http://groups.yahoo.com/group/aspartameNM/message/934
24 recent formaldehyde toxicity [Comet assay] reports:
Murray 12.31.2 rmforall:
FDA Docket 02P-0317 Recall Aspartame as a Neurotoxic Drug

Please post this to the FDA Dockets website.

Rich Murray, MA Room For All rmforall@...
1943 Otowi Road, Santa Fe, New Mexico 87505 USA 505-986-9103

http://groups.yahoo.com/group/aspartameNM/message/910
formaldehyde & formic acid from 11% methanol in aspartame:
Murray: 12.9.2 rmforall

It is certain that high levels of aspartame use, above 2 liters daily
for months and years, must lead to chronic formaldehyde-formic acid
toxicity, since 11% of aspartame (1,120 mg in 2L diet soda, 5.6 12-oz
cans) is 123 mg methanol (wood alcohol), immediately released into the
body after drinking (unlike the large levels of methanol locked up in
molecules inside many fruits), then quickly transformed into
formaldehyde, which in turn becomes formic acid, both of which in
time become carbon dioxide and water-- however, about 30% of the
methanol remains in the body as cumulative durable toxic metabolites of
formaldehyde and formic acid-- 37 mg daily, a gram every month.
If 10% of the methanol is retained as formaldehyde, that would give 12
mg daily formaldehyde accumulation, about 60 times more than the 0.2 mg
from 10% retention of the 2 mg EPA daily limit for formaldehyde in
drinking water.

Bear in mind that the EPA limit for formaldehyde in
drinking water is 1 ppm,
or 2 mg daily for a typical daily consumption of 2 L of water.

http://groups.yahoo.com/group/aspartameNM/message/835
RTM: ATSDR: EPA limit 1 ppm formaldehyde in drinking water July 1999
5.30.2 rmforall

This long-term low-level chronic toxic exposure leads to typical
patterns of increasingly severe complex symptoms, starting with
headache, fatigue, joint pain, irritability, memory loss, and leading to
vision and eye problems and even seizures. In many cases there is
addiction. Probably there are immune system disorders, with a
hypersensitivity to these toxins and other chemicals.

Confirming evidence and a general theory are given by Pall (2002):
http://groups.yahoo.com/group/aspartameNM/message/909
testable theory of MCS type diseases, vicious cycle of nitric oxide &
peroxynitrite: MSG: formaldehyde-methanol-aspartame:
Martin L. Pall: Murray: 12.9.2 rmforall

FASEB J 2002 Sep; 16(11): 1407-17
NMDA sensitization and stimulation by peroxynitrite, nitric oxide, and
organic solvents as the mechanism of chemical sensitivity in multiple
chemical sensitivity. Pall ML. [ 162 references, received 1.3.2 ]
School of Molecular Biosciences, Washington State University,
Pullman, Washington 99164-4660, USA. martin_pall@...

http://groups.yahoo.com/group/aspartameNM/message/915
formaldehyde toxicity: Thrasher & Kilburn: Shaham: EPA: Gold: Murray:
Wilson: CIIN: 12.12.2 rmforall

http://www.drthrasher.org/formaldehyde_1990.html [full text]
Arch Environ Health 1990 Jul-Aug; 45(4): 217-23
Immune activation and autoantibodies in humans
with long-term inhalation exposure to formaldehyde.
Thrasher JD, Broughton A, Madison R.
Thrasher & Associates, Northridge, California.

Arch Environ Health 2001 Jul-Aug; 56(4): 300-11
Embryo toxicity and teratogenicity of formaldehyde. [100 references]
Thrasher JD, Kilburn KH.
Sam-1 Trust, Alto, New Mexico, USA.
http://www.drthrasher.org/formaldehyde_embryo_toxicity.html
[127K full text] http://www.drthrasher.org
Jack D. Thrasher, PhD toxicology@... Sam-1 Trust,
PO Box 874 Alto, New Mexico 88312 505-336-8312 fax 425-675-7379

A millenium surge in formaldehyde toxicity research is
noticable at: http://www.ncbi.nlm.nih.gov/PubMed . The new,
fast, sensitive convenient Comet assay,
which can reveal genetic damage in a single white blood cell,
is being widely used to study the details of cellular damage
from formaldehyde, one of the most potent, cumulative
toxins, produced by the liver from methanol (wood alcohol),
which in turn happens to be 11% of the sweetener
aspartame, used by 200 million, sadly misled by the
incessant industry refrain: "Aspartame is
the most widely tested food additive in history." As a
medical layman, I can safely mention that DNA-protein
crosslinks means: cellular malfunctions and death,
mutations, cancers, and birth defects. I hope some of
these teams will immediately study the white blood
cells of the many aspartame reactors, people who
report a dismaying, bewildering suite of symptoms
after months and years of 1-4 L/day use of diet
drinks, which translates to 56-224 mg methanol. Results
could be quickly and definitively achieved that would be
of immense scientific and public health value.

Can a medical doctor send a sample of his patient's
blood to any of these labs for testing? What would be the
procedure, and cost? Could medical insurance support
innovative diagnostic research of the greatest value, for
the patient and for the public? How much genetic damage
arises from daily use of aspartame?

http://groups.yahoo.com/group/aspartameNM/message/870 full text
Aspartame: Methanol and the Public Interest 1984:
Monte: Murray 9.23.2 rmforall

Dr. Woodrow C. Monte Aspartame: methanol, and the public health.
Journal of Applied Nutrition 1984; 36 (1): 42-54.
(62 references) Professsor of Food Science
Director of the Food Science and Nutrition Laboratory
Arizona State University, Tempe, Arizona 85287
6411 South River Drive #61 Tempe, Arizona 85283-3337
602-965-6938 woody.monte@... [now retired in New Zealand]
The methanol from 2 L of diet soda, 5.6 12-oz cans, 20 mg/can, is
112 mg, 10% of the aspartame. The EPA limit for water is 7.8 mg daily
for methanol (wood alcohol), a deadly cumulative poison. Many users
drink 1-2 L daily. The reported symptoms are entirely consistent
with chronic methanol toxicity. (Fresh orange juice has 34 mg/L, but,
like all juices, has 16 times more ethanol, which strongly protects
against methanol.)

http://groups.yahoo.com/group/aspartameNM/message/925
aspartame puts formaldehyde adducts into tissues, Part 1/2
full text, Trocho & Alemany 6.26.98: Murray 12.22.2 rmforall

http://groups.yahoo.com/group/aspartameNM/message/926
aspartame puts formaldehyde adducts into tissues, Part 2/2
full text, Trocho & Alemany 6.26.98: Murray 12.22.2 rmforall

http://ww.presidiotex.com/barcelona/index.html
Trocho C, Pardo R, Rafecas I, Virgili J, Remesar X,
Fernandez-Lopez JA, Alemany M ["Trok-ho"]
Formaldehyde derived from dietary aspartame binds to tissue
components in vivo. Life Sci 1998 Jun 26; 63(5): 337-49.
Departament de Bioquimica i Biologia Molecular, Facultat de Biologia,
Universitat de Barcelona, Spain.
http://www.presidiotex.com/barcelona/index.html
Maria Alemany, PhD (male) alemany@...

Abstract:
Adult male rats were given an oral dose of 10 mg/kg aspartame,
14C-labeled in the methanol carbon. At timed intervals of up to 6
hours, the radioactivity in plasma and several organs was investigated.
Most of the radioactivity found (>98% in plasma, >75% in liver) was
bound to protein. Label present in liver, plasma and kidney was in the
range of 1-2% of total radioactivity administered per g or mL, changing
little with time. Other organs (brown and white adipose tissues,
muscle, brain, cornea and retina) contained levels of label in the
range of 1/12th to 1/10th of that of liver. In all ,the rats retained,
6 hours after administration, about 5% of the label, half of it in
the liver.

The specific radioactivity of tissue protein, RNA and DNA was quite
uniform. The protein label was concentrated in amino acids, different
from methionine, and largely coincident with the result of protein
exposure to labeled formaldehyde. DNA radioactivity was essentially in
a single different adduct base, different from the normal bases present
in DNA. The nature of the tissue label accumulated was, thus, a direct
consequence of formaldehyde binding to tissue structures.

The administration of labeled aspartame to a group of cirrhotic rats
resulted in comparable label retention by tissue components, which
suggests that liver function (or its defect) has little effect on
formaldehyde formation from aspartame and binding to biological
components. The chronic treatment of a series of rats with 200 mg/kg
of non-labeled aspartame during 10 days results in the accumulation of
even more label when given the radioactive bolus, suggesting that the
amount of formaldehyde adducts coming from aspartame in tissue proteins
and nucleic acids may be cumulative.

It is concluded that aspartame consumption may constitute a hazard
because of its contribution to the formation of formaldehyde adducts.
PMID: 9714421, UI: 98378223

Life Sci 1999; 65(13): PL157-60 [ letter, not peer-reviewed ]
Comments on the purported generation of formaldehyde and adduct
formation from the sweetener aspartame.
Tephly TR Thomas R. Tephly 319-335-7979 thomas-tephly@...
ttephly@... Department of Pharmacology
The University of Iowa, Iowa City 52242, USA.

A recent paper by Trocho et al. (1) describes experiments meant to
show that formaldehyde adducts are formed when rats are administered
the sweetener aspartame. These authors assume that the methanol carbon
of aspartame generates formaldehyde which then forms adducts with
protein, DNA, and RNA. Doses employed range widely. In this letter,
studies which have been published previously and which were not cited
by these authors are reviewed in order to put into perspective the
disposition of methanol and formaldehyde in monkeys and humans, species
relevant to the toxicity of methanol and its toxic metabolite, formic
acid. PMID: 10503962, UI: 99431287

http://groups.yahoo.com/group/aspartameNM/message/864
Murray: Butchko, Tephly, McMartin: Alemany: aspartame formaldehyde
adducts in rats 9.8.2 rmforall
Prof. Alemany vigorously affirms the validity of the Trocho study
against criticism:
Butchko, HH et al [ 24 authors ], Aspartame: review of safety.
Regul. Toxicol. Pharmacol. 2002 April 1; 35 (2 Pt 2): S1-93, review
available for $35, [ an industry paid organ ]. Butchko:
"When all the research on aspartame, including evaluations in both the
premarketing and postmarketing periods, is examined as a whole, it is
clear that aspartame is safe, and there are no unresolved questions
regarding its safety under conditions of intended use."
[ They repeatedly pass on the ageless industry deceit that the methanol
in fruits and vegetables is as as biochemically available as that in
aspartame-- see the 1984 rebuttal by Monte. ]

http://groups.yahoo.com/group/aspartameNM/message/911
RTP ties to industry criticized by CSPI: Murray: 12.9.2 rmforall

Cell Biol Toxicol 2002; 18(1): 43-50
Cytotoxic effects of methanol, formaldehyde, and formate
on dissociated rat thymocytes: a possibility of aspartame toxicity.
Oyama Y, Sakai H, Arata T, Okano Y, Akaike N, Sakai K, Noda K.
Laboratory of Cellular Signaling, Faculty of Integrated Arts and
Sciences, University of Tokushima, Japan. oyama@...

Aspartame is a widely used artificial sweetener added to many soft
beverages and its usage is increasing in health-conscious societies.
Upon ingestion, this artificial sweetener produces methanol as a
metabolite. In order to examine the possibility of aspartame toxicity,
the effects of methanol and its metabolites (formaldehyde and formate)
on dissociated rat thymocytes were studied by flow cytometry. While
methanol and formate did not affect cell viability in the
physiological pH range, formaldehyde at 1-3 mmol/L started to induce
cell death. Further increase in formaldehyde concentration produced a
dose-dependent decrease in cell viability. Formaldehyde at 1 mmol/L or
more greatly reduced cellular content of glutathione, possibly
increasing cell vulnerability to oxidative stress. Furthermore,
formaldehyde at 3 mmol/L or more significantly increased intracellular
concentration of Ca2+ ([Ca2+]i) in a dose-dependent manner. Threshold
concentrations of formaldehyde, a metabolite of methanol, that affected
the [Ca2+]i and cellular glutathione content were slightly higher than
the blood concentrations of methanol previously reported in subjects
administered abuse doses of aspartame. It is suggested that aspartame
at abuse doses is harmless to humans. PMID: 11991085

Mutat Res 2002 Feb 15; 514(1-2): 115-23
Sister chromatid exchange in pathology staff occupationally exposed to
formaldehyde. Shaham J, Gurvich R, Kaufman Z. judiths@...
[ http://www.ioh.org.il/1_3_5.htm
National Institute of Occupational and Environmental Health
P.O Box 3 Raanana 43100, Israel
+972 9 - 770 7200 Fax- +972 9 - 771 4969
Dr. Judith Shaham, MD MOccH 972-3-5404786 fax 972-3-5497293
Head of Occupational Cancer Department
Dr. Shaham was the Chairman of the Organizing Committee of the 14th
International Conference on Epidemiology in Occupational Health that
was held in Herzlia, Israel, in 1999.]

Sister chromatid exchange (SCE) was measured in peripheral lymphocytes
of 90 workers from 14 hospital pathology departments in Israel who were
occupationally exposed to formaldehyde (FA) and of 52 unexposed workers
from the administrative section of the same hospitals. The mean
exposure period to FA was 15.4 years (range 1-39). The results of SCEs
are expressed in two variables: (a) mean number of SCEs per chromosome
and (b) proportion of high frequency cells (cells with more than eight
SCEs). A high correlation was found between these two variables. The
adjusted means of both SCEs variables were significantly higher among
the exposed compared with that of the unexposed group (P<0.01).
Adjustment was made for age, sex, smoking habits, education, workers and
origin. Evaluation of the influence of years of exposure on the
frequency of SCEs showed that the two variables of SCEs were higher
among those who were exposed to FA for 15 or more than among those with
less than 15 years of exposure. Concerning levels of exposure, both
variables of SCEs were the same in the low and in the high levels of
exposure sub-groups. However, among the smokers, both variables of SCEs
were higher in the high exposure sub-group than in the low exposure
sub-group. Our finding of a significant increase of SCEs frequency in
peripheral lymphocytes in pathology staff indicates a potential
cytogenetic hazard due to FA exposure. We conclude that our data
indicate that FA is mutagenic to humans. PMID: 11815250

Carcinogenesis 1996 Jan; 17(1): 121-5
DNA--protein crosslinks, a biomarker of exposure to formaldehyde-- in
vitro and in vivo studies.
Shaham J, Bomstein Y, Meltzer A, Kaufman Z, Palma E, Ribak J
Occupational Cancer Unit, Occupational Health and Rehabilitation
Institute, Loewenstein Hospital, P.O. Box 3, Ra'anana 43100, Israel.

Formaldehyde (FA) is a widely produced industrial chemical. Sufficient
evidence exists to consider FA as an animal carcinogen. In humans the
evidence is not conclusive. DNA-protein crosslinks (DPC) may be one of
the early lesions in the carcinogenesis process in cells following
exposures to carcinogens. It has been shown in in vitro tests that FA
can form DPC. We examined the amount of DPC formation in human white
blood cells exposed to FA in vitro and in white blood cells taken from
12 workers exposed to FA and eight controls. We found a significant
difference (P = 0.03) in the amount of DPC among exposed (mean +/-
SD 28 +/- 5%, minimum 21%, maximum 38%) than among the unexposed
controls (mean +/- SD 22 +/- 6%, minimum 16%, maximum 32%). Of the 12
exposed workers, four (33%) showed crosslink values above the upper
range of controls. We also found a linear relationship between years of
exposure and the amount of DPC. We conclude that our data indicate a
possible mechanism of FA carcinogenicity in humans and that DPC can be
used as a method for biological monitoring of exposure to FA.
PMID: 8565120, UI: 96152634

Int J Occup Environ Health 1997 Apr; 3(2): 95-104
DNA-Protein Crosslinks and Sister Chromatid Exchanges as Biomarkers
of Exposure to Formaldehyde.
Shaham J, Bomstein Y, Melzer A, Ribak J Occupational Cancer Unit,
Occupational Health and Rehabilitation Institute, P.O. Box 3, Raanana
43100, Israel. [Record supplied by publisher]

Formaldehyde is classified as a probable human carcinogen.
DNA-protein crosslinks (DPCs) and sister chromatid exchanges (SCEs) may
represent early lesions in the carcinogenic process. The authors
examined the DPCs and SCEs in peripheral-blood lymphocytes of 12 and 13
workers exposed to formaldehyde and eight and 20 unexposed workers,
respectively. The amounts of DPCs and SCEs in the exposed and the
unexposed differed significantly after adjustment for smoking. There
was a linear relationship between years of exposure and the amounts of
DPC and SCE. The authors conclude that the data indicate a possible
mechanism of carcinogenicity of formaldehyde, and that formaldehyde is
mutagenic to humans. These results support the use of DPCs as a
biomarker of occupational exposure to formaldehyde and to detect
high-risk populations for secondary prevention. PMID: 9891106

Carcinogenesis 1996 Sep; 17(9): 2097-101
Comments on 'DNA-protein crosslinks, a biomarker of exposure to
formaldehyde-- in vitro and in vivo studies' by Shaham et al.
Casanova M, Heck HD, Janszen D Letter PMID: 8824543, UI: 96421926

Mutat Res 2000 Sep 20; 469(2): 279-85
Evaluation of DNA damage in workers occupationally exposed to
pesticides using single-cell gel electrophoresis (SCGE) assay.
Pesticide genotoxicity revealed by comet assay.
Garaj-Vrhovac V, Zeljezic D
Mutagenesis Division, Institute for Medical Research and
Occupational Health, Zagreb, Croatia.

The comet assay, also called the single-cell gel electrophoresis (SCGE)
assay, is a rapid and sensitive method for the detection of DNA damage
(strand breaks and alkali-labile sites) in individual cells. The assay
is based on the embedding of cells in agarose, their lysis in alkaline
buffer and finally subjection to an electric current. In the present
study, alkaline SCGE was used to evaluate the extent of primary DNA
damage and DNA repair in peripheral blood lymphocytes of workers
employed in pesticide production. After the period of high pesticide
exposure, lymphocytes of the occupationally exposed workers manifested
increased tail length and tail moment compared to the control group.
After the workers spent 6 months out of the pesticide exposure zone,
both endpoints were still above that of the control but significantly
decreased as compared to the results of the first analysis.
PMID: 10984689, UI: 20442322

Mutagenesis 2000 Jan; 15(1): 85-90
Induction and repair of formaldehyde-induced DNA-protein crosslinks in
repair-deficient human cell lines.
Speit G, Schutz P, Merk O guenter.speit@...
Universitatsklinikum Ulm, Abteilung Medizinische
Genetik, D-89070 Ulm, Germany.

We have previously shown that the alkaline Comet assay (single cell gel
electrophoresis) in a modified version is a sensitive test for the
detection of formaldehyde-induced DNA-protein crosslinks (DPC). Our
results also indicated that formaldehyde-induced DPC are related to the
formation of chromosomal effects such as micronuclei and sister
chromatid exchanges. To better understand the genetic consequences of
formaldehyde-induced DPC we have now investigated the induction and
removal of DPC in relationship to the formation of micronuclei in normal
and repair-deficient human cell lines. We did not find significant
differences between normal cells, a xeroderma pigmentosum (XP) cell line
and a Fanconi anaemia (FA) cell line with respect to the induction and
removal of DPC. However, the induction of micronuclei was enhanced in
both repair-deficient cell lines, particularly in XP cells, under the
same treatment conditions. Comparative investigations with the DNA-DNA
crosslinker mitomycin C (MMC) revealed a delayed removal of crosslinks
and enhanced induction of micronuclei in both repair-deficient cell
lines. FA cells were found to be particularly hypersensitive to
micronucleus induction by MMC. In contrast to the results with
formaldehyde, induction of micronuclei by MMC occurred at much lower
concentrations than the effects in the Comet assay. Our results suggest
that more than one repair pathway can be involved in the repair of
crosslinks and that disturbed excision repair has more severe
consequences with regard to the formation of chromosomal aberrations
after formaldehyde treatment than has disturbed crosslink repair.
PMID: 10640535, UI: 20109169

Teratog Carcinog Mutagen 2000; 20(5): 265-72
Chromosomal aberrations analysis in a brazilian
population exposed to pesticides.
Antonucci GA, de Syllos Colus IM Department of General Biology, CCB,
State University of Londrina, PR, Brazil.

In spite of being harmful, pesticides are widely used in Brazil. Their
genotoxic effects might be studied through population monitoring by
means of the analysis of chromosomal aberrations in occupationally
exposed individuals. The aim of this study was to evaluate the
chromosomal aberration frequencies in temporary cultures of lymphocytes
from periferic blood of 23 workers professionally exposed to a mixture
of pesticides. The workers were employed by the Agronomic Institute of
Parana (Brazil) and used all of the prevention measures provided. A
detailed history of pesticide use, as well as personal data, smoking
habits, and history of recent illnesses and medical treatment were
collected through a standardized questionnaire administered to each
subject. Nonexposed subjects, matched for age, sex, and smoking habits,
served as the negative control. A total of 100 cells were analyzed from
each individual. A significant increase in chromosomal aberration
frequencies was observed in exposed individuals when compared to the
control group. Some individual characteristics such as age, sex,
time of exposure to the pesticides, and smoking habits showed no
correlation with chromosomal aberrations. Therefore, the positive
results may be considered true effects of pesticides on human
somatic cells. PMID: 10992273, UI: 20449336

Carcinogenesis 2000 Aug; 21(8): 1573-80
Loss of DNA-protein crosslinks from formaldehyde-exposed cells occurs
through spontaneous hydrolysis and an active repair process linked to
proteosome function.
Quievryn, George A.; Zhitkovich, Anatoly
Department of Pathology and Laboratory Medicine,
Brown University, Box G-B511, Providence, RI 02912, USA.
George_Quievryn@... Anatoly_Zhitkovich@...

DNA-protein crosslinks (DPC) involving all major histones are the
dominant form of DNA damage in formaldehyde-exposed cells. In order to
understand the repair mechanisms for these lesions we conducted detailed
analysis of the stability of formaldehyde-induced DPC in vitro and
in human cells. DNA-histone linkages were found to be hydrolytically
unstable, with t(1/2) = 18.3 h at 37 degrees C. When histones were
allowed to remain bound to DNA after crosslink breakage, the half-life
of DPC increased to 26.3 h. This suggests that approximately 30% of
spontaneously broken DPC could be re-established under physiological
conditions. The half-lives of DPC in three human cell lines (HF/SV
fibroblasts, kidney Ad293 and lung A549 cells) were similar and averaged
12.5 h (range 11.6-13.0 h). After adjustment for spontaneous loss, an
active repair process was calculated to eliminate DPC from these cells
with an average t(1/2) = 23.3 h. Removal of DPC from peripheral human
lymphocytes was slower (t(1/2) = 18.1 h), due to inefficient active
repair (t(1/2) = 66.6 h). This indicates that the major portion of DPC
is lost from lymphocytes through spontaneous hydrolysis rather than
being actively repaired. Depletion of intracellular glutathione from
A549 cells had no significant effect on the initial levels of DPC, the
rate of their repair or cell survival. Nucleotide excision repair does
not appear to be involved in the removal of DPC, since the kinetics of
DPC elimination in XP-A and XP-F fibroblasts were very similar to normal
cells. Incubation of normal or XP-A cells with lactacystin, a specific
inhibitor of proteosomes, caused inhibition of DPC repair, suggesting
that the active removal of DPC in cells may involve proteolytic
degradation of crosslinked proteins. XP-F cells showed somewhat higher
sensitivity to formaldehyde, possibly signaling participation of XPF
protein in the removal of residual peptide-DNA adducts.
PMID: 10910961, UI: 20372597

Toxicol Vitr 2000 Aug; 14(4): 287-95
In vitro genotoxicity of ethanol and acetaldehyde in human lymphocytes
and the gastrointestinal tract mucosa cells.
Blasiak J, Trzeciak A, Malecka-Panas E, Drzewoski J, Wojewodzka M
Department of Molecular Genetics, University of Lodz, 12/16,
90-237 Lodz, Banacha, Poland. januszb@...

The influence of ethanol and acetaldehyde on DNA in human lymphocytes,
gastric mucosa (GM) and colonic mucosa (CM) was investigated by using
the comet assay. All kinds of cells were exposed to ethanol and
acetaldehyde in two regimens: the cells were incubated with either
chemical and analysed or they were exposed first to ethanol, washed and
then exposed to acetaldehyde and analysed. Lymphocytes were exposed
to ethanol at final concentrations of 30 mM and acetaldehyde at 3 mM. GM
cells were incubated with ethanol at 1 M and acetaldehyde at 100 mM. CM
cells were exposed to ethanol at 10 mM and acetaldehyde at 100 mM. In
combined exposure, the cells were subsequently exposed to ethanol and
acetaldehyde at all combination of the concentrations of the agents.
Ethanol caused DNA strand breaks, which were repaired during 4 hr,
except when this agent was applied in GM cells at a concentration of 1
M. A dose-dependent decrease in the tail moment of all types of
acetaldehyde-treated cells was observed. Similar results were obtained
when a recognized DNA crosslinking agent, formaldehyde, was used. These
results suggest that acetaldehyde may form crosslinks with DNA.
These crosslinks were poorly repaired. CM cells showed the highest
sensitivity of all cell types to ethanol than lymphocytes and GM cells.
There were no differences in the sensitivity to acetaldehyde of all the
cell types. Our results clearly indicate that ethanol and acetaldehyde
can contribute to cancers of the digestive tract.
PMID: 10906435, UI: 20368927

Mutat Res 2000 Jul 10; 468(2): 93-108
Validation of single cell gel assay in human
leukocytes with 18 reference compounds.
Frenzilli G, Bosco E, Barale R
Dipartimento di Scienze dell'Uomo e dell'Ambiente,
Universita di Pisa, Italy. r.barale@...

To validate the alkaline single cell gel (SCG) assay as a tool for the
detection of DNA damage in human leukocytes, we investigated the in
vitro activity of 18 chemicals. Thirteen of these chemicals
(pyrene (PY), benzo(a)pyrene (BaP), cyclophosphamide (CP),
4-nitroquinoline-1-oxide (4NQO), bleomycin (BLM), methylmercury chloride
(MMC), mitomycin C (MTC), hydrogen peroxide (HP), diepoxybutane (DEB),
glutaraldehyde (GA), formaldehyde (FA), griseofulvin (GF), sodium azide
(NA)) are genotoxic in at least one cell system, while five compounds
(ascorbic acid (AA), glucose (GL), D-mannitol (MAN), O-vanillin (VAN),
chlorophyllin (CHL)) are classified as non-genotoxic. In this in vitro
SCG assay, PY, BaP and CP were positive with exogeneous metabolic
activation (rat S9 mix) while 4NQO, BLM, MMC, MTC, hydrogen peroxide,
and diepoxbutane were positive in the absence of metabolic activation.
CHL and VAN were unexpectedly found to induce a dose-dependent increase
in DNA migration. AA, GL, and MAN were negative in a non-toxic range of
doses. GF gave equivocal results, while FA and GA increased DNA
migration at low doses and decreased DNA migration at higher doses. This
behaviour is consistent with the known DNA damaging and crosslinking
properties of these compounds. These data support the sensitivity and
specificity of this assay for identifying genotoxic agents.
PMID: 10882888, UI: 20342076

Mutat Res 1999 Sep; 437(2): 151-63
Comparison of the spectra of genetic damage in formaldehyde-induced ad-3
mutations between DNA repair-proficient and -deficient heterokaryons of
Neurospora crassa. de Serres FJ, Brockman HE
Mammalian Mutagenesis Group, Laboratory of
Toxicology, Systems Toxicology Branch,
Environmental Toxicology Program, National Institute of Environmental
Health Sciences, Research Triangle Park, NC 27703-27709, USA.
deserres@... 919-541-3345 info

The mutagenic effects of formaldehyde (FA) have been compared in DNA
repair-proficient (heterokaryon 12) and DNA repair-deficient
(heterokaryon 59) two-component heterokaryons of Neurospora crassa. The
data from forward-mutation experiments were used to compare the
spectra of FA-induced specific-locus mutations at two closely linked
loci in the adenine-3 (ad-3) region and on the FA-induced inactivation
of heterokaryotic conidia. Previous studies have demonstrated that
specific-locus mutations at these two loci result from five major
genotypic classes, namely two classes of gene/point mutations
(ad-3A(R) and ad-3B(R)), and three classes of multilocus deletion
mutations ([ad-3A](IR), [ad-3B](IR), and [ad-3A ad-3B](IR)). Genetic
analysis of ad-3 mutants recovered from both heterokaryons after FA
treatment demonstrates that predominantly gene/point mutations were
found in H-12 (93.2% ad-3(R), 6.8% [ad-3](IR)) and a
significantly higher frequency of multilocus deletion mutations in H-59
(62.8% ad-3(R), 37.0% [ad-3](IR)). The data from our experiments with FA
on H-12 demonstrate and confirm the data from other assays that FA is a
weak mutagen in this DNA repair-proficient strain. However, the
data from our experiments with the DNA repair-deficient strain H-59
demonstrate that comparable concentrations of FA cause more
pronounced inactivation of heterokaryotic conidia and, at the highest
concentration tested, about a 35-fold higher frequency of ad-3
mutations. In addition, FA induced a 5.4-fold higher frequency of
ad-3 mutations resulting from multilocus deletion mutation in H-59 than
in H-12. Based on our earlier studies with X-ray-induced multilocus
deletion mutations, it is this class of FA-induced ad-3 mutations that
might be most expected to show deleterious heterozygous effects.
The implications of the present data base from our experiments with
Neurospora are that the mutagenic (and possibly the carcinogenic) effect
of FA exposure might well vary in different human population subgroups.
PMID: 10556619, UI: 20027293

Toxicol Appl Pharmacol 1999 Oct 1; 160(1): 86-100
Pharmacodynamics of formaldehyde: applications of a model for the arrest
of DNA replication by DNA-protein cross-links.
Heck H, Casanova M Chemical Industry Institute of Toxicology, Research
Triangle Park, North Carolina 27709, USA. casaheck@...

A variety of evidence suggests that formaldehyde (HCHO)-induced
DNA-protein cross-links (DPX) are genotoxic as a result of their ability
to arrest DNA replication. Although DPX can be removed and the DNA can
be repaired, failure to remove the blockage prior to cell division or
excision followed by incomplete repair could cause cell death or a
mutation. To characterize the concentration and time dependence of this
mechanism, a biologically based model for DNA replication in the
presence of DPX was developed based on the assumptions that (1) DPX are
formed randomly in the DNA and (2) a replication fork can advance up to
but not past a DPX. Using a combination of Poisson and binomial
statistics, a quantitative relationship between the amount of newly
synthesized DNA and the concentration of DPX was derived, which predicts
that the rate of DNA replication should decrease nonlinearly with
increasing concentrations of DPX. Because the latter is a nonlinear
function of the airborne concentration of HCHO, an inverse sigmoidal
relationship is predicted between the rate of DNA replication and the
concentration of inhaled formaldehyde. The model was parameterized
using data derived from a study of the incorporation of
[methyl-(14)C]thymidine monophosphate into the DNA of the nasal
respiratory mucosa of Fischer-344 rats exposed to (3)HCHO and
H(14)CHO (6 ppm, 6 h). The model was then applied to measurements of DNA
replication in the nasal mucosa of experimental animals
exposed to wide ranges of H(14)CHO (rats: 0.7, 2, 6, or 15 ppm, 3 h;
rhesus monkeys: 0.7, 2, or 6 ppm, 6 h). The results indicate that, at
airborne concentrations above 6 ppm in rats, there is a marked decrease
(ca. 62% at 15 ppm) in the amount of newly synthesized DNA due to DPX
formation during a single 6-h exposure to HCHO. The arrest of DNA
replication at high HCHO concentrations could result in cytolethality or
genotoxicity, both of which are critical factors in the induction of rat
nasal cancer by HCHO. However, at concentrations below 2 ppm in monkeys
or 1 ppm in rats, the decrease in the rate of DNA replication is
predicted to be <1% after a 6-h exposure. This small decrease is
probably undetectable using currently available techniques. The
parameterized model suggests that the arrest of DNA replication by DPX
is mainly a high-dose phenomenon and that at ambient exposure
concentrations it is unlikely to be a major risk factor.
PMID: 10502505, UI: 99434227

Risk Anal 2000 Apr; 20(2): 273-91
Air toxics and health risks in California: the
public health implications of outdoor concentrations.
Morello-Frosch RA, Woodruff TJ, Axelrad DA, Caldwell JC
University of California-Berkeley, School of Public Health,
Environmental Health Sciences Division 94720-7360, USA.
rmf@... woodruff.tracey@...
Caldwell.Jane@...

Of the 188 hazardous air pollutants (HAPs) listed in the Clean Air Act,
only a handful have information on human health effects, derived
primarily from animal and occupational studies. Lack of consistent
monitoring data on ambient air toxics makes it difficult to assess the
extent of low-level, chronic, ambient exposures to HAPs that could
affect human health, and limits attempts to prioritize and evaluate
policy initiatives for emissions reduction. Modeled outdoor HAP
concentration estimates from the U.S. Environmental Protection Agency's
Cumulative Exposure Project were used to characterize the extent of the
air toxics problem in California for the base year of 1990. These air
toxics concentration estimates were used with chronic toxicity data to
estimate cancer and noncancer hazards for individual HAPs and the risks
posed by multiple pollutants. Although hazardous air pollutants are
ubiquitous in the environment, potential cancer and noncancer health
hazards posed by ambient exposures are geographically concentrated in
three urbanized areas and in a few rural counties. This analysis
estimated a median excess individual cancer risk of 2.7E-4 for all air
toxics concentrations and 8600 excess lifetime cancer cases, 70% of
which were attributable to four pollutants: polycyclic organic matter,
1,3 butadiene, formaldehyde, and benzene. For noncancer effects,
the analysis estimated a total hazard index representing the combined
effect of all HAPs considered. Each pollutant contributes to the index a
ratio of estimated concentration to reference concentration. The median
value of the index across census tracts was 17, due primarily to
acrolein and chromium concentration estimates. On average, HAP
concentrations and cancer and noncancer health risks originate mostly
from area and mobile source emissions, although there are several
locations in the state where point sources account for a large portion
of estimated concentrations and health risks. Risk estimates from this
study can provide guidance for prioritizing research, monitoring, and
regulatory intervention activities to reduce potential hazards to the
general population. Improved ambient monitoring efforts can help clarify
uncertainties inherent in this analysis. PMID: 10859786, UI: 20317367

Ann Allergy Asthma Immunol 1999 Dec; 83(6 Pt 2): 618-23
Toxicologic considerations in the diagnosis of occupational asthma.
Waddell, William "Bill" J. bwaddell@...
Department of Pharmacology and Toxicology, School of
Medicine, University of Louisville, Kentucky, USA.

BACKGROUND: The consideration of dose for chemicals inducing
occupational asthma is examined from the point of view of a
toxicologist. Two widely used chemicals in industry, toluene
diisocyanate (TDI) and formaldehyde, are used as examples of agents that
are formally recognized by OSHA to cause occupational asthma. The
Permissible Exposure Limit (PEL) of OSHA and the Threshold Limit Value
(TLV) of ACGIH for TDI are identical and are in the range of values
for which occupational asthma has been reported in some workers. The
narrow range of exposure values for TDI in studies of workers with and
without asthma is discussed and correlated with the background
concentration of TDI in the ambient atmosphere. For formaldehyde, the
PEL and TLV, in contrast, offer a wide margin of safety for the
inducement of occupational asthma. CONCLUSION: From this disparity in
exposure limits for TDI and formaldehyde, it is concluded that
occupational exposure limits by agencies for specific chemicals do not
provide a reliable indication of the concentration of a chemical that is
necessary to produce occupational asthma. The need for a better
appreciation of dose response, particularly relative to background,
ambient levels, in the evaluation of occupational asthma is emphasized.
PMID: 10619332, UI: 20084350

Toxicol Environ Health 1999 Jul 23; 57(6): 431-42
Activity of cathepsin G, elastase, and their
inhibitors in plasma during methanol intoxication.
Skrzydlewska E, Szmitkowski M, Farbiszewski R
Department of Analytical Chemistry, Medical
University, Bialystok, Poland. skrzydle@...

Methanol oxidation in the liver is accompanied by formation of
formaldehyde and free radicals. These compounds can react with
biologically active proteins, including proteolytic enzymes and their
inhibitors. The activity of cathepsin G and elastase and their
inhibitors such as alpha-1-antitrypsin and alpha-2-macroglobulin in
plasma of rats given methanol orally in doses of 1.5, 3, and 6 g/kg was
investigated for 7 days. The activity of cathepsin G and elastase was
increased from 12 h to 5 d, proportionally to methanol dose. At the same
time, activity of their inhibitors was reduced. Methanol ingestion in
humans caused changes in activities of proteases and their inhibitors
with similar direction as in rats. These changes in activity of
proteases and their inhibitors produce significant disturbances in
proteolytic-antiproteolytic balance after methanol administration.
PMID: 10478824, UI: 99405938

Pathol Res Pract 2000;196(3):193-8 pitten@...
Formaldehyde neurotoxicity in animal experiments.
Pitten FA, Kramer A, Herrmann K, Bremer J, Koch S
Institute of Hygiene and Environmental Medicine,
[Institut fur Hygiene und Umweltmedizin]
Ernst-Moritz-Arndt-University, Greifswald, Germany.

The aim of this study was to determine whether the inhalation of
formaldehyde has a neurotoxicological impact. Forty Wistar rats
(Lew.1/K) were trained to find food in a maze within a particular time.
When all animals were at an equal level, 13 rats inhaled 2.6 ppm and 13
others inhaled 4.6 ppm formaldehyde 10 min/d, 7 d/week for 90 d. The
control group comprised 14 animals inhaling water steam according to the
same exposure pattern. During the exposure period and the post-trial
observation stage (30 d), the time required to find the food and the
number of mistakes made on the way were recorded. Between the animals
exposed to formaldehyde and the control group a statistically
significant difference for both parameters was observed (p < 0.05).
The animals exposed to formaldehyde needed more time and made more
mistakes than the animals of the control group while going through the
maze. The results underline the necessity for a systematic observance of
precautions in case of occupational or dwelling-related formaldehyde
exposure, and allow us to classify formaldehyde as "probably
neurotoxic". Further investigations are required to assess the
neurotoxicologic impact of subchronic formaldehyde exposure.
PMID: 10729924, UI: 20194117

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