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High-power light-emitting diodes (LEDs) today are twice as powerful as four years ago while meantime their price has been divided by 4 making them promising sources for laser pumping. However, their irradiance still falls short by one order of magnitude of what is needed to efficiently pump solid-state lasers. We demonstrate that an LED-pumped Ce:YAG luminescent concentrator (LC) can increase the irradiance of blue LEDs by a factor of 10, with an optical efficiency of 25%, making them much more suitable to pump solid-state lasers. In our demonstration, we used 100 Hz pulsed LEDs emitting 190  W/cm^2 at 430 nm to illuminate a Ce:YAG LC, leading to an output irradiance of 1830  W/cm^2. The LC is used to pump a Nd:YVO_4 laser producing 360 μJ at 1064 nm, corresponding to an optical efficiency of 2.2% with respect to the LC. LED-pumped luminescent concentrators pave the way for high-power, low-cost, solid-state lasers.

Brevundimonas vesicularisis a non-fermenting gram-negative bacillus, aerobic and motile. This microrganism is ubiquitous in the environment and has rarely been implicated in human infections. We present the second case of cutaneous infection caused by B. vesicularisin an immunocompetent patient.

Although supraphysiological levels of 1α, 25 dihydroxyvitamin D3 (VD) have been demonstrated extensively to induce the monomacrophagic differentiation of leukemic myelo‐ and monoblasts, little is known about the role that physiological levels of this vitamin could play in the regulation of normal hematopoiesis. To clarify this issue, we adopted a liquid‐culture model in which cord blood CD34+ hematopoietic progenitors, induced to differentiate in the presence of different combinations of cytokines, were exposed to VD at various concentrations and stimulation modalities. The data obtained show that physiological levels of VD promote a differentiation of CD34+ hematopoietic progenitors characterized by the induction of all the monomacrophagic immunophenotypic and morphological markers. This effect is not only exerted at the terminal maturation but also at the commitment level, as demonstrated by the decrease of highly undifferentiated CD34+CD38− hematopoietic stem cells, the down‐regulation of CD34 antigen, and the increase of monocyte‐committed progenitors. Molecular analysis suggests that the VD genomic signaling pathway underlies the described differentiation effects.

The present study analyses the susceptibility of human bladder-derived cells (HT-1376) to the infection by herpes simplex virus type 2 (HSV-2) andChlamydia trachomatis, as well as to the adhesiveness of uropathogenic bacteria. HT-1376 cells were efficiently infected by HSV-2 strain 333, as demonstrated by immunofluorescence staining of viral antigens, titration of cytopathic effect, and visualisation by transmission electron microscopy. This cell model was also prone toC. trachomatis(serovar E, Bour strain) replication and to the adherence of clinical uropathogenic isolates ofEscherichia coli,Pseudomonas aeruginosa, Proteus vulgarisandEnterococcus faecalis. The pre-infection of HT-1376 cells with HSV-2 caused a tenfold increased adherence of anE. colistrain (U1), isolated from a patient affected by severe haemorrhagic cystitis, whereas in HSV-2 pre-infected cells the number ofC. trachomatisinclusion bodies was significantly reduced. Our findings indicate that these cells are a suitable in vitro model for studying infection and super-infection of the lower urinary tract by viruses and bacteria.

The aim of the study was to evaluate the plasma thromboxane and plasma viscosity in relation with Doppler flow parameters in postmenopausal patients treated with hormone replacement therapy.Thirty-two postmenopausal (follicle-stimulating hormone >40 IU/l and estradiol < WO pmol/l) women (mean age pmSD, 54.7 pm2.9 years) participated in the study and were submitted to continuous estradiol transdermal supplementation and 12-day courses of medroxyprogesterone acetate every second month. Doppler resistances at the level of the uterine and internal carotid arteries, thromboxane plasma levels and plasma viscosity were analyzed in basal condition and after 1, 3 and 6 months.During hormone supplementation, the pulsatility index significantly decreased at the level of the analyzed arteries. Similarly, plasma thromboxane levels and plasma viscosity were significantly reduced. Significant correlations were found between thromboxane plasma concentrations, plasma viscosity and uterine artery resistances. Thus hormone replacement therapy seems to be responsible for both direct and indirect modifications at the level of the vessel wall physiology.

The aim of the present study was to evaluate possible variations in cardiac hemody-namic parameters related to the natural changes of ovarian estrogen production.

Antisera against adrenocorticotropic hormone (ACTH), α-melanocyte stimulating hormone (α-MSH) and β-endorphin were used to localize, by immunohistochemistry, proopiomelanocortin (POMC)-derived peptides in the skin excised from different regions of the African lungfish Protopterus annectens. Immunoreactivity was observed in the epidermis mainly in the germinal layer. Using human POMC cDNA as hybridization probe, POMC-like mRNA was identified in situ in epidermal cells. The demonstration in the same cells of POMC mRNA and POMC-related peptides immunoreactivity indicates a local production of opiate hormones.

The objective of the study was to evaluate, in patients with unexplained infertilty, the possible relationship between anticardiolipin antibodies and indices of uterine artery Doppler measurements. A total of 46 infertile women participated in the study and underwent ovarian stimulation. Transvaginal ultrasonography and colour Doppler were performed on the day of embryo transfer and patients were divided on the basis of pulsatility index (PI): group I, PI <2.5; group II, PI 2.5-3.0; and group III, PI >3.0. On the same day that Doppler analysis took place, peripheral blood was obtained and circulating anticardiolipin antibodies were assayed. The response to ovarian stimulation was similar in the three studied groups. No significant differences in oestradiol and ultrasonographic parameters were observed between the groups. A significant increase in anticardiolipin antibodies was observed in those patients with higher resistance to flow at the level of the uterine artery. A significant relationship was found between the uterine artery PI and anticardiolipin immunoglobulin G class (F = 14.35; P = 0.001), and immunoglobulin M class (F = 5.88; P = 0.020). It is concluded that, in unexplained infertility, anticardiolipin antibodies may be involved in uterine vascular modifications and that Doppler flow analysis of uterine arteries may be an important tool in the assessment and management of ovarian stimulation.

Several data emphasize the neuroendocrine aspects of human placenta. Classical hypophyseo-tropic neurohormones are produced and secreted by the human placenta. Indeed, in contrast with non pregnant subjects, gonadotropin-releasing hormone (GnRH) and corticotropin-releasing factor (CRF) are measurable in maternal plasma during pregnancy. The aim of the present study was to investigate the characteristics of the secretory pattern of maternal plasma GnRH and CRF levels. A total of 25 healthy pregnant women participated in the present cross-sectional study. Plasma levels of the two neurohormones were measured according to three different time-intervals: 1) every five minutes for eight hours (n=4), 2) every ten minutes for four hours (n= 15), 3) every four hours for 24 hours (n =7). Following an acidic extraction plasma GnRH and CRF levels were measured by specific radioimmunoassay. Using two different algorithms (Detect and Cluster) a pulsatile pattern for both plasma GnRH and CRF levels was observed. Specific pulse frequency, amplitude, and duration were found. In the groups of women studied with a longer sampling interval, pulse frequency of GnRH or CRF levels did not differ between first and third trimester of gestation. However, amplitude of CRF pulses were significantly higher at term than at early stages of pregnancy (p≤0.01), while GnRH pulse amplitude was highest in women at first trimester of gestation. Evaluating the degree of concordance in all subjects, GnRH pulses significantly correlated with CRF pulses at 30 min. lag (p≤0.01). No significant circadian changes were found for any circulating neurohormone measured. The present study showed that maternal circulating neurohormone levels change according to a pulsatile pattern, probably reflecting the placental secretory events.

To evaluate maternal serum activin A levels in pregnant women at parturition, correlated to the mode of delivery, and to localize activin receptor messenger RNA in human placenta and fetal membranes.

The high concentration of pro-opiomelanocortin (POMC)-derived peptides in human follicular fluid, which is several times higher than in plasma, suggested a local expression of the POMC gene. This has previously been observed in the animal ovaries. Peripheral POMC-like mRNAs are not translated in POMC-derived peptides but recent evidence supports the presence of a small amount of full-length transcript in human testes and lymphocytes. The purpose of this study was to test two hypotheses: firstly, that there is a different pattern of POMC mRNA expression in the human ovary of fertile and post-menopausal women, and secondly that there is a tissue-specific localization of POMC transcript. Northern blot analysis showed that a potential relationship exists between POMC gene expression and the reproductive age of a woman, and that POMC mRNA has a tissue-specific localization. The expression of POMC messenger in the ovarian parenchyma collected from women of fertile age and in the germinative follicles appeared higher than that observed in samples from post-menopausal women. No signals were detected in corpora lutea. In conclusion, we believe that the physiological role of the POMC gene in the human ovary remains an unsolved problem, necessitating more sensitive methods of mRNA detection as well as further studies in vitro.

Gallinelli A, Gallo R, Genazzani AD, Matteo ML. Caruso A, Woodruff TK. Petraglia F. Episodic secretion of activin A in pregnant women. Eur J Endocrinol 1996,135:340–4. ISSN 0804–4643The aim of the present study was to determine the characteristics of activin A secretion in women with normal and abnormal pregnancy. With this purpose, a prospective study was done to evaluate the putative pulsatile pattern of serum activin A in serial specimens of blood collected during a certain amount of time (every 15 min for 3 h). A group of pregnant women (N = 24) participated in a crosssectional study. They were subdivided into three groups: healthy pregnant women (N = 8), patients with preterm labor (N = 8) and patients with gestational diabetes (N = 8) before and after insulin therapy. Secretory pulses of serum activin A were determined in all patients with a specific frequency and amplitude by using two different computerized analyses, i.e. DETECT and CLUSTER. Mean ± semvalues of serum activin A were significantly higher in patients with preterm labor and gestational diabetes than in controls (p < 0.01), showing a significant decrease following insulin therapy in diabetic patients (p < 0.01). Specific pulses of serum activin A levels were observed in all women. The mean pulse frequency did not change significantly between healthy controls and the different pathological groups. Patients with gestational diabetes after insulin therapy showed a pulse frequency that was significantly higher than in controls (p < 0.05). When the mean peak amplitude of activin A pulses was evaluated, patients with preterm labor or gestational diabetes showed values that were significantly higher than in healthy pregnant women (p < 0.01). A significant, inverse correlation between pulse frequency and amplitude was found both in healthy pregnant women (p < 0.05) and in patients with gestational diabetes (p < 0.001). The present study showed that circulating activin A levels in pregnant women change in a pulsatile pattern whose pulse amplitude is modified in the presence of gestational diseases, such as preterm labor or gestational diabetes.Felice Petraglia, Department of Obstetrics and Gynecology, University of Pisa, via Roma 67, 56100 Pisa, Italy

The high concentration of pro-opiomelanocortin (POMC)derived peptides in human follicular fluid, which is several times higher than in plasma, suggested a local expression of the POMC gene. This has previously been observed in the animal ovaries. Peripheral POMC-like mRNAs are not translated in POMC-derived peptides but recent evidence supports the presence of a small amount of full-length transcript in human testes and lymphocytes. The purpose of this study was to test two hypotheses: firstly, that there is a different pattern of POMC mRNA expression in the human ovary of fertile and post-menopausal women, and secondly that there is a tissue-specific localization of POMC transcript. Northern blot analysis showed that a potential relationship exists between POMC gene expression and the reproductive age of a woman, and that POMC mRNA has a tissue-specific localization. The expression of POMC messenger in the ovarian parenchyma collected from women of fertile age and in the germinative follicles appeared higher than that observed in samples from postmenopausal women. No signals were detected in corpora lutea. In conclusion, we believe that the physiological role of the POMC gene in the human ovary remains an unsolved problem, necessitating more sensitive methods of mRNA detection as well as further studies in vitro.

Nitric Oxide (NO) recently becomes of clinical interest because of its relaxant effects on smooth muscle. In addition to endothelial cells, also myometrial cells contain the enzyme implicated in the No production. This review is aimed toward those studies concerned with the production, metabolism, and effects of NO that could be relevant for the obstetricians. The potential clinical interest of such information covers the main areas of pregnancy complications, namely preterm delivery, preeclampsia, and intrauterine growth retardation. Moreover, original data are included in order to support the therapeutical implications of the manipulation of L-arginine-NO system in case of pregnancy disorders.