Metastable CrMnNi steels processed by laser powder bed fusion: experimental assessment of elementary mechanisms contributing to microstructure, properties and residual stress.

The complex thermal history imposed by the laser-based powder bed fusion of metals (PBF-LB/M) process is known to promote the evolution of unique microstructures. In the present study, metastable CrMnNi steels with different nickel contents and, thus, different phase stabilities are manufactured by PBF-LB/M. Results clearly reveal that an adequate choice of materials will allow to tailor mechanical properties as well as residual stress states in the as-built material to eventually redundantize any thermal post-treatment. The chemical differences lead to different phase constitutions in as-built conditions and, thus, affect microstructure evolution and elementary deformation mechanisms upon deformation, i.e., twinning and martensitic transformation. Such alloys designed for additive manufacturing (AM) highlight the possibility to tackle well-known challenges in AM such as limited damage tolerance, porosity and detrimental residual stress states without conducting any post treatments, e.g., stress relieve and hot isostatic pressing. From the perspective of robust design of AM components, indeed it seems to be a very effective approach to adapt the material to the process characteristics of AM.

A lever action hypothesis for pendulous hummingbird flowers: experimental evidence from a columbine.

BACKGROUND AND AIMS: Pendulous flowers (due to a flexible pedicel) are a common, convergent trait of hummingbird-pollinated flowers. However, the role of flexible pedicels remains uncertain despite several functional hypotheses. Here we present and test the 'lever action hypothesis': flexible pedicels allow pendulous flowers to move upwards from all sides, pushing the stigma and anthers against the underside of the feeding hummingbird regardless of which nectary is being visited. METHODS: To test whether this lever action increased pollination success, we wired emasculated flowers of serpentine columbine, Aquilegia eximia, to prevent levering and compared pollination success of immobilized flowers with emasculated unwired and wire controls. KEY RESULTS: Seed set was significantly lower in wire-immobilized flowers than unwired control and wire control flowers. Video analysis of visits to wire-immobilized and unwired flowers demonstrated that birds contacted the stigmas and anthers of immobilized flowers less often than those of flowers with flexible pedicels. CONCLUSIONS: We conclude that flexible pedicels permit the levering of reproductive structures onto a hovering bird. Hummingbirds, as uniquely large, hovering pollinators, differ from flies or bees which are too small to cause levering of flowers while hovering. Thus, flexible pedicels may be an adaptation to hummingbird pollination, in particular due to hummingbird size. We further speculate that this mechanism is effective only in radially symmetric flowers; in contrast, zygomorphic hummingbird-pollinated flowers are usually more or less horizontally oriented rather than having pendulous flowers and flexible pedicels.

Obesity and its relationship to infertility in men and women.

This review focuses on the negative impact of obesity in reproduction by considering the pathophysiology of obesity and infertility in men and women, the influence of obesity on the prevalence of polycystic ovary syndrome, and the benefits of weight loss on reproduction and on menstruation, ovulation, semen parameters, and reproductive outcomes.

Impact of ovarian endometrioma on assisted reproduction outcomes.

The effects of ovarian endometrioma on fertility outcomes with IVF and embryo transfer have been causally related to poor outcomes. The objective of this meta-analysis was to evaluate the ovarian reserve and ovarian responsiveness to ovarian stimulation and assisted reproduction outcomes in patients with ovarian endometrioma. The odds for clinical pregnancy were not affected significantly in patients with ovarian endometrioma compared with controls, with an overall odds ratio of 1.07 from three studies [95% CI: (0.63, 1.81), P = 0.79]. The overall pregnancy rate was similar with an estimated odds ratio of 1.17 [95% CI: (0.85, 1.60), P = 0.34]. Decreased ovarian responsiveness to ovarian stimulation in patients with ovarian endometrioma may be due to a reduced number of follicles in these patients compared with controls (P = 0.002). Prospective randomized controlled trials are needed to assess whether surgical treatment versus no surgical treatment improves pregnancy outcomes in patients with ovarian endometrioma undergoing assisted reproduction cycles.

Comparison of two culture systems for the in-vitro growth and maturation of mouse preantral follicles.

The objective of our study was to compare to ability of collagen-treated membranes and bovine collagen gels to maintain murine preantral follicle growth and development in-vitro. To fulfill that objective, murine follicle and oocyte growth rates were followed for ten days in culture. Meiotic competence and the capacity to reach the two-cell stage after in-vitro maturation and fertilization, respectively, were then assessed. We used preantral follicles from 12 day-old CF-1 female mice that were isolated by enzymatic digestion from ovaries. Follicles were placed either on collagen-treated membranes or embedded in a bovine collagen matrix. The follicles were grown, changing the media and obtaining measurements every other day for ten days. Following culture, the granulosa-oocyte complexes were matured; the resultant metaphase II arrested oocytes were inseminated and cultured to the two-cell stage. The data was analyzed with significance considered for probability values of p < 0.05. We performed individual measurements on 650 follicles in seven separate experiments. Forty-eight hours after initial seeding and throughout the entire length of culture, both the follicles and oocytes grown in the collagen matrix were larger than follicles cultured on collagen-treated membranes (p < .0001). However, oocyte recovery rates were higher among follicles cultured on collagen-treated membranes (p < .01). Similar percentages of meiotically competent oocytes, fertilization and cleavage rates were observed in both groups. Our results show that mouse preantral follicles display a greater growth rate when grown embedded in a collagen gel matrix. This may be due to the maintenance of a normal three-dimensional organization of the follicle within the collagen matrix. However, this system does not enhance meiotic competency or fertilization rates in the mouse when compared to culture on collagen-treated membranes.

Treatment of murine breast cancer cells with antisense RNA to the type I insulin-like growth factor receptor decreases the level of plasminogen activator transcripts, inhibits cell growth in vitro, and reduces tumorigenesis in vivo.

AIMS: To establish that cells from the murine mammary carcinoma cell line, EMT6, express type I insulin-like growth factor receptor (IGF-IR), tissue-type plasminogen activator (tPA), and urokinase-type plasminogen activator (uPA). To investigate the role of IGF-IR in growth, transformation, and tumorigenesis in addition to its relation to tPA and uPA in EMT6 cells. To assess the suitability of the EMT6/syngeneic mouse model for studying the role of IGF-IR in tumorigenesis. METHODS: The presence of transcripts for IGF-IR, tPA, and uPA was determined by northern blot analysis using poly (A(+)) RNA derived from EMT6 cells transfected with an antisense IGF-IR construct or a construct lacking the antisense IGF-IR insert. Flow cytometry was used to measure IGF-IR protein. Assays were performed to determine cell proliferation, transformation, and the tumorigenicity of antisense IGF-IR transfected EMT6 cells and control transfected EMT6 cells. RESULTS: There was strong expression of IGF-IR, tPA, and uPA in EMT6 cells. EMT6 cells from clones carrying antisense IGF-IR displayed a significant decrease in cell proliferation and lost the ability to form colonies in soft agar. A decrease in tumour size occurred when cells carrying the antisense IGF-IR were injected into syngeneic mice. Reduced expression of tPA and uPA was seen in EMT6 cells carrying the antisense IGF-IR construct. CONCLUSIONS: The IGF-IR plays a role in the progression, transformation, and tumorigenesis of EMT6 murine mammary carcinoma cells. The suppression of IGF-IR mRNA in EMT6 cells decreases tPA and uPA expression. EMT6 cells and the syngeneic mouse provide a suitable model for studying the role of IGF-IR in breast tumour progression.

[Decreasing susceptibility to vancomycin in isogenic Staphylococcus aureus strains isolated from a single patient]. / Sensibilidad disminuida a vancomicina en cepas isogénicas de Staphylococcus aureus aisladas del mismo paciente.

BACKGROUND: We aimed at evaluating the microbiological characteristics and clinical implication of 7 isogenic strains of Staphylococcus aureus with decreased susceptibility to vancomycin. SUBJECT AND METHOD: A patient with nosocomial trival vularendocarditis due to methicillin-resistant S. aureus had positive blood cultures for 8 weeks despite antimicrobial therapy with vancomycin (normal serum levels) and rifampicin. The patient rejected surgical treatment but the process cured with antimicrobial therapy. The epidemiological relationship of strains was evaluated by pulsed field gel electrophoresis. The susceptibility to vancomycin was evaluated by microdilution and E-test using two different in ocula. The activity of oxacillin, ampicillin and cephalotin was evaluated in Mueller Hinton (MH) agar containing different concentrations of vancomycin (0.06 to 4 mg/l). Heteroresistant subpopulations were determined in both MH and brain heart infussion agar containing vancomycin (0.5 to 512 mg/l). All seven strains belonged to the same clone. Vancomycin MIC ranged from 1 mg/l (isolates 1 to 5) to 4 mg/l (isolates 6 and 7). Isolates 6 and 7 displayed differences in pigmentation and slower growth rates. The susceptibility of these isolates to betalactams inMH containing different concentrations of vancomycin was greater than that in controls. Subpopulations heteroresistant to vancomycin were not detected. CONCLUSION: The decreased susceptibility of the isogenic S. aureus strains evaluated in this study was not due to heteroresistance and did not cause therapeutic failure.

Subclavian deep vein thrombosis associated with the use of recombinant follicle-stimulating hormone (Gonal-F) complicating mild ovarian hyperstimulation syndrome.

OBJECTIVE: To describe two cases of subclavian deep vein thrombosis (DVT) associated with the use of recombinant gonadotropins and mild ovarian hyperstimulation syndrome (OHSS) and review the literature associated with this condition. DESIGN: Retrospective study (case report). SETTING: Tertiary academic IVF program. PATIENT(S): Two women undergoing IVF with intracytoplasmic sperm injection due to male factor infertility. INTERVENTION(S): Ovaluation induction with recombinant FSH, IVF, and therapeutic heparinization. MAIN OUTCOME MEASURE(S): Coagulation studies, resolution of DVT, delivery at term. RESULT(S): Mild OHSS with left subclavian thrombosis occurred in two patients. Laboratory evaluation revealed normal protein C, protein S, antinuclear antibodies (ANA), and absence of antiphospholipid (APA) and anticardiolipin antibodies (ACA). Antithrombin III levels and coagulation studies were also within normal limits. Both patients tested negative for a factor V Leiden mutation and delivered healthy infants at term. CONCLUSION(S): Arm swelling associated with the use of gonadotropins during controlled ovarian hyperstimulation should be promptly evaluated and treated. Subclavian vein thrombosis is a rare complication of ovulation induction, and the possibility that recombinant gonadotropins increase the risk for this complication should be further studied.

Fifteen years experience with an in-vitro fertilization surrogate gestational pregnancy programme.

The purpose of our study was to review and evaluate retrospectively the experience of an in-vitro fertilization (IVF) surrogate gestational programme in a tertiary care and academic centre. In a 15 year period from 1984 to 1999, a total of 180 cycles of IVF surrogate gestational pregnancy was started in 112 couples. On average, the women were 34.4 +/- 4.4 years of age, had 11.1 +/- 0.72 oocytes obtained per retrieval, 7.1 +/- 0.5 oocytes fertilized and 5. 8 +/- 0.4 embryos subsequently cleaved. Sixteen cycles (8.9%) were cancelled due to poor stimulation. Except for six cycles (3.3%) where there were no embryos available, an average of 3.2 +/- 0.1 embryos was transferred to each individual recipient. The overall pregnancy rate per cycle after IVF surrogacy was 24% (38 of 158), with a clinical pregnancy rate of 19% (30 of 158), and a live birth rate of 15.8% (25 of 158). When compared to patients who underwent a hysterectomy, individuals with congenital absence of the uterus had significantly more oocytes retrieved (P < 0.006), fertilized, cleaved and more embryos available for transfer despite being of comparable age. IVF surrogate gestation is an established, yet still controversial, approach to the care of infertile couples. Take-home baby rates are comparable to conventional IVF over the same 15 year span in our programme. Patients with congenital absence of the uterus responded to ovulation induction better than patients who underwent a hysterectomy, perhaps due in part to ovarian compromise from previous surgical procedures.

Gonadotropins induce higher active renin levels in the follicular fluid of normal and hyperstimulated cycles.

The objective of this study was to analyze follicular fluid active renin and its relationship to steroid hormones throughout the normal and gonadotropin-stimulated menstrual cycle. Active renin was measured in the follicular fluid of patients undergoing tubal sterilization (n = 16) and in vitro fertilization (IVF) (n = 25); IVF patients were either in a natural cycle (n = 7) or undergoing controlled ovarian hyperstimulation (n = 18). The largest visible follicle was aspirated at the time of laparoscopic tubal sterilization; ultrasound guided transvaginal follicular aspiration was used in the IVF group. Follicular fluid active renin, estradiol and progesterone levels were measured with immunoradiometric and fluoroimmunoassays. The cycle day was correlated with the spontaneous luteinizing hormone (LH) surge or human chorionic gonadotropin (hCG) administration, as well as active renin, estradiol, progesterone levels and the estradiol/progesterone ratio using simple and multiple regression and analysis of variance (ANOVA). Cycle day independently influenced active renin, progesterone and the estradiol/progesterone ratio in a statistically significant manner (p < 0.0001). The active renin and progesterone levels were highest during the periovulatory period (p < 0.0001 and p < 0.002, respectively) and the estradiol/progesterone ratio correlated inversely with cycle day (p < 0.003). Although the follicular fluid active renin, estradiol and progesterone levels were higher after controlled ovarian hyperstimulation when compared to natural cycles, this difference did not reach statistical significance. Our findings suggest that active renin levels in follicular fluid increase in the follicular phase of the menstrual cycle, reaching peak levels in the periovulatory period following the LH surge or hCG administration, providing indirect support for the hypothesis that the ovarian renin-angiotensin system (RAS) is under gonadotropin control.

Indirect prediction of fetal lung maturity. Value of ultrasonographic colonic and placental grading.

OBJECTIVE: To correlate fetal morphometrics with studies of fetal lung maturity. STUDY DESIGN: One hundred six patients undergoing amniocentesis for fetal lung maturity studies were examined prospectively. Eighty-four patients were normal (79%), and 22 were diabetic (21%). Fetal morphometrics were obtained prior to amniocentesis. The fetal colon and placenta were graded. Discriminant analysis was used to identify variables that were predictive of a mature lecithin/sphingomyelin ratio and the presence of phosphatidylglycerol (PG). All patients delivered within 48 hours of amniocentesis. RESULTS: In the normal group, 28 (33%) fetuses had a grade 3 colon, which was 68% sensitive and 98% specific for a mature amniocentesis. A grade 3 colon was the single best predictor of a mature amniocentesis (P < .001). Twenty-five (29%) fetuses had a grade 3 placenta, which was 64% sensitive and 96% specific for a mature amniocentesis (P < .005). Diabetes did not influence colonic grading since a grade 3 colon was present in seven (32%) patients (47% sensitivity and 100% specificity for PG) (P < .02). Interexaminer and intraexaminer variability for the study was excellent, kappa = 1.0 (P < .001). CONCLUSION: Colonic and placental stage 3 grading are reliable and reproducible ultrasonographic scales that can help predict the findings of fetal lung maturity studies.

Reliability of intraobserver and interobserver sonographic endometrial stripe thickness measurements.

OBJECTIVE: To determine the intraobserver and interobserver reliability of endometrial stripe thickness measurements in women undergoing controlled ovarian hyperstimulation. DESIGN: Prospective blinded study. SETTING: Tertiary care, university hospital. PATIENT(S): Sixty-three patients undergoing controlled ovarian hyperstimulation and being monitored with transvaginal ultrasound were studied. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Intraobserver and interobserver variability of endometrial stripe thickness measurements between 2 blinded observers, with 2 observations made by each observer. RESULT(S): A statistically significant correlation was detected between the 2 measurements of each observer. The mean (+/-SD) interobserver difference between the average of the 2 measurements performed by both observers was 1.02 +/- 0.82 mm. A statistically significant correlation between the measurements of the 2 observers was detected. For both observers A and B, who used < or =6 mm as an abnormal endometrial thickness, an excellent level of agreement was detected between the 2 measurements made on each patient. When comparing the average values obtained by the 2 observers for each of the patients, an excellent level of agreement was detected. CONCLUSION(S): There is an excellent correlation between intraobserver and interobserver measurements of endometrial stripe thickness.

Gonadotropins induce the release of interleukin-1 beta, interleukin-6 and tumor necrosis factor-alpha from the human preovulatory follicle.

PROBLEM: The effects of exogenous gonadotropin administration and steroid levels on the release of various cytokines into the human follicular fluid (FF) were studied. METHOD OF STUDY: Forty patients were included in two groups, those undergoing controlled ovarian hyperstimulation (COH) (n = 33) and natural cycles (n = 7). FF transvaginal aspirations were performed 36 hr after administration of human chorionic gonadotropin or a spontaneous surge of luteinizing hormone, respectively. FF cytokine measurements were performed with sensitive immunoassays. RESULTS: FF cytokine levels were higher after COH [interleukin (IL)-1 beta, 6.6 +/- 0.32 pg/ml; IL-6, 18.7 +/- 2.1 pg/ml; and tumor necrosis factor (TNF)-alpha, 32.5 +/- 4.9 pg/ml] than in natural unstimulated cycles (0.52 +/- 0.1 pg/ml, P < 0.001; 8.9 +/- 1.2 pg/ml, P < 0.01; and 13.2 +/- 2.6 pg/ml, P < 0.001, respectively). FF estradiol (E2) and progesterone levels were not statistically different between groups, despite the higher serum E2 levels observed in patients after COH. CONCLUSIONS: Gonadotropins might regulate ovarian secretion of cytokines, because FF IL-1 beta, IL-6, and TNF-alpha levels after COH were higher than during natural cycles.

Identification of oncofetal fibronectin in patients with advanced epithelial ovarian cancer: detection in ascitic fluid and localization to primary sites and metastatic implants.

BACKGROUND: The mechanisms by which metastatic ovarian cancer adheres to peritoneal surfaces are not well understood. A role for tumor-derived extracellular matrix adhesive molecules such as fibronectin (FN) has been proposed. Because oncofetal fibronectin (onfFN) isoforms function in the adhesion of trophoblasts and have been identified in association with several malignancies, we sought to study onfFN in patients with advanced epithelial ovarian cancer. METHODS: Total FN was identified with the nonspecific anti-FN monoclonal antibody CAF. OnfFN was identified using the specific monoclonal antibodies FDC-6 and X18A4. These antibodies were applied to: 1) ascitic fluid from advanced epithelial ovarian cancer patients and peritoneal fluid from patients without pathologic conditions and 2) tissue sections of primary lesions and metastatic ovarian cancer implants. Comparative histologic specimens included normal ovarian tissue and small bowel implants of endometriosis. RESULTS: When measured by sandwich enzyme-linked immunoadsorbent assay, all peritoneal fluids (32 malignant and 32 benign) contained marked quantities of total (CAF reactive) FN, although malignant ascites had higher concentrations than benign samples (173.2 +/- 36.8 microg/mL vs. 76.4 +/- 31.8 microg/mL; P = 0.001). Malignant ascites also had significantly higher levels of onfFN than benign peritoneal fluid (FDC-6: 3.4 +/- 0.6 vs. 0.9 +/- 0.2 microg/mL; and X18A4: 5.1 +/- 1.3 vs. 1.1 +/- 0.4 microg/mL; P = 0.0001). Immunohistochemical staining of malignant lesions revealed prominent localization of both CAF reactive FN and onfFN to the stroma surrounding epithelial tumor nests. More delicate fibrillar staining within tumor nests also was evident. In contrast, implants of endometriosis revealed strong stromal staining for CAF reactive FN but not for onfFN. CONCLUSIONS: These results demonstrate the presence of onfFN in advanced ovarian malignancies. We speculate that onfFN may participate in tumor-associated peritoneal adhesive interactions.

Hydrosalpinx fluid enhances human trophoblast viability and function in vitro: implications for embryonic implantation in assisted reproduction.

OBJECTIVE: To assess the effects of hydrosalpinx fluid on human cytotrophoblast viability and function in vitro. DESIGN: Human cytotrophoblasts obtained from third-trimester placentas were cultured in vitro with hydrosalpinx fluid, and cell viability and protein production were assayed. SETTING: A university hospital. PATIENT(S): Ten hydrosalpinx fluid samples obtained from seven women with clearly diagnosed hydrosalpinges. INTERVENTION(S): Recovery of hydrosalpinx fluid by transvaginal aspiration or at the time of surgery. MAIN OUTCOME MEASURE(S): Cell viability was assessed by the XTT assay. Secretion of trophoblast oncofetal fibronectin (tropho-uteronectin) and beta-hCG by cultured trophoblasts was determined by Western blot and ELISA of the culture media. RESULT(S): With increasing concentrations of hydrosalpinx fluid from 0% to 20%, there was a significant increase in trophoblast cell viability (1.63-fold increase in 20% hydrosalpinx fluid). Likewise, both Western blot and ELISA assays demonstrated a significant increase in tropho-uteronectin production by trophoblasts with increasing hydrosalpinx fluid concentrations (3.76-fold increase in 20% hydrosalpinx fluid). beta-Human chorionic gonadotropin production also increased significantly in the presence of hydrosalpinx fluid (3.31-fold increase in 20% hydrosalpinx fluid). CONCLUSION(S): These findings suggest that hydrosalpinx fluid improves human trophoblast viability in vitro and enhances the production of tropho-uteronectin and beta-hCG by these cells.

Analysis of the human zona pellucida during culture: correlation with diagnosis and the preovulatory hormonal environment.

PURPOSE: The objective of this study was to analyze sequentially the human zona pellucida changes in an in vitro fertilization program as it relates to several variables. METHODS: The zona pellucida thickness was measured daily in zygotes and cleavage-stage embryos on a Nikon inverted microscope equipped with Hoffman modulation contrast optics, using an ocular micrometer. A total of 512 embryos from 96 patients was evaluated. RESULTS: There was a highly significant direct correlation between zona thickness and preovulatory estradiol and basal day 3 FSH levels (P < 0.02 and P < 0.0006, respectively). This relationship showed a rapid reversal following 48 hr of culture; embryos from patients with the highest FSH levels had thinner zonae prior to transfer (P < 0.0007). The zonae from patients with unexplained infertility were thicker (19.4 +/- 2.7 microns) than those from patients with endometriosis (17.7 +/- 2.2 microns), tubal (17.5 +/- 2.4 microns), or male-factor infertility (16.4 +/- 2.7 microns) (P < 0.0001) on the first day of culture. CONCLUSIONS: We hypothesize that the thickness of the human zona pellucida is influenced by the preovulatory hormonal environment and diagnosis. These factors should be considered as part of the embryo quality evaluation prior to transfer or when assessing the possibility of using assisted hatching. More studies are needed to understand the factors regulating the thickness of the human zona pellucida.

Endometrial changes with chronic tamoxifen use.

Tamoxifen is a nonsteroidal antiestrogenic drug used successfully to reduce recurrences in all stages of breast carcinoma. Recent reports have emphasized an increased incidence of premalignant and neoplastic endometrial changes that have questioned the risk-benefit ratio of this medication. It appears that the use of tamoxifen increases the incidence of endometrial abnormalities in 1.2 individuals per 1000 women treated with tamoxifen, increasing to 6.3 per 1000 women after 5 years. However, current evidence suggests that the use of tamoxifen as an adjuvant for breast carcinoma overrides the risk of developing endometrial neoplasias. It is not clear which long-term method of surveillance is most cost-effective for these patients. Therefore, individuals should be alerted to the potential risks of tamoxifen use. At present, the screening method of choice should be decided by each individual practitioner, bearing in mind that any vaginal bleeding should be readily investigated. If high-grade hyperplasias of the endometrium or cancer are found, management should be tailored in conjunction with the physician responsible for the woman's breast care.