Re: lead & gastrointestinal function

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The search

lead[ti] AND (gastrointestinal[ti] OR intestin*[ti])

generated >100 citations.

W/o the title-word restrictions, the search generates >6000 citations.

Here are several from the first 20 of the >100. Several are free online

by clicking the links that are presented so clearly when I send this email.

*1: *J Appl Toxicol. <javascript:AL_get(this, 'jour', 'J Appl

Toxicol.');> 2005 Sep-Oct;25(5):361-4.

<http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Display & dopt=pubmed\

_pubmed & from_uid=16092086>

Click here to read

<http://www.ncbi.nlm.nih.gov/entrez/utils/lofref.fcgi?PrId=3058 & uid=16092086 & db=\

pubmed & url=http://dx.doi.org/10.1002/jat.1079>

*Expression of brush border enzymes in response to lead exposure in

rat intestine.*

*Kapur P*

<http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Search & itool=pubmed\

_Abstract & term=%22Kapur+P%22%5BAuthor%5D>,

*Kaur K*

<http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Search & itool=pubmed\

_Abstract & term=%22Kaur+K%22%5BAuthor%5D>,

*Mahmood A*

<http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Search & itool=pubmed\

_Abstract & term=%22Mahmood+A%22%5BAuthor%5D>.

Department of Biochemistry, Panjab University, Chandigarh-160 014,

India.

The effect of feeding lead (50 mg kg(-1) body weight) daily for 7

days on the development of various brush border enzymes in the

intestine has been studied. The activities of brush border sucrase

(P < 0.001), lactase (P < 0.001), gamma-glutamyl transpeptidase (P <

0.05) and leucine aminopeptidase were reduced (P < 0.05), whereas

the alkaline phosphatase level was augmented (P < 0.05) in lead fed

rats compared with controls. Kinetic studies with sucrase revealed a

low Vmax (0.224 in control and 0.160 units mg(-1) protein in lead

exposed) with no change in Km (12.6-13.5 mM). Western blot analysis

for alkaline phosphatase yielded intense staining of enzyme protein

in lead fed rats compared with controls, however, the intensity of

the antigen signal was reversed for sucrase under these conditions.

These findings suggest that ingestion of lead may interfere with the

crypt cell differentiation process thus affecting enzyme functions

in the rat intestine. 2005 Wiley & Sons, Ltd.

PMID: 16092086 [PubMed - indexed for MEDLINE]

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*2: *Environ Health Perspect. <javascript:AL_get(this, 'jour', 'Environ

Health Perspect.');> 2005 Apr;113(4):491-3.

<http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Display & dopt=pubmed\

_pubmed & from_uid=15811841>

Click here to read

<http://www.ncbi.nlm.nih.gov/entrez/utils/lofref.fcgi?PrId=3040 & uid=15811841 & db=\

pubmed & url=http://ehpnet1.niehs.nih.gov/members/2005/7594/7594.html>

*Intoxication from an accidentally ingested lead shot retained in

the gastrointestinal tract.*

*Gustavsson P*

<http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Search & itool=pubmed\

_Abstract & term=%22Gustavsson+P%22%5BAuthor%5D>,

*Gerhardsson L*

<http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Search & itool=pubmed\

_Abstract & term=%22Gerhardsson+L%22%5BAuthor%5D>.

Department of Occupational and Environmental Health, Stockholm

Centre for Public Health, Stockholm, Sweden. per.gustavsson@...

A 45-year-old woman was referred to the Department of Occupational

and Environmental Health in January 2002 because of increased blood

lead concentrations of unknown origin. She suffered from malaise,

fatigue, and diffuse gastrointestinal symptoms. She had a blood lead

level of 550 microg/L (normal range < 40 microg/L). The patient had

not been occupationally exposed to lead, and no potential lead

sources, such as food products or lead-glazed pottery, could be

identified. Her food habits were normal, but she did consume game

occasionally. Clinical examination, including standard neurologic

examination, was normal. No anemia was present. Laboratory tests

showed an increased excretion of lead in the urine, but there were

no signs of microproteinuria. An abdominal X ray in October 2002

revealed a 6-mm rounded metal object in the colon ascendens. Before

the object could be further localized, the patient contracted winter

vomiting disease (gastroenteritis) and the metal object was

spontaneously released from the colon during a diarrhea attack. The

object was a lead shot pellet, possibly but not normally used in

Sweden for hunting wild boar or roe deer. Blood lead levels slowly

decreased. Nine months later the patient's blood lead levels were

almost normal (approximately 70 microg/L) and her symptoms had

almost completely disappeared. In this case, a rare source of lead

exposure was found. In investigations of blood lead elevations of

unknown origin, we recommend abdominal X ray in parallel with

repeated blood lead determinations.

Publication Types:

* Case Reports <javascript:AL_get(this, 'ptyp', 'Case Reports');>

PMID: 15811841 [PubMed - indexed for MEDLINE]

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*3: *Rev Environ Health. <javascript:AL_get(this, 'jour', 'Rev Environ

Health.');> 2003 Oct-Dec;18(4):231-50.

<http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Display & dopt=pubmed\

_pubmed & from_uid=15025188>

*Toxicity of environmental lead and the influence of intestinal

absorption in children.*

*Heath LM*

<http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Search & itool=pubmed\

_Abstract & term=%22Heath+LM%22%5BAuthor%5D>,

*Soole KL*

<http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Search & itool=pubmed\

_Abstract & term=%22Soole+KL%22%5BAuthor%5D>,

*McLaughlin ML*

<http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Search & itool=pubmed\

_Abstract & term=%22McLaughlin+ML%22%5BAuthor%5D>,

*McEwan GT*

<http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Search & itool=pubmed\

_Abstract & term=%22McEwan+GT%22%5BAuthor%5D>,

* JW*

<http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Search & itool=pubmed\

_Abstract & term=%22+JW%22%5BAuthor%5D>.

Department of Environmental Health, School of Medicine, Flinders

University, Adelaide, South Australia.

Exposure to metals, particularly lead, remains a widespread issue

that is associated with historical and current industrial practices.

Whereas the toxic properties of metals are well described, exposure

to metals per se is only one of many factors contributing to

elevated blood metal concentrations and their consequent health

effects in humans. The absorbed dose of metal is affected by

geochemical, biochemical, and physiological parameters that

influence the rate and extent of absorption. In children, the

interplay among these factors can be of critical importance,

especially when biochemical and physiological processes might not

have matured to their normal adult status. Such immaturity

represents an elevated risk to metal-exposed children because they

might be more susceptible to enhanced absorption, especially via the

oral route. This review brings together the more recent findings on

the physiological mechanisms of metal absorption, especially lead,

and examines several models that can be useful in assessing the

potential for metal uptake in children.

Publication Types:

* Review <javascript:AL_get(this, 'ptyp', 'Review');>

PMID: 15025188 [PubMed - indexed for MEDLINE]

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*4: *Arch Environ Contam Toxicol. <javascript:AL_get(this, 'jour', 'Arch

Environ Contam Toxicol.');> 2003 Jan;44(1):116-24.

<http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Display & dopt=pubmed\

_pubmed & from_uid=12434226>

Click here to read

<http://www.ncbi.nlm.nih.gov/entrez/utils/lofref.fcgi?PrId=3055 & uid=12434226 & db=\

pubmed & url=http://dx.doi.org/10.1007/s00-z>

*In vitro intestinal lead uptake and transport in relation to

speciation.*

*Oomen AG*

<http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Search & itool=pubmed\

_Abstract & term=%22Oomen+AG%22%5BAuthor%5D>,

*Tolls J*

<http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Search & itool=pubmed\

_Abstract & term=%22Tolls+J%22%5BAuthor%5D>,

*Sips AJ*

<http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Search & itool=pubmed\

_Abstract & term=%22Sips+AJ%22%5BAuthor%5D>,

*Groten JP*

<http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Search & itool=pubmed\

_Abstract & term=%22Groten+JP%22%5BAuthor%5D>.

RITOX, Environmental Toxicology and Chemistry, Utrecht University,

The Netherlands. agnes.oomen@...

Children might be exposed substantially to contaminants such as lead

via soil ingestion. In risk assessment of soil contaminants there is

a need for information on oral bioavailability of soilborne lead.

Oral bioavailability can be seen as the result of four steps: (1)

soil ingestion; (2) mobilization from soil during digestion, i.e.,

bioaccessibility; (3) transport across the intestinal epithelium;

and (4) first-pass effect. Lead bioaccessibility and speciation in

artificial human small intestinal fluid, i.e., chyme, have been

investigated in previous studies. In the present study, transport of

bioaccessible lead across the intestinal epithelium was investigated

using the Caco-2 cell line. Cell monolayers were exposed to

(diluted) artificial chyme. In 24 h, approximately 27% of the lead

were associated to the cells and 3% were transported across the cell

monolayer, without signs of approaching equilibrium. Lead associated

to the cells showed a linear relationship with the total amount of

lead in the system. Bile levels did not affect the fraction of lead

associated to Caco-2 cells. Extrapolation of the lead flux across

the Caco-2 monolayer to the in vivo situation indicates that only a

fraction of the bioaccessible lead is transported across the

intestinal epithelium. Furthermore, the results indicate that as the

free Pb(2+) concentration in chyme was negligible, lead species

other than the free metal ion must have contributed to the lead flux

toward the cells. On the basis of lead speciation in chyme, this can

be attributed to dissociation of labile lead species, such as lead

phosphate and lead bile complexes, and subsequent transport of the

released free metal ions toward the intestinal membrane.

PMID: 12434226 [PubMed - indexed for MEDLINE]

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*5: *Environ Health Perspect. <javascript:AL_get(this, 'jour', 'Environ

Health Perspect.');> 2001 Jun;109(6):613-9.

<http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Display & dopt=pubmed\

_pubmed & from_uid=11445516>

Click here to read

<http://www.ncbi.nlm.nih.gov/entrez/utils/lofref.fcgi?PrId=3040 & uid=11445516 & db=\

pubmed & url=http://ehpnet1.niehs.nih.gov/members/2001/109p613-619cremin/cremin-fu\

ll.html>

*Oral succimer decreases the gastrointestinal absorption of lead in

juvenile monkeys.*

*Cremin JD Jr*

<http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Search & itool=pubmed\

_Abstract & term=%22Cremin+JD+Jr%22%5BAuthor%5D>,

*Luck ML*

<http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Search & itool=pubmed\

_Abstract & term=%22Luck+ML%22%5BAuthor%5D>,

*Laughlin NK*

<http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Search & itool=pubmed\

_Abstract & term=%22Laughlin+NK%22%5BAuthor%5D>,

* DR*

<http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Search & itool=pubmed\

_Abstract & term=%22+DR%22%5BAuthor%5D>.

Environmental Toxicology, University of California, Santa Cruz,

California, USA.

Although succimer (Chemet, meso-2,3-dimercaptosuccinic acid, DMSA)

is considered to be a safe and effective chelating agent for the

treatment of lead poisoning in humans, there is concern that it may

increase the gastrointestinal (GI) absorption and retention of Pb

from exposures suffered concurrent with treatment. This concern is

justified because the availability of Pb-safe housing during

outpatient treatment with oral succimer is limited. We used a

juvenile nonhuman primate model of moderate childhood Pb

intoxication and a sensitive double stable Pb isotope tracer

methodology to determine whether oral succimer chelation affects the

GI absorption and whole-body retention of Pb. Infant rhesus monkeys

(n = 17) were exposed to Pb daily for 1 year postpartum to reach and

maintain a target blood lead (BPb) level of 35-40 microg/dL. Animals

were administered succimer (n = 9) or vehicle (n = 8) over two

successive 19 day succimer treatment regimens beginning at 53 and 65

weeks of age. The present study was conducted over the second

chelation regimen only. Animals received a single intravenous (iv)

dose of stable (204)Pb tracer (5 microg, 24.5 nmol) followed by a

single oral dose of stable (206)Pb tracer (72.6 microg, 352 nmol)

immediately before chelation, in order to specifically evaluate GI

Pb absorption and whole-body Pb retention with treatment. We

collected complete urine and fecal samples over the first 5 days and

whole blood over the first 8 days of treatment for analyses of

stable Pb isotopes using magnetic sector inductively-coupled plasma

mass spectrometry. Results indicate that succimer significantly

reduced the GI absorption of Pb (vehicle, 64.9% +/- 5.5; succimer,

37.0% +/- 5.8; mean +/- SEM). Succimer also significantly increased

the urinary excretion of endogenous Pb by approximately 4-fold over

the vehicle treatment, while endogenous fecal Pb excretion was

decreased by approximately 33%. Finally, although succimer reduced

the whole-body retention of endogenous Pb by approximately 10%

compared to vehicle, the majority (77%) of the administered internal

dose of Pb tracer was retained in the body when assessed after 5

days of treatment. These data do not support the concern that

succimer treatment increases GI Pb absorption.

PMID: 11445516

boomerone2004 wrote:

>I thought a while back you posted an abstract on lead poisoning and

>it's effects on the GI system but of course now I can't find it after

>I mentioned it to our doc.

>

>If you have any articles mentioning a connection I would appreciate it.

>

>Thanks,

>Marie

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>Many frequently asked questions and answers can be found at

<http://forums.autism-rxguidebook.com/default.aspx>

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