intermediate Phenotype

2008 ◽  
Vol 52 (12) ◽  
pp. 4289-4299 ◽  
Author(s):  
Ilana Lopes Baratella da Cunha Camargo ◽  
Hui-Min Neoh ◽  
Longzhu Cui ◽  
Keiichi Hiramatsu
Keyword(s):  
Staphylococcus Aureus ◽  
Teichoic Acid ◽  
Regulatory System ◽  
Intermediate Phenotype ◽  
Free Medium ◽  
Atp Binding Cassette Transporter ◽  
Drug Free ◽  
Isogenic Strains ◽  
Derivative Strain

ABSTRACT In order to better understand the mechanism of daptomycin resistance, we generated a daptomycin-nonsusceptible derivative strain, strain 10*3d1 (MIC = 3.0 μg/ml), by in vitro exposure of methicillin-resistant Staphylococcus aureus strain N315ΔIP (MIC = 0.5 μg/ml) to daptomycin. We also obtained a daptomycin-susceptible phenotypic revertant strain, strain 10*3d1-10 (MIC = 1.0 μg/ml), by passaging 10*3d1 in drug-free medium for 10 days. The resultant triple-isogenic strains were analyzed for their phenotypes and gene expression by microarray analysis. No significant differences in the membrane fluidities of 10*3d1 and 10*3d1-10 compared to the membrane fluidity of N315ΔIP were observed. Resistant strain 10*3d1 had the highest membrane potential, followed by strains 10*3d1-10 and N315ΔIP. The vancomycin and teicoplanin MICs also increased. Teichoic acid genes (tagA, tagG), mprF encoding lysyl-phosphatidylglycerol, and cls encoding cardiolipin synthase were downregulated in 10*3d1 and 10*3d1-10. The vraF and vraG genes, which encode ATP binding cassette transporter proteins, were upregulated in 10*3d1. The vraSR two-component regulatory system was upregulated, and electron microscopy revealed that the cell wall of 10*3d1 was significantly thicker than that of the parental strain. Taken together, daptomycin exposure selected a daptomycin-nonsusceptible strain with a phenotype similar to that of heterogeneous vancomycin-intermediate S. aureus and a transcription profile that partially overlapped that of heterogeneous vancomycin-intermediate S. aureus.

scholarly journals Cytofluorometric studies on the action of podophyllotoxin and epipodophyllotoxins (VM-26, VP-16-213) on the cell cycle traverse of human lymphoblasts.

1975 ◽  
Vol 66 (3) ◽  
pp. 521-530 ◽  
Author(s):  
A Krishan ◽  
K Paika ◽  
E Frei
Keyword(s):  
Cell Cycle ◽  
Dna Content ◽  
Major Part ◽  
Lymphoid Cells ◽  
Free Medium ◽  
Drug Concentrations ◽  
Cell Cycle Block ◽  
Drug Free ◽  
Number Of Cells

Flow microfluorometric analysis of human lymphoid cells exposed in vitro to cytostatic concentrations of podophyllotoxin (0.01-5 mug/ml for 24 h) shows that a major part of this population (40-60%) has the DNA content of cells in the G2-M part of the cell cycle, and that approximately 60% of these cells are arrested in mitosis. Although a similar pattern of DNA distribution is seen in cultures exposed to cytostatic concentrations of VM-26(0.01 mug/ml) and VP--16-213(0.1 mug/ml), no mitotic cells are seen in these cultures. Exposure to higher concentrations: of VM-26 (0.1 mug/ml) and VP-16-213 (1.0 mug/ml) inhibits cell cycle traverse, and after 24 hr of exposure a major part of the population is arrested with the DNA content of cell in the S part of the cell cycle. Exposure to higher drug concentrations leads to a reduction in the number of cells with the late S-G2DNA content. Whereas the cell cycle block induced by cytostatic concentrations of podophyllotoxin (0.01 mug/ml) is readily reversible by reincubation of cells in drug-free medium, cells blocked by VM-26 and VP-16-213 are unable to resume cell-cycle traverse under similar conditions.

MAPK/ERK kinase (MEK) signalling is required for resumption of meiosis in cultured cumulus-enclosed pig oocytes

Zygote ◽  
2003 ◽  
Vol 11 (1) ◽  
pp. 7-16 ◽  
Author(s):  
B. Meinecke ◽  
C. Krischek
Keyword(s):  
Germinal Vesicle ◽  
Cumulus Cells ◽  
Mek Inhibitor ◽  
Free Medium ◽  
Germinal Vesicle Breakdown ◽  
Nuclear Maturation ◽  
Mitogen Activated Protein ◽  
Drug Free ◽  
Medium Culture

Resumption of meiosis of mammalian oocytes is facilitated by the maturation promoting factor (MPF) and accompanied by activation of mitogen activated protein kinases (MAPK) which are phosphorylated by the MAPK kinase (MEK). In this study we examined the effects of PD 98059, which inhibits the activity of MEK, on in vitro maturation of pig oocytes. Cumulus-oocyte complexes (COCs) were cultured in the presence or absence of the drug (50 μM) for various time periods. To elucidate the influence of cumulus cells, COCs were first cultured in inhibitor-free medium, subsequently denuded, and incubated further in PD 98059 supplemented medium. Reversibility of drug action as tested following PD 98059 treatment of COCs by transferring them to drug-free medium. Culture of COCs in medium supplemented with PD 98059 prevents resumption of nuclear maturation in the majority of COCs. This inhibition was reversible and accompanied by a non-activation of both MAP and MPF. Addition of the MEK inhibitor to extracts of in vitro matured oocytes revealed that the kinase activities were not directly influenced by the inhibitor, suggesting a link between MAP and MPF kinases. Preincubation of COCs in inhibitor-free medium for 6 h followed by further culture of COCs or denuded oocytes in the presence of PD 98059 for various periods resulted in elevated MAP and MPF kinase activities, indicating an early and transient MEK signalling in the oocyte itself. These results support the idea that MAP and MPF are involved in the induction of germinal vesicle breakdown in porcine oocytes.

1196 Use of a novel continuous culture fermentor system for in vitro determination of enteric methane output from ruminants

2016 ◽  
Vol 94 (suppl_5) ◽  
pp. 574-574
Author(s):  
A. I. Roca-Fernandez ◽  
S. L. Dillard ◽  
M. D. Rubano ◽  
R. J. Tillmann ◽  
K. J. Soder
Keyword(s):  
Continuous Culture ◽  
Enteric Methane

scholarly journals Effects of individual fatty acids on glucose uptake and glycogen synthesis in soleus muscle in vitro

2000 ◽  
Vol 279 (3) ◽  
pp. E577-E584 ◽  
Author(s):  
Alison L. Thompson ◽  
Megan Y.-C. Lim-Fraser ◽  
Edward W. Kraegen ◽  
Gregory J. Cooney
Keyword(s):  
Fatty Acids ◽  
Glucose Transport ◽  
Soleus Muscle ◽  
Glycogen Synthesis ◽  
Free Medium ◽  
Impaired Insulin ◽  
Chain Acyl ◽  
Control Response

Soleus muscle strips from Wistar rats were preincubated with palmitate in vitro before the determination of insulin-mediated glucose metabolism in fatty acid-free medium. Palmitate decreased insulin-stimulated glycogen synthesis to 51% of control in a time- (0–6 h) and concentration-dependent (0–2 mM) manner. Basal and insulin-stimulated glucose transport/phosphorylation also decreased with time, but the decrease occurred after the effect on glycogen synthesis. Preincubation with 1 mM palmitate, oleate, linoleate, or linolenate for 4 h impaired glycogen synthesis stimulated with a submaximal physiological insulin concentration (300 μU/ml) to 50–60% of the control response, and this reduction was associated with impaired insulin-stimulated phosphorylation of protein kinase B (PKB). Preincubation with different fatty acids (all 1 mM for 4 h) had varying effects on insulin-stimulated glucose transport/phosphorylation, which was decreased by oleate and linoleate, whereas palmitate and linolenate had little effect. Across groups, the rates of glucose transport/phosphorylation correlated with the intramuscular long-chain acyl-CoA content. The similar effects of individual fatty acids on glycogen synthesis but different effects on insulin-stimulated glucose transport/phosphorylation provide evidence that lipids may interact with these two pathways via different mechanisms.

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