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Title
Effect of choline supplementation on fatigue in trained cyclists.
Author
Spector SA; Jackman MR; SabounJian LA; Sakkas C; Landers DM;
Willis WT
Address
Department of Neurology' St. Joseph`s Hospital' Phoenix' AZ 85001'
USA.
Source
Med Sci Sports Exerc, 27(5):668-73 1995 May
Abstract
The availability of choline' the precurser of the neurotransmitter'
acetylcholine' in the diet is sufficient to provide the body`s
requirements under normal conditions. However' preliminary evidence
indicates that depletion of choline may limit performance' while
oral
supplementation may delay fatigue during prolonged efforts. A
double-blind cross-over design was used to determine the relationship
between plasma choline and fatigue during supramaximal brief
and
submaximal prolonged activities. Twenty male cyclists (ages 23-29)
with
maximal aerobic power (VO2max) between 58 and 81 ml.min-1.kg-1
were
randomly divided into BRIEF (N = 10) and PROLONGED (N = 10) groups.
One
hour after drinking a beverage with or without choline bitartrate
(2.43
g)' cyclists began riding at a power output equivalent to approximately
150% (BRIEF) and 70% (PROLONGED) of VO2max at a cadence of 80-90
rpm.
Time to exhaustion' indirect calorimetry and serum choline' lactate'
and glucose were measured. Increases in choline levels of 37
and 52%
were seen within one hour of ingestion for BRIEF and PROLONGED
groups'
respectively. Neither group depleted choline during exercise
under the
choline or placebo conditions. Fatigue times and work performed
under
either test condition for the BRIEF or PROLONGED groups were
similar.
Consequently' trained cyclists do not deplete choline during
supramaximal brief or prolonged submaximal exercise' nor do they
benefit from choline supplementation to delay fatigue under these
conditions.
Title
Nicotinamide megadosing increases hepatic poly(ADP-ribose) levels
in
choline-deficient rats.
Author
ApSimon MM; Rawling JM; Kirkland JB
Address
Department of Nutritional Sciences' University of Guelph' Ontario'
Canada.
Source
J Nutr, 125(7):1826-32 1995 Jul
Abstract
Previous work in our laboratory has shown that dietary megadoses
of
nicotinamide' used in the prevention of diabetes' cause increases
in
hepatic poly(ADP-ribose). Poly(ADP-ribose) is synthesized from
NAD+ by
a nuclear enzyme' poly(ADP-ribose)polymerase' which is activated
by DNA
strand breaks. The nicotinamide-induced increase in poly(ADP-ribose)
could result from an increase in substrate' NAD+' or the induction
of
strand breaks in DNA. Strand breaks may result from the depletion
of
single carbon groups' through the excretion of methylated derivatives
of nicotinamide. To differentiate between these mechanisms' a
3 x 3
factorial experiment was conducted in which rats were fed diets
containing various supplements of choline bitartrate (0' 2' 20
g/kg
diet) and nicotinamide (0' 1' 2 g/kg diet). At the conclusion
of
treatments' blood NAD+ and liver lipid' NAD+ and poly(ADP-ribose)
levels were determined. Choline deficiency caused the characteristic
accumulation of fat in the liver at all levels of nicotinamide.
In
choline deficient rats' nicotinamide supplements further increased
liver lipid concentration. Blood and liver NAD+ concentrations
were
increased by nicotinamide supplementation' irrespective of choline
status. In contrast' liver poly(ADP-ribose) levels were increased
by
nicotinamide supplementation only in choline deficient rats.
These
results show that nicotinamide-induced increases in poly(ADP-ribose)
levels appear to be dependent on decreased methyl donor status
and
suggest that adequate choline status is important for preventing
some
deleterious effects of nicotinamide treatment.
Title
Polyenylphosphatidylcholine attenuates alcohol-induced fatty
liver and
hyperlipemia in rats.
Author
Navder KP; Baraona E; Lieber CS
Address
Alcohol Research and Treatment Center' Bronx Veterans Affairs
Medical
Center' New York' New York' USA.
Source
J Nutr, 127(9):1800-6 1997 Sep
Abstract
Chronic administration of a soybean-derived polyenylphosphatidylcholine
(PPC) extract prevents the development of cirrhosis in alcohol-fed
baboons. To assess whether this phospholipid also affects earlier
changes induced by alcohol consumption (such as fatty liver and
hyperlipemia)' 28 male rat littermates were pair-fed liquid diets
containing 36% of energy either as ethanol or as additional
carbohydrate for 21 d' and killed 90 min after intragastric
administration of the corresponding diets. Half of the rats were
given
PPC (3 g/l)' whereas the other half received the same amount
of
linoleate (as safflower oil) and choline (as bitartrate salt).
PPC did
not affect diet or alcohol consumption [15.4 +/- 0.5 G/(kg.d)
' but the
ethanol-induced hepatomegaly and the hepatic accumulation of
lipids
(principally triglycerides and cholesterol esters) and proteins
were
about half those in rats not given PPC. The ethanol-induced
postprandial hyperlipemia was lower with PPC than without' despite
an
enhanced fat absorption and no difference in the level of plasma
free
fatty acids. The attenuation of fatty liver and hyperlipemia
was
associated with correction of the ethanol-induced inhibition
of
mitochondrial oxidation of palmitoyl-1-carnitine and the depression
of
cytochrome oxidase activity' as well as the increases in activity
of
serum glutamate dehydrogenase and aminotransferases. Thus' PPC
attenuates early manifestations of alcohol toxicity' at least
in part'
by improving mitochondrial inJury. These beneficial effects of
PPC at
the initial stages of alcoholic liver inJury may prevent or delay
the
progression to more advanced forms of alcoholic liver disease.
Title
Effect of para-aminobenzoic acid on the pharmacokinetics and
urinary
excretion of cis-diamminedichloroplatinum(II) in rats.
Author
Esposito M; Vannozzi M; Viale M; Pellecchia C; Civalleri D; Gogioso
L
Address
Servizio di Farmacologia Tossicologica' Istituto Nazionale per
la
Ricerca sul Cancro' Genova' Italy.
Source
Anticancer Res, 15(6B):2541-7 1995 Nov-Dec
Abstract
Para-aminobenzoic acid (PABA) has been previously reported as
being an
inhibitor of DDP toxicity' and its use did not result in any
observable
loss in antitumor activity of DDP. The following studies investigated
the effect of PABA on the pharmacokinetics and urinary excretion
of
cis-diamminedichloroplatinum(II) (DDP) in male Sprague-Dawley
rats. DDP
was inJected i.p. at the dose of 7.5 mg/kg in normal saline alone
and
with a concurrent i.p. inJection of PABA (100 mg/kg). The combined
treatment with PABA produced a significant increase in the plasma
concentrations of total platinum' without affecting the levels
of
platinum species in the plasma ultrafiltrate. Similar results
were also
obtained in additional studies in rats receiving the same dose
of DDP
plus PABA through different routes of administration (i.e. DDP
i.v. and
PABA i.p.). Both the area under the total platinum plasma
concentration-time curve (AUC) up to 60 min and AUC0-120 min
were
increased by PABA by an average of 113% and 66% respectively.
The
administration of PABA in rats was followed by a substantial
reduction
in total urinary excretion of platinum (P < 0.05) and by a
significant
(P < 0.01) lower concentration of DDP derived platinum in
the urine
collected during the first 4 h after treatment. The renal clearance
of
filterable platinum was reduced by PABA by an average of 67.5%
from
1.11 to 0.36 ml/min/100 g body wt. Total 24-h urinary excretion
of
platinum was also decreased' although not significantly' by PABA.
Urine
volumes from rats treated with DDP+PABA were similar to those
from
animals receiving DDP alone. HPLC studies indicate that PABA
reacts
readily with the species generated from DDP in vitro' while the
agent
is essentially unreactive toward the parent DDP and does not
influence
its decomposition rate. The overall data of this study suggest
that the
protective effect exerted by PABA on DDP toxicity may be at least
partially due to its ability to interact with aquated DDP as
well as to
alter the renal excretion of platinum.
Title
Diagnostic value of the NBT-PABA test in chronic pancreatitis
Author
Turecka-Kulesza E; D ugosz J; Gabryelewicz A
Address
Kliniki Gastroenterologii AM w Bia ymstoku.
Source
Pol Arch Med Wewn, 84(6):363-9 1990 Dec
Abstract
The aim of this study was an assessment of the usefulness of
indirect
test NBT-PABA in evaluation of pancreatic exocrine function in
patients
from our department treated for chronic pancreatitis. The study
was
carried out on 67 persons divided in three groups: I - healthy
controls
(n = 23)' II - patients with non-pancreatic diseases (n = 17)'
III -
patients with chronic pancreatitis (n = 27). On the basis of
degree of
impairment of exocrine function in the secretin-pancreozymin
test
(SPT)' group III was divided in three subgroups: with mild (A)'
moderate (B)' severe (C) exocrine insufficiency. NBT-PABA test
was
performed using reagents (firm`s Hoffman-La Roche) in accordance
with
the added instructions. In healthy persons (I) average PABA excretion
in urine was 62% and lower normal limit was 30%. In patients
with
non-pancreatic diseases (II) mean urinary PABA excretion was
52% and in
the group with chronic pancreatitis (III) markedly lower results
were
obtained (mean = 26%)' p less than 0.05. In order to evaluate
diagnostic sensitivity in relation to the degree of pancreatic
insufficiency' results of NBT-PABA test were compared with the
results
of SPT. The results of both tests completely coincided in subgroups
III
B' and III C' but in subgroups III A' in only 43% of cases it
was
observed. The specificity of NBT-PABA test (i.e. frequency of
normal
results in controls and patients with non-pancreatic diseases)
was 87%.
Our results suggest that NBT-PABA test may be a useful procedure
in
diagnosis of chronic pancreatitis with severe and moderate exocrine
insufficiency. In cases of mild exocrine dysfunction its value
is
limited.
Title
PABA' benzocaine' and other PABA esters in sunscreens and after-sun
products.
Author
Bruze M; Gruvberger B; Thulin I
Address
Department of Occupational Dermatology' University Hospital Lund'
Sweden.
Source
Photodermatol Photoimmunol Photomed, 7(3):106-8 1990 Jun
Abstract
Contact/photocontact allergy to PABA and benzocaine are not uncommon.
PABA and PABA esters are used in sunscreens and benzocaine may
contaminate such sunscreens or may be an intentional constituent
in
after-sun products. Labelling of ingredients in sunscreens and
after-sun products is not required by law in Sweden. The presence
of
PABA' PABA esters used as sunscreen agents' and benzocaine was
therefore investigated by HPLC in 97 sunscreens and 15 after-sun
products. PABA was detected in 2 sunscreens while almost 50%
of the
sunscreens contained 2-ethylhexyl p-dimethyl-aminobenzoate. Benzocaine
was not found in any after-sun product but was present in 1 sunscreen
containing 4-bis(hydroxypropyl)aminobenzoate. Glyceryl p-aminobenzoate
and amyl p-dimethyl-aminobenzoate were labeled on 1 and 3 sunscreens'
respectively' but glyceryl p-aminobenzoate was not found in any
of them
and only traces of amyl p-dimethylaminobenzoate were found in
1
sunscreen.
Title
The ursodeoxycholic acid-p-aminobenzoic acid deconJugation test'
a new
tool for the diagnosis of bacterial overgrowth syndrome.
Author
Kiss ZF; W olfling J; Cs]ati S; Nagy F; Wittmann T; Schneider
G;
Lonovics J
Address
First Department of Medicine' Albert Szent-Gy orgyi Medical University'
Szeged' Hungary.
Source
Eur J Gastroenterol Hepatol, 9(7):679-82 1997 Jul
Abstract
OBJECTIVE: To determine the possible complementary role of the
ursodeoxycholic acid-p-aminobenzoic acid (UDCA-PABA) loading
test in
the diagnosis of intestinal bacterial overgrowth. DESIGN: A prospective
clinical study. PATIENTS AND METHODS: The hydrogen breath and
UDCA-PABA
tests were performed simultaneously in 68 patients with suspected
contaminated small bowel syndrome (CSBS)' and in 10 healthy control
subJects. The hydrogen breath test was performed by oral loading
of 25
g of lactose and/or 10 g of lactulose. The UDCA-PABA test was
carried
out by oral loading of 250 mg of UDCA-PABA conJugate' followed
by
measurement of the amount of PABA excreted in the urine. The
diagnosis
of bacterial overgrowth was considered to be established when
either
the hydrogen breath test or the UDCA-PABA test produced abnormal
results. RESULTS: Thirty-five of the 68 patients proved to have
CSBS.
In 13 of these 35 patients' only the enhanced urinary PABA excretion
(11.7 +/- 1.42 mg vs. 3.6 +/- 0.68 mg) indicated bacterial overgrowth'
15 of the 35 patients gave only a positive hydrogen breath test'
and in
the remaining seven cases the results of both tests were abnormal.
In
eight CSBS patients' the urinary excretion of PABA was decreased
significantly following 10-day tinidazole treatment (5.5 +/-
1.29 mg
vs. 13.1 +/- 2.07 mg). CONCLUSION: The UDCA-PABA test is a valuable
clinical method for the detection of bacterial overgrowth' especially
in cases where hydrogen production alone fails to reveal CSBS.
It is
also a useful procedure for evaluating the efficacy of antibacterial
treatment.
Title
Use of PABA test to check completeness of 24-h urine collections
in
elderly subJects.
Author
Leclercq C; Maiani G; Polito A; Ferro-Luzzi A
Address
Unit of Human Nutrition' National Institute of Nutrition' Rome'
Italy.
Source
Nutrition, 7(5):350-4 1991 Sep-Oct
Abstract
The p-aminobenzoic acid (PABA) test has been successfully used
as an
indicator of completeness of 24-h urine collection in field studies
of
the general population. Our study was designed to investigate
its
validity for elderly people. Urinary excretion of fractionated
oral
doses of PABA was measured in 21 young control subJects (19-39
yr old)
and 356 elderly (60-89 yr old) men and women. PABA excretion
over 24 h
was lower in elderly than in control subJects. SubJects aged
greater
than or equal to 70 yr had a lower recovery of the PABA dose
than
subJects aged 60-69 yr over the first 24 h' followed by a higher
recovery over the next 24-48 h. The cumulative 48-h recovery
was
similar in all age classes of elderly subJects. However' 48%
of the
elderly subJects had a cumulative PABA recovery below the conventional
cutoff for completeness (85%). These subJects also had consistently
lower creatinine output and urinary volume. The lower 24-h urinary
PABA
recovery over 70 yr of age is interpreted to reflect the delayed
renal
clearance of the marker substance and indicates that the PABA
test is
unsuitable for this age group. The low 48-h cumulative recoveries
found
in all age classes of the elderly are thought to be caused by
small
unreported losses' which are recurrent in free-living populations.
Title
Para-aminobenzoic acid suppression of cis-diamminedichloroplatinum(II)
nephrotoxicity.
Author
Esposito M; Vannozzi MO; Viale M; Fulco RA; Collecchi P; Merlo
F; De
Cian F; Zicca A; Cadoni A; Poirier MC
Address
Servizio di Farmacologia Tossicologica' Istituto Nazionale per
la
Ricerca sul Cancro' Genova' Italy.
Source
Carcinogenesis, 14(12):2595-9 1993 Dec
Abstract
Concurrent administration of para-aminobenzoic acid (PABA) reduced
the
toxicity of cis-diamminedichloroplatinum(II) (DDP) in a dose-related
manner in rats. When administered i.p. simultaneously with 7.5
mg/kg
DDP' PABA (100 mg/kg) significantly reduced plasma urea nitrogen
(PUN)
and plasma creatinine levels as well as DDP-induced weight loss.
Increasing doses of PABA (25' 50 and 100 mg/kg) correlated with
progressively better parameters of renal activity and body wt
and with
lower levels of platinum in plasma and tissues in rats killed
5 days
after drug administration. The formation of cisplatin-DNA adducts'
the
total platinum levels in kidney and testes and the DDP-induced
tumor
response were investigated in the presence and absence of PABA
exposure
in mice bearing P388 leukemic cells. Renal and testicular DNA-adducts
in mice treated i.p. with 16 mg/kg DDP in normal saline were
higher
than those observed in mice receiving the same protocol and added
PABA.
Analysis of tissue platinum content demonstrated significantly
lower
platinum levels both in kidneys (P < 0.05) and testes (P <
0.01) of
mice receiving DDP and PABA in normal saline compared to those
receiving only DDP in normal saline. PABA did not affect the
in vivo
and in vitro antitumor activity of DDP against P388 leukemia'
and there
was no significant PABA-induced modification in the concentration
of
platinum both in the tumor cells and in DNA samples isolated
from P388
leukemic cells of DDP-treated mice. We conclude that PABA may
be a
promising compound for reducing DDP-toxic side effects' including
nephrotoxicity' without compromising its antitumor activity.
Title
Effects of dietary proteins on absorption and gastrointestinal
movement
of p-aminobenzoic acid in conscious rats.
Author
Hara H; Yamada C; Kiriyama S
Address
Department of Agricultural Chemistry' Hokkaido University' Sapporo'
Japan.
Source
J Nutr Sci Vitaminol (Tokyo), 37(4):379-88 1991 Aug
Abstract
We monitored the absorption and movement of dietary soluble components
along the gastrointestinal tract of rats by using p-aminobenzoic
acid
(PABA) as a marker after feeding 8 and 16% casein or soybean
protein
isolate (SPI) diets containing 1% PABA. The portal concentration
of
PABA' as an index of absorption' increased rapidly and reached
the same
high level 10 min after the feeding of all four diets' and the
increased level of portal PABA was maintained for 30-80 min in
each
group. The increased levels of the SPI-fed groups continued longer
than
those of the casein-fed groups. In contrast' the gastric emptying
rate
slowed after 20 min in all the groups' and the gastric emptying
of PABA
for the initial 60 min in the 8% casein group was significantly
faster
than that in the 8% SPI group. The PABA content of the first
small
intestinal segment' which may be influenced by small intestinal
transit' was higher in the casein group. These results indicate
that
the absorptive rate of PABA is determined not only by gastric
emptying
but also by small intestinal transit. The gastric emptying and
the
content of PABA in the first segment of the small intestine was
not
correlated in 8% protein groups. This suggests that the effect
of SPI
on gastrointestinal movement is different from that of casein.
Title
Human placental transfer and metabolism of p-aminobenzoic acid.
Author
Derewlany LO; Knie B; Koren G
Address
Division of Pharmacology and Toxicology' Hospital for Sick Children'
Toronto' Ontario' Canada.
Source
J Pharmacol Exp Ther, 269(2):761-5 1994 May
Abstract
Studies in our laboratory have shown that the N-acetylation activity
of
the human term placenta is a predominantly attributable to the
NAT1
form of arylamine N-acetyltransferase (NAT). To further assess
the
acetylation capacity of the placenta' the N-acetylation of the
prototype NAT1-selective substrate' p-aminobenzoic acid (PABA)'
was
studied using the in vitro human placental perfusion model. This
study
compared the net N-acetylation of PABA in intact placental tissue
with
the PABA acetylation activity observed in a subcellular fraction
(cytosol). Such studies with intact tissue can permit assessment
of the
exposure of the fetus in vivo to drugs and their metabolites.
Acetylated metabolite (N-acetyl-p-aminobenzoic acid) was detectable
in
fetal and maternal venous samples taken less than 5 min from
the start
of perfusion with PABA. In a closed recirculating system' the
rate of
placental PABA transfer decreased as PABA concentrations equilibrated
across the placenta. In contrast' the rate of N-acetyl-p-aminobenzoic
acid formation continued to increase throughout the entire time
of
perfusion. Kinetic parameters of PABA N-acetylation measured
in cytosol
prepared from perfused placental tissue show that the placenta
retains
its ability to N-acetylate PABA at fresh tissue levels even after
6 hr
of in vitro perfusion (Vmax = 5.75 +/- 0.42 nmol/min/mg (fresh)
vs.
Vmax = 7.24 +/- 0.31 nmol/min/mg (perfused); mean +/- S.E.M.'
n = 6).
These studies indicate that the human placenta has a significant
capacity to N-acetylate NAT1-selective substrates of NAT and
that it
maintains its ability to metabolize xenobiotics during in vitro
perfusion.(Abstract TRUNCATED AT 250 WORDS)
Title
A new simple test for evaluation of intestinal bacteria.
Author
Takahashi M; Maeda Y; Tashiro H; Eto T; Goto T; Sanada O
Address
Department of Surgery' Chugoku Rosai Hospital' Hiroshima' Japan.
Source
World J Surg, 14(5):628-34; discussion 635 1990 Sep-Oct
Abstract
We investigated a newly synthesized conJugate of ursodeoxycholic
acid
with para-aminobenzoic acid (PABA) to determine its suitability
to
evaluate enteric bacteria. This compound' PABA-UDCA' is deconJugated
by
cholylglycine hydrolase to release free PABA whereas it is completely
resistant to deconJugation by pancreatic and intestinal mucosal
enzymes. In bacteriological experiments' almost all of the
microorganisms which split glycocholic acid deconJugated this
compound.
In animal experiments' urinary excretions of PABA were measured
for 6
hours following oral administration of 10 mg PABA-UDCA. Ten control
rats excreted 338.5 +/- 43.8 micrograms (mean +/- SD) of PABA;
10 rats
with intestinal bacterial overgrowth due to enteric stagnant
loops
excreted more (673.6 +/- 222.1 micrograms; p less than 0.01)'
whereas
10 rats in each of 8 groups with intestinal antisepsis by oral
administration of various antibiotics excreted significantly
less (p
less than 0.001) (ampicillin + doxycycline + fradiomycin: 18.3
+/-
16.7' polymixin B + tinidazole: 14.0 +/- 8.0' polymixin B: 224.9
+/-
74.3' tinidazole: 42.7 +/- 27.3' kanamycin: 50.3 +/- 18.2' clindamycin:
57.4 +/- 23.3' vancomycin: 70.4 +/- 27.0' and paromomycin: 160.4
+/-
51.9 micrograms). These observations indicate that this compound
is
likely to offer a simple and rapid method for evaluation of intestinal
microorganisms without the use of radioisotopes or expensive'
special
apparatus.
Title
Absorption and metabolic characteristics of p-aminobenzoic acid
and its
isomer' m-aminobenzoic acid' from the rat small intestine.
Author
Yamamoto A; Sakane T; Shibukawa M; Hashida M; Sezaki H
Address
Department of Basic Pharmaceutics' Faculty of Pharmaceutical
Sciences'
Kyoto University' Japan.
Source
J Pharm Sci, 80(11):1067-71 1991 Nov
Abstract
Absorption and metabolic characteristics of p-aminobenzoic acid
(PABA)
and m-aminobenzoic acid (MABA) from the rat small intestine were
examined by means of in situ recirculation and in vitro everted
sac
experiments. p-Aminobenzoic acid was extremely rapidly absorbed
from
the rat small intestine' whereas the absorption of MABA' the
m-isomer
of PABA' was comparably slower. This finding was partly explained
by
the result that PABA is more lipophilic than MABA. The metabolite
percentage of PABA was considerably greater than that of MABA
in
mucosal fluid' tissue' and serosal fluid. On the other hand'
a
concentration-dependent and a directional difference in the transfer
rate of these drugs were observed in everted and noneverted sacs
of rat
small intestine. Furthermore' mucosal uptake of PABA or MABA
was
inhibited by 1 mM 2'4-dinitrophenol' 10 mM sodium azide' and
pretreatment with HgCl2 (10 mM). These results indicate that
MABA' as
well as PABA' is transported through the intestine by a
carrier-mediated transport system' and that the molecular structure
of
these drugs is important for their absorption and metabolic
characteristics. |
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