PMID- 10633176
OWN - NLM
STAT- MEDLINE
DCOM- 20000713
LR  - 20190702
IS  - 0027-5107 (Print)
IS  - 0027-5107 (Linking)
VI  - 464
IP  - 1
DP  - 2000 Jan 3
TI  - Evaluation of thresholds for benomyl- and carbendazim-induced aneuploidy in 
      cultured human lymphocytes using fluorescence in situ hybridization.
PG  - 41-51
AB  - Threshold mechanisms of activity for mutagenic agents have been debated for some 
      time, especially for those substances which induce aneuploidy by inhibiting 
      mitotic spindle function. No observed effect levels (NOELs) or "practical 
      thresholds" have been demonstrated for several aneugens both in vitro and in vivo 
      generally by either counting chromosomes in metaphase preparations or by 
      observing micronuclei. Recently, fluorescence in situ hybridization (FISH) has 
      proven to be a sensitive and useful technique for the assessment of aneuploidy at 
      low concentrations. Using binucleate human lymphocytes coupled with FISH, we have 
      been able to characterize a threshold mechanism of action for two spindle 
      inhibitors, benomyl and its active metabolite, carbendazim. Test chemicals were 
      added 24 h following culture initiation. After a further 20 h, cytochalasin B was 
      added, and cells were harvested 28 h later (72 h post initiation). The 
      distribution of chromosomes between the nuclei of binucleate cells was evaluated 
      by fluorescence microscopy for the simultaneous detection of centromeres labeled 
      with FITC (green) or Cy-3 (red). Six human chromosomes were investigated in pairs 
      (1 and 8, 11 and 18, and X and 17). Abnormalities were classified as chromosome 
      loss (including centromeric positive micronuclei), chromosome gain, 
      non-disjunction, or polyploidy. Dose-response data were generated over a range of 
      closely spaced concentrations at 100 ng/ml intervals. The threshold, defined as 
      the lowest "effect" concentration using statistical methods, was determined for 
      each chromosome. Non-disjunction proved to be the most sensitive endpoint for the 
      detection of aneuploidy occurring at higher frequencies and lower concentrations. 
      Results for the six chromosomes demonstrated similar dose-response data which 
      included a series of concentrations with no statistically significant increase 
      above background, followed by a second range of higher concentrations with a 
      statistically significant, concentration-dependent increase. Nearly equimolar 
      threshold concentrations were determined for benomyl- and carbendazim-induced 
      non-disjunction.
FAU - Bentley, K S
AU  - Bentley KS
AD  - DuPont Agricultural Products, Wilmington, DE 19880-0038, USA. 
      karin.s.bentley-1@usa.dupont.com
FAU - Kirkland, D
AU  - Kirkland D
FAU - Murphy, M
AU  - Murphy M
FAU - Marshall, R
AU  - Marshall R
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - Netherlands
TA  - Mutat Res
JT  - Mutation research
JID - 0400763
RN  - 0 (Benzimidazoles)
RN  - 0 (Carbamates)
RN  - 0 (Fungicides, Industrial)
RN  - H75J14AA89 (carbendazim)
RN  - TLW21058F5 (Benomyl)
SB  - IM
MH  - Adult
MH  - *Aneuploidy
MH  - Benomyl/*toxicity
MH  - Benzimidazoles/*toxicity
MH  - *Carbamates
MH  - Cells, Cultured
MH  - Dose-Response Relationship, Drug
MH  - Female
MH  - Fungicides, Industrial/*toxicity
MH  - Humans
MH  - In Situ Hybridization, Fluorescence
MH  - Lymphocytes/cytology/drug effects
MH  - Micronucleus Tests
EDAT- 2000/01/14 09:00
MHDA- 2000/07/15 11:00
CRDT- 2000/01/14 09:00
PHST- 2000/01/14 09:00 [pubmed]
PHST- 2000/07/15 11:00 [medline]
PHST- 2000/01/14 09:00 [entrez]
AID - S1383571899001655 [pii]
AID - 10.1016/s1383-5718(99)00165-5 [doi]
PST - ppublish
SO  - Mutat Res. 2000 Jan 3;464(1):41-51. doi: 10.1016/s1383-5718(99)00165-5.