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1.
Clin Microbiol Infect ; 23(12): 924-930, 2017 Dec.
Article in English | MEDLINE | ID: mdl-28529025

ABSTRACT

BACKGROUND: Since 2013, several stool banks have been developed following publications reporting on clinical success of 'faecal microbiota transplantation' (FMT) for recurrent Clostridium difficile infections (CDI). However, protocols for donor screening, faecal suspension preparation, and transfer of the faecal suspension differ between countries and institutions. Moreover, no European consensus exists regarding the legislative aspects of the faecal suspension product. Internationally standardized recommendations about the above mentioned aspects have not yet been established. OBJECTIVE: In 2015, the Netherlands Donor Feces Bank (NDFB) was founded with the primary aim of providing a standardized product for the treatment of patients with recurrent CDI in the Netherlands. Standard operation procedures for donor recruitment, donor selection, donor screening, and production, storage, and distribution of frozen faecal suspensions for FMT were formulated. RESULTS AND DISCUSSION: Our experience summarized in this review addresses current donor recruitment and screening, preparation of the faecal suspension, transfer of the faecal microbiota suspension, and the experiences and follow-up of the patients treated with donor faeces from the NDFB.


Subject(s)
Biological Specimen Banks/organization & administration , Fecal Microbiota Transplantation , Feces , Biological Specimen Banks/standards , Humans , Netherlands
2.
Eur J Neurol ; 21(1): 21-7, 2014.
Article in English | MEDLINE | ID: mdl-23711185

ABSTRACT

BACKGROUND AND PURPOSE: Detection of paroxysmal atrial fibrillation (pAF) after an ischaemic cerebrovascular event is of imminent interest, because oral anticoagulation as a highly effective secondary preventive treatment is available. Whereas permanent atrial fibrillation (AF) can be detected during routine electrocardiogram (ECG), longer detection duration will detect more pAF but might be resource consuming. The current study tried to identify clinical predictors for pAF detected during long-term Holter ECG and clinical follow-up. METHODS: Patients with acute ischaemic stroke were prospectively investigated with an intensified algorithm to detect pAF (7-day Holter ECG, follow-up investigations after 90 days and 1 year). RESULTS: Two hundred and eighty-one patients were included, 44 of whom had to be excluded since they presented with permanent AF and another 13 patients had to be excluded due to other causes leaving 224 patients (mean age 68.5 years, 58.5% male). Twenty-nine (12.9%) patients could be identified to have pAF during prolonged Holter monitoring, an additional 13 (5.8%) after follow-up investigations. Multivariate analysis identified advanced age [odds ratio (OR) 1.05, 95% confidence interval (CI) 1.01-1.08] as well as clinical symptoms >24 h (OR 5.17, 95% CI 1.73-15.48) and a history of coronary artery disease (OR 3.14, 95% CI 1.35-7.28) to be predictive for the detection of pAF. CONCLUSIONS: In acute stroke patients with advanced age, history of coronary artery disease and clinical symptoms >24 h, a prolonged Holter ECG monitoring and follow-up is warranted to identify pAF. This could increase the detection rate of patients requiring anticoagulation and may be able to reduce the risk of recurrent stroke in the case of successful anticoagulation of these patients.


Subject(s)
Algorithms , Atrial Fibrillation/diagnosis , Stroke/complications , Aged , Atrial Fibrillation/complications , Electrocardiography , Electrocardiography, Ambulatory , Female , Humans , Male
3.
Herzschrittmacherther Elektrophysiol ; 22(2): 107-12, 2011 Jun.
Article in German | MEDLINE | ID: mdl-21538162

ABSTRACT

The second most frequent category of syncope is cardiac syncope. In contrast to syncope of noncardiac causes, the 1-year mortality of patients presenting with cardiac syncope without treatment is as high as 33%. Therefore, immediate diagnosis and treatment are necessary. Bradyarrhythmias or tachyarrhythmias are the most common causes of cardiac syncope. In many cases, an initial evaluation including history, physical examination, and electrocardiogram identifies the cause of syncope, so that specific treatment can be initiated immediately. In the remainder of cases, implantable loop recorders are useful to identify arrhythmias, while the presence or absence of structural cardiac disease is diagnosed by echocardiography. Syncope due to arrhythmias is typically treated with implantation of a pacemaker or an implantable cardioverter-defibrillator; treatment of syncope of other cardiac causes requires therapy of the underlying heart disease.


Subject(s)
Arrhythmias, Cardiac/diagnosis , Arrhythmias, Cardiac/prevention & control , Electrocardiography , Hypotension, Orthostatic/diagnosis , Hypotension, Orthostatic/prevention & control , Syncope/diagnosis , Syncope/therapy , Arrhythmias, Cardiac/complications , Diagnosis, Differential , Humans , Hypotension, Orthostatic/complications , Medical History Taking , Physical Examination , Syncope/etiology
4.
Med Hypotheses ; 58(2): 171-6, 2002 Feb.
Article in English | MEDLINE | ID: mdl-11812198

ABSTRACT

Recently it was shown that extracellular ATP, acting through purinergic receptors, has many physiological functions, including opening of Ca(2+)-ion channels, activation and mediation of signal transduction mechanisms as well as activation of the pain sensation. Since electrical stimulation is also known to affect many signal transduction processes as well as the alleviation of pain, we hypothesized that electric stimulation may affect the extracellular release of ATP. We investigated the effects of a small DC electric field (10(1)--10(2) V m(-1) range and with frequencies below 150 Hz) on the release of ATP in vitro (HeLa cells), and on the levels of ATP in vivo (the plasma of healthy volunteers). In HeLa cells ATP release was increased 50 fold, while the total amount of ATP in the cells was increased by 163%. In the plasma a significant decrease (P<0.05) in ATP concentration was seen after electrical stimulation, in all the volunteers. The small DC electric field also affected the cAMP signal transduction system in vitro (HeLa cells and human lymphocytes) and in vivo (human plasma). Decreased levels of cAMP (P<0.05) were seen in HeLa cells and increased levels of cAMP (P<0.05) in isolated human lymphocytes. The cAMP levels in the plasma of the electrically treated volunteers were lower than control values. These results show that the frequency, waveform and signal strength of the applied electric field are suitable for effecting measurable changes on signal transduction in vitro and in vivo.


Subject(s)
Adenosine Triphosphate/metabolism , Receptors, Purinergic P2/metabolism , Adenosine Triphosphate/blood , Cyclic AMP/metabolism , Electric Stimulation , HeLa Cells , Humans , In Vitro Techniques , Lymphocytes/metabolism , Models, Biological , Signal Transduction
5.
Article in English | MEDLINE | ID: mdl-11728168

ABSTRACT

The effects of 20 microg/ml exogenous arachidonic acid (AA) and prostaglandin A(2) (PGA(2)) were evaluated on total tyrosine kinase (TK) activity and tyrosine phosphorylation status in HeLa and MCF-7 cells. AA and PGA(2) increased TK activity in both HeLa and MCF-7 cells. Western blotting employing an anti-phosphotyrosine antibody showed only one protein of approximately 55 kDa (approximately 55 kDa) to be phosphorylated in the MCF-7 cells, while a variety of proteins were phosphorylated in the HeLa cells, including the approximately 55 kDa protein. Amino acid analyses as well as Matrix Assisted Laser Desorption Ionization were conducted on this protein from different cell lines and it was shown to be similar. Comparison to p53 did not show similarities. The identity of this protein needs to be further characterized to help elucidate the signal transduction pathways of AA and PGA(2).


Subject(s)
Arachidonic Acid/pharmacology , Phosphoproteins/analysis , Prostaglandins A/pharmacology , Protein-Tyrosine Kinases/metabolism , Amino Acids/analysis , Animals , Blotting, Western , Cell Line , HeLa Cells , Humans , Kinetics , Phosphorylation , Signal Transduction , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Tumor Cells, Cultured
6.
Med Hypotheses ; 57(2): 224-30, 2001 Aug.
Article in English | MEDLINE | ID: mdl-11461178

ABSTRACT

Successful treatment of various medical complaints with an applied electric field has been reported over the years. The identities of the cellular mechanisms that are influenced by this type of treatment and facilitate the positive effects, remain elusive. A study of many in vitro and in vivo reports revealed that the beneficial effects can be attributed to the activation of membrane proteins, and specifically proteins involved in signal-transduction mechanisms. Not only may the proteins be affected but it is now well established that enhanced Ca(2+)influx, observed to follow electric stimulation of cells, also contributes to many calcium-dependent cellular processes which can be linked to the therapeutic effects discussed in this paper. An hypothesis of the physical changes caused by an applied, relatively small (10(3)to 10(4)V m(-1)range), electric field with low to moderate frequency (below 150 Hz), is postulated.


Subject(s)
Electricity , Membrane Proteins/physiology , Signal Transduction , Animals , Humans
8.
Eur J Cell Biol ; 80(1): 111-8, 2001 Jan.
Article in English | MEDLINE | ID: mdl-11211931

ABSTRACT

Chelidonine is a tertiary benzophenanthridine alkaloid known to cause mitotic arrest and to interact weakly with tubulin. Our interest in chelidonine began when we found it to be a major contaminant of Ukrain, which is a compound reported to be selectively toxic to malignant cells. The effects of chelidonine in two normal (monkey kidney and Hs27), two transformed (Vero and Graham 293) and two malignant (WHCO5 and HeLa) cell lines, were examined. Chelidonine proved to be a weak inhibitor of cell growth, but no evidence for selective cytotoxicity was found in this study. It was confirmed that chelidonine inhibits tubulin polymerisation (IC50 = 24 microM), explaining its ability to disrupt microtubular structure in cells. A G2/M arrest results, which is characterised by abnormal metaphase morphology, increased levels of cyclin B1 and enhanced cdc2 kinase activity. Exposure of all cell lines examined to chelidonine leads to activation of the stress-activated protein kinase/jun kinase pathway (SAPK/JNK).


Subject(s)
Alkaloids/pharmacology , Berberine Alkaloids , Phenanthridines , Signal Transduction/physiology , Tubulin/metabolism , Alkaloids/chemistry , Animals , Benzophenanthridines , CDC2 Protein Kinase/metabolism , Cell Cycle/drug effects , Cell Division/drug effects , Cell Line , Chlorocebus aethiops , Cyclin B/metabolism , Cyclin B1 , HeLa Cells , Humans , Mitogen-Activated Protein Kinase 8 , Mitogen-Activated Protein Kinases/metabolism , Molecular Structure , Polymers , Vero Cells
9.
Cancer Lett ; 160(2): 149-57, 2000 Nov 28.
Article in English | MEDLINE | ID: mdl-11053644

ABSTRACT

Ukrain(TM) has been described as a semisynthetic Chelidonium majus alkaloid derivative, which exhibits selective toxicity towards malignant cells only. Its mechanism of action has hitherto been uncertain. We found that Ukrain(TM) inhibits tubulin polymerization, leading to impaired microtubule dynamics. This results in activation of the spindle checkpoint and thus a metaphase block. The effects of Ukrain(TM) on the growth, cell cycle progression and morphology of two normal, two transformed and two malignant cell lines did not differ. We could thus find no evidence for the selective cytotoxicity previously reported for Ukrain(TM).


Subject(s)
Alkaloids/pharmacology , Antineoplastic Agents, Phytogenic/pharmacology , Tubulin Modulators , Alkaloids/toxicity , Animals , Antineoplastic Agents, Phytogenic/toxicity , Berberine Alkaloids , Cell Cycle , Cell Division/drug effects , Cell Line, Transformed , Chlorocebus aethiops , Fibroblasts/cytology , Fibroblasts/drug effects , Flow Cytometry , Fluorescent Antibody Technique, Indirect , HeLa Cells , Humans , Kidney/cytology , Kidney/drug effects , Papaver , Phenanthridines , Plants, Medicinal , Tubulin/metabolism , Vero Cells
10.
Cancer Lett ; 160(2): 237-41, 2000 Nov 28.
Article in English | MEDLINE | ID: mdl-11053654

ABSTRACT

Ukrain has been described as a semi-synthetic Chelidonium majus alkaloid derivative, consisting of three chelidonine alkaloids combined to triaziridide. We found the actions of Ukrain to be similar to the Chelidonium alkaloids it is prepared from, and therefore became concerned about its chemical integrity. Chemical analyses of Ukrain by thin layer chromatography, high-performance liquid chromatography and liquid chromatography-mass spectrometry was inconsistent with the proposed trimeric structure and demonstrated that at least some commercial preparations of Ukrain consist of a mixture of C. majus alkaloids (including chelidonine).


Subject(s)
Alkaloids/chemistry , Antineoplastic Agents/chemistry , Berberine Alkaloids , Chromatography, High Pressure Liquid , Chromatography, Thin Layer , Mass Spectrometry , Papaver/chemistry , Phenanthridines , Plant Extracts/chemistry , Plants, Medicinal , Powders
11.
Article in English | MEDLINE | ID: mdl-10780872

ABSTRACT

In a previous study, we showed that, of a group of lipids including arachidonic acid (AA), prostaglandins E2 (PGE2) and A2 (PGA2), PGA2 had the most marked effect on the inhibition of cell growth, activation of tyrosine kinase activity, lowering of the number of G1-phase cells, and induction of p53 levels in oesophageal carcinoma (WHCO3) cells. No significant effects by the three lipids were seen in normal monkey kidney cells. In the present study, the effects of the inhibitor of ceramide synthesis, fumonisin B1 (FB1), a metabolite of Fusarium verticillioides (= F. moniliforme) which is implicated in the high incidence of oesophageal cancer, were determined on AA, PGE2 and PGA2 WHCO3 treated cells. In the presence of FB1, the lipid-enhanced tyrosine kinase activity was lowered. Flow cytometric and morphological studies showed that FB1 lowered the marked apoptosis induced by especially PGA2. FB1, however, in combination with AA, PGE2 or PGA2 increased the number of G2/M cells. AA>PGE2>PGA2 alone decreased CDC2-kinase activity, but, in the presence of FB1, CDC2-kinase activity was significantly increased. The PGA2- and AA-induced p53 levels were lowered in the presence of FB1. We concluded that FB1 diminished the cytotoxic effects of the lipids on oesophageal tumour cells.


Subject(s)
Arachidonic Acid/pharmacology , Carboxylic Acids/pharmacology , Cell Cycle/drug effects , Esophageal Neoplasms/pathology , Fumonisins , Prostaglandins/pharmacology , Protein Kinases/metabolism , Animals , Apoptosis/drug effects , CDC2 Protein Kinase/metabolism , Carcinogens, Environmental/pharmacology , Carcinoma, Squamous Cell/enzymology , Carcinoma, Squamous Cell/pathology , Cell Division/drug effects , Dinoprostone/pharmacology , Esophageal Neoplasms/enzymology , Humans , Protein-Tyrosine Kinases/metabolism , Tumor Cells, Cultured , Tumor Suppressor Protein p53/metabolism
12.
Curr Opin Mol Ther ; 2(1): 94-9, 2000 Feb.
Article in English | MEDLINE | ID: mdl-11249657

ABSTRACT

By expression of foreign antigens in attenuated strains derived from bacterial pathogens and in non-pathogenic commensal bacteria, recombinant vaccines are being developed that aim to stimulate mucosal immunity. Recent advances in the pathogenesis and molecular biology of these bacteria have allowed rational development of new and improved bacterial carriers and more effective gene expression systems. These advances have improved the performance and versatility of these delivery systems to induce mucosal immunity to recombinant antigens in animal models. Application of these (improved) technologies for development of human vaccines is still limited and awaits further exploration.


Subject(s)
Immunity, Mucosal , Vaccines, Synthetic/administration & dosage , Animals , BCG Vaccine/administration & dosage , Bacteria/genetics , Bacteria/immunology , Drug Delivery Systems , Genetic Vectors , Humans , Lactobacillus/genetics , Lactobacillus/immunology , Lactococcus lactis/genetics , Lactococcus lactis/immunology , Salmonella/genetics , Salmonella/immunology , Staphylococcus/genetics , Staphylococcus/immunology , Streptococcus/genetics , Streptococcus/immunology , Vaccines, Attenuated/administration & dosage , Vaccines, Attenuated/genetics , Vaccines, Synthetic/genetics , Vibrio cholerae/genetics , Vibrio cholerae/immunology
13.
Cancer Lett ; 150(1): 85-92, 2000 Mar 13.
Article in English | MEDLINE | ID: mdl-10755391

ABSTRACT

Ukrain is alleged to be an effective chemotherapeutic drug which causes minimal side-effects as a result of selective toxicity towards malignant cells only. We previously failed to confirm this claim and found Ukrain to be equally toxic to normal, transformed and malignant cell lines by causing a metaphase arrest. In this study we have found the antimitotic actions of Ukrain to be reversible in low doses in vitro, as shown by flow cytometry and concurrent haematoxylin and eosin stains. We hypothesize that the lack of side-effects found in vivo may be due to the lack of therapeutically effective dosages being administered, therefore enabling cells to overcome the metaphase arrest and survive.


Subject(s)
Alkaloids/pharmacology , Antineoplastic Agents/pharmacology , Mitosis/drug effects , Papaver/chemistry , Plants, Medicinal , Animals , Berberine Alkaloids , Cell Cycle/drug effects , Chlorocebus aethiops , Dose-Response Relationship, Drug , Flow Cytometry , HeLa Cells , Histocytochemistry , Humans , Phenanthridines , Time Factors , Tumor Cells, Cultured/cytology , Tumor Cells, Cultured/drug effects , Vero Cells
14.
J Bacteriol ; 182(1): 30-7, 2000 Jan.
Article in English | MEDLINE | ID: mdl-10613859

ABSTRACT

The replication region of the lactococcal plasmid pCI2000 was subcloned and analyzed. The nucleotide sequence of one 5.6-kb EcoRI fragment which was capable of supporting replication when cloned on a replication probe vector revealed the presence of seven putative open reading frames (ORFs). One ORF exhibited significant homology to several replication proteins from plasmids considered to replicate via a theta mode. Deletion analysis showed that this ORF, designated repA, is indeed required for replication. The results also suggest that the origin of replication is located outside repA. Upstream and divergently transcribed from repA, an ORF that showed significant (48 to 64%) homology to a number of proteins that are required for faithful segregation of chromosomal or plasmid DNA of gram-negative bacteria was identified. Gene interruption and transcomplementation experiments showed that this ORF, designated parA, is required for stable inheritance of pCI2000 and is active in trans. This is the first example of such a partitioning mechanism for plasmids in gram-positive bacteria.


Subject(s)
Bacterial Proteins/genetics , DNA Helicases , DNA Replication/genetics , DNA-Binding Proteins , Lactococcus lactis/genetics , Plasmids/genetics , Proteins/genetics , Trans-Activators , Amino Acid Motifs , Amino Acid Sequence , Bacterial Proteins/metabolism , Base Sequence , Cloning, Molecular , Gene Expression Regulation, Bacterial , Molecular Sequence Data , Open Reading Frames , Proteins/metabolism , Replication Origin , Sequence Homology, Amino Acid
15.
Article in English | MEDLINE | ID: mdl-10582657

ABSTRACT

The effects of exogenous gamma-linolenic acid (GLA), arachidonic acid (AA), prostaglandin E2 (PGE2) and prostaglandin A2 (PGA2) were evaluated on cell growth in two squamous oesophageal carcinoma cell lines, WHCO1 and WHCO3 and normal monkey kidney (NMK) cells. In both cancer cell lines all four compounds inhibited cell growth significantly. Indomethacin (I) alone, or in combination with either GLA or AA, caused marked inhibition of cell growth in WHCO3. Total tyrosine kinase (TK) activity was determined after exposure of all three cell types to the lipid compounds. Negligible differences were observed in TK activity between treated and untreated NMK cells. Small increases were noticed in WHCO1. Marked TK stimulation was observed in WHCO3. Addition of indomethacin to WHCO3 also increased TK activity above control value. Tyrosine phosphorylation status of exposed cells indicated that a band of approximately 55 kDa (approximately 55 kDa) was primarily influenced in both WHCO3 and WHCO1. PGA2 caused a decrease in tyrosine phosphorylation of the approximately 55 kDa protein in all three cell types. Negligible differences were observed in the tyrosine phosphorylation status of the approximately 55 kDa in NMK cells exposed to GLA, AA and PGE2 respectively. However, tyrosine phosphorylation of a number of other proteins (21.5-97.4 kDa) was observed in NMK cells. Flow cytometry studies showed an increase in S phase and decrease in G1 phase in WHCO3 exposed to PGE2 and PGA2. Indomethacin alone, or in combination with GLA and AA, respectively, lead to an increase in G1 and a decrease in S phase. Induction of p53 levels was observed in WHCO3 cells exposed to GLA, AA, PGA2, indomethacin and the combination of indomethacin and GLA or AA.


Subject(s)
Cell Division/drug effects , Esophageal Neoplasms/enzymology , Esophageal Neoplasms/pathology , Fatty Acids, Unsaturated/pharmacology , Protein-Tyrosine Kinases/metabolism , Animals , Arachidonic Acid/pharmacology , Carcinoma, Squamous Cell/enzymology , Carcinoma, Squamous Cell/pathology , Cell Line , Chlorocebus aethiops , Dinoprostone/pharmacology , Flow Cytometry , Humans , Kidney , Phosphorylation , Prostaglandins A/pharmacology , Tumor Cells, Cultured , Tumor Suppressor Protein p53/analysis , Tyrosine/metabolism , gamma-Linolenic Acid/pharmacology
16.
Appl Environ Microbiol ; 65(5): 1891-9, 1999 May.
Article in English | MEDLINE | ID: mdl-10223975

ABSTRACT

A specific fragment of the genome of Tuc2009, a temperate lactococcal bacteriophage, was shown to contain several open reading frames, whose deduced protein products exhibited similarities to proteins known to be involved in DNA replication and modification. In this way, a putative single-stranded binding protein, replisome organizer protein, topoisomerase I, and a methylase were identified. When the genetic information coding for the putative replisome organizer protein of Tuc2009, Rep2009, was supplied on a high-copy-number plasmid vector, it was shown to confer a phage-encoded resistance (Per) phenotype on its lactococcal host UC509.9. The presence of this recombinant plasmid was shown to cause a marked reduction in Tuc2009 DNA replication, suggesting that the observed phage resistance was due to titration of a factor, or factors, required for Tuc2009 DNA replication. Further experiments delineated the phage resistance-conferring region to a 160-bp fragment rich in direct repeats. Gel retardation experiments, which indicated a protein-DNA interaction between this 160-bp fragment and the Rep2009 protein, were performed. UC509.9 strains harboring plasmids with randomly mutated versions of this fragment were shown to display a variable phage resistance phenotype, depending on the position of the mutations.


Subject(s)
Bacteriophages/genetics , Lactococcus lactis/genetics , Lactococcus lactis/virology , Bacteriophages/physiology , Base Sequence , DNA Replication/genetics , DNA, Bacterial/genetics , DNA, Viral/biosynthesis , DNA, Viral/genetics , Genome, Viral , Molecular Sequence Data , Open Reading Frames , Phenotype , Plasmids/genetics
17.
Article in English | MEDLINE | ID: mdl-9849656

ABSTRACT

The effects of gamma-linolenic acid (GLA), the lithium salt of gamma-linolenic acid (LiGLA) and arachidonic acid (AA) were compared at doses of 50 microg/ml for periods of 6 and 24 h on cell cycle progression and apoptosis induction in transformed and in normal cells. In WHCO3 (oesophageal cancer) cells and on primary embryonic equine lung cells, we found LiGLA to be the most effective in apoptosis induction. After 24 h, 94% of the WHCO3 cancer cells and 44% of the primary embryonic equine lung cells exposed to LiGLA were apoptotic. The WHCO3 cancer cells were also very susceptible to the apoptosis-inducing effects of AA (56%) and GLA (44%), whereas the embryonic equine lung cells were much less affected by these two fatty acids. After 6 h exposure to all three compounds, most of the cycling WHCO3 cancer cells were blocked in S-phase. After 24 h treatment, some of the S-phase cells exposed to AA and GLA were apparently able to move into the G2/M phase, the LiGLA exposed cells were mostly apoptotic and no cycling cells were present. The primary embryonic equine lung cells were fairly resistant to the cytotoxic effects of GLA and AA. From our studies we conclude that, although LiGLA was the most toxic to the cancer cells, it is apparently less selective, compared to AA and GLA, in the killing of cancer and normal cells. It would also appear that the lithium might have added to the cytotoxic effects of LiGLA. The mechanism needs to be clarified.


Subject(s)
Arachidonic Acid/pharmacology , Cell Cycle/drug effects , Lithium Compounds/pharmacology , Mitosis/drug effects , gamma-Linolenic Acid/pharmacology , Animals , Apoptosis/drug effects , Cell Line , Embryonic Induction , Flow Cytometry , G1 Phase/drug effects , Horses , Humans , S Phase/drug effects
18.
Cancer Lett ; 122(1-2): 17-23, 1998 Jan 09.
Article in English | MEDLINE | ID: mdl-9464486

ABSTRACT

Melatonin was previously shown to inhibit proliferation of MCF-7 human breast cancer cells. In this study the effect of melatonin on MCF-7 cells was further examined, while human cervical carcinoma (HeLa), osteosarcoma (MG-63) and lymphoblastoid (TK6) cells were tested for the first time. Haemocytometer counts, DNA content, flow cytometry and indirect immunofluorescence for nucleolar proteins, actin and beta-tubulin showed no differences in the growth, cell cycle or morphology between melatonin-exposed and control cells. The direct antiproliferative effect of melatonin thus seems to be confined to a melatonin-responsive subclone of MCF-7 cells and not applicable to the majority of cancer cells.


Subject(s)
Antineoplastic Agents/pharmacology , Melatonin/pharmacology , Breast Neoplasms/pathology , Cell Cycle/drug effects , Cell Division/drug effects , DNA, Neoplasm/analysis , Dose-Response Relationship, Drug , Female , Flow Cytometry , HeLa Cells , Humans , Osteosarcoma/pathology , Tumor Cells, Cultured
19.
J Steroid Biochem Mol Biol ; 62(4): 253-67, 1997 Jul.
Article in English | MEDLINE | ID: mdl-9408079

ABSTRACT

The endogenous metabolite, 2-methoxyestradiol (2ME), is an inhibitor of tubulin polymerization and is therefore toxic to dividing fast-growing tumor cells. Transformed cells are not equally susceptible to the effects of 2ME. In this study the effects of 1-2 microM doses of 2ME on cell cycle progression, apoptosis induction and on p53 levels were evaluated using flow cytometry in cells with different p53 status. No effect of 2ME was seen in normal human skin fibroblast strain HSF43 with wild-type (wt) p53. However, in SV40 T antigen transformed HSF43 cells (line E8T4), 2ME caused a prominent G2/M arrest, with subsequent micronuclei formation followed by apoptosis. Increased p53 levels were present in the G2/M cells. Our results suggest that 2ME, being a microtubule poison, may release the bound p53 from T antigen, and that this p53 may enhance the apoptotic effects. Two lymphoblast cell lines derived from the same donor, TK6, expressing low levels of wt p53, and WTK1, expressing high levels of mutant p53, showed similar moderate responses to 2ME at 37 degrees C. The effects included enhanced apoptosis and a modest G2/M block. No increase in p53 levels was seen. However, at the permissive temperature of 30 degrees C marked increases in apoptosis and a prominent G2/M-phase block, similar to that seen in the E8T4 cells, were present in the WTK1 cells, indicating that the high levels of mutant p53 have now become functional, enhancing the apoptotic effects initiated by 2ME.


Subject(s)
Apoptosis/drug effects , Cell Cycle/drug effects , DNA/metabolism , Estradiol/analogs & derivatives , Tubulin/drug effects , Tumor Suppressor Protein p53/drug effects , 2-Methoxyestradiol , Apoptosis/physiology , Cell Cycle/physiology , Cell Line, Transformed , Estradiol/pharmacology , Estradiol/physiology , Fibroblasts/cytology , Fibroblasts/drug effects , Flow Cytometry , Fluorescent Antibody Technique, Indirect , G2 Phase/drug effects , Humans , Mitosis/drug effects , Tubulin Modulators , Tumor Suppressor Protein p53/analysis
20.
Article in English | MEDLINE | ID: mdl-9150372

ABSTRACT

The effects of arachidonic acid (AA) and gamma-linolenic acid (GLA) on cell cycle progression and apoptosis induction, using flow cytometry, were compared on normal human skin fibroblasts, strain HSF43 with wild type (wt) p53, large T antigen transformed HSF43 cells (line E8T4) with non functional p53, and on two lymphoblast cell lines, TK6 with wt p53 and WTK1 with mutant p53. AA and GLA caused similar dose (50, 75 and 100 microg/ml AA and GLA) and time dependent (24 and 48 h) induction of apoptosis in each cell line. The degrees of the response of the four cell lines were, however, different. The normal HSF43 cells were most resistant against apoptosis induction and the WTK1 cells most susceptible. The apoptosis induction appeared to be independent of functional p53. Cell cycle progression was also similarly affected by AA and GLA in the two cell types. In the fibroblast type cells (HSF43 and E8T4) S- and G2/M-phase arrests were evident after 48 h exposure to AA and GLA, and in the lymphoblast cell lines (TK6 and WTK1) the cells were arrested in the G1-phase.


Subject(s)
Apoptosis/drug effects , Arachidonic Acid/pharmacology , Cell Cycle/drug effects , gamma-Linolenic Acid/pharmacology , Benzimidazoles , Cell Line , Cell Line, Transformed , Cell Nucleus/drug effects , DNA/analysis , Flow Cytometry , Fluorescent Dyes , Humans , Interphase/drug effects , Microscopy, Fluorescence , Mitosis/drug effects
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