590 research outputs found
Human Breast Milk Contamination with Phthalates and Alterations of Endogenous Reproductive Hormones in Infants Three Months of Age
Phthalates adversely affect the male reproductive system in animals. We investigated whether phthalate monoester contamination of human breast milk had any influence on the postnatal surge of reproductive hormones in newborn boys as a sign of testicular dysgenesis. DESIGN: We obtained biologic samples from a prospective Danish–Finnish cohort study on cryptorchidism from 1997 to 2001. We analyzed individual breast milk samples collected as additive aliquots 1–3 months postnatally (n = 130; 62 cryptorchid/68 healthy boys) for phthalate monoesters [mono-methyl phthalate (mMP), mono-ethyl phthalate (mEP), mono-n-butyl phthalate (mBP), mono-benzyl phthalate (mBzP), mono-2-ethylhexyl phthalate (mEHP), mono-isononyl phthalate (miNP)]. We analyzed serum samples (obtained in 74% of all boys) for gonadotropins, sex-hormone binding globulin (SHBG), testosterone, and inhibin B. RESULTS: All phthalate monoesters were found in breast milk with large variations [medians (minimum–maximum)]: mMP 0.10 (< 0.01–5.53 μg/L), mEP 0.95 (0.07–41.4 μg/L), mBP 9.6 (0.6–10,900 μg/L), mBzP 1.2 (0.2–26 μg/L), mEHP 11 (1.5–1,410 μg/L), miNP 95 (27–469 μg/L). Finnish breast milk had higher concentrations of mBP, mBzP, mEHP, and Danish breast milk had higher values for miNP (p = 0.0001–0.056). No association was found between phthalate monoester levels and cryptorchidism. However, mEP and mBP showed positive correlations with SHBG (r = 0.323, p = 0.002 and r = 0.272, p = 0.01, respectively); mMP, mEP, and mBP with LH:free testosterone ratio (r = 0.21–0.323, p = 0.002–0.044) and miNP with luteinizing hormone (r = 0.243, p = 0.019). mBP was negatively correlated with free testosterone (r = −0.22, p = 0.033). Other phthalate monoesters showed similar but nonsignificant tendencies. CONCLUSIONS: Our data on reproductive hormone profiles and phthalate exposures in newborn boys are in accordance with rodent data and suggest that human Leydig cell development and function may also be vulnerable to perinatal exposure to some phthalates. Our findings are also in line with other recent human data showing incomplete virilization in infant boys exposed to phthalates prenatally
Impaired Reproductive Development in Sons of Women Occupationally Exposed to Pesticides during Pregnancy
OBJECTIVES: The aim of this prospective study was to investigate whether occupational pesticide exposure during pregnancy causes adverse effects on the reproductive development in the male infants. DESIGN AND MEASUREMENTS: Pregnant women employed in greenhouses in Denmark were consecutively recruited, and 113 mother–son pairs were included. The mothers were categorized as occupationally exposed (91 sons) or unexposed (22 sons) to pesticides during pregnancy. Testicular position and volume, penile length, and position of urethral opening were determined at 3 months of age using standardized techniques. Concentrations of reproductive hormones in serum from the boys were analyzed. RESULTS: The prevalence of cryptorchidism at 3 months of age was 6.2 % [95 % confidence interval (CI), 3.0–12.4]. This prevalence was considerably higher than among Danish boys born in the Copenhagen area (1.9%; 95 % CI, 1.2–3.0) examined by the same procedure. Boys of pesticideexposed mothers showed decreased penile length, testicular volume, serum concentrations of testosterone, and inhibin B. Serum concentrations of sex hormone-binding globulin, follicle-stimulating hormone, and the luteinizing hormone:testosterone ratio were increased compared with boys of nonexposed mothers. For individual parameters, only the decreased penile length was statisticall
Quark-diquark Systematics of Baryons: Spectral Integral Equations for Systems Composed by Light Quarks
For baryons composed by the light quarks () we write spectral integral
equation using the notion of two diquarks: (i) axial--vector state,
, with the spin and isospin and (ii) scalar one,
, with the spin and isospin . We present spectral
integral equations for the and states taking into
account quark--diquark confinement interaction.Comment: 13 pages, 2 figure
Brane gravity, higher derivative terms and non-locality
In brane world scenarios with a bulk scalar field between two branes it is
known that 4-dimensional Einstein gravity is restored at low energies on either
brane. By using a gauge-invariant gravitational and scalar perturbation
formalism we extend the theory of weak gravity in the brane world scenarios to
higher energies, or shorter distances. We argue that weak gravity on either
brane is indistinguishable from 4-dimensional higher derivative gravity,
provided that the inter-brane distance (radion) is stabilized, that the
background bulk scalar field is changing near the branes and that the
background bulk geometry near the branes is warped. This argument holds for a
general conformal transformation to a frame in which matter on the branes is
minimally coupled to the metric. In particular, Newton's constant and the
coefficients of curvature-squared terms in the 4-dimensional effective action
are determined up to an ambiguity of adding a Gauss-Bonnet topological term. In
other words, we provide the brane-world realization of the so called
-model without utilizing a quantum theory. We discuss the appearance of
composite spin-2 and spin-0 fields in addition to the graviton on the brane and
point out a possibility that the spin-0 field may play the role of an effective
inflaton to drive brane-world inflation. Finally, we conjecture that the
sequence of higher derivative terms is an infinite series and, thus, indicates
non-locality in the brane world scenarios.Comment: Latex, 18 pages; a comment on the spurious tensor mode was added;
recovery condition of higher derivative gravity clarifie
Neutron electric dipole moment: Constituent-dressing and compositeness
Contributions to the neutron's EDM, are calculated using a well-constrained
Ansatz for the nucleon's Poincare' covariant Fadde'ev amplitude. The
momentum-dependent quark dressing amplifies the contribution from the
current-quarks' EDMs; and dressed-quark confinement and binding make
distinguishable the effect of the two CP and T violating interactions: i
gamma_5 sigma_{mu nu} (p_1-p_2)_nu and gamma_5 (p_1+p_2)_mu, where p_{1,2} are
the current-quarks' momenta. The value of |d_n| obtained using the
current-quark EDMs generated by a minimal three Higgs doublet model of
spontaneous CP violation is close to the current experimental upper bound.Comment: 9 pages, LaTeX2e. Errors in Table 1 corrected; five references added.
To appear in Phys. Rev.
QCD strings with spinning quarks
We construct a consistent action for a massive spinning quark on the end of a
QCD string that leads to pure Thomas precession of the quark's spin. The string
action is modified by the addition of Grassmann degrees of freedom to the
string such that the equations of motion for the quark spin follow from
boundary conditions, just as do those for the quark's position.Comment: REVTeX4, 10 pages, no figure
Automatic Assignment of EC Numbers
A wide range of research areas in molecular biology and medical biochemistry require a reliable enzyme classification system, e.g., drug design, metabolic network reconstruction and system biology. When research scientists in the above mentioned areas wish to unambiguously refer to an enzyme and its function, the EC number introduced by the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (IUBMB) is used. However, each and every one of these applications is critically dependent upon the consistency and reliability of the underlying data for success. We have developed tools for the validation of the EC number classification scheme. In this paper, we present validated data of 3788 enzymatic reactions including 229 sub-subclasses of the EC classification system. Over 80% agreement was found between our assignment and the EC classification. For 61 (i.e., only 2.5%) reactions we found that their assignment was inconsistent with the rules of the nomenclature committee; they have to be transferred to other sub-subclasses. We demonstrate that our validation results can be used to initiate corrections and improvements to the EC number classification scheme
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Impaired Reproductive Development in Sons of Women Occupationally Exposed to Pesticides during Pregnancy
Objectives
The aim of this prospective study was to investigate whether occupational pesticide exposure during pregnancy causes adverse effects on the reproductive development in the male infants.
Design and measurements
Pregnant women employed in greenhouses in Denmark were consecutively recruited, and 113 mother–son pairs were included. The mothers were categorized as occupationally exposed (91 sons) or unexposed (22 sons) to pesticides during pregnancy. Testicular position and volume, penile length, and position of urethral opening were determined at 3 months of age using standardized techniques. Concentrations of reproductive hormones in serum from the boys were analyzed.
Results
The prevalence of cryptorchidism at 3 months of age was 6.2% [95% confidence interval (CI), 3.0–12.4]. This prevalence was considerably higher than among Danish boys born in the Copenhagen area (1.9%; 95% CI, 1.2–3.0) examined by the same procedure. Boys of pesticide-exposed mothers showed decreased penile length, testicular volume, serum concentrations of testosterone, and inhibin B. Serum concentrations of sex hormone-binding globulin, follicle-stimulating hormone, and the luteinizing hormone:testosterone ratio were increased compared with boys of nonexposed mothers. For individual parameters, only the decreased penile length was statistically significant (p = 0.04). However, all observed effects were in the anticipated direction, and a joint multivariate test showed that this finding had a p-value of 0.012.
Conclusions
Our findings suggest an adverse effect of maternal occupational pesticide exposure on reproductive development in the sons despite current greenhouse safeguards and special measures to protect pregnant women
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