Biodegradable Polymers for the Environment Gross, Richard A.; Kalra, Bhanu
Science (American Association for the Advancement of Science),
08/2002, Letnik:
297, Številka:
5582
Journal Article
Recenzirano
Odprti dostop
Biodegradable polymers are designed to degrade upon disposal by the action of living organisms. Extraordinary progress has been made in the development of practical processes and products from ...polymers such as starch, cellulose, and lactic acid. The need to create alternative biodegradable water-soluble polymers for down-the-drain products such as detergents and cosmetics has taken on increasing importance. Consumers have, however, thus far attached little or no added value to the property of biodegradability, forcing industry to compete head-to-head on a cost-performance basis with existing familiar products. In addition, no suitable infrastructure for the disposal of biodegradable materials exists as yet.
AMH is a glycoprotein dimer composed of two 72kDa monomers linked by disulfide bridges. It belongs to the transforming growth factor-β family. AMH performs various physiological functions. In males, ...AMH is secreted by the Sertoli cells of the testis. During embryonic development, AMH is responsible for Müllerian duct regression. AMH continues to be produced by the testicles until puberty and then decreases slowly to residual post-puberty values. In females, AMH is produced in small amounts by ovarian granulosa cells after birth, until menopause, and then becomes undetectable. A two-step, sandwich-type enzymatic microplate assay has been developed to measure AMH levels in 20μL of sample in less than 3h. AMH calibrators range from 0.2 to 28ng/mL. The antibodies used in the assay bind to the mature region of AMH, which is more stable to proteolysis compared to prohormone region. The AMH Gen II assay (Beckman Coulter, Inc., Webster, Texas) was standardized to the Immunotech (IOT, Beckman Coulter, Inc., Marseilles, France) AMH assay. AMH Gen II, when compared to IOT using 120 serum samples in the range of 0–20.4ng/mL yielded a correlation coefficient of 0.98 and a slope of 1.0. Total imprecision, calculated on four samples over 40 runs, four replicates per run, between two lots using CLSI EP5-A guidelines, was 5.7% at 3.8ng/mL, 7.7% at 4.4ng/mL, 5.8% at 14ng/mL and 5.3% at 16.4ng/mL. The average analytical sensitivity calculated by the interpolation of the mean plus two standard deviations of 16 replicates of the zero calibrator on two independent lots was 0.08ng/mL. Dilution and spiking studies showed an average recovery of 91–110%. Lot-to-lot comparison of two independent lots testing 38 serum samples (1.5–33ng/mL range) yielded a slope of 1.01, intercept of −0.08ng/mL and r of 0.99. When potential interferents (hemoglobin, triglycerides, and bilirubin) were added at two times the physiological concentrations, AMH concentrations were within ±10% of the control. A highly specific and reproducible microplate AMH Gen II assay has been developed to standardize the measurement of AMH between methods. The performance of the AMH Gen II assay is ideal for investigation into the physiologic roles of AMH in men and women.
The oocyte-secreted factors growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) play essential roles in follicle development and oocyte maturation, and aberrant ...regulation might contribute to the pathogenesis of polycystic ovary syndrome.
Are there measurable differences in concentrations of GDF9, BMP15, and the GDF9/BMP15 heterodimer in small antral follicle fluids from women with and without polycystic ovaries (PCO)?
Follicle fluids (n = 356) were collected from 4- to 11-mm follicles in unstimulated ovaries of 87 women undergoing ovarian tissue cryopreservation for fertility preservation.
Twenty-seven women with PCO were identified and 60 women without PCO-like characteristics (non-PCO women) were matched according to age and follicle size.
Intrafollicular concentrations of GDF9, BMP15, GDF9/BMP15 heterodimer, anti-Mullerian hormone (AMH), inhibin-A and -B, total inhibin, activin-B and -AB, and follistatin were measured using enzyme-linked immunosorbent assays.
The detectability of GDF9, BMP15, and the GDF9/BMP15 heterodimer were 100%, 94.4%, and 91.5%, respectively, and concentrations were significantly negatively correlated with increasing follicle size (P < 0.0001). GDF9 was significantly higher in women with PCO (PCO: 4230 ± 189 pg/mL mean ± SEM, n = 188; non-PCO: 3498 ± 199 pg/mL, n = 168; P < 0.03), whereas BMP15 was lower in women with PCO (PCO: 431 ± 40 pg/mL, n = 125; non-PCO: 573 ± 55 pg/mL, n = 109; P = 0.10), leading to a significantly higher GDF9:BMP15 ratio in women with PCO (P < 0.01). Significant positive associations between BMP15 and AMH, activins, and inhibins in non-PCO women switched to negative associations in women with PCO.
Intrafollicular concentrations of GDF9 and BMP15 varied inversely in women with PCO reflecting an aberrant endocrine environment. An increased GDF9:BMP15 ratio may be a new biomarker for PCO.
Abstract
Background
The suggested effects of the oocyte secreted GDF9 and BMP15 growth factors on oocyte maturation are currently based on recombinant proteins, and little is known about native GDF9 ...and BMP15 in humans.
Methods
Human immature cumulus-oocyte complexes (COCs) obtained in connection with ovarian tissue cryopreservation (OTC) underwent in vitro maturation (IVM). Oocyte-produced GDF9 and BMP15 were detected in COCs using immunofluorescence, and in fresh GV oocytes and in GV and MII oocytes after IVM by western blot. Concentrations of GDF9, BMP15 homodimers, and GDF9/BMP15 heterodimer in spent media after IVM were measured by ELISA. The relative expression of seven genes from the GDF9 and BMP15 signaling pathways (
BMPR2, ALK5, ALK6, SMAD1, SMAD2, SMAD3,
and
SMAD5
) was evaluated in fresh cumulus cells (before IVM) and in cumulus cells from GV and MII oocytes after IVM by RT-qPCR.
Results
We detected native pro-mature GDF9 and BMP15 in human oocytes with molecular weights (Mw) of 47 kDa and 43 kDa, respectively. Concentrations of GDF9 and BMP15 in spent media after IVM were detected in 99% and 64% of the samples, respectively. The GDF9/BMP15 heterodimer was detected in 76% of the samples. Overall, the concentration of GDF9 was approximately 10-times higher than BMP15. The concentrations of both GDF9 and BMP15 were significantly lower in spent medium from MII oocytes than in media from oocytes that remained at the GV stage. Concentrations of the GDF9/BMP15 heterodimer did not differ between GV and MII oocytes. Furthermore,
BMPR2
,
SMAD3
, and
SMAD5
were significantly upregulated in cumulus cells from MII oocytes, indicating that both GDF9 and BMP15 signaling were active during oocyte meiotic resumption in vitro
.
Conclusion
These data suggest that the driving mechanisms for oocyte nuclear maturation may involve both GDF9 and BMP15 homodimers, while the role of the GDF9/BMP15 heterodimer is questionable.
Abstract
Bioactive free IGF-I is critically important for growth. The bioavailability of IGF-I is modulated by the IGF-binding proteins (IGFBPs) and their proteases, such as pregnancy-associated ...plasma protein-A2 (PAPP-A2). We have created a mouse model with a specific mutation in PAPPA2 identified in a human with PAPP-A2 deficiency. The human mutation was introduced to the mouse genome via a knock-in strategy, creating knock-in mice with detectable protein levels of Papp-a2 but without protease activities. We found that the Pappa2 mutation led to significant reductions in body length (10%), body weight (10% and 20% in males and females, respectively), and relative lean mass in mice. Micro-CT analyses of Pappa2 knock-in femurs from adult mice showed inhibited periosteal bone expansion leading to more slender bones in both male and female mice. Furthermore, in the Pappa2 knock-in mice, insulin resistance correlated with decreased serum free IGF-I and increased intact IGFBP-3 concentrations. Interestingly, mice heterozygous for the knock-in mutation demonstrated a growth rate for body weight and length as well as a biochemical phenotype that was intermediate between wild-type and homozygous mice. This study models a human PAPPA2 mutation in mice. The mouse phenotype closely resembles that of the human patients, and it provides further evidence that the regulation of IGF-I bioavailability by PAPP-A2 is critical for human growth and for glucose and bone metabolism.
Purpose
The activins-follistatins-inhibins (AFI) hormonal system is considered to regulate muscle and bone mass. We aimed to evaluate AFI in postmenopausal women with an incident hip fracture.
...Methods
In this post-hoc analysis of a hospital based case-control study, we evaluated circulating levels of the AFI system in postmenopausal women with a low-energy hip fracture admitted for fixation compared with postmenopausal women with osteoarthritis scheduled for arthroplasty.
Results
Circulating levels of follistatin (
p
= 0.008), FSTL3 (
p
= 0.013), activin B and AB (both
p
< 0.001), as well as activin AB/follistatin and activin AB/FSTL3 ratios (
p
= 0.008 and
p
= 0.029, respectively) were higher in patients than controls in unadjusted models. Differences for activins B and AB remained after adjustment for age and BMI (
p
= 0.006 and
p
= 0.009, respectively) and for FRAX-based risk for hip fracture (
p
= 0.008 and
p
= 0.012, respectively) but were lost when 25OHD was added to the regression models.
Conclusions
Our data indicate no major changes in the AFI system in postmenopausal women at the time of hip fracture compared to postmenopausal women with osteoarthritis except for higher activin B and AB levels, whose significance, however, was lost when 25OHD was added to the adjustment models.
Clinical Trials
Clinical Trials identifier: NCT04206618.
To investigate for differences in reproductive hormone levels in male relatives of women with polycystic ovary syndrome (PCOS).
Cross-sectional study.
Academic medical center.
Sixty-three fathers and ...66 brothers of women with PCOS as well as two groups of control men of comparable age to fathers (older control, n = 30) and brothers (younger control, n = 58).
A single early morning fasting blood sample was obtained for the measurement of reproductive hormone levels.
Testosterone, LH, FSH, antimüllerian hormone (AMH), inhibin B, estradiol (E2), and estrone (E1) levels were measured.
The AMH, LH, and FSH levels were significantly increased in male relatives compared with their respective control groups. The levels of E2, E1, T, and inhibin B did not differ between the groups.
The AMH, LH, and FSH levels were increased in adult male relatives of women with PCOS, suggesting that they may have altered testicular function and changes in neuroendocrine regulation of gonadotropin secretion. These changes may reflect effects of PCOS susceptibility genes such as the recently mapped chromosome 11p14.1 locus in the region of the FSH B polypeptide gene.
In the veterinary practice, there is a need for a diagnostic tool to check the gonadal status in female dogs because it may be difficult to determine whether a female animal has been spayed or ...whether there are ovarian remnants. Although less prevalent, a similar situation pertains to male dogs. Anti-Müllerian hormone (AMH) is an important regulator of gonadal function and is a specific gonadal product that can be determined in circulation. The objective of this study was to develop and test a canine blood AMH assay as a diagnostic tool to determine the presence of functional gonadal tissue in dogs. A prospective study with a training-validation set paradigm was used. A canine AMH assay was developed and serum and plasma AMH concentrations were determined in blood samples from 46 intact female dogs, 48 spayed females, 50 intact males, and 48 castrated males collected at two separate institutes. Using a training-validation set paradigm, it was found that using cutoff values of 1.1 ng/mL (female) and 5.5 ng/mL (male) AMH, the assay reported excellent specificity and sensitivity of 100% and 90% in female dogs, and good specificity and sensitivity of 100% and 76%, in male dogs, respectively. The sensitivity in male dogs could be further enhanced by including a serum testosterone determination. This newly developed canine AMH assay is a valuable diagnostic tool to determine gonadal status in veterinary medicine.
Women with
-thalassemia (BT) and sickle cell disease (SCD) have a high risk of infertility and premature ovarian insufficiency. Different fertility preserving strategies, including ovarian tissue ...cryopreservation (OTC) and oocyte cryopreservation has been considered, and healthy babies have been born after successful OTC and transplantation. We evaluated follicle number and follicle health in ovarian tissue from a cohort of BT and SCD patients who underwent OTC before the age of 18 years. Patients undergoing OTC from 2002 to 2019 were included. A total of 14 girls and adolescents with BT and four with SCD, aged 2.8-17.4 years at OTC were included together with a reference group of 43 girls and adolescents with non-anemia diseases considered to have normal ovaries aged 0.6-17.9 years at OTC. Ovarian follicle density was measured in cortex biopsies and compared to the reference group. Expression of proteins associated with follicular health was evaluated using immunohistochemistry. Follicles were detected in the ovarian cortex biopsies from all patients with BT and SCD. The follicle densities were within the 95% prediction interval of the reference group in all cases. A similar expression of six proteins essential for follicular health was detected using immunohistochemistry in BT, SCD, and references. OTC should be considered an option for young girls and adolescents with BT and SCD.
Current antimüllerian hormone (AMH) immunoassays are insufficiently sensitive to detect circulating AMH levels in ovulatory women approaching menopause. The aim of this study was to detect serum AMH ...levels across the menstrual cycle with age, using two new AMH enzyme-linked immunosorbent assay (ELISA) kits with increased sensitivity and differing specificity.
Serum AMH levels were determined every 2 to 3 days across the interovulatory interval of menstrual cycles among women of early-mid reproductive age (18-35 y; n = 10) and late reproductive age (45-55 y; n = 17). Two highly sensitive AMH ELISAs (designated 24/32 and 24/37) with differing sensitivities were developed and applied to sera using a recombinant human pro-mature AMH preparation as reference. A third AMH ELISA (Gen II AMH ELISA kit; Beckman Coulter, Brea, CA) used was directed on mature-pro regions of AMH.
AMH levels in all cycles were detectable with the 24/32 and 24/37 AMH ELISAs. AMH levels across the menstrual cycle were highly correlated (r = 0.98) between the 24/32 and 24/37 AMH ELISAs and the Gen II AMH ELISA (r = 0.94), but with large intracycle variations observed in older women. In late reproductive age, more than 95% of AMH values were detectable with the 24/32 and 24/37 AMH ELISAs, whereas only 36% of AMH values were detectable with the Gen II AMH ELISA. AMH levels were detected in cycles with lower antral follicle count and at a later age using the 24/32 and 24/37 AMH ELISAs compared with the Gen II AMH ELISA. AMH level correlated with antral follicle count in younger women, but not in older women.
The new 24/32 and 24/37 AMH ELISAs have the sensitivity to monitor ovarian follicle profiles in late reproductive age.
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