Heat release at the wetting front during capillary filling of cellulosic micro-substrates.

Spontaneous imbibition in cellulosic materials is an expanding field of research due to the direct applicability in paper-based microfluidics. Here, we show experimentally, using simultaneous thermal and optical imaging that the temperature at the wetting front during capillary filling of paper is temporarily increased, even if the imbibed fluid and the cellulosic substrate are initially at isothermal conditions. Several liquids and two types of filter paper, characterised by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis, were investigated demonstrating a significant temperature rise at the wetting front that cannot be neglected form the process. The temperature rise is found to be related to the energetics of imbibition compounds, including acid-base contributions, that result in electrostatic attractions as the liquid molecules are adhered on the fiber surfaces upon capillary contact.

Numerical modeling of compensation mechanisms for peripheral arterial stenoses.

The goal of this paper is to develop a numerical model for physiological mechanisms that help to compensate reduced blood flow caused by a peripheral arterial stenosis. Thereby we restrict ourselves to the following compensation mechanisms: Metabolic regulation and arteriogenesis, i.e., growth of pre-existing collateral arteries. Our model is based on dimensionally reduced differential equations to simulate large time periods with low computational cost. As a test scenario, we consider a stenosis located in the right posterior tibial artery of a human. We study its impact on blood supply for different narrowing degrees by the help of numerical simulations. Moreover, the efficiency of the above compensation mechanisms is examined. Our results reveal that even a complete occlusion of this artery exhibiting a cross-section area of 0.442cm(2) can be compensated at rest, if metabolic regulation is combined with collateral arteries whose total cross-section area accounts for 8.14% of the occluded artery.

Maternal and foetal outcomes in pregnant systemic lupus erythematosus patients: an incident cohort from a stable referral population followed during 1990-2010.

OBJECTIVES: To assess the impact of systemic lupus erythematosus (SLE) on pregnancy outcome in a cohort of incident pregnant lupus patients referred to a Danish university hospital during 1990-2010. METHOD: All pregnant lupus patients were referred to the university hospital from a stable referral area with approximately 1.4 million inhabitants. Eighty-four pregnancies in 39 women were registered using the Danish National Registry and retrospective reviewing of medical records, laboratory results, and midwifery records from the Department of Rheumatology, the Department of Obstetrics and Gynaecology, and possible other departments. Data were compared to 29 059 births during 2005-2010, covering all births from the referral area. RESULTS: The 84 SLE pregnancies resulted in 62 live births. SLE flares developed in 46.4%, pre-eclampsia in 8.3%, and HELLP syndrome in 4.8% of cases. Significantly higher rates of premature delivery (p=0.0032), caesarean section (p=0.015), hypertension (p=0.025), and intrauterine growth retardation (IUGR) (p=0.003) were found. Disease activity significantly (p=0.021) increased the risk of prematurity threefold. Antiphospholipid antibody (aPL) presence significantly (p=0.002) increased the risk of spontaneous abortion threefold. Two babies died after extreme preterm birth. Two had neonatal lupus syndrome (NLS) and one had congenital heart block (CHB). Birth weight and length were significantly lower in the SLE cohort. An unexpectedly high number of cardiac septum defects (9.7%) were observed. CONCLUSIONS: From a stable referral area, an incident cohort of SLE pregnancies were mostly successful, but maternal and foetal complications were observed in one-half and one-third of cases, respectively. Outcome risk factors were identified. A possible new observation is a high frequency of cardiac septum defects.

Simultaneous thermal and optical imaging of two-phase flow in a micro-model.

In the study of non-equilibrium heat transfer in multiphase flow in porous media, parameters and constitutive relations, like heat transfer coefficients between phases, are unknown. In order to study the temperature development of a relatively hot invading immiscible non-wetting fluid and, ultimately, approximate heat transfer coefficients, a transparent micro-model is used as an artificial porous medium. In the last few decades, micro-models have become popular experimental tools for two-phase flow studies. In this work, the design of an innovative, elongated, PDMS (polydimethylsiloxane) micro-model with dimensions of 14.4 × 39 mm(2) and a constant depth of 100 microns is described. A novel setup for simultaneous thermal and optical imaging of flow through the micro-model is presented. This is the first time that a closed flow cell like a micro-model is used in simultaneous thermal and optical flow imaging. The micro-model is visualized by a novel setup that allowed us to monitor and record the distribution of fluids throughout the length of the micro-model continuously and also record the thermal signature of the fluids. Dynamic drainage and imbibition experiments were conducted in order to obtain information about the heat exchange between the phases. In this paper the setup as well as analysis and qualitative results are presented.

Randomised trial of cervical cerclage, with and without occlusion, for the prevention of preterm birth in women suspected for cervical insufficiency.

OBJECTIVE: To evaluate the effect of cerclage, with and without cervical occlusion. DESIGN: Multicentre, stratified, randomised controlled trial. SETTING: Hospital-based multicentre study with 18 tertiary centres from nine countries. POPULATION: Women with a history of cervical insufficiency (prophylactic trial) and women with a short cervix (therapeutic trial) were recruited from August 2006 to August 2011. METHODS: A centralised telephone randomisation service with a computer system was used to randomise women to cervical cerclage with or without cervical occlusion. Only the analyst performing the interim analyses was blinded. MAIN OUTCOME MEASURES: The take-home baby rate (number of infants discharged alive from the hospital), gestational age at delivery, and the number of days in the neonatal intensive care unit (NICU). RESULTS: Women (n = 309) were stratified into the prophylactic trial (n = 213) or the therapeutic trial (n = 96). The trial stopped early due to slow recruitment and an interim analysis showing no benefit of occlusion. Final analysis comprised 197 women in the prophylactic trial and 87 women in the therapeutic trial. No added effect of cervical occlusion was found in terms of the take-home baby rate in the prophylactic trial (92 versus 90%, RR 1.03, 95% CI 0.94-1.12) or in the therapeutic trial (81 versus 85%, RR 0.96, 95% CI 0.79-1.16). No effect of cervical occlusion was found in terms of gestational age at delivery and number of days the neonate spent in the NICU. Cervical occlusion was associated with no harm. CONCLUSIONS: Cervical occlusion with cerclage had no significant additional effect.

Could a cervical occlusion suture be effective at improving perinatal outcome?

Cervical weakness and infection have long been regarded as major causes of preterm birth. Cervical cerclage has been used extensively to reduce the risk of preterm birth arising as a result of cervical weakness, but increasing evidence suggests that the cervix plays more than just a mechanical role. Immunological function of the cervix and mucus plug is thought to be important in minimising the ingress of microbes, which can lead to chorioamnionitis and rupture of the amniotic membranes. In this review, we examine the background of traditional cervical cerclage and introduce the concept of the occlusion suture and its potential benefit in reducing the risk of recurrent preterm prelabour rupture of membranes.

Cervical occlusion in women with cervical insufficiency: protocol for a randomised, controlled trial with cerclage, with and without cervical occlusion.

OBJECTIVE: To evaluate the effect of double cerclage compared with a single cerclage. DESIGN: Randomised, controlled multicentre trial. SETTING: Ten different countries are participating with both secondary and tertiary centres. The countries participating are Denmark, Sweden, Germany, United Kingdom, Spain, South Africa, Australia and India. This gives both a broad spectrum of diversity global and local. We expect a total of 242 women enrolled per year. POPULATION: Prophylactic study: 1. History of cervical incompetence/insufficiency. (Delivery 15 to <36 weeks.) 2. Congenital short cervix (secondary to maternal administration of diethyl stilbestrol) or traumatic/surgical damage rendering the vaginal approach difficult (e.g. conisation). 3. Cervical suture applied in previous pregnancy, successful outcome. 4. Previous failed cerclage. Therapeutic study: 5. Secondary cerclage: Short cervix, without the membranes being exposed to the vagina. 6. Tertiary cerclage: Short cervix, membranes exposed to the vagina. Observational study: Eligible women who refuse to be randomised will participate in an observational study. 7. Repeat/requested cervical occlusion. METHODS: The women will be randomised between a single (vaginal or abdominal) and a double cerclage. The cervical cerclage (McDonald or Shirodkar) as well as the abdominal suture will be performed with the same material and technique normally used by the participating department. Those randomised to the double cerclage will have their external os closed with a continuous nylon 2-0/3-0 suture, in addition to the standard single cerclage. Local guidelines concerning antibiotics, Heparin, bed rest, tocolytics etc. are followed and recorded in the follow-up form. MAIN OUTCOME MEASURES: Primary endpoint is take home baby rate. The secondary endpoints are gestational age at delivery, incidence of preterm birth (<34+0 days) and number of days in neonatal unit.

An in vitro study of antibacterial properties of the cervical mucus plug in pregnancy.

OBJECTIVE: To evaluate whether cervical mucus plugs are antibacterial in vitro. STUDY DESIGN: Cervical mucus plugs from 56 healthy women in labor were studied by 2 different antimicrobial assays: (1) analysis of the inhibition by the cervical mucus plug of several gram-positive and gram-negative bacteria by overlaying the cervical mucus plug onto an agar plate with imbedded bacteria, and (2) determination of the antibacterial property of the cervical mucus plug material by radial diffusion assay with group B Streptococcus and Escherichia coli. RESULTS: In the agar overlay assay, there was complete inhibition of clinical isolates of Staphylococcus saprophyticus, E coli, and Pseudomonas aeruginosa and patient-variable partial-to-complete inhibition of Enterococcus faecium, Staphylococcus aureus, Streptococcus pyogenes, and Streptococcus agalactiae. In the radial diffusion assay, cervical mucus plugs had activity toward group B Streptococcus equivalent to 0.075 microg/mL of gentamicin and toward E coli equivalent to 0.5 microg/mL of gentamicin. CONCLUSION: A low-molecular substance with antibacterial activity in the cervical mucus plug may protect the fetus against ascending infections.

[The value of vaginal swabs]. / Vaerdien af vaginalpodninger.

INTRODUCTION: The use of culture of vaginal secretions by physicians and their use of microscopy of vaginal secretions were assessed. METHODS: The study was conducted partly as a registration of all microbiological requests and reports from the Department of Clinical Microbiology in a selected period, and partly as a questionnaire sent to all general practitioners (GPs) and specialists in obstetrics and gynaecology in the county of Arhus. RESULTS: In only 19% of 1,354 vaginal swabs received in a month could the findings lead to a specific antimicrobial treatment; 48% of these cases could be diagnosed by microscopy of vaginal secretions alone. Sixty-four per cent of the physicians returned the questionnaire. Half of the specialists and 60% of the GPs performed microscopy. Twenty-five per cent of the physicians treated patients solely on the basis of clinical symptoms. DISCUSSION: General culture of vaginal secretions has a limited clinical value. The diagnosis in patients complaining of vaginal discharge can often be made by microscopy. There is, however, a need for training GPs in microscopy, as well as specialists.

Proteoglycans and hyaluronan in human fetal membranes.

OBJECTIVE: The aim of this study was to describe the distributions of major extracellular matrix components, such as proteoglycans, collagen and hyaluronan, in the fetal membranes at term. STUDY DESIGN: Fetal membranes were obtained from elective cesarean deliveries at term. Guanidinium extracts were analyzed for proteoglycans with alcian blue precipitation, sodium dodecyl sulfate- polyacrylamide gel electrophoresis, and Western blotting and for hyaluronan with a radioimmunoassay. Collagen was measured by estimating hydroxyproline content. Tissue sections were immunostained for decorin and biglycan and stained for hyaluronan with a biotin-labeled hyaluronan-binding protein. RESULTS: The fetal membranes contained predominantly smaller proteoglycans, such as biglycan and decorin. The amnion consisted of typical fibrous connective tissue with a high concentration of collagen. The amnion was dominated by decorin located in close connection with the collagen fibrils. The chorion was composed of a fibroblastic part containing collagen and decorin and a trophoblastic part mainly containing biglycan. In addition, large amounts of hyaluronan were found, especially in the amnion and in the decidual cell layers. CONCLUSION: The distributions of proteoglycans, collagen, and hyaluronan in human fetal membranes may explain the biomechanical properties of this tissue. We suggest that changes in the relative proportions of these extracellular molecules are crucial for the proposed maturation process in the fetal membranes during the last weeks of pregnancy.

Antibacterial properties of human amnion and chorion in vitro.

OBJECTIVE: The purpose of the present study was to explore the direct effects of amnion and chorion on bacterial growth in vitro including the antibacterial spectrum. Chorioamniotic membranes were obtained under sterile conditions from 13 healthy women undergoing elective cesarean section at term. Likewise, chorioamniotic membranes were obtained from 10 healthy women with spontaneous vaginal delivery at term. Five strains of Hemolytic streptococci group B (GBS) were tested and one clinical isolate of the following species or bacterial groups: Hemolytic streptococcus group A, Staphylococcus aureus, Staphylococcus saprophyticus, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Acinetobacter calcoaceticus and Lactobacillus species. Bacteriological media included (1) blood-agar medium; (2) a transparent agar medium for submerged cultures; and (3) a nutrient broth medium. RESULTS: An inhibitory effect of fetal membranes against a range of bacteria was found. Consistent results were obtained in experiments with cultures on agar and cultures suspended in agar (membranes from eight women in both studies). In experiments with liquid cultures (seven women) only chorion showed a marginal inhibitory effect. All strains were inhibited, but the most pronounced inhibition was obtained for streptococcus group A, S. aureus and S. saprophyticus by both chorion and amnion. CONCLUSION: This study demonstrated an inhibitory effect of the fetal membranes on a diverse panel of bacteria

[Life-threatening puerperal sepsis caused by group A streptococci]. / Livstruende puerperal sepsis forårsaget af gruppe A-streptokokker.

A case of postpartum streptococcal toxic shock syndrome due to group A streptococci is described. The patient suffered multiorgan failure, was critically ill and stayed in the intensive care unit for 18 days before recovering. The patient received massive antibiotic treatment as well as intravenous immunoglobulin therapy. The case is described to draw attention to the reoccurrence of serious group A streptococcal infections.

Chorioamniotic membranes constitute a competent barrier to group b streptococcus in vitro.

OBJECTIVE: To study the penetration of group B streptococcus (GBS) through human chorioamniotic membranes in vitro. STUDY DESIGN: Chorioamniotic membranes from seventeen healthy women were mounted onto glass cylinders and placed in tissue culture trays constituting a two-compartment system with a maternal compartment internally and a fetal compartment externally. GBS from healthy pregnant women and from newborn babies with sepsis were added to the maternal compartment at densities from 10(7) to 10(9) colony forming units (cfu) per ml. RESULTS: Irrespective of inoculum density, GBS was not recovered from the fetal compartment within a 20 h incubation period. By histology, micro-colonies of GBS were found on the maternal surface after 8 h, but invasion of the morphologically intact membranes was not observed. A five log reduction in cfu occurred in the maternal compartment with amnion when GBS were suspended in saline. CONCLUSION: In this in vitro model the membranes appear to constitute an effective barrier against ascending infection.

Secretory leukocyte protease inhibitor in the cervical mucus and in the fetal membranes.

OBJECTIVE: The purpose was to determine the concentration of leukocyte elastase and SLPI in the cervical mucus plug, cervical tissue, fetal membranes, amniotic fluid and serum from pregnant women. STUDY DESIGN: Samples were analysed using radioimmunoassay, immunodiffusion, immunohistological and enzyme assay techniques. Statistical comparisons were performed by the Mann-Whitney two-sample rank sum test. RESULTS: Concentrations of SLPI and elastase in cervical tissue are significantly increased during pregnancy and after delivery. Very high concentrations of SLPI and elastase were found in the cervical mucus plug. The concentrations of SLPI and elastase in human fetal membranes are highest at the rupture site. The concentration of elastase in amnion from preterm delivery was significantly higher than in amnion from term deliveries. CONCLUSION: The high molar ratio of SLPI/elastase in the cervical mucus plug suggests that inhibition of elastase is important during normal pregnancy. The role of SLPI may be protection of the fetal membranes and cervical tissue.

Relaxin (hRLX-2)-induced weakening of human fetal membranes in vitro.

We examined the effect of human relaxin (hRLX-2) on the biomechanical properties of human fetal membranes in vitro. Intact chorioamniotic membranes were obtained from twelve elective cesarean sections before the onset of labor. Membrane strips with a fixed width were biomechanically tested after incubation for 20 h with hRLX-2 in concentrations of 10(-7) mol/l and 10(-9) mol/l. Incubation with hRLX-2 (10(-9) mol/l) changed the load-strain values as the membrane stiffness was decreased by 19% when compared with controls: median 2.45 N (range, 0.81-4.31) versus 3.03 N (1.28-5.46), P = 0.02 (Mann-Whitney test). For description of the membrane material as such, the stress-strain values were calculated by dividing the load-strain values with the cross sectional area of the membranes. Incubation with hRLX-2 (10(-9) mol/l) decreased the tensile strength of the membranes by 30%-0.817 N/mm2 (0.282-1.139) vs. 0.575 N/mm2 (0.101-1.150), P = 0.03--and reduced the elastic modulus by 31%--2.26 N/mm2 (0.82-5.08) versus 1.57 N/mm2 (0.51-3.71), P = 0.002. Less pronounced effects were found after incubation with hRLX (10(-7) mol/l). No quantitative or qualitative changes of the membrane collagen were found after relaxin incubation. Although the mechanism for rupture of the fetal membranes remains unknown, the present results suggest that relaxin might be involved in the process leading to rupture of the membranes.

Clonal analysis of Streptococcus agalactiae isolated from infants with neonatal sepsis or meningitis and their mothers and from healthy pregnant women.

The purpose of this study was to evaluate if group B streptococci (GBS) isolated from infants with neonatal sepsis or meningitis and their mothers differ from GBS isolated from healthy pregnant women who gave birth to healthy infants. Danish clinical isolates of GBS (n = 118) were characterized by multilocus enzyme electrophoresis, a method recently used to identify virulent clones of GBS type III from North American infants. By analysis of allelic profiles of 11 metabolic enzyme loci, 43 different electrophoretic types were found. Clustering analysis revealed two primary phylogenetic divisions at a distance of > 0.8, both containing serotype III isolates. One division, comprising virtually all disease isolates, showed a population structure like that of traditional pathogens. The other division, containing the majority of carrier isolates, had a structure reminiscent of that of mucosal commensals, with each isolate being different.

Different biomechanical properties of human fetal membranes obtained before and after delivery.

The aim of this study was to elucidate whether the mechanical properties of fetal membranes change during late pregnancy and labour. Membranes delivered by elective caesarean section in week 38 showed different load-strain curves to membranes obtained after spontaneous vaginal delivery at term. A major change in mechanical properties was a decrease in strength of the intact chorioamniotic membrane from 1.39 N to 0.98 N (width of biopsy 4 mm), mainly due to loss of strength of the amniotic component, from 1.27 N to 0.72 N. Moreover, the extensibility of the chorionic component (epsilon Fmax) increased after vaginal delivery from 0.42 to 0.54, resulting in a two-component behaviour of the intact chorioamniotic membrane and further decrease of strength. Based on these observations it is suggested that the amnion is attached to the chorion, act biomechanically in parallel and possess relatively high mechanical strength during pregnancy. After vaginal delivery the two membranes are separated, and pronounced changes are induced in their mechanical properties.

Quantitative production of prostaglandin E2 and its metabolites by human fetal membranes.

Cultured amnion, choriodecidua and intact fetal membrane produced similar quantities of prostaglandin E2 (PGE2) (1-5 ng/ml). Choriodecidua and intact fetal membrane also produced very high levels of PGE2 metabolites (100-1000 ng/ml). The total production of PGE (PGE2 + PGE2 metabolites) was similar in intact fetal membrane and in choriodecidua, suggesting that the amnion, although a source of PGE2, contributes little to the overall PGE production by fetal membranes.

[Bacterial genesis of preterm delivery]. / Bakteriel genese til praeterm fødsel.

From a review of the literature it is concluded that one forth of preterm deliveries are associated with infections. The presence of Group B Streptococci (GBS), Ureaplasma urealyticum, Chlamydia specific IgM antibodies, and bacterial vaginosis may be of importance, but the odds-ratio is seldom more than two, and the studies do not include confounder control. Treatment with penicillin may be indicated in pregnant women (1) with GBS-uri (2) who have given birth to at child with neonatal GBS meningitis, or (3) with preterm labour and/or rupture of fetal membranes.