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A report on seasonal profiles of plasma sex steroid in sympatric populations of the western diamond-backed rattlesnake, Crotalus atrox and the black-tailed rattlesnake, Crotalus molossus is presented. The possible scenario for the evolution of the different mating seasons in the two species of sympatric rattlesnakes is discussed.

Abstract In most mammals oogonia proliferate by mitosis and begin meiotic development during fetal life. Previous studies indicated that there is a delay in the progression to the first stage of meiotic arrest in germ cells of female fetuses of undernourished ewes. We report that underfeeding (50% NRC requirement beginning on Day 28 of pregnancy) provokes an increase in oxidative base lesions within DNA of mid-gestational (Day 78) fetal oogonia; this condition was associated with up-regulation of the tumor suppressor/cell-cycle arrest modulator p53, antiapoptotic factor Bcl-2, and base-excision repair polymerase β. Fetal ovarian weights and germ cell concentrations were not altered by nutrient deprivation. Ovaries of ewes on control diets (100% NRC) contained more tertiary follicles than their restricted counterparts; however, peripheral venous estradiol-17β was not different between groups. There was no effect of treatment on p53 accumulation in maternal oocytes. Luteal structure-function was not perturbed by undernutrition. No fetal losses were attributed to the dietary restriction. It is proposed that DNA of interphase fetal oogonia is vulnerable to oxidative insults perpetrated by a nutritional stress to the dam, and that multiple/integrated adaptive molecular response mechanisms of cell-cycle inhibition (providing the time required for base repairs) and survival hence sustain the genomic integrity and population stability of the germline.

A new concept directly using drug molecules to fabricate nanocarriers in order to minimize use of inert materials, substantially increase the drug loading content, and suppress premature burst release is described. The concept directly using drugs as part of a carrier could be applied to fabricate other highly efficient nanocarriers with a substantially reduced use of inert carrier materials and increased drug loading content without premature burst release.

ABSTRACT Polyethylene glycol (PEG) is widely used as a carrier to improve the pharmaceutical properties of drugs with low molecular weight. However, PEG has few functional groups (usually two) for drug conjugation and the resulting low drug content (1-2%) has hampered its clinical applications. For this study, we synthesized biodegradable poly(ethylene glycol- co-anhydride). This polyester-based polymer possesses multiple carboxylic acid groups that can be used as facile drug carriers. Two anticancer drugs, camptothecin (CPT) and doxorubicin (DOX) were loaded into the carrier and their releasing properties and in vitro anticancer activities were studied. The polymer-drug conjugates exhibited esterase-promoted degradation and drug release. Their cytotoxicity against the human ovarian cancer cell line SKOV-3 was comparable to unconjugated drugs. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 507-515 [ABSTRACT FROM AUTHOR]

Tumor-targeting, redox-responsive and high drug-loaded nanoparticles were synthesized from poly(ethylene glycol)-b-poly(l-lysine) (PEG–PLL) for enhanced cancer therapy. A hydrophobic drug camptothecin (CPT) was anchored to the lysine residual amines in PEG–PLL via disulfide bonds. Folate acid as targeting group was further introduced to the PLL block via long PEG chains. The conjugate self-assembled into nanoparticles of around 100 nm with hydrophobic CPT moieties forming the core and folate acid targeting groups on the shell. The nanoparticles were expected to be stable in the blood circulation but once internalized via folate receptor-mediated endocytosis, disintegrate and release the drug by glutathione in the cytosol. The nanoparticles could be used as a nanocarrier to further encapsulate other drugs such as doxorubicin for combined chemotherapy. The CPT-conjugated nanoparticles had comparable cytotoxicity to free CPT at low doses but higher cytotoxicity than CPT at high doses. [ABSTRACT FROM AUTHOR]

The structural preciseness of dendrimers makes them perfect drug delivery carriers, particularly in the form of dendrimer-drug conjugates. Current dendrimer-drug conjugates are synthesized by anchoring drug and functional moieties onto the dendrimer peripheral surface. However, functional groups exhibiting the same reactivity make it impossible to precisely control the number and the position of the functional groups and drug molecules anchored to the dendrimer surface. This structural heterogeneity causes variable pharmacokinetics, preventing such conjugates to be translational. Furthermore, the highly hydrophobic drug molecules anchored on the dendrimer periphery can interact with blood components and alter the pharmacokinetic behavior. To address these problems, we herein report molecularly precise dendrimer-drug conjugates with drug moieties buried inside the dendrimers. Surprisingly, the drug release rates of these conjugates were tailorable by the dendrimer generation, surface chemistry, and acidity. [ABSTRACT FROM AUTHOR]

Background: Previously we reported decreased circulating progesterone and fertility in one and two year old ewes born to undernourished mothers. This study was designed to investigate if this reduction in progesterone persisted into old age, and if it did, what mechanisms are involved. Methods: Ewes were fed a nutrient restricted (NR, 50% of NRC recommendations) or control (C, 100% of NRC) diets from day 28 to 78 of gestation, then all were fed to requirements through parturition and weaning. Female offspring (4 per treatment group) were maintained as a group and fed to requirements from weaning until assigned to this study at 6 years of age. Ewes were synchronized for estrus (day 0) and blood samples were collected daily from day 0 to day 11 before necropsy on day 12. Blood serum and luteal tissue were assayed for progesterone concentrations by validated radioimmunoassay. Results: Circulation progesterone concentrations tended to be lower (P = 0.06) in NR than C offspring from day 0 to 11 of the estrous cycle. While total luteal weight was similar across groups, total progesterone content also tended to be reduced (P = 0.07) in luteal tissue of NR than C offspring. Activity of hepatic progesterone catabolizing enzymes and selected angiogenic factors in luteal tissue were similar between groups. Messenger RNA expression of steroidogenic enzymes StAR and P450scc were reduced (P < 0.05), while protein expression of StAR tended to be reduced (P < 0.07) and P450scc was reduced (P < 0.05) in luteal tissue of NR versus C offspring. Conclusions: There appears to be no difference in hepatic steroid catabolism that could have led to the decreased serum progesterone. However, these data are consistent with the programming of decreased steroidogenic enzyme expression in CL of NR offspring, leading to reduced synthesis and secretion of progesterone. [ABSTRACT FROM AUTHOR]

Abstract: Objectives: The underlying premise of these investigations was that the lipophilic hormone progesterone, which partitions into and (at relatively high concentrations) impedes the fluid mechanics of the plasmalemma, would perturb integral associations between membrane lipids and exporter pumps that otherwise confer drug resistance. That progesterone can affect susceptibility of ovarian adenocarcinoma cells and xenografts to cisplatin was tested. Methods: The cisplatin-resistant human cell lines SKOV-3 and OVCAR-3 were treated for 24 hours with cisplatin (0.1 μg/ml)±progesterone (0.01, 0.1 μg/ml). Cytotoxicity and platinum were measured by MTT assay and inductively coupled plasma mass spectrometry, respectively. Athymic mice were inoculated intraperitoneal (ip) with SKOV-3 cells. Cisplatin (2 mg/kg/week)±progesterone (25 mg sustained-release pellet) regimens were initiated ip at one week (when micrometastases were present) and continued to six weeks post-xenograft. Tumor burdens, histopathology, and platinum concentrations were assessed upon necropsy at 24 hours after the final injection of cisplatin. Results: There were no significant in vitro/vivo anticancer effects of cisplatin alone. High-dose progesterone enhanced platinum accretion and induced drug toxicity in both cell lines. Tumorigenesis was suppressed by cisplatin+progesterone. The treatment synergy was related to elevated tumor platinum and morphological evidence of apoptosis. Conclusion: It appears that the addition of progesterone to ovarian cancer therapeutic modalities represents a step in improving responses. [Copyright &y& Elsevier]

Cisplatin conjugated onto macromolecules or loaded in micelles can be preferentially delivered to tumors to minimize its toxicity to healthy tissues and increase its drug efficacy. Herein, we report cisplatin-containing nanogels possibly useful for targeted delivery of cisplatin. Carboxylic acid-functionalized poly(β -aminoester)graft-poly(ethylene glycol) copolymers were synthesized by cocondensation polymerization of piperazine with 2,2-bis(acryloxymethyl)propionic acid, PEG 2,2-bis(acryloxymethyl)propionate macromonomer (mPEG). The graft copolymers formed 100-200 nm nanogels with low size-distribution by the complexation of their carboxylic groups with cisplatin. The nanogels were negatively charged and had a PEG outer layer. Thus, they had "stealth properties" suitable for in vivo applications. The nanogels had significantly lower in vitro cytotoxicity to SKOV-3 ovarian cancer cells than free cisplatin, but similar anticancer activity toward SKOV-3 tumors xenografted to immunocompromised mice. [ABSTRACT FROM AUTHOR]

That ovulation is a predisposing factor in common (surface) epithelial ovarian cancer is widely recognized; however, the molecular events which underscore early-stage disease have not been elucidated. In vivo and in vitro studies using an ovine model system were designed to address a premise that oxidative distresses to DNA inflicted upon ovarian surface epithelial cells within a limited diffusion radius of the ovulatory site of follicular rupture, if gone uncorrected by p53-dependent cycle arrest/repair pathways, could yield a progenitor of tumorigenic potential. Immunofluorescence image analysis was used to quantitate the DNA damage marker 8-oxoguanine, the tumor suppressor p53, the base-excision repair polymerase β, and apoptotic internucleosomal DNA fragmentation in ovarian surface epithelial cells isolated from the perimeter of ovulated follicles. Up-regulation of p53 coincided with accretion of 8-oxoguanine lesions. Oxidative disturbances to DNA were reconciled during the consequent luteal phase (before replicative repair of the ovarian rupture wound). Production of p53 was not related to apoptosis, but rather to induction of polymerase β. Oxoguanine modifications persisted in cells affected by ovulation in which synthesis of p53 was negated in culture by an antisense oligonucleotide. Inhibition of p53 was associated with discordant cellular growth rates and expression of the cancer antigen CA-125 – a phenotype of metaplastic transformation. It is suggested that the integrity of DNA of ovarian surface epithelial cells is compromised by reactive oxidants and inflammatory mediators generated during the ovulatory process and that malfunction in a damage-recognition and(or) repair mechanism is a determinant in the etiology of ovarian metaplasia and carcinogenesis. [Copyright &y& Elsevier]

The connective tissue matrix of the wall of ovarian follicles is degraded and remodeled during ovulatory rupture and formation of the corpus luteum. Ovarian surface epithelial cells in close contact with the apical wall of preovulatory ovine follicles secrete a urokinase-type plasminogen activator in response to surge levels of gonadotropins. Urokinase activates latent collagenases and stimulates release of tumor necrosis factor α from thecal endothelium. Tumor necrosis factor α progressively induces matrix metalloproteinase gene expression, apoptosis, and inflammatory necrosis. Collagenolysis and cellular death are a prelude to stigma formation and ovarian rupture. Ovulation is blocked by intrafollicular injection of TNFα or MMP-2 antisera. Unruptured follicles luteinize but are deficient in collagenous/vascularized trabeculae, and produce less progesterone than their control luteal counterparts. It appears that TNFα, via MMP-2 induction, contributes to the reorganization of an ovulatory follicle into a fully competent corpus luteum. [ABSTRACT FROM AUTHOR]

In most mammals oogonia proliferate by mitosis and begin meiotic development during fetal life. Previous studies indicated that there is a delay in the progression to the first stage of meiotic arrest in germ cells of female fetuses of undernourished ewes. We report that underfeeding (50% NRC requirement beginning on Day 28 of pregnancy) provokes an increase in oxidative base lesions within DNA of mid-gestational (Day 78) fetal oogonia; this condition was associated with upregulation of the tumor suppressor/cell-cycle arrest modulator p53, antiapoptotic factor Bcl-2, and base-excision repair polymerase β. Fetal ovarian weights and germ cell concentrations were not altered by nutrient deprivation. Ovaries of ewes on control diets (100% NRC) contained more tertiary follicles than their restricted counterparts; however, peripheral venous estradiol-17β was not different between groups. There was no effect of treatment on p53 accumulation in maternal oocytes. Luteal structure-function was not perturbed by undernutrition. No fetal losses were attributed to the dietary restriction. It is proposed that DNA of interphase fetal oogonia is vulnerable to oxidative insults perpetrated by a nutritional stress to the dam, and that multiple/integrated adaptive molecular response mechanisms of cell-cycle inhibition (providing the time required for base repairs) and survival hence sustain the genomic integrity and population stability of the germline. [ABSTRACT FROM AUTHOR]

Ovarian surface epithelial cells have been implicated in the genesis of common ovarian cancers. The integrity of DNA of ovarian surface epithelial cells contiguous with the ovulatory stigma becomes compromised during the rupture process; most cells degenerate by apoptosis, however some, bearing sublethal lesions, persist along the margins of ovulated follicles. Clonal expansion of a genetically-damaged surface epithelial cell (i.e. with unrepaired DNA, but not committed to death) can presumably give rise to ovarian carcinoma. It was hypothesized that estradiol and progesterone regulate ovarian surface epithelial cell-cycle dynamics associated with folliculo-luteal transitions and ovulatory wound repair/remodeling. Progesterone up-regulated the tumor suppressor p53 and inhibited baseline and estradiol-stimulated proliferation of cultured sheep ovarian surface epithelial cells. Anti/mitotic responses to steroid hormones were transcriptionally- and receptor-dependent. Rates of apoptosis (DNA fragmentation) were unaffected by progesterone. High concentrations of estradiol, via a nongenomic (perhaps antioxidant) mechanism, suppressed basal and H2O2-induced apoptosis. We suggest that, progesterone serves to inhibit proliferation of ovarian surface epithelial cells throughout the luteal phase—providing the time (growth arrest) required to correct any metabolic disturbances to DNA that are perpetrated as an inevitable by-product of the ovulatory process. With luteolysis and dominance of an estrogenic preovulatory follicle the ovarian surface epithelium is then regenerated. Thus, it is conceivable that perturbations to the steroid hormonal milieu of ovarian cycles could be a predisposing factor for cancerous transformation of an ovarian surface epithelial cell. [Copyright &y& Elsevier]

Diluted ram sperm can be held for 24h at 5°C prior to cryopreservation without impacting cryosurvival rates, however, the effects this storage has on subsequent fertility are unknown. These studies were conducted to evaluate the fertility of semen held for 24h (to mimic shipping semen to a cryopreservation center), prior to freezing. Semen from Suffolk rams (n =3 in experiment 1 and n =6 in experiment 2) with initial motility of greater than 70%, were diluted to 200×106 sperm/mL, in one step, with a Tris–egg yolk–glycerol diluent. In experiment 1, diluted samples were cooled to 5°C over 2h, and then divided. Sperm in one fraction were loaded into 0.5mL straws, frozen (T0) and stored in liquid nitrogen until thawing. Sperm in the second fraction were held at 5°C for 24h (T24) before being frozen. In experiment 2 ejaculates were collected and divided into two fractions. Sperm in one fraction were treated with cholesterol-loaded cyclodextrin (CLC) and sperm in the other served as control. Both fractions were diluted, cooled, and cryopreserved as described in experiment 1. Stage of the estrous cycle was synchronized in ewes (n =196) using controlled internal drug releasing devices (CIDR) for 12d and at CIDR removal each ewe was administered PMSG (500IU in experiment 1 and 350IU in experiment 2) immediately before insemination. Ewes were stratified by age and randomly assigned to one of the semen treatments; experiment 1: Fresh (F), T0, or T24; experiment 2: F, T24, or CLC, and inseminated laparoscopically 56h after CIDR removal. Differences in fertility were detected between experiments, but not for treatments within experiments. Differences in fertility were also observed due to ewe age, with the 3-year-old ewes having the greatest fertility (50.7%) and 6-year-old ewes having the least fertility (9.6%; P <0.05). Differences in the prolificacy rates due to semen treatment were also observed but differences due to ewe age were not detected. Therefore, sperm can be held at 5°C for 24h prior to cryopreservation without altering sperm fertility. [Copyright &y& Elsevier]