مجال
التميز
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تميز دراسي و بحثي
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البحوث المنشورة
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البحث (1):
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عنوان البحث:
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Insulin-Like
Growth Factor II (IGF-II) In Adipocyte Regulation: Depot-Specific Actions
Suggest A Potential Role Limiting Excess Visceral Adiposity
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رابط إلى البحث:
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Click
here
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تاريخ النشر:
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24/07/2018
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موجز عن البحث:
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The
IGF system has an important role in growth and development. IGF-II is a
recognized fetal growth promoter. However, its physiological post-natal role
remains uncertain although it is maintained in the circulation at a
substantially high level throughout life. IGF-II has been strongly linked to
obesity in genetic studies and more recent evidence suggests a metabolic
role. We examined fat depot differences in IGF-II’s action on differentiation
and metabolism. We speculate a specific effect on visceral adipocytes in
relation to the differential distribution of insulin receptors between
visceral and subcutaneous fat depots. Using a previously established adipocyte,
cell culture system of matched pairs of visceral and subcutaneous fat
biopsies from 20 normal weight children undergoing routine surgery for
non-malignant, non-septic conditions. Preadipocytes were differentiated for
14 days in the presence or absence of IGF-II. Oil Red O staining, western
blotting and reverse transcription polymerase chain reaction techniques were
employed to assess levels of adipogenesis markers and levels of the insulin
receptor and insulin receptor isoforms. Our data indicate that IGF-II
promotes preadipocyte differentiation in subcutaneous preadipocytes but
showed a protective effect restricting visceral preadipocyte differentiation,
confirmed by reductions in the differentiation markers PPARγ and adiponectin
and in triglyceride staining. Additionally, IGF-II reduced mRNA expression of
the insulin receptor in adipocytes, and downregulated IR-A and GLUT4
abundance and corresponding glucose uptake in visceral adipocytes. In
conclusion, IGF-II is a regulator of preadipocyte differentiation and
metabolism by acting as a differential modulator of fat accumulation favoring
less visceral fat deposition in children.
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البحث (2):
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عنوان البحث:
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Effect
of energy drink intake before exercise on indices of physical performance in
untrained females
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رابط إلى البحث:
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Click here
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تاريخ النشر:
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16/05/2015
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موجز عن البحث:
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OBJECTIVES:To determine
the effect of energy drink consumption before exercise on indices of physical
performance in untrained females.
METHODS:This
single blind placebo controlled experimental study was carried out at the
Physiology Department, University of Dammam, Dammam, Kingdom of Saudi Arabia
from September 2011 to May 2012, on 32 healthy female students, in a
crossover design. They were given either a standardized energy drink or the
placebo 45 minutes before the exercise. Time to exhaustion and the stages of
Bruce protocol achieved were noted. Heart rate, blood pressure, peripheral
capillary oxygen saturation, and blood lactate were recorded before and after
the exercise. Maximum oxygen consumption (VO2max) was calculated by formula.
Paired sample t-test was used for statistics.
RESULTS:The
mean age was 19.93±0.8 years, mean height 156.40±3.83 cm, and the mean weight
51.73±3.65 kg. Time to exhaustion in the placebo group was 11.67±1.51 minutes
and 11.41±1.56 in the energy drink group (p less than 0.157). The VO2max in
the placebo group was 34.06±6.62, while it was 32.89±6.83 in the energy drink
group (p less than 0.154). There were no significant differences between the
placebo and the energy drinks groups in regards to heart rate, blood
pressure, and blood lactate levels, before or after the exercise. However,
there were significant differences before, immediately, and 30 minutes post
exercise for all parameters between each group.
CONCLUSION:The
effects of energy drinks intake on physical performance during the exercise
in our small sample does not significantly differ from placebo.
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المؤتمرات العلمية:
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المؤتمر (1):
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عنوان المؤتمر:
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The 25th European Congress
On Obesity
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تاريخ الإنعقاد:
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23/05/2018
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مكان
الإنعقاد:
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Vienna, Austria
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طبيعة المشاركة:
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Poster presentation
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عنوان المشاركة:
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Correlation Between Pre-Pubertal
IGF-II And Pubertal Fat Distribution: Findings From The Avon Longitudinal
Study Of Parents And Children (ALSPAC)
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ملخص المشاركة:
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Background: Recent reports have
suggested a role for IGF-II in body fat regulation and metabolism. IGF-II has
also been strongly linked to obesity in genetic studies. The genetic polymorphisms
in IGF-II expression were also reflected in IGF-II circulatory levels; higher
levels of IGF-II were associated with decreased body weight and less susceptibility to future weight gain in adults. However, limited
studies have investigated IGF-II’s role in children, and whether IGF-II
levels may be an indicative marker for body weight and tissue compartment
distribution in adolescents.
Subjects/Methods: Data of 631 children were used for analysis; the participants were collected as part of the Avon
Longitudinal Study of Parents and Children, Bristol, UK. IGF-II levels were
determined using direct enzyme-linked immunosorbent assay (ELISA; Diagnostic
Systems Laboratories, Inc., Sinsheim, Germany), and were measured from
cord blood and at 61 months of age. Fat mass for (total, trunk, arms, legs,
android and gynoid) and lean mass was measured by dual-energy X-ray
absorptiometry at 15 and 17 years of age. Body mass index (BMI) was
calculated as weight (kg) divided by height squared (m). Regression coefficient
comparison between the outcome measures was performed using z-scores for fat
mass compartments and lean mass. Data analysis was conducted using IBM SPSS
statistics version 23 software.
Results: Cord blood IGF-II showed strong evidence of an
inverse association with total body fat (b -.014 ;P=0.017) and trunk fat mass (b-.016 ;P=0.011) measured at 17 years of age. These correlations were found when
adjustment of sex and age confounders was used; however, the associations
were attenuated when further confounders were adjusted. There was no evidence
of an association between IGF-II and lean mass at puberty. Conclusion: Early
life IGF-II levels have been associated negatively with body fat,
particularly trunk fat mass measured by DXA at puberty. However, there is no
evidence of an association with lean body mass.
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المؤتمر (2):
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عنوان المؤتمر:
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2016 International Conference On Diabetes And Metabolism
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تاريخ الإنعقاد:
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13/10/2016
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مكان
الإنعقاد:
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Seoul- South Korea
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طبيعة المشاركة:
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Oral presentation
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عنوان المشاركة:
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A
Novel Role For Insulin Like Growth Factor Ii (IGF-II) In Adipocyte Regulation:
Site-Specific Actions Due To Differences In Insulin Receptor Distribution
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ملخص المشاركة:
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Objective:
IGF-II levels in the circulation are maintained at high levels throughout life
and IGF-II has been strongly linked to obesity in genetic studies but its
metabolic role is still far from understood. We aim to investigate the role
of IGF-II as a regulator of adipocytes and its specific effects on visceral
adipocytes in relation to the differential distribution of insulin receptors
between visceral and subcutaneous fat depots and the possible metabolic
consequences.
Methods:
Matched pairs of visceral and subcutaneous pre-adipocytes were collected from
biopsies of normal children undergoing routine surgery for non-malignant,
non-septic conditions. These cells were grown and differentiated into mature
adipocytes using a unique adipocyte cell culture system developed in our
laboratory. Tritiated thymidine incorporation Assay was used to assess cell
proliferation after dosing with IGF-II in different glycaemic conditions (5
& 25 mM). Oil red O staining, western blotting and reverse transcription
polymerase chain reaction techniques were employed to assess levels of
adipogenesis markers and levels of the insulin receptor and insulin receptor
isoforms.
Results: We
found that IGF-II promote proliferation of primary preadipocytes from
subcutaneous and visceral fat depots and this proliferative effect was more
profound in subcutaneous preadipocytes in euglycemic (5mM) conditions.
Furthermore, IGF-II promoted preadipocyte differentiation into adipocytes in
subcutaneous preadipocytes but showed an inhibitory effect on visceral
preadipocyte differentiation. Visceral adipocytes had a higher level of
insulin receptors in comparison to subcutaneous preadipocytes and IGF-II
caused a down regulation of insulin receptor mRNA expression and protein
abundance that was more profound in visceral fat cells.
Conclusion:
IGF-II is a regulator of preadipocyte proliferation and this effect is
altered by the concentration of glucose. IGF-II may have a protective role
against visceral adiposity by reducing preadipocyte differentiation into
mature adipocytes and by reducing insulin receptor expression.
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