bluuebunny/crossref_metadata_2025 huggingface dataset:
Proliferation and apoptosis in bovine placentomes during pregnancy and around induced and spontaneous parturition as well as in cows retaining the fetal membranes
Authors: Boos A , Janssen V , Mulling C
Published: March 2004

Placental growth can be achieved by either cellular proliferation or hypertrophy. Tissue regeneration and the nutrition of the fetus via embryotrophe require high rates of cellular turnover and the so-called pre-term 'maturation' of the placenta is correlated with a reduction of maternal crypt epithelial cells. Placentomes of 45 pregnant cows were collected from an abattoir to assess the role of proliferation and apoptosis in placental physiology and pathology. Placentomes were also taken from five cows undergoing premature Caesarean section and from ten naturally calving cows immediately after the expulsion of the fetus. Five of these animals had not released the fetal membranes after 12 h. Tissue sections of placentome were assessed for the Ki-67 protein; the TUNEL procedure was performed and verified by transmission electron microscopy. The maternal crypt epithelium and the fetal chorionic epithelium had a higher percentage of Ki-67-positive cells than the stroma. The percentage of Ki-67-positive cells increased significantly during pregnancy in fetal chorionic epithelium and was significantly decreased in fetal chorionic epithelium and maternal crypt epithelium after the expulsion of the fetus in comparison with tissue from month 9 of pregnancy. The number of apoptotic cells increased significantly during pregnancy in maternal crypt epithelium, maternal stroma and fetal chorionic epithelium as detected in slaughtered animals. Significantly more apoptotic fetal chorionic epithelial cells were found in animals retaining their fetal membranes in comparison with prepartum cattle during month 9 of pregnancy, at premature section and in animals releasing the fetal membranes completely. The results strongly indicate that bovine placentomes have cell type-specific rates of cellular turnover reflecting tissue growth, embryotrophe and placental maturation. Retention of fetal membranes is characterized by a large number of fetal chorionic epithelial cells undergoing apoptosis immediately after the expulsion of the fetus. This finding indicates that incomplete maturation of placentomes plays an important role in fetal membrane retention and that massive apoptosis after the expulsion of the fetus should be the consequence of diminished blood supply to the uterus, as verified in a recent study.
Influence of progesterone supplementation during the first third of pregnancy on fetal and placental growth in overnourished adolescent ewes
Authors: Wallace JM , Bourke DA , Da Silva P , Aitken RP
Published: March 2004

Overnourishing adolescent ewes throughout pregnancy promotes maternal tissue synthesis at the expense of placental growth, which in turn leads to a major decrease in lamb birth weight. As maternal dietary intakes are inversely related to peripheral progesterone concentrations in these adolescent dams, it was hypothesized that sup-optimal progesterone concentrations in overnourished dams may compromise the growth of the differentiating conceptus resulting in fewer uterine caruncles being occupied and, hence, fewer placentomes formed. This hypothesis was tested by supplementing overnourished adolescent dams with exogenous progesterone during early pregnancy and determining the impact on pregnancy outcome at term. Embryos recovered from superovulated adult ewes inseminated by a single sire were transferred in singleton to the uterus of peripubertal adolescent recipients. After transfer of embryos, ewes were offered a moderate or high amount of a complete diet (n=11 per group). A further high intake group received a progesterone supplement each day from day 5 to day 55 of gestation (term=145 days) to restore circulating progesterone concentrations to moderate values throughout the first third of pregnancy (n=11). For ewes establishing pregnancies (n=7 per group), live weight gain during the first 100 days of gestation was 66+/-4, 323+/-17 and 300+/-7 g per day, body condition score at term was 2.1+/-0.05, 3.0+/-0.08 and 3.1+/-0.07 units and the duration of gestation after spontaneous delivery was 148+/-1.7, 144+/-0.8 and 143+/-0.8 days for the moderate intake, high intake and high intake plus progesterone groups, respectively. At delivery, fetal cotyledon mass (136+/-12.1 versus 57+/-8.2g, P<0.001) and lamb birth weight (5164+/-151 versus 2893+/-381 g, P<0.001) were higher in moderate intake than in high intake dams. Progesterone supplementation restored circulating concentrations to moderate values during the first third of gestation. Lamb birth weight in the high intake plus progesterone group (4150+/-389 g) was intermediate between the high intake (P<0.02) and moderate intake (P<0.05) groups, but this change in birth weight was not associated with corresponding changes in fetal cotyledon mass (76+/-10.3 g). Moreover, the number of fetal cotyledons was similar in all three groups. Thus, progesterone did not directly affect the growth of the fetal cotyledon but may have influenced placental vascularity, blood flow or nutrient transfer capacity or alternatively the development of the embryonic inner cell mass.
Intracellular calcium oscillations and activation in horse oocytes injected with stallion sperm extracts or spermatozoa
Authors: Bedford SJ , Kurokawa M , Hinrichs K , Fissore RA
Published: March 2004

In oocytes from all mammalian species studied to date, fertilization by a spermatozoon induces intracellular calcium ([Ca(2+)](i)) oscillations that are crucial for appropriate oocyte activation and embryonic development. Such patterns are species-specific and have not yet been elucidated in horses; it is also not known whether equine oocytes respond with transient [Ca(2+)](i) oscillations when fertilized or treated with parthenogenetic agents. Therefore, the aims of this study were: (i) to characterize the activity of equine sperm extracts microinjected into mouse oocytes; (ii) to ascertain in horse oocytes the [Ca(2+)](i)-releasing activity and activating capacity of equine sperm extracts corresponding to the activity present in a single stallion spermatozoon; and (iii) to determine whether equine oocytes respond with [Ca(2+)](i) transients and activation when fertilized using the intracytoplasmic sperm injection (ICSI) procedure. The results of this study indicate that equine sperm extracts are able to induce [Ca(2+)](i) oscillations, activation and embryo development in mouse oocytes. Furthermore, in horse oocytes, injection of sperm extracts induced persistent [Ca(2+)](i) oscillations that lasted for >60 min and initiated oocyte activation. Nevertheless, injection of a single stallion spermatozoon did not consistently initiate [Ca(2+)](i) oscillations in horse oocytes. It is concluded that stallion sperm extracts can efficiently induce [Ca(2+)](i) responses and parthenogenesis in horse oocytes, and can be used to elucidate the signalling mechanism of fertilization in horses. Conversely, the inconsistent [Ca(2+)](i) responses obtained with sperm injection in horse oocytes may explain, at least in part, the low developmental success obtained using ICSI in large animal species.
Effects of stage of oestrous cycle and progesterone supplementation during culture on maturation of canine oocytes in vitro
Authors: Willingham-Rocky LA , Hinrichs K , Westhusin ME , Kraemer DC
Published: March 2004

The aim of this study was to evaluate the effect of progesterone supplementation and stage of oestrous cycle on in vitro maturation (IVM) of canine oocytes. Oocytes were cultured in medium supplemented with 0, 2000, 4000 or 8000 ng progesterone ml(-1) (Expt 1; n=274 oocytes) or 0, 20, 200 or 2000 ng progesterone ml(-1) (Expt 2; n=789 oocytes). In Expt 3, oocytes (n=1202) were cultured in a bi-phasic system of meiotic arrest followed by IVM, both in the presence of 0, 20, 200 or 2000 ng progesterone ml(-1). Rates of meiotic resumption for Expt 1 ranged from 40.0% to 58.5%; there were no significant differences among groups. In Expt 2, rate of meiotic resumption was significantly lower in the 2000 ng progesterone ml(-1) treatment (35.5%) compared with the 200 ng progesterone ml(-1) treatment (54.0%; P<0.05). There were no significant differences in rates of maturation to metaphase II among treatments in Expt 1 (1.8-8.6%) or Expt 2 (8.4-14.7%); however, oocytes collected from ovaries of bitches in oestrus and dioestrus had higher rates of maturation to metaphase II than did oocytes from bitches at pro-oestrus or anoestrus (P<0.01). In Expt 3, no differences were observed in rates of maturation among treatment groups. Rates of maturation to metaphase II of oocytes from bitches in dioestrus were significantly higher than those from bitches in pro-oestrus (P<0.01). These results indicate that supplementation of culture medium with progesterone either during maturation or during meiotic arrest before maturation does not increase the rate of IVM of canine oocytes. However, stage of oestrous cycle is a key factor in the selection criteria for meiotically competent canine oocytes for use in in vitro experiments.
Interaction of bovine granulosa and theca cells in a novel serum-free co-culture system
Authors: Allegrucci C , Hunter MG , Webb R , Luck MR
Published: March 2004

The objective of this study was to develop a defined culture system in which bovine follicular and granulosa cells are grown in close contact with each other and with the extracellular matrix (ECM) component laminin. Granulosa and theca cells from follicles 4-6 mm in diameter were cultured on either side of laminin-coated BioCoat cell culture inserts in a serum-free medium containing 10 ng insulin ml(-1) at plating densities of 10(5) and 3 x 10(5) cells per membrane side. The cells adopted a clumped arrangement, maintained steroidogenic activity for at least 7 days and demonstrated paracrine communication by increased steroidogenesis and enhanced cell survival compared with cells in mono-culture. Co-cultured theca cells secreted significantly more androstenedione compared with cells in mono-culture. Granulosa cell viability was doubled by co-culture with theca cells. Co-cultures at both cell plating densities were responsive to treatment with physiological combinations of either FSH, LH and LR3 insulin-like growth factor I (IGF-I) (treatment A) or FSH, LR3 IGF-I and androstenedione (treatment B). Significantly more androstenedione was secreted in the presence of treatment A compared with controls. In contrast, oestradiol secretion was increased only by treatment B. Progesterone secretion was unaffected by treatment and did not increase during culture. Co-cultures at the higher plating density demonstrated higher theca cell survival and better maintenance of the follicular cell phenotype. In conclusion, this novel co-culture system provides a unique model for the study of paracrine communication between ovarian somatic cells and cell-ECM interactions during follicle growth.
Cyclooxygenase enzymes and prostaglandins in pathology of the endometrium
Authors: Sales KJ , Jabbour HN
Published: March 2004

Prostaglandins are bioactive lipids produced from arachidonic acid by cyclooxygenase (COX) enzymes and specific terminal prostanoid synthase enzymes. After biosynthesis, prostaglandins exert an autocrine-paracrine function by coupling to specific prostanoid G protein-coupled receptors to activate intracellular signalling and gene transcription. For many years, prostaglandins have been recognized as key molecules in reproductive biology by regulating ovulation, endometrial physiology and proliferation of endometrial glands and menstruation. More recently, a role for COX enzymes and prostaglandins has been ascertained in reproductive tract pathology, including carcinomas, menorrhagia, dysmenorrhoea and endometriosis. Although the mechanism by which prostaglandins modulate these pathologies is still unclear, a large body of evidence supports a role for COX enzymes, prostaglandins and prostaglandin receptor signalling pathways in angiogenesis, apoptosis and proliferation, tissue invasion and metastases and immunosuppression. Here, an overview is provided of some of the findings from these studies with specific emphasis on the role of COX enzymes, prostaglandin E(2) and F(2alpha) in disorders of endometrial proliferation and menstruation in non-pregnant women.
Angiogenesis during primate placentation in health and disease
Authors: Wulff C , Weigand M , Kreienberg R , Fraser HM
Published: March 2004

Normal embryonic development is dependent upon a sufficient oxygen, nutrient and waste exchange through the placenta. In primates including humans, this exchange is attained by successful haemochorial placentation which requires the transformation of maternal intramyometrial spiral arterioles by trophoblast invasion to gain uteroplacental circulation, and establishment and maintenance of a competent fetoplacental vasculature. Thus, trophoblast and endothelial cell differentiation, proliferation and invasion occurring during placentation have to be tightly regulated. This review focuses on the diverse developmental steps during haemochorial placentation in humans and other primates and the possible involvement of angiogenic growth factors (vascular endothelial growth factor (VEGF) and angiopoietins (Ang)) in these processes, highlighting the importance of specific actions of angiogenic ligand-receptor pairs. It is hypothesized that VEGF/VEGF-R1 and Ang-1/Tie receptor 2 (Tie-2) may regulate trophoblast differentiation and invasion; VEGF/VEGF-R2 and Ang-1/Tie-2 may promote fetoplacental vascular development and stabilization; and Ang-2/Tie-2 may be involved in maternal vascular remodelling. The importance of a tight regulation of angiogenic factors and their endogenous antagonists for normal development of the placenta is demonstrated by failure of this system, resulting in abnormal placenta vascularization and trophoblast invasion associated with intrauterine growth retardation or pre-eclampsia.
Influence of the CBA genetic background on sperm morphology and fertilization efficiency in mice with a partial Y chromosome deletion
Authors: Styrna J , Kilarski W , Krzanowska H
Published: March 2004

Males of the B10.BR-Ydel mouse strain, with a deletion in the long arm of the Y chromosome, were backcrossed to CBA females to introduce the Ydel chromosome to the genetic background of the CBA mice. The CBA-Ydel males (sixth backcross generation) had similar symptoms to those previously described for B10.BR-Ydel males (deterioration of sperm quality and of efficiency of fertilization), but these effects were much less pronounced, showing a favourable influence of the CBA genetic background. The CBA-Ydel males produced only 12% severely misshapen spermatozoa, and mating with B10.BR females gave 100% successful fertilization. Although nearly all sperm heads were abnormal (92% versus 6% in control males), most of the spermatozoa (76%) had deformation only in the acrosomal part, that is, flat heads, which were not found in the control males. These abnormalities were analysed in detail. As shown by differential staining, the acrosomes of the spermatozoa with flat heads were deformed; 18% of these acrosomes looked damaged, and often contained a vesicle, which stained in a similar way to the acrosome but lacked the reaction for acrosomal proteinase. Electron microscopy of testis sections revealed that deformations appeared already in round spermatids as distortion of the acrosomal vesicle and asymmetrical position of the acrosomal granule; in many elongating spermatids the proximal end had a flat or concave shape, and the acrosomes contained a translucent vesicle. It is possible that the genes that are missing in the Yq deletion have some important regulatory function in the course of spermiogenesis, which may explain the various sperm defects observed in Y-del males.
Evidence of oocyte donor cow effect over oocyte production and embryo development in vitro
Authors: Tamassia M , Heyman Y , Lavergne Y , Richard C , Gelin V , Renard JP , Chastant-Maillard S
Published: March 2004

There have been few studies on a possible maternal influence on in vitro embryo production in cows. The objective of this study was to evaluate the maternal influence on oocyte production and in vitro blastocyst formation rate using repeated ovum pick-up and in vitro fertilization. Six contemporary cows raised on the same farm and with varied genetic origins were submitted to 42 weeks of ovum pick-up organized into four series. Collected oocytes were fertilized in vitro with spermatozoa from a different bull for each series. In total, 1933 oocytes were recovered from 3936 follicles with a recovery rate of 57.2% and a mean oocyte collection of 4.6+/-0.2 (mean+/-SEM) per animal per session. Animals were ranked according to their oocyte production. The best oocyte donor was the same female in all four series. No relationship was identified between oocyte production and blastocyst production rate (r=-0.08). The mean blastocyst rate was 28.8% with significant variation among animals. The best and the worst blastocyst producers were always the same animals independent of the semen used. The results of the present study support the hypothesis that in cattle, the oocyte donor influences the production of blastocysts. Furthermore, they demonstrate that oocyte and embryo production are independent factors. Further studies are necessary to identify the maternal or oocyte factors responsible for such differences.
Hormonal mechanism of follicle deviation as indicated by major versus minor follicular waves during the transition into the anovulatory season in mares
Authors: Ginther OJ , Woods BG , Meira C , Beg MA , Bergfelt DR
Published: March 2004

Follicle growth and circulating hormone concentrations were compared between an interovulatory interval and the first 60 days of the anovulatory season in pony mares. Daily observations were made from November of three groups: (i) ablation of follicles of >/=6 mm in diameter at day 10 after an ovulation that initiated an interovulatory interval, as determined retrospectively (ovulatory group, n=8), (ii) ablation at day 10 after the last ovulation of the year (anovulatory-10 group, n=6); and (iii) ablation at day 60 after the last ovulation of the year (anovulatory-60 group, n=6). Follicular waves were defined as major (dominant follicle) and minor (no dominant follicle). The percentage of mares with major waves after ablation for the ovulatory, anovulatory-10 and anovulatory-60 groups was 100, 33 and 0%, respectively, and the percentage with minor waves was 0, 67 and 100%, respectively. Minor waves were also detected in 83% of anovulatory mares between day 20 and day 60. Growth of the largest follicle was similar for major waves and minor waves but only until the beginning of deviation in the major waves. FSH surges after ablation were similar for all groups and for surges detected during days 20-60. Concentrations of LH were greater in association with major waves than with minor waves. Both diameter of the largest follicle and LH concentrations for minor waves were greater after ablation at day 10 after the last ovulation of the year than after ablation at day 60. The results of this study indicate that major follicular waves developed in some mares early in the anovulatory season and that minor waves developed throughout the first 2 months. Despite similarities in the wave-stimulating FSH surge, differences in follicle growth occurred and were attributable, on a temporal basis, to differences in LH concentrations. A minor wave developed into a major wave when the largest follicle reached a diameter characteristic of the beginning of deviation in the presence of an adequate LH stimulus for continued growth of a dominant follicle.
Multiple aneuploidies in the oocytes of balanced translocation carriers: a preimplantation genetic diagnosis study using first polar body
Authors: Pujol A , Durban M , Benet J , Boiso I , Calafell JM , Egozcue J , Navarro J
Published: March 2004

Preimplantation genetic diagnosis (PGD) of first polar bodies (1PBs) has been used in carriers of balanced chromosomal reorganizations and also for aneuploidy screening. Although an acceptable number of normal or balanced embryos is usually obtained using PGD in translocation carriers, the pregnancy rate is disappointingly low. To determine whether aneuploidy of chromosomes not involved in the chromosome rearrangements could be the cause of the low pregnancy rates achieved, the present authors analysed the segregation products of three translocation carriers, t(8;13)(q24.1;q22) and two Robertsonian (Rob)(13;14), using 1PBs, and afterwards another eight chromosomes in the same 1PBs, for a total of 10 chromosomes in each 1PB, that is chromosomes 1, 8, 13, 14, 15, 16, 17, 18, 21, 22 and X. In the reciprocal translocation, chromosomes with different chromatids due to meiotic recombination were found. Only one out of nine 1PBs was normal for the reorganization products but no aneuploidies were found after PGD in this case. In the two balanced Rob(13;14), six out of 12 and four out of 11 1PBs were normal or balanced for the reorganization but only one oocyte was euploid for all the chromosomes analysed in each case; a single embryo transfer was made in both but no pregnancy was achieved. The incidence of aneuploidy for the chromosomes not involved in the Robertsonian translocations was extremely high (91.7% and 81.8%). Extra chromosomes were present in most of the aneuploid oocytes (81.8% and 90%). The reason for this increase could be the tendency to non-disjunction related to advanced maternal age combined with an interchromosomal effect resulting in the presence of synaptic errors in other chromosome pairs.
Expression and presence of osteopontin and integrins in the bovine oviduct during the oestrous cycle
Authors: Gabler C , Chapman DA , Killian GJ
Published: March 2004

Osteopontin and integrin alpha(v)beta(3) are known to mediate cell-cell attachment and cell migration. Western blot analysis was used to demonstrate the presence of osteopontin in oviductal fluid collected from ampullar and isthmic regions. Three different osteopontin isoforms of 55 kDa, 48 kDa and 25 kDa were detected in the oviductal fluid. Each isoform was observed during the luteal and non-luteal phases and in both ampullar and isthmic fluids. The 25 kDa osteopontin was the most prevalent isoform in oviductal fluid except in isthmic fluid during the non-luteal phase of the oestrous cycle. RT-PCR was performed with RNA from oviductal cells collected from cows in the post-ovulatory, early to mid-luteal, late luteal or pre-ovulatory stages of the oestrous cycle to reveal the oviduct as a site of osteopontin and integrin synthesis. Only one osteopontin mRNA transcript was detected, and amounts did not vary throughout the oestrous cycle. In contrast, the relative expression of the integrin subtypes alpha(v) and beta(1) during the late luteal phase was lower compared with the other oestrous cycle phases. Integrin beta(3) mRNA content increased significantly from the lowest level during the late luteal phase to the highest level before ovulation. In conclusion, differential presence of osteopontin isoforms and integrins in the bovine oviduct throughout the oestrous cycle indicate that osteopontin-integrin interactions have functional roles in normal oviduct physiology which may potentially influence interactions between the gametes, the embryo, and the epithelium.
Localization of centromere proteins and their association with chromosomes and microtubules during meiotic maturation in pig oocytes
Authors: Ma W , Hou Y , Sun QY , Sun XF , Wang WH
Published: March 2004

Centromere proteins (CENPs) are required for the attachment of microtubules to chromosomes. However, their structure and mechanism of action are not well understood, especially in mammalian meiosis. The present study was conducted to examine (i). whether a human nuclear centromere autoantibody can be used to localize the CENPs in pig oocytes and (ii). the dynamics of CENPs and their association with microtubules and chromosomes during meiosis in pigs. Oocytes at various stages were double-labelled for CENPs, chromosomes or microtubules and examined by confocal fluorescence microscopy. Quantification of tubulin and CENPs in the oocytes was determined by immunoblotting. CENPs were detected in all oocytes from germinal vesicle (GV) to metaphase II (MII) stages. The changes in the location were associated with chromosome movement and spindle formation. Tubulin was detected in the oocytes from GV to MII stages and no differences in content were observed. Two major CENPs at 80 kDa (CENP-B) and 50 kDa (CENP-D) were also found in the oocytes by the autoantibody and its content was significantly lower in the oocytes at GV stage compared with oocytes at other stages. These results indicate that the autoantibody used in this study can be used to detect CENPs in the kinetochores, and the proteins are expressed in pig oocytes at all stages during meiosis. As the localization of CENPs is associated with spindle formation and chromosome movement, CENPs may participate in cell cycle changes during meiosis in mammals.
Attenuation by leptin of the effects of fasting on ovarian function in hens (Gallus domesticus)
Authors: Paczoska-Eliasiewicz HE , Gertler A , Proszkowiec M , Proudman J , Hrabia A , Sechman A , Mika M , Jacek T , Cassy S , Raver N , Rzasa J
Published: March 2004

Thirty-four-week-old laying hens received injections of recombinant chicken leptin to assess the role of leptin in avian ovarian function. In the first experiment, the hens (n=60) were divided into three groups: (i). fed ad libitum; (ii). fasted; and (iii). fasted + leptin. Hens were fasted for 5 days and those treated with leptin received 250 microg leptin kg-1 body weight twice a day, i.p. In the second experiment, the hens (n=72) were divided into four groups: (i). fed ad libitum; (ii). fasted; (iii). fasted + leptin given only during fasting (5 days); or (iv). fasted and leptin given during both fasting and 5 days of re-feeding (10 days). LH was measured in blood plasma, and progesterone and oestradiol were measured in blood plasma and the ovary by radioimmunoassay. Apoptosis was examined in the walls of the three largest yellow hierarchical follicles (F3-F1; F3 25-35 mm) by the TdT-mediated dUTP nick-end labelling method. Results showed that the injections of leptin during fasting: (i). delayed cessation of egg laying; (ii). attenuated regression of yellow hierarchical follicles; (iii). altered ovarian steroidogenesis; and (iv). abolished the fasting-induced apoptosis in the wall of F3-F1 follicles during the first 2 days of fasting and partially attenuated apoptosis after 5 days of fasting. Prolongation of leptin injections into the re-feeding period considerably delayed the restoration of the ovary. Expression of leptin receptor in laying hens was determined by RT-PCR. The highest expression of leptin receptor was observed in the hypothalamus. Lower receptor mRNA expression was found in the hypophysis, whereas the lowest expression was observed in the ovary. Within the ovary, a relatively high expression of leptin receptor was found in the stroma with cortical follicles <1 mm, the wall of white (1-8 mm) and small yellow follicles (>8-12 mm), and the granulosa layer of F3 follicles. The expression of leptin receptor in the granulosa layer of F2 and F1 follicles was barely detectable. This was in contrast to a much higher expression of leptin receptor maintained in the theca layer of F3-F1 follicles. The present results indicate that in chickens leptin might be involved in the adaptation to starvation due to attenuation of follicular apoptosis. The presence of leptin receptors in the ovary indicates the possibility of a peripheral effect of the hormone.
Autologous and homologous transplantation of bovine spermatogonial stem cells
Authors: Izadyar F , Den Ouden K , Stout TA , Stout J , Coret J , Lankveld DP , Spoormakers TJ , Colenbrander B , Oldenbroek JK , Van der Ploeg KD , Woelders H , Kal HB , De Rooij DG
Published: March 2004

The aim of this study was to develop a method for spermatogonial stem cell transplantation into the bovine testis. Five-month-old Holstein-Friesian calves were used and half of the calves were hemicastrated to allow autologous transplantation and the other half were used for homologous transplantation. Approximately 20 g of each testis was used for cell isolation. On average 106 cells per gram of testis containing about 70% type A spermatogonia were isolated. The cells were frozen in liquid nitrogen until transplantation. Testes were irradiated locally with 10-14 Gy of X-rays to deplete endogenous spermatogenesis. At 2 months after irradiation, cells (approximately 10 x 10(6) were injected into the rete testis through a long injection needle (18 gauge), using ultrasonography and an ultrasound contrast solution. At 2.5 months after transplantation, calves were castrated and samples of testes were taken for histological examination. After 2.5 months in the irradiated non-transplanted control testes, only 45% of the tubules contained type A spermatogonia. However, after autologous spermatogonial transplantation, >80% of the tubule cross-sections contained type A spermatogonia. In addition, only 20% of the tubules of the control testes contained spermatocytes and, except for a few tubules (5%) with round spermatids, no more advanced germ cells were found. After autologous spermatogonial transplantation, about 60% of the tubules contained spermatocytes; 30% contained spermatids and in about 15% of tubules spermatozoa were found. No improvement in spermatogonial repopulation was found after homologous transplantation. The results of this study demonstrate, for the first time, successful autologous transplantation of bovine spermatogonial stem cells resulting in a complete regeneration of spermatogenesis.
Fas and Fas ligand protein and mRNA in normal and atretic mouse ovarian follicles
Authors: Dharma SJ , Kelkar RL , Nandedkar TD
Published: March 2004

Apoptosis is the underlying mechanism of follicular atresia in the mammalian ovary. However, the apoptotic pathways governing this ovarian process are not completely elucidated. In the present study, expression of Fas and Fas ligand, the proximal members of the death receptor pathway, was evaluated in mouse ovarian follicles using immunofluorescence and in situ hybridization. Normal or atretic follicles were obtained from immature female Swiss mice after administration of 10 iu equine chorionic gonadotrophin for 48 or 72 h, respectively. Expression of both Fas and Fas ligand mRNA and protein was observed in granulosa cells of normal and atretic follicles. Although the oocytes of normal follicles failed to show any staining, those of atretic follicles stained intensely for Fas, indicating that the presence of Fas in the oocyte determines the fate of the follicle.
Expression of Fas and Fas ligand protein and mRNA in mouse oocytes and embryos
Authors: Kelkar RL , Dharma SJ , Nandedkar TD
Published: March 2004

During mammalian embryonic development, abnormal eggs and embryos are eliminated by apoptosis; however, the precise apoptotic pathways remain as yet unidentified. In the present study, expression of Fas and Fas ligand - the proximal members of the death receptor pathway, was evaluated in mouse preimplantation embryos by immunofluorescence and in situ hybridization techniques. Ovulated oocytes were collected from oviducts of cyclic mice on the day of oestrus (day 0), and one-cell, two-cell embryos and eight-cell morulae were collected from oviducts of mated animals on days 1, 2 and 3 of pregnancy, respectively. Blastocysts were flushed from the uterine horns on day 4. Expression of Fas and Fas L mRNAs and proteins was absent from embryos at days 0, 1 and 2. A marked increase in Fas and Fas L mRNA and protein expression was detected in all morphologically normal embryos on day 3 and day 4. In addition, embryos on days 3 and 4 were positive for terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL) staining; however, absence of caspase 8 and 3 and intense localization of proliferating cell nuclear antigen confirmed the proliferative status of these embryos. Furthermore, TUNEL staining was absent in postimplantation embryonic sections obtained on day 6. The results of the present studies thus indicate an equilibrium between proliferation and apoptosis in the preimplantation embryo.
Overcoming poor in vitro nuclear maturation and developmental competence of domestic cat oocytes during the non-breeding season
Authors: Comizzoli P , Wildt DE , Pukazhenthi BS
Published: March 2004

The domestic cat experiences circannual variations in ovarian activity and intrafollicular oocyte quality. One result is poor nuclear and cytoplasmic maturation during in vitro maturation (IVM) conducted during the annual non-breeding season (July through November). In an attempt to overcome this seasonal phenomenon immature oocytes were collected from July through November and cultured in a conventional IVM medium (IVM1) or in IVM1 supplemented with different FSH concentrations and antioxidant (ascorbic acid or cysteine). Nuclear status of oocytes was assessed after IVM or IVF. Embryo stage and blastocyst quality were evaluated after 7 days of in vitro culture. Although the addition of antioxidant alone had no effect, the presence of 10 microg FSH ml(-1) improved nuclear maturation (75.4+/-4.1% versus 48.7+/-8.8% in IVM1; P<0.05) and fertilization success (47.9+/-3.2% versus 35.0+/-5.1% in IVM1; P<0.05). Furthermore, developmental competence of fertilized oocytes was enhanced (P<0.05) only in the presence of ascorbic acid (30.6+/-6.7%) or cysteine (33.6+/-5.1%) compared with IVM1 (8.1+/-8.8%). Consequently, blastocyst yield (17% of total oocytes cultured) was highest when oocytes were matured in medium containing higher FSH concentration and antioxidants. The results of this study demonstrate that meiotic and developmental competences are inherent to the immature cat oocyte collected during the non-breeding season. However, appropriate mechanisms (perhaps seasonal variation in FSH receptors or lack of antioxidant capacity of the cumulus-oocyte complex) are inadequate during this period of gonadal quiescence. Regardless, this compromised oocyte function during the non-breeding season can be overridden by altering in vitro culture conditions to include supplemental FSH and antioxidant.
Boosting the Efficiency of Quantum Dot‐Sensitized Solar Cells Over 17% via Sequential Deposition of Water‐ and Oil‐Soluble Quantum Dots
Authors: Zhang Zhengyan , Wang Wenran , Rao Huashang , Pan Zhenxiao , Zhong Xinhua
Published: February 2025

High loading of quantum dots (QDs) on TiO2 photoanode is essential for high power conversion efficiency (PCE) for quantum dot‐sensitized solar cells (QDSCs). However, there remains a large portion (≈60%) of TiO2 substrate uncovered by QDs, which results in insufficient light harvesting and the undesired charge recombination, consequently suppressing the enhancement of performance in QDSCs. Herein, a convenient and effective method for improving QD loading is proposed, wherein a direct deposition (DA) mode is carried out after a chemical deposition of capping ligand‐induced self‐assembly (CLIS). It is found that the DA compared with CLIS modes leads to different adsorption behaviors and the interactions of QDs with TiO2 substrate, thus additional QDs can be successfully deposited. The elevated QD loading amount enhances the light‐harvesting capability and effectively inhibits undesired charge recombination at the photoanode/electrolyte interfaces. Consequently, the average PCE is boosted to 16.89% from the pristine 14.95%, and a champion PCE of 17.04% is achieved, which is the new record for liquid‐junction QDSCs.
Cholesterol Cocrystal Ferroelectrics Modulated by Solvent Effect
Authors: Sun Wenbo , Zhang Han‐Yue , Liu Xiaomeng , Xiong Ren‐Gen
Published: February 2025

Cholesterol (CHOL) is an inherently biodegradable material with multiple chiral centers, being an essential component for cell membranes. Considering the close relationship between chirality and ferroelectric feature, this compound with chiral‐polar structure is an intrinsic polar material. However, the ferroelectricity of CHOL crystals has never been found to date. Herein, a series of ferroelectric cocrystals of CHOL methanol (CHOL‐MeOH) and CHOL ethanol (CHOL‐EtOH) have been constructed through the solvent effect. It is found that the introduction of some solvent molecules containing hydroxyls such as methanol and ethanol can reduce the acceptor···donor length and thus form a 1D electroactive channel and further induce ferroelectricity in CHOL. Based on the density functional theory (DFT) calculation analyses represented by CHOL‐EtOH, the largely decreased maximum energy barrier for the polarization reversal of ≈50% suggests that the electric polarization of the cocrystal is much easier to be reoriented under the external electric field through the solvent effect. These ferroelectric materials show good biocompatibility and biodegradability through in vitro and in vivo evaluation. These attributes make these CHOL cocrystals good candidates for the application of next‐generation smart implantable electronic devices. This work sheds light on the chemical design of biodegradable ferroelectrics in biomaterials.
Organomolecular Ferroelectric Nanocatalyst Augments Tumor Immunotherapy by Inducing Apoptosis and Ferroptosis
Authors: Xu Huning , Qiao Xiaohui , Liang Jing , Qiu Luping , Xue Liyun , Fang Yan , Xiang Huijing , Li Xingguang , Chen Yu , Ding Hong
Published: February 2025

Immunogenic programmed cell death effectively triggers acute inflammatory responses, thereby enhancing antitumor immunity. The advancement of biodegradable nonmetallic dual inducers represents a promising strategy. Herein, a biodegradable organomolecular ferroelectric nanoplatform (C60‐TCNQ, CT) is designed to facilitate effective ferroelectric catalysis, thereby augmenting tumor immunotherapy through apoptosis and ferroptosis. CT‐mediated ultrasound‐triggered ferroelectric catalysis promotes ferroelectric polarization and significantly increases the production of reactive oxygen species, leading to substantial tumor cell apoptosis. Moreover, the polycyano group of CT nanoparticles selectively reacts with cysteine under mild conditions, resulting in redox imbalances and the accumulation of lipid peroxides, which contribute to the induction of ferroptosis in tumor cells. Additionally, the apoptosis and ferroptosis induced by CT stimulate immunogenic cell death progression, eliciting robust immune responses. In vivo evaluation using a bilateral tumor model demonstrates the capacity of CT to sensitize anti‐PD‐L1 therapy under ultrasound irradiation, achieving an impressive antitumor response rate of 96.2% against malignant melanoma and an 80% inhibition of tumor metastasis. RNA sequencing analysis revealed that treatment with CT resulted in a downregulation of gene signatures associated with the immune‐related Jak‐Stat signaling pathway. This study opens a novel avenue to developing organomolecular ferroelectric nanomedicines for effective tumor immunotherapy.
Amyloid‐Templated Ceria Nanozyme Reinforced Microneedle for Diabetic Wound Treatments
Authors: Xuan Qize , Cai Jiazhe , Gao Yuan , Qiao Xinchi , Jin Tonghui , Peydayesh Mohammad , Zhou Jiangtao , Sun Qiyao , Zhan Lijian , Liu Bin , Wang Ping , Li Hui , Chen Chao , Mezzenga Raffaele
Published: February 2025

Amyloid fibrils have emerged as excellent templates and building blocks for the development of ordered functional materials with considerable potential in biomedical applications. Here, lysozyme amyloid fibrils (Lys‐AFs) are employed as templates for the in situ synthesis of ceria nanozymes (Lys‐AFs‐Ceria) with ultrafine dimensions, an optimized Ce3+/Ce4+ ratio, and uniform distribution on the fibril surface, addressing the challenges of low catalytic efficiency and high susceptibility to aggregation typical of traditional methods. As a proof of concept, it is further applied Lys‐AFs‐Ceria to develop hydrogel/microneedle for treating bacteria‐infected diabetic wounds via non‐covalent interactions between polyphenols and amyloid fibrils incorporating glucose oxidase (GOX). The hydrogel/microneedle facilitates superoxide dismutase and catalase cascade catalysis by Lys‐AFs‐Ceria, and integrates GOX‐mediated glucose consumption, synergistically achieving glucose reduction, reactive oxygen species elimination, and hypoxia alleviation in the diabetic wound infection microenvironment. In addition to antibacterial properties and tissue regeneration promotion of Lys‐AFs scaffold, Lys‐AFs‐Ceria regulates macrophages polarization toward an anti‐inflammatory M2 state. Collectively, these attributes contribute to the enhanced efficacy of diabetic wound healing, with in vivo studies demonstrating increased healing efficiency following a single application, and more in general an effective strategy toward high‐catalytic and stable nanozymes.
Optimization of Zirconium Oxide Nanoparticle‐Enhanced Photocurable Resins for High‐Resolution 3D Printing Ceramic Parts
Authors: Trembecka‐Wójciga Klaudia , Jankowska Magdalena , Lepcio Petr , Sevriugina Veronika , Korčušková Martina , Czeppe Tomasz , Zubrzycka Paulina , Ortyl Joanna
Published: February 2025

In this study, photocurable acrylate resins with different concentrations of zirconium oxide (50% and 70% by weight) are polymerized according to a radical mechanism. The research focused on three main aspects: 1) the effect of ZrO₂ nanoparticles on the kinetics of photopolymerization, 2) the optimization of digital light processing (DLP) 3D printing conditions for nanoparticle‐filled and unfilled resins, and 3) the influence of nanoparticle addition on the thermomechanical properties of the 3D‐printed structures. Photopolymerization kinetics are examined using photo‐DSC and photo‐rheology to assess the impact of nanoparticles on polymerization rates, shrinkage, and induction times. Despite challenges related to limited light penetration in highly nanoparticle‐filled resins, optimal printing parameters are established, enabling the fabrication of high‐performance 3D‐printed materials. The inclusion of ZrO₂ nanoparticles significantly enhances the thermomechanical properties of the final products, demonstrating the potential for advanced applications in additive manufacturing.
Revolutionizing the Future of Smart Materials: A Review of 4D Printing, Design, Optimization, and Machine Learning Integration
Authors: Azher Kashif , Nazir Aamer , Farooq Muhammad Umar , Haq Muhammad Rizwan ul , Ali Zulfiqar , Dalaq Ahmed S. , Abubakar Abba Abdulhamid , Hussain Sajjad , Syed Mujahid Naqeebuddin , Ullah Abid , Laghari Rashid Ali , Khan Sikandar
Published: February 2025

With technological advancement and development, there is a tremendous increase in demand for different smart materials because of their stimulation from external sources. Moreover, the time‐dependent response of smart materials provides insight into the fabrication of these materials using 4D printing (4DP) techniques. Hence, this study presents a comprehensive review of the 4DP of smart materials. The review covers different aspects of smart material, from design and optimization to printing. Herein, smart materials have been discussed in detail based on the physical, biological, and chemical stimuli‐responsive and their subtype's behavior. For designing smart materials, different usage of tools such as new designing software, finite element analysis, and machine learning are also discussed. The design of smart materials is challenging because of the different responsive natures and complexity of design and mechanisms. Hence, a detailed review of present 3D printing techniques, the use of 4DP, and how future applications can be incorporated with smart material and 4DP is presented. With the help of machine learning, the fabrication of smart materials using 4DP is also discussed. The review provides future directions for fabricating smart materials using 4DP. The design and printing challenges of smart materials for future utilization have also been comprehensively covered.
Extreme‐Wideband Transmission/Shielding Switching in a Dual‐Polarized Reconfigurable Metasurface with High Incident Angle Tolerance
Authors: Shi Haoyang , Tian Jie , Wu Xiangming , He Chong , Zhu Weiren
Published: February 2025

A thin screen with tunable transmission/shielding properties plays a pivotal role in various electromagnetic and communication systems. Despite extensive research efforts dedicated to investigating this type of metasurfaces, achieving an ultra‐wideband design remains a formidable challenge. This paper introduces a dual‐polarized reconfigurable metasurface capable of switchable transmission and shielding, highlighting features such as extremely wideband and high incident angle tolerance. The proposed metasurface primarily operates in four distinct modes: transmission or shielding for both TE and TM‐polarized waves, in addition to polarization‐selective transmission for either TE or TM waves. Simulation and experimental results have verified that the metasurface demonstrates an exceptionally wide bandwidth ranging from 0.1 to 4 GHz (with a relative bandwidth of 190%), with efficient switchable transmission and shielding functions. Furthermore, the ultra‐compact periodic structure endows the meta‐device with exceptional insensitivity to incident angles. Within the frequency range of 0.1–1.6 GHz, the metasurface consistently exhibits high levels of transmission and shielding for both TE and TM waves across incident angles up to 80°. The reconfigurable metasurface introduced in this paper possesses ultra‐wideband capabilities and high versatility, demonstrating significant potential across the fields of electromagnetic compatibility, interference suppression, and antenna design.
Double‐sided control of product type preference in the visible‐light initiated reaction of 1,3‐dicarbonyl compounds with alkenes
Authors: Pałyga Małgorzata , Rzepiela Jan , Baś Sebastian
Published: February 2025

Abstract. The demonstrated light‐initiated addition of radicals formed on an active methylene group to styrene derivatives exhibits a product selectivity influenced by the presence of a protic solvent. Under protic conditions, the predominant products are branched compounds with the alkene moiety attached to the methylene group. In the absence of a proton source, an alkene is incorporated between the carbonyl group and the methylene group, forming products known from the De Mayo reaction. The utility of the presented method was confirmed by a broad substrate range of alkenes and compounds bearing active methylene groups. A comprehensive mechanistic study revealed that both types of products can be formed via the radical pathway. This suggests a previously unreported mechanistic path as an alternative to the De Mayo reaction, which gives the same type of products.