Fear of Childbirth and Preference for Cesarean Delivery Among Young American Women Before Childbirth: A Survey Study

BACKGROUND

Fear of birth and mode of delivery preferences are similar among pregnant and nonpregnant women, suggesting that attitudes toward birth are formed in young adulthood or earlier. Understanding why some young women fear birth and prefer obstetric interventions can inform public health initiatives aimed at reducing fear and promoting birth as a normal life event.

METHODS

We conducted an online survey with 752 American nulliparous young women to assess their preferences and attitudes toward childbirth. We identified explanatory variables associated with reported fear of childbirth and cesarean delivery (CD) preferences.

RESULTS

A preference for CD was reported by 14 percent of young women and 27 percent had scores indicating elevated fear of birth. Fear of birth increased the likelihood of cesarean preference (adjusted relative risk (ARR) 3.84 [95% CI 2.49-5.95]) as did a family history of CD (ARR 1.65 [95% CI 1.13-2.42]). The likelihood of reporting elevated childbirth fear was increased among young women who reported concerns about the physical changes pregnancy and birth have on women's bodies (ARR 2.04 [95% CI 1.50-2.78]). Young women who reported a high degree of confidence in their knowledge about childbirth were significantly less likely to report childbirth fear (ARR 0.61 [95% CI 0.42-0.87]). Access to childbirth information was also associated with a decreased likelihood of fear of birth (ARR 0.75 [95% CI 0.59-0.95]).

CONCLUSIONS

Young women reporting high levels of childbirth fear are nearly four times more likely to prefer a CD. Specific fears, such as worries over the influence of pregnancy and birth on the female body, need to be addressed before pregnancy.

Midwifery care in rural and remote British Columbia: a retrospective cohort study of perinatal outcomes of rural parturient women with a midwife involved in their care, 2003 to 2008

INTRODUCTION

Midwifery has been regulated and publicly funded in British Columbia since 1998. Midwives are currently concentrated in urban areas; access to care is limited in rural communities. Rural midwifery practice can be challenging because of low birth numbers, solo practice, lack of on-site cesareans and specialist backup, and interprofessional tensions resulting from the integration of midwives into rural maternity care systems. Despite these barriers, rural midwives have made a substantial contribution to rural maternity care in British Columbia. The purpose of this retrospective cohort study is to examine outcomes of midwife-involved births in rural British Columbia in the postregionalization era.

METHODS

We analyzed the outcomes of all parturient women with postal codes outside of the core urban areas of the province, and their singleton infants without a diagnosed congenital anomaly, who had a midwife involved in their care between April 1, 2003, and March 31, 2008. Outcomes are reported for 6 obstetric service levels. Service levels are assigned to parturient women via maternal postal codes. Women who reside further than 60 minutes from a hospital with maternity services were assigned a distance category (2 levels: >2 hours, 1-2 hours); women residing within one hour of a hospital with maternity services were assigned the level of service available at their catchment hospital (4 levels, ranging from maternity care without cesarean to cesarean provided by general surgeons or obstetricians).

RESULTS

Eight percent of rural parturient women had a midwife involved in their care. Rates of planned home birth exceeded the provincial average (26.1%) in 5 of the 6 service levels. Rates of actual home birth were lowest among women who resided 2 or more hours away from maternity services. Obstetric intervention rates were lower for women residing in communities without cesareans or with intermittent access to cesareans. The prevalence of adverse neonatal outcomes was very low across service levels; perinatal mortality was elevated among women residing in communities more than 2 hours away from services.

DISCUSSION

Despite numerous challenges, midwives provide safe maternity care to rural parturient women and offer choice of birth place. Given the difficulty of recruiting and retaining maternity care providers to rural settings in British Columbia and across Canada, these findings open the door for a more sustained planning process involving midwives in rural communities. Reasons for the elevated perinatal mortality rate among women who live more than 2 hours away from services should be explored in more detail, perhaps via in-depth interviews with rural midwives who serve this population.

The Canadian birth place study: examining maternity care provider attitudes and interprofessional conflict around planned home birth

BACKGROUND

Available birth settings have diversified in Canada since the integration of regulated midwifery. Midwives are required to offer eligible women choice of birth place; and 25-30% of midwifery clients plan home births. Canadian provincial health ministries have instituted reimbursement schema and regulatory guidelines to ensure access to midwives in all settings. Evidence from well-designed Canadian cohort studies demonstrate the safety and efficacy of midwife-attended home birth. However, national rates of planned home birth remain low, and many maternity providers do not support choice of birth place.

METHODS

In this national, mixed-methods study, our team administered a cross-sectional survey, and developed a 17 item Provider Attitudes to Planned Home Birth Scale (PAPHB-m) to assess attitudes towards home birth among maternity providers. We entered care provider type into a linear regression model, with the PAPHB-m score as the outcome variable. Using Students' t tests and ANOVA for categorical variables and correlational analysis (Pearson's r) for continuous variables, we conducted provider-specific bivariate analyses of all socio-demographic, education, and practice variables (n=90) that were in both the midwife and physician surveys.

RESULTS

Median favourability scores on the PAPHB-m scale were very low among obstetricians (33.0), moderately low for family physicians (38.0) and very high for midwives (80.0), and 84% of the variance in attitudes could be accounted for by care provider type. Amount of exposure to planned home birth during midwifery or medical education and practice was significantly associated with favourability scores. Concerns about perinatal loss and lawsuits, discomfort with inter-professional consultations, and preference for the familiarity of the hospital correlated with less favourable attitudes to home birth. Among all providers, favourability scores were linked to beliefs about the evidence on safety of home birth, and confidence in their own ability to manage obstetric emergencies at a home birth.

CONCLUSIONS

Increasing the knowledge base among all maternity providers about planned home birth may increase favourability. Key learning competencies include criteria for birth site selection, management of obstetric emergencies at planned home births, critical appraisal of literature on safety of home birth, and inter-professional communication and collaboration when women are transferred from home to hospital.

Vicarious birth experiences and childbirth fear: does it matter how young canadian women learn about birth?

In our secondary analysis of a cross-sectional survey, we explored predictors of childbirth fear for young women (n = 2,676). Young women whose attitudes toward pregnancy and birth were shaped by the media were 1.5 times more likely to report childbirth fear. Three factors that were associated with reduced fear of birth were women's confidence in reproductive knowledge, witnessing a birth, and learning about pregnancy and birth through friends. Offering age-appropriate birth education during primary and secondary education, as an alternative to mass-mediated information about birth, can be evaluated as an approach to reduce young women's childbirth fear.

Translation and validation of the German version of the Mother-Generated Index and its application during the postnatal period

OBJECTIVE

the Mother-Generated Index (MGI) is a validated tool to assess postnatal quality of life. It is usually administered several weeks or months after birth and correlates with indices of post partum mood states and physical complaints. The instrument had not been translated into German before or validated for use among German-speaking women, nor have the results of the tool been assessed specifically for the administration directly after birth. This paper aims to describe the systematic translation process of the MGI into German and to assess the convergent validity of the German version of the instrument directly after birth and seven weeks post partum.

DESIGN

prospective two-stage survey.

SETTING

two rural hospitals in the south of Germany and in the north of Switzerland.

PARTICIPANTS

all women giving birth between 1st October and 15th December 2012 with sufficient knowledge of German and whose babies were not referred to a neonatal care unit; 226 women were eligible to participate.

MEASUREMENT INSTRUMENTS

two questionnaires including questions relating to socio-demographic factors and perinatal care, and incorporating the MGI, the Hospital Anxiety and Depression Scale (HADS) and the Postnatal Morbidity Index (PMI). All instruments were subjected to forward and back translation and pilot-tested; the first questionnaire was then administered in the first two days after birth and the second six weeks post partum. Parametric and non-parametric tests were computed using SPSS.

FINDINGS

129 surveys were returned an average of three days after birth and 83 after seven weeks. Higher postnatal quality of life showed a significant correlation with a lower anxiety and depression score (p<0.01), fewer maternal physical complaints (p<0.05) and more favourable baby adjective scores (p<0.05) after birth. Significant associations were found between MGI scores and sufficient help (p=0.03) as well as ability to cope at home (p<0.01). MGI scores three days and seven weeks after birth correlated highly significantly and positively (p<0.001).

KEY CONCLUSIONS

convergent validity of the MGI with the HADS and the PMI suggests that the German version of the MGI is a valid indicator of physical and emotional post partum well-being.

IMPLICATION FOR PRACTICE

the German version of the MGI can be used in the post partum period to identify women whose quality of life is impaired during the first days after birth, in order to initiate extended midwifery care and referral if necessary.

Attitudes and preferences of young women with low and high fear of childbirth

We examined constructions of labor and birth for 461 Canadian women who attended the University of British Columbia (Canada) and participated in an online survey about pregnancy and birth, using a combination of Likert items and open-ended questions. We performed a content analysis of women's open-ended responses about their feelings toward birth and analyzed comments of women with high and low fear of childbirth separately. Students with high fear of birth described childbirth as a frightening and painful ordeal and viewed obstetric interventions as a means to make labor and birth more manageable. Students with low fear constructed birth as a natural event and regarded interventions more critically. Students in both groups supported women's autonomous maternity care decisions. Our findings contribute to care providers' and educators' knowledge about preferences and fears expressed by the next generation of maternity care consumers and potential strategies to reduce their fear of childbirth.

Why are young Canadians afraid of birth? A survey study of childbirth fear and birth preferences among Canadian University students

OBJECTIVE

to examine attitudes towards birth that may be common among young adults who have been socialised into a medicalised birth culture. Specifically, we were interested in examining factors that might be associated with fear of birth and preferences for elective obstetric interventions among the next generation of maternity care consumers.

DESIGN

secondary analysis of an online survey of university students.

SETTING

British Columbia, Canada.

PARTICIPANTS

students from the University of British Columbia (n=3680). A quarter of the sample comprised Asian students, which allowed for analysis of cultural differences in attitudes towards birth. Both male and female students participated in the study; results are reported for the full sample, and by gender.

MEASUREMENTS

a six item fear of childbirth scale was developed, as well as a 4 item index that measures students' concerns over physical changes following pregnancy and birth and a 2 item scale that assesses students' attitudes towards obstetric technology.

FINDINGS

as we hypothesised, students who were more fearful of birth preferred epidural anaesthesia and birth by CS. Worries over physical changes following pregnancy and birth, favourable attitudes towards obstetric technology, and exposure to pregnancy and birth information via the media were also significantly associated with a preference for CS. Fear of birth scores were highest among students who reported that the media had shaped their attitudes towards pregnancy and birth. Asian students had significantly higher fear of birth scores and were more likely to prefer CS, compared to Caucasian students.

IMPLICATIONS FOR PRACTICE

young adults are contemplating pregnancy and birth in an increasingly technology-dependent society. Educational programmes aimed at reducing fear of childbirth and concerns over physical changes following pregnancy and childbirth might contribute to vaginal birth intentions among young adults. Midwives may use the findings to identify and counsel nulliparas who exhibit fear of birth and other childbirth attitudes that may predispose them to choose elective obstetric interventions.

Control Strategies for Cyclic Polymer Processes

This paper presents the simulation of a typical cyclic polymer processing operation with respect to the performance of different control strategies for part quality when subjected to disturbances with realistic load-profiles. Disturbances enter the simulation in a complex, probabilistic manner creating a unique flexibility in load representation which helps the simulation more accurately capture the performance of real processing operations. Realistic simulations can provide necessary information and be less costly than benchmark studies on actual processes. The objective of the research is to examine the effect of different control strategies on the overall control of part-to-part quality, not the control of the continuous processes that occur in part fabrication. The performance of six different control strategies is compared; two strategies are conventional feedback, and four strategies are statistically based. The statistically based algorithms effect closed loop control, but only when a true load exists. Results are analyzed using statistical analysis of variance (ANOVA) via a completely randomized block experimental design, and Duncan's multiple range test is used to rank the control strategies. The results indicate that as more disturbances enter the system, the conventional controllers perform better than the other strategies. When fewer disturbances are present, however, the statistically based controllers perform better. The most notable result is that one statistically based controller, the Western Electric runs rules controller, performs well over the entire range of disturbances.

An observational study of umbilical cord clamping practices of maternity care providers in a tertiary care center

BACKGROUND

Severing the umbilical cord at birth is likely the oldest intervention, the timing of which remains fraught with controversy. Emerging evidence suggests benefit in delaying cord clamping for both term and preterm infants. The objective of this study was to investigate actual cord clamping time and circumstances at a large tertiary care center in Canada.

METHODS

We used a stopwatch to time the interval from the time the infant was born as far as the umbilicus until the time that the umbilical cord was clamped before cutting. We reported on timing of the umbilical cord clamping overall and by practitioner group (obstetrician, midwife, and family practitioner).

RESULTS

A total of 98 women and their practitioners consented to be observed at the British Columbia Women's Hospital and Health Center, Vancouver, Canada. More than one-half (56.2%) of all infants had their umbilical cord clamped within 15 seconds. The median (5th, 95th percentile) clamping time in seconds for the full sample was 12 (4, 402) with practitioner subgroups as follows: obstetricians (12 [3, 107]), family physicians (19 [6, 325]), and midwives (81 [6, undefined]). The median clamping time was likely to be longer when the birth occurred spontaneously, no umbilical cord blood was collected, and no birth or neonatal complications occurred.

CONCLUSIONS

In our sample taken in 2006 to 2007, most infants had umbilical cords clamped immediately after the birth, with more than one-half clamped within 15 seconds of birth. Since the time of our study, delayed umbilical cord clamping for the healthy term newborn has become a part of recommended management of third stage of labor and resuscitation guidelines. It would be informative to repeat a study like this one to determine compliance with the current standards of care.

The outcomes of perinatal surgical services in rural British Columbia: a population-based study

INTRODUCTION

A substantial number of small surgical services in rural Canada have been discontinued in the past 15 years because of difficulties recruiting and retaining practitioners, health care restructuring and a lack of a coherent evidence base regarding the safety of small services. The objective of this study was to examine the safety of small perinatal surgical services.

METHODS

We accessed perinatal data for singleton births that occurred in British Columbia between Apr. 1, 2000, and Mar. 31, 2007. We defined hospital service levels, population catchment areas surrounding each hospital and the postal codes linked to those catchment areas. Births were linked with specific catchment areas and amalgamated by service level. We made comparisons among service strata populations and adjusted for potentially confounding characteristics.

RESULTS

A total of 87 294 births occurred during the study period. The births were distributed across 6 strata of services, which ranged from no local maternity services to services supported by obstetricians. Fifteen catchment areas were served by general practitioners with enhanced surgical skills (GPESSs), and 9174 births were included from this obstetric service level. Outcomes for surgical services provided by GPs compared favourably to those provided by obstetricians.

CONCLUSION

Our results suggest that small surgical services supported by GPESSs are a safe health services model to meet the needs of rural women and families.

A prospective study of effects of psychological factors and sleep on obstetric interventions, mode of birth, and neonatal outcomes among low-risk British Columbian women

Background

Obstetrical interventions, including caesarean sections, are increasing in Canada. Canadian women’s psychological states, fatigue, and sleep have not been examined prospectively for contributions to obstetric interventions and adverse neonatal outcomes.

Context and purpose of the study: The prospective study was conducted in British Columbia (BC), Canada with 650 low-risk pregnant women. Of those women, 624 were included in this study. Women were recruited through providers’ offices, media, posters, and pregnancy fairs. We examined associations between pregnant women’s fatigue, sleep deprivation, and psychological states (anxiety and childbirth fear) and women’s exposure to obstetrical interventions and adverse neonatal outcomes (preterm, admission to NICU, low APGARS, and low birth weight).

Methods

Data from our cross-sectional survey were linked, using women’s personal health numbers, to birth outcomes from the Perinatal Services BC database. After stratifying for parity, we used Pearson’s Chi-square to examine associations between psychological states, fatigue, sleep deprivation and maternal characteristics. We used hierarchical logistic regression modeling to test 9 hypotheses comparing women with high and low childbirth fear and anxiety on likelihood of having epidural anaesthetic, a caesarean section (stratified for parity), assisted vaginal delivery, and adverse neonatal outcomes and women with and without sleep deprivation and high levels of fatigue on likelihood of giving birth by caesarean section, while controlling for maternal, obstetrical (e.g., infant macrosomia), and psychological variables.

Results

Significantly higher proportions of multiparas, reporting difficult and upsetting labours and births, expectations of childbirth interventions, and health stressors, reported high levels of childbirth fear. Women who reported antenatal relationship, housing, financial, and health stressors and multiparas reporting low family incomes were significantly more likely to report high anxiety levels. The hypothesis that high childbirth fear significantly increased the risk of using epidural anaesthesia was supported.

Conclusions

Controlling for some psychological states and sleep quality while examining other contributors to outcomes decreases the likelihood of linking childbirth fear anxiety, sleep deprivation, and fatigue to increased odds of caesarean section. Ameliorating women’s childbirth fear to reduce their exposure to epidural anaesthesia can occur through developing effective interventions. These include helping multiparous women process previous experiences of difficult and upsetting labour and birth.

Distance matters: a population based study examining access to maternity services for rural women

BACKGROUND

In the past fifteen years there has been a wave of closures of small maternity services in Canada and other developed nations which results in the need for rural parturient women to travel to access care. The purpose of our study is to systematically document newborn and maternal outcomes as they relate to distance to travel to access the nearest maternity services with Cesarean section capability.

METHODS

Study population is all women carrying a singleton pregnancy beyond 20 weeks and delivering between April 1, 2000 and March 31, 2004 and residing outside of the core urban areas of British Columbia. Maternal and newborn data was linked to specific geographic catchments by the B.C. prenatal Health Program. Catchments were stratified by distance to nearest maternity service with Cesarean section capability if greater than 1 hour travel time or level of local service. Hierarchical logistic regression was used to test predictors of adverse newborn and maternal outcomes.

RESULTS

49,402 cases of women and newborns resident in rural catchments were included. Adjusted odds ratios for prenatal mortality for newborns from catchments greater than 4 hours from services was 3.17 (95% CI 1.45-6.95). Newborns from catchments 2 to 4 hours, and 1 to 2 hours from services generated rates of 179 and 100 NICU 3 days per thousand births respectively compared to 42 days for newborns from catchments served by specialists.

CONCLUSIONS

Distance matters: rural parturient women who have to travel to access maternity services have increased rates of adverse prenatal outcomes.

Development and Psychometric Testing of the Rural Pregnancy Experience Scale (RPES)

Rural pregnant woman who lack local access to maternity care due to their remote living circumstances may experience stress and anxiety related to pregnancy and parturition. The Rural Pregnancy Experience Scale (RPES) was designed to assess the unique worry and concerns reflective of the stress and anxiety of rural pregnant women related to pregnancy and parturition. The items of the scale were designed based on the results of a qualitative study of the experiences of pregnant rural women, thereby building a priori content validity into the measure. The relevancy content validity index (CVI) for this instrument was 1.0 and the clarity CVI was .91, as rated by maternity care specialists. A field test of the RPES with 187 pregnant rural women from British Columbia indicated that it had two factors: financial worries and worries/concerns about maternity care services, which were consistent with the conceptual base of the tool. Cronbach’s alpha for the total RPES was .91; for the financial worries subscale and the worries/concerns about maternity care services subscale, alpha were .89 and .88, respectively. Construct validity was supported by significant correlations between the total scores of the RPES and the Depression Anxiety Stress Scales (DASS [r =.39, p < .01]), and subscale scores on the RPES were significantly correlated and converged with the depression, anxiety, and stress subscales of the DASS supporting convergent validity (correlations ranged between .20; p < .05 and .43; p < .01). Construct validity was also supported by findings that the level of access and availability of maternity care services were significantly associated with RPES scores. It was concluded that the RPES is a reliable and valid measure of worries and concerns reflective of rural pregnant women’s stress and anxiety related to pregnancy and parturition.

Childbirth fear, anxiety, fatigue, and sleep deprivation in pregnant women

OBJECTIVE

To explore women's levels of childbirth fear, sleep deprivation, anxiety, and fatigue and their relationships during the third trimester of pregnancy.

DESIGN

A cross-sectional descriptive survey of a community sample.

PARTICIPANTS

Six hundred and fifty English-speaking nulliparous and multiparous women, 17 to 46 years of age and between 35 and 39 weeks gestation, with uncomplicated pregnancies.

METHODS

Wijma Delivery Expectancy/Experience Questionnaire, Spielberger State Anxiety Inventory, Mindell's Sleep Questionnaire, and the Multidimensional Assessment of Fatigue Questionnaire.

RESULTS

Twenty-five percent of women reported high levels of childbirth fear and 20.6% reported sleeping less than 6 hours per night. Childbirth fear, fatigue, sleep deprivation, and anxiety were positively correlated. Fewer women attending midwives reported severe fear of childbirth than those attending obstetricians. Women with high childbirth fear were more likely to have more daily stressors, anxiety, and fatigue, as well as less help. Higher levels of anxiety predicted higher levels of childbirth fear among women.

CONCLUSION

One fourth of women reported high childbirth fear. Women's fear of childbirth was related to fatigue, available help, stressors, and anxiety. Fear of childbirth appears to be part of a complex picture of women's emotional experiences during pregnancy.

Nurse-midwives' experiences with planned home birth: impact on attitudes and practice

BACKGROUND

Health care providers' attitudes toward maternity care options influence the nature of informed decision-making discussions and patient choice. A woman's choice of birth site may be affected by her provider's opinion and practice site. The objectives of this study were to describe American nurse-midwives' attitudes toward, and experiences with, planned home birth, and to explore correlates and predictors of their attitudes toward planned home birth as measured by the Provider Attitudes towards Planned Home Birth (PAPHB) scale.

METHODS

A survey instrument, which incorporates the PAPHB and assesses demographic, education, practice, personal experience, and external barrier variables that may predict attitudes toward planned home birth practice, was completed by 1,893 nurse-midwives. Bivariate analysis identified associations between variables and attitudes. Linear regression modeling identified predictors of attitudes.

RESULTS

Variables that significantly predicted favorable attitudes to planned home birth were increased clinical and educational experiences with planned home birth (p < 0.001), increased exposure to planned home birth (p < 0.001), and younger age (p < 0.001). External barriers that significantly predicted less favorable attitudes included financial (p = 0.03) and time (p < 0.001) constraints, inability to access medical consultation (p < 0.001), and fear of peer censure (p < 0.001). Willingness to practice in the home was correlated with factors related to nurse-midwives' confidence in their management abilities and beliefs about planned home birth safety.

CONCLUSIONS

The results suggest that nurse-midwives' choice of practice site and comfort with planned home birth are strongly influenced by the nature and amount of exposure to home birth during professional education or practice experiences, in addition to interprofessional, logistic, and environmental factors. Findings from this research may inform interdisciplinary education and collaborative practice in the area of planned home birth.

"It's all the rage these days": University students' attitudes toward vaginal and cesarean birth

BACKGROUND

At 30 percent, British Columbia has the highest cesarean section rate in Canada. Little is known about the childbirth views and birthing preferences of college-aged women and men. The objectives of this study were to document (a) the prevalence of cesarean versus vaginal delivery as the preferred mode of delivery among nonpregnant university students without a history of childbirth, (b) the reasons for reported childbirth preferences, and (c) confidence in vaginal birth as a predictor of childbirth preference.

METHODS

A cohort of 3,680 male and female university students without a history of childbirth participated in an online survey of childbirth preferences. The study used a mixed methods approach (quantitative thematic analysis and logistic regression modeling). Prevalence of, and reasons for, preferred mode of delivery were analyzed separately for male and female respondents.

RESULTS

Most men and women responded that they preferred vaginal delivery, with 9 percent stating a preference for cesarean delivery. Reasons for preferred mode of delivery were similar for men and women. For women, confidence in vaginal birth emerged as a significant predictor of childbirth preference.

CONCLUSIONS

Results indicate that a preference for cesarean section is linked to fear of childbirth and driven by low confidence in vaginal birth. Educational strategies targeting university-aged men and women may be helpful in alleviating fears of vaginal birth and providing evidence-based information about different birth options.

Recognition and invasion of human skin by Schistosoma mansoni cercariae: the key-role of L-arginine

The attachment of Schistosoma mansoni cercariae to mammalian skin is specifically stimulated by L-arginine. As L-arginine is an unsuitable signal for a specific identification of mammalian skin we examined the following 5 hypotheses to explain the advantage of the cercarial sensitivity to L-arginine. (1) A Schistosoma infection lowered the arginine concentration in the serum of mice, and this could enable the cercariae to avoid attachments to already infected mice. However, the infection did not reduce the arginine concentration in the skin and the cercarial attachment responses to it. (2) Creeping cercariae showed chemotactic orientation specifically along increasing L-arginine gradients. L-arginine could act as a pheromone which could guide cercariae towards common penetration sites. However, the cercarial acetabular gland contents were not attractive and they did not (in contrast to previous reports) contain much arginine. (3) Schistosomula (transformed cercariae) could use L-arginine to produce nitric oxide (NO) for blood vessel dilation during their migration in the host. However, in vitro the transformed cercariae did not convert L-arginine into citrulline and NO. (4) Schistosomula could bind L-arginine from the surrounding tissues and so escape the cellular immune attack (which needs L-arginine as the precursor of NO). However, transformed cercariae bound no more L-arginine than L-serine and L-lysine. (5) Schistosomula, migrating parallel to the surface in the mammalian epidermis, are dependent on information on their position between the inner and the surface layers of the skin. In the mouse skin, they adjusted their body axis with the ventral side toward the deeper (arginine-residue rich) epidermis layers. When migrating in agar, they showed chemo-orientation toward serum, and D-glucose and L-arginine were the stimulating compounds therein. The burrowing schistosomula adjusted their body axis (as in the epidermis) with the ventral side toward the higher concentration of L-arginine and not of glucose. We argue that the sensitivity for L-arginine has its primary function in orientation within mammalian skin and in location of blood vessels.

Characterization of lineage-specific chimaerism in patients with acute leukaemia and myelodysplastic syndrome after allogeneic stem cell transplantation before and after relapse

Recently, we have shown that patients with acute leukaemias and myelodysplastic syndromes (MDS), who showed increasing mixed chimaerism (MC) upon serial PCR analysis after transplant, have a significantly increased risk of relapse. To determine whether the increasing MC in these patients is caused by the reappearance of normal recipient haematopoiesis or by the reoccurrence of malignant cells, we purified different leucocyte subpopulations and analysed these subfractions with regard to their donor-recipient ratio by a PCR-based method for the analysis of minisatellite DNA regions. In 14 patients [eight acute lymphoblastic leukaemia (ALL), three acute myelogenous leukaemia (AML) and three MDS] subfractions were analysed when increasing MC was first noted upon serial analysis of the peripheral blood. In seven of these 14 patients (four ALL, two AML and one MDS), subfractions were characterized at the time of frank haematological relapse. In all 14 patients investigated with increasing MC, recipient cells were detected in different mononuclear cell subpopulations. In patients characterized during frank relapse, two distinct distribution patterns were found. Patients who relapsed before day +300 (one ALL, two AML and one MDS) showed recipient-derived (normal) cells in addition to blast populations in different mononuclear subsets as well as granulocytes. In patients with acute leukaemias who relapsed after day +300 (two ALL and one AML), only leukaemic cells were found that were of recipient origin, whereas all other haematopoietic cell lines were donor derived. These data show that persistent MC in the early post-transplant period is caused predominantly by normal recipient haematopoietic cells. This finding further supports the hypothesis that a state of mixed haematopoietic chimaerism may reduce the clinical graft-versus-leukaemia (GVL) effect of alloreactive donor-derived effector cells in patients with acute leukaemias and MDS, and thus facilitate the proliferation of residual malignant cells that may have survived the preparative regimen.

Fourth-harmonic generation of a continuous-wave CO(2) laser by use of an AgGaSe(2)/ZnGeP(2) doubly resonant device

We report a doubly resonant continuous-wave CO(2) laser frequency-quadrupling device that generates 200nW of 2.55-mum (4?) and as much as 2mW of 5.1-mum (2?) radiation out of 1.7-W fundamental radiation at 10.2 mum (?). The quadrupling process results from two resonant cascading second-harmonic generations by use of a walk-off-compensated twin AgGaSe(2) device (??2?) and a ZnGeP(2)nonlinear crystal (2??4?).

The use of plasma levels for FK 506 dosing in liver-grafted patients

FK 506 plasma levels were analyzed in 89 liver-grafted patients under FK 506-based immunosuppression. Plasma levels were found to be influenced by the patients' liver function: compared to patients without major liver dysfunction, those with cholestasis had higher plasma levels and these plasma levels were able to differentiate between rejection and toxicity. In patients with stable liver function, no clear difference was observed with regard to the plasma levels detectable during toxicity or rejection. We conclude that plasma levels can be used to determine the FK 506 dose but only in patients with cholestasis (i.e., during the early post-transplant course, or in patients with cholestatic rejection). In patients with stable liver function, plasma levels are only of limited clinical relevance.

Comparison of different assays for the quantitation of FK 506 levels in blood or plasma

In a prospective study, we evaluated the analytical performance of different assays for the quantitation of FK 506 in blood and plasma. The new whole blood IMX assay was compared with four modifications (liquid/liquid or solid/liquid extraction of blood or plasma respectively) of the standard enzyme-linked immunosorbent assay (ELISA). Both assays utilize the same monoclonal antibody for detection of FK 506. Using isolated FK 506 metabolites generated in vitro, this antibody was shown to recognize not only the unmodified parent drug but also FK 506 metabolites. In stable liver-grafted patients, sensitivity of both modifications of the whole blood ELISA was adequate. In contrast, in some stable patients, plasma ELISA was not able to detect FK 506; this was observed mainly after liquid/liquid extraction of FK 506. Sensitivity of the IMX assay was also low; in six of 10 stable liver-grafted patients, IMX levels were below the limit of detection. In all assays, FK 506 levels were found to be elevated during episodes of liver dysfunction; a possible explanation for this effect would be that of accumulation of cross-reacting FK 506 metabolites. As FK 506 metabolites are known to be less immunosuppressive than the parent drug, liver function should always be taken into account if IMX or ELISA levels are used for drug monitoring.