The majority of infants who die in the neonatal period are born with a low birth weight , or prematurely (before 37 weeks). Most deaths among these infants could be prevented with simple, low-cost interventions like kangaroo mother care (KMC) or prevention and early identification of infection. It is difficult, however, to determine birth weight and gestational age in community settings, and therefore necessary to find an appropriate alternative screening tool that can identify LBW and preterm infants.This cross-sectional study was conducted at a tertiary hospital in Nepal to compare the validity of using three different foot length measurement methods  as screening tools for identifying babies with birth weights <2000 grams or infants born preterm (<37 weeks). LBW was defined as less than 2000 grams because of the implication for use of KMC for these infants. Non-parametric receiver operating characteristics (ROC) analysis was completed to determine which measurement method best predicted LBW and preterm birth. For the method that was the best predictor for each outcome (i.e. highest area under the curve), further analyses were completed to determine sensitivity, specificity, likelihood ratios and predictive values of an operational screening cutoff to predict LBW or preterm birth in this setting.Of the 811 infants included in this study, 30 infants had LBW and 54 were born preterm. The plastic ruler was the measurement method with the highest area under the curve, and thus predictive score for estimating both outcomes, so operational cutoffs were identified based on this method. An operational cutoff of 7.2 cm was identified to screen for infants weighing <2000 grams at birth , and 7.8 cm was determined as the operational cutoff to identify preterm infants .In Nepal, at least in community settings, foot length measurement with a hard ruler may be a valid proxy to identify at-risk infants when birth weight or gestational age is unavailable. Further studies and piloting should be conducted to identify exact cutoffs that can be used within community settings. Of the 135 million live births worldwide in 2010, around 14.9 million infants were born preterm, prior to 37 weeks of gestational age, representing a preterm birth rate of 11.1% [The biggest direct cause of neonatal death is complication due to preterm birth, leading to 35% of the 2.6 million neonatal deaths each year globally -7. AlthoIn the community setting, it can be difficult to identify preterm and LBW infants when they are born due to the absence of weighing scales, accurate gestational age measurement, or skilled health workers to assess the newborn’s condition. In fact, birth weight is assessed for only about half of the infants born in these settings, and gestational age is known for even fewer . PreviouIn Nepal, a low-income country in Southeast Asia, more than 60% of deliveries still occur at home, and only 36% of babies are weighed at birth . Nepal hThe aim of this study was to assess the use of foot length measurement as a screening tool to identify LBW or preterm infants in a hospital setting in Nepal. Three different low-cost tools, requiring minimal training, to measure newborn foot length were evaluated in order to determine an operational cutoff that could be used to screen infants as follows: (1) infants weighing less than 2000 grams or (2) infants with a gestational age less than 37 weeks.This study was conducted at a tertiary, government-run maternity hospital in Kathmandu, Nepal that serves as a central referral hospital. It is also used as a training site for reproductive and neonatal health for the country. The hospital is equipped with 415 inpatient beds, and between 2012–2013 there were 18,132 deliveries at the hospital .This was a cross-sectional study examining and comparing the validity of the use of three different foot length measurement methods as screening tools to identify LBW or preterm infants. The validity of these tools was determined based on their comparison to the gold standards of birth weight measured with a scale and gestational age based on last menstrual period. We used the Standards for the Reporting of Diagnostic accuracy studies (STARD) checklist for reporting of the diagnostic accuracy of this study .Our study was a subset of a larger study evaluating the impact of the implementation of a simplified neonatal resuscitation protocol on perinatal outcomes at the hospital. For the larger study, a reference population was created to assess the change in perinatal outcomes over a set period of time . This poExclusion criteria included multiple births and infants with any of the following conditions: severe respiratory distress (oxygenation support required), severe birth asphyxia (Apgar score <3 at 5 minutes), extreme prematurity , extremely low birth weight (<1000 grams), and congenital abnormalities . Furthermore, if parental consent for foot length measurement was not provided, infants were also excluded.This study was conducted from January 1 to March 30, 2014. During this time, 20% of the women admitted in the hospital for delivery were randomly selected using a lottery technique. Specifically, an opaque jar with 100 balls was kept in the admission unit, of which 80 were white and 20 were yellow. For each admission, a ball was drawn from the opaque jar; if a yellow ball was drawn, the woman was enrolled into the study as part of the referent population. The woman was then tracked until delivery, and if the infant was born alive, the mother-infant pair were included as study participants.In order to complete sampling and data collection, a surveillance team was formed under the close supervision of a research manager (RV). The team consisted of nine female surveillance officers with an academic background in nurse-midwifery and sufficient experience in clinical research to complete round-the-clock surveillance. Four surveillance officers were stationed in the admission unit to conduct the sampling of the referent population and four others in the delivery room to measure birth weight and assess the gestational age. At least one of these surveillance officers was present in these units at all times of day. Finally, one surveillance officer was placed in the postnatal ward during the day shift to measure foot length using each of the three different measurement tools. Surveillance officers were trained in the use of the random sampling technique, weighing of the babies immediately after birth, and foot length measurement methods. Training was completed using demonstration and practice with a skill checklist for 15 infants. RV closely supervised the surveillance officers and reassessed the foot length of each baby in the postnatal ward using all three techniques and provided constructive feedback.Study participants were weighed using a plastic pan scale with a 50-gram unit of measurement , which was calibrated at zero before taking the weight of each baby. The gestational age of the babies was estimated from the last menstrual period of the mother. Foot length was assessed using the left foot of the baby and each of the three different measurement tools: a hard plastic ruler, a measuring tape, and by placing the infant’s footprint on a piece of plan white paper. Foot length was measured from the heel to the tip of the big toe in millimeters, for every method. First, the hard plastic ruler was pressed vertically against the babies sole and the reading was done. Then, the baby’s sole was pressed vertically on a hard wooden board and the measuring tape was used to measure the foot length. Finally, the infant’s footprint was taken on a white sheet of paper by using a pencil to mark the tip of the big toe and the heel while keeping the sole of foot vertical on a hard wooden board. The distance between the two marks on the paper, i.e. the infant’s footprint, was then measured using a hard plastic ruler. Surveillance officers were blinded to outcome cutoff values for preterm birth and LBW.Babies having birth weight less than 2000 grams.Babies having a gestational age of less than 37 completed weeks at the time of birth.Data processing and entry was done using CS-Pro . The processed data was then analyzed using SPSS Version 17.0 . Two binary variables were used to classify birth weight as less than 2000 grams (LBW) or more, and gestational age as less than 37 weeks (preterm birth) or higher. A cutoff of 2000 grams was used for LBW because of the implication for use of KMC to treat these infants. For the remainder of this paper, LBW refers to infants <2000 grams unless otherwise stated. Only infants with outcome measurements according to the gold standards  were included in the analysis.Non-parametric receiver operating characteristics (ROC) analysis was completed individually for each of the foot length measurement tools, and the area under the curve (AUC) was calculated to identify which of the three tools best predicted LBW and preterm birth outcomes. Further analyses were only completed for the method that best predicted LBW and preterm birth, as determined by the AUC. Sensitivity, specificity, likelihood ratios, and predictive values were calculated for a range of foot length measurements so that an operational cutoff could be determined to screen for LBW or preterm infants in the community. For comparison reasons, the cutoff was determined by identifying the foot length with the highest average of sensitivity plus specificity to predict LBW or preterm birth, as this method was used in previous studies. Data are shown as mean ± standard deviation. All differences are considered significant when p <0.05.The Institutional Review Committee of Paropakar Maternity and Women’s Hospital, Development Board (Ref. no. 55–11 ka-559) and the Nepal Health Research Council (Ref. no. 1191) approved this study. Verbal consent was chosen as minimal risk was involved in the procedure, and was received from the parents of each infant included in the study. The verbal consent form included an easy to understand explanation of the purpose of the study in the local language, a simple description of the procedures, and the duration of the baby’s participation. The verbal consent form was reviewed and approved by the institutional review committee.During the study period, there were a total of 4,490 women who delivered at the hospital. Twenty percent of this population was randomly selected to be included in the study for foot length measurement, a total of 898 infants. Eighteen (2.0%) infants in the referent population were stillborn and thus excluded from the study population. Further, 55 (6.3%) of the remaining infants were excluded because of exclusion criteria given in the methods section. Fourteen (2.0%) of these infants were also excluded in the final analysis due to missing data, thus the final study population with foot length and outcome measurements included 811 infants (90% of the randomly selected population) . The mean birth weight of the infants was 2929 (±532.3) grams, and there were 30 infants who were LBW (3.7%). The mean birth weight of these LBW infants (i.e. weighing between 1000–2000 grams) was 1631 ± 241.6 grams. The mean gestational age of the study population was 39.5 ± 5.7 weeks, and fifty-four of the infants were born preterm (6.7%). The mean gestational age of the preterm infants was 35.0 ± 1.6 weeks.Mean foot lengths for the various measurement tools were: 7.72 ± 0.02 cm for the plastic ruler, 7.85 ± 0.02 cm for the measurement tape, and 7.65 ± 0.02 cm for paper footprint method p < 0.001). Table . Table 1The sensitivity, specificity, likelihood ratios and predictive values of a range of foot length measurements using the plastic ruler are shown in Table For determining preterm birth, the potential cutoff for foot length identified with the initial criteria was 7.8 cm. At this length, the sensitivity was 76.9% and the specificity was 53.9% (average of 65.4%), and the PPV was 10.6% while the NPV was 97.0%. Using the adjusted criteria, giving more weight to specificity, resulted in a cutoff of 7.0 cm. This increased PPV to 32.2%, but reduced sensitivity drastically to 17.3%. Thus the initial criterion for cutoff was chosen. Within this study population, 390 (48.1%) infants had a foot length below the cutoff of 7.8 cm.This hospital-based study in Nepal found that in order to predict LBW (<2000 grams) or preterm birth, the plastic ruler method for measuring foot length had the highest predictive score. Within this population, 7.2 cm was identified as the foot length cutoff to predict LBW infants, while a foot length cutoff of 7.8 cm was found to predict preterm birth, when using the plastic ruler as the measurement method. Foot length measured by plastic ruler was a better predictor for LBW than preterm birth with a higher specificity and PPV; however, the PPV for both outcomes was still quite low, likely due to the low prevalence of LBW and preterm birth within this population.To our knowledge, this is the first study in South Asia that compares the use of three different foot length measurement methods to identify at-risk infants, including LBW or preterm infants. By comparing the use of these three tools it was possible to identify which method was the most reliable predictor.There were, however, some limitations within this study. Although a scale was available and the surveillance officers were trained in its use, there was heaping of the infant’s weights around the hundred marks in the measurements, especially at 2,500 grams. There were also some inconsistencies in gestational age within individual mother’s medical records. This may limit the reliability of the outcome data and thus the cutoffs determined. Furthermore, the exclusion of very LBW infants and extremely preterm infants could lead to an underestimation of the sensitivity and specificity, as these infant’s foot lengths would likely have fallen below the determined cutoff.Additionally, this was a hospital-based study and therefore the rates of preterm birth and LBW may differ from those in the community, our target population. Thus validation for this tool must be completed within in the community among those health workers who will actually be using the measurement tools. Finally, the prevalence of preterm birth and LBW (<2000 grams) were lower in this study population than expected and therefore the PPV for each screening cutoff was low.The operational cutoff of 7.2 cm to identify LBW <2000 grams) infants was similar to a previous study from Nepal using a classification for LBW of 2000 grams. This study, from a community setting, found the operational cutoff to be 6.9 cm with a sensitivity of 88% and specificity of 86% . This lo00 grams If the adjusted cutoff for LBW (<2000 grams) of 7.2 cm would be used in the community setting, for every 1,000 deliveries, 136 infants would be identified as having a birth weight <2000 grams and receive counseling for extra care practices like KMC, early and exclusive breastfeeding, etc. Of these 136 infants, only 38 would actually weigh less than 2000 grams, while 98 would not have a birth weight less than 2000 grams . However, even if these infants are included in the program and given additional counseling on care practices, there is no harm done to the infants by receiving these interventions and they can be given at little or no additional cost. Of the 864 infants who would be identified as not weighing less than 2000 grams according to this cutoff, eight infants who actually did would be missed.If the initial cutoff for preterm birth of 7.8 cm would be used in the community setting, for every 1,000 deliveries, 481 infants would be identified as preterm. Of these infants, 51 would actually be preterm and 430 would not be. Of the 519 infants who would be identified as not preterm, 16 infants who were actually preterm would be missed.In Nepal, a country where exact data regarding the prevalence of LBW and preterm birth is not completely known and the majority of deliveries occur at home, foot length measurement as a screening tool has the potential to identify at-risk infants who are in need of additional care. In the community setting, foot length measurement with a hard ruler may be a valid proxy when birth weight or gestational age is unknown. By identifying these at-risk infants early, there is the possibility to provide them with simple interventions like skin-to-skin contact, early and exclusive breastfeeding, and prevention and early treatment of infection, thereby reducing neonatal mortality. Furthermore, even if some infants are falsely identified as LBW or preterm, these interventions will not harm them. Further studies and piloting should be conducted to identify the exact cutoff that can be used in different communities.


With rising obstetric anal sphincter injury (OASI) rates, the number of women at risk of OASI recurrence is in turn increasing. Decisions regarding mode of subsequent birth following an OASI are complex, and depend on a variety of factors. We sought to identify the risk factors for OASI recurrence from first and subsequent births, and to investigate the effect of OASI birth factors on planned caesarean for the second birth.Using two linked population datasets from New South Wales, Australia, we selected women giving birth between 2001 and 2011 with a first birth OASI and a subsequent birth. Multivariable logistic regression was used to identify the association of first and second birth factors with OASI recurrence, and to determine which factors were associated with a planned pre-labour caesarean at the second birth.Of 6,380 women with a first birth OASI who proceeded to a subsequent birth, 75.4% had a vaginal second birth, 19.4% a pre-labour caesarean, and 5.2% an intrapartum caesarean. Although the OASI recurrence rate of 5.7% was significantly higher than the first birth OASI rate of 4.5% (p < 0.01), this may not reflect a clinically significant increase. Following adjustment for first and second birth factors, first birth diabetes and second birthweight ≥3.5 kg were associated with increased likelihood of OASI recurrence, while first birthweight ≥4.0 kg and second gestation at 37–38 weeks were associated with decreased likelihood. A fourth degree tear at the first birth was the strongest factor associated with planned caesarean at the second birth, with other factors including epidural, spinal or general anaesthetic, birthweight, gestation, country of birth and maternal age.Compared with previous reports, the low OASI recurrence rate (approximately one in twenty) may reflect appropriate decision-making about subsequent mode of delivery following first birth OASI. This assertion is supported by evidence of different risk profiles for women who have planned caesareans compared with planned vaginal births. Obstetric anal sphincter injuries (OASIs) are recognised as a serious complication of vaginal births, and can result in long term problems including anal incontinence, ongoing perineal pain, dyspareunia and complex psychological issues -4. A recWithin the last twenty years reported rates of OASI have varied considerably, from less than 0.6% in Finland . DespiteNot surprisingly, there is general agreement that women feel apprehensive about subsequent births, with some women wishing to delay a further pregnancy ,4,19. ThIn recognition of the complexities in counselling a woman approaching a second birth following an OASI at her first, we undertook a large population-based study to determine risk factors from first and second births for OASI recurrence. In addition, we examined the effect of first birth factors on planning for either caesarean or vaginal second birth.The study population consisted of women who sustained an OASI at first birth and proceeded to a subsequent second birth in New South Wales (NSW) between 2001 and 2011. NSW is the most populous state in Australia, and with over 95,000 births occurring in 2011, it contributes to approximately one third of all Australian births . Where aData sources consisted of two population-based previously validated data collections: the NSW Perinatal Data Collection (birth data) and the NSW Admitted Patients Data Collection . The birth data are a legislated surveillance of demographic characteristics, pregnancy, and maternal and infant outcomes for all births in NSW ≥20 weeks gestation or ≥400 g birthweight, with data recorded by the attending midwife or doctor. The hospital data collection is a census of all admissions to NSW hospitals, with diagnoses and procedures coded from clinical patient records according to the International Classification of Diseases, Australian Modification (ICD-10-AM) and the Australian Classification of Health Interventions (ACHI) ,23. The Obstetric anal sphincter injuries (OASIs) were identified from the hospital data by the ICD-10-AM diagnosis codes: ‘O70.2’  or ‘O70.3’ , or by the ACHI procedure coding ‘16573-00’ (suture of third or fourth degree tear of the perineum) ,23. WithRecognised risk factors for OASIs ,16,26-28Firstly, we determined the first birth OASI rate among women having vaginal births who proceeded to a second birth. We then calculated the rates for second vaginal birth, intrapartum and pre-labour caesarean, and OASI recurrence. The OASI first birth rate and OASI recurrence rate were compared using McNemar’s test of paired data.Descriptive analysis was used to determine the distribution of birth factors from the first and second births among women with an OASI recurrence, and among those without. The crude odds ratios (cORs) were calculated. First birth risk factors that were considered included episiotomy, mode of birth, birthweight and analgesia/anaesthesia. As regional or general anaesthetic is recommended for OASI suturing to allow for repair without tension ,33, a coUsing information regarding labour onset, we categorised caesareans as pre-labour (recorded as ‘no labour’) or intrapartum (recorded as ‘spontaneous labour’ or ‘induced’). Women who underwent a pre-labour caesarean were classified as ‘planned caesarean’. Among the intrapartum caesarean group, some women may have been booked for a planned caesarean but commenced spontaneous labour prior to the planned date. These women were also classified as ‘planned caesarean’ if their medical record indicated that labour was not intended. Such indications included not having had an induction nor augmentation, and the reason for caesarean section not related to fetal distress nor failure to progress. All other women who laboured were classified as ‘planned vaginal’, including those from the intrapartum caesarean group who did have an induction or augmentation, or whose reason for caesarean was ‘failure to progress’ or ‘fetal distress’.The distribution of factors potentially influential in decision-making for mode of second birth was compared between the ‘planned vaginal’ group and the ‘planned caesarean’ group. These factors included country of birth; morbidity (diabetes or hypertension), gestation, induction/augmentation, analgesia/anaesthesia, instrumental birth, episiotomy, third or fourth degree tear, and birthweight at first birth, as well as interpregnancy interval. Second pregnancy factors included maternal age, diabetes, hypertension, gestation, and year of second birth. Multivariable logistic regression was then used to ascertain aORs for factors that may be predictive of planned caesarean.Ethics approval was obtained from the NSW Population and Health Services Research Ethics Committee.Among 141,894 primiparous women in NSW 2001–2011 with a vaginal first birth and a subsequent second birth, 6,380 (4.5%) sustained an OASI. Of these women, 4,808 (75.4%) proceeded to a second vaginal birth, 1,238 (19.4%) to a pre-labour caesarean section, and 334 (5.2%) to an intrapartum caesarean. The OASI recurrence rate at second birth was 5.7% which was significantly higher than the first birth OASI rate (p < 0.01)  records were available for analysis. After adjustment, the only factor from the first birth associated with an increased likelihood of OASI recurrence was diabetes , with a first born infant of ≥4.0 kg associated with decreased likelihood. Gestation at second birth of 37–38 weeks (compared with 39–40 weeks) was associated with a decreased odds of second OASI , while birthweight ≥ 4.0 kg increased the likelihood of recurrence when compared with birthweights of 3.0- < 3.5 kg  as did birthweight of 3.5- < 4.0 kg   were planned for a caesarean for their subsequent birth. Among those planned for a vaginal birth, 125 (2.5%) had a caesarean section. After exclusion of records with missing data, 6,337 (99.3%) records were available for analysis. Following adjustment, the following first birth factors remained associated with planned Caesarean: non-Asian country of birth; gestation ≥41 weeks; epidural, spinal or general anaesthetic; a fourth degree tear; birthweight ≥3.5 kg. Gestation at second birth <39 weeks and year of birth 2009–2011 were also predictive, with maternal age <25 years associated with a decreased likelihood of a planned caesarean section  following a first OASI than those without symptoms . This isThe results of this study demonstrate the complexity of counselling a woman approaching a second birth following a first birth OASI, when the option of a caesarean section may be being discussed. If a woman does progress to a second labour and vaginal birth, and requires an induction or augmentation, an epidural, episiotomy or vacuum birth, the results from this large population study provide some reassurance that there is no increased risk for OASI recurrence. In addition, with only a small increase in OASI rates from one birth to the next and with a paucity of risk factors identified for recurrence, it appears that women who were at higher risk were appropriately being delivered by caesarean section.Longitudinal linkage of these large population-based datasets allowed exploration of the association of first and second birth factors and obstetric interventions with a subsequent adverse outcome. Our data allowed us to identify consecutive births, and exclude the small number of women who birthed outside NSW for either their first or second birth. Records that were excluded due to missing data were small in number (less than 1%), and the variables we used for analysis have previously been validated as reliably and accurately reported ,29-31. EWe have demonstrated that for women who proceed to a subsequent vaginal birth the recurrence risk of OASI is approximately 1 in 20, and not markedly higher than the risk for an OASI at first birth. Significant risk factors for OASI recurrence included diabetes recorded at first birth and large infant birthweight at second birth. The profile for women having a planned caesarean section differed from those who planned to deliver vaginally, which likely influenced the OASI recurrence rate.


Objective: Extrahepatic biliary atresia (EHBA) is one of the main causes of neonatal cholestasis. Its early diagnosis could increase the survival of the infants with early surgery. We evaluated the diagnostic accuracy of procalcitonin and apolipoprotein E (Apo-E) levels in infants with and without EHBA.Methods: This prospective study included 18 infants with EHBA and 15 infants with other causes of cholestasis. Blood samples were taken from each patient and different markers including procalcitonin and Apo-E levels were measured. ROC analysis was used to define sensitivity, specificity, positive and negative predictive value (PPV and NPV) for procalcitonin and Apo-E.Findings: There was a significantly positive correlation between Apo-E and SGOT , SGPT  and GGT , and an inverse correlation between procalcitonin and GGT . Area under curve (AUC) for procalcitonin was 0.69 (P=0.05) with cut-point of 0.735 ng/ml. The sensitivity, specificity, PPV and NPV was 67%, 61%, 69% and 59%, respectively. AUC for Apo-E was 0.68 (P=0.06) for cut-point of 61.25 ng/ml with sensitivity, specificity, PPV and NPV of 67%, 67%, 71% and 67%, respectively.Conclusion: Both PCT and Apo-E have relatively good accuracy in diagnosing EHBA cases; we could not rely on these markers for diagnosis of EHBA, however, combinations of these biomarkers with other markers and imaging tests could improve their accuracy and may help to achieve a rapid and accurate diagnosis of EHBA. Extrahepatic biliary atresia (EHBA) is the most common cause of pathologic jaundice and the most commonly recognized cause of neonatal cholestasis throughout the world and one of the most common reasons for liver transplantation in children[3-6]. The incidence is 1:8000 to 1:15,000 live births.Neonatal cholestasis is a common neonatal liver disease which results in diminished bile flow and excretion, and is defined serologically as prolonged conjugated hyperbilirubinemia in neonates. There are numerous causes of neonatal cholestasis[10]. Early diagnosis is essential in order to maximize the survival of the infant’s native liver[9].  Several reports suggest that it results from prenatal injury and post-inflammatory fibrous obliteration of extra hepatic biliary tree. Because of the need for early diagnosis of the EHBA, efforts are focused on biomarkers especially inflammatory markers. Since cholestasis is frequently associated with abnormalities in the lipid transport system, we have focused on plasma lipoproteins. One of these markers is apolipoproteins (Apo). Apolipoprotein E (Apo-E) is an ingredient of VLDL, IDL and chylomicrons. There are increasing facts that it protects against atherogenesis through a variety of mechanisms. The Apo E gene is polymorphic and there are three common Apo-E proteins: Apo-E2, Apo-E3 and Apo-E4. The genetic variation in Apo-E has a strong effect on its anti-atherogenic properties[13]. Although definitive diagnosis requires a cholangiogram, liver biopsy, and surgery, there are essential limitations such as invasiveness and need for an experienced team. Thus there is need for other surrogates for precise differentiation between BA and other neonatal cholestatic diseases[14-17]. However, most of these findings are reported more than 20 years ago and there is a need for defining Apo-E levels in biliary atresia and EHBA.  It was shown that Apo-E is higher in serum from biliary atresia and EHBA than non-EHBA infants; such elevation is reported previously in individuals with biliary tract obstruction, is a stable protein present ex vivo in plasma with a half-life of about 24–30 hr. Procalcitonin levels are shown to raise in infections and is therefore considered as a novel inflammatory marker and as an acute phase reactant biosynthesized in the liver[20]. PCT levels are not evaluated in neonatal cholestasis or EHBA, however, different values are reported according to the mechanism responsible for liver injury and hepatic disease[21]. Considering the above mentioned reports, we evaluated possible diagnostic values of Apo-E and PCT levels in EHBA. Procalcitonin (PCT), the prohormone of calcitoninBetween April 2010 and 2012 all infants admitted to gastroenterology ward, Children’s Hospital, Tabriz, with jaundice at 2 weeks of age and the diagnosis of cholestasis were recruited. Patients with renal or liver failure or any disorder causing reduced production and clearance of acute phase proteins, hypoxia, shock, patients receiving antibiotics, anti-inflammatory drugs or corticosteroids before admission to the ward and patients receiving TPN were excluded. The protocol was approved by the Institutional Review Board of Tabriz University of Medical Sciences and carried out in compliance with the Helsinki Declaration. Written parental consent was obtained for each study participant during the study.  All neonates with cholestasis enrolled underwent physical examination, laboratory and imaging studies to define the cause for the cholestasis. Due to the results, neonates were divided into groups with extrahepatic biliary atresia (n=18) and with other causes of neonatal cholestasis (n=15).  Along with other laboratory evaluations, procalcitonin and Apo-E levels were also measured. Fasting blood samples were obtained via venous puncture in the first day of admission. Samples were centrifuged within 30 minutes of collection and the serum was stored at -70℃ before analysis for determination of procalcitonin and Apo-E levels.Determination of biomarkersFor the determination of procalcitonin concentration, the Liaison Brahms procalcitonin assay  was used. This assay has an improved functional assay sensitivity of 0.06 ng/ml and results range from 0.06 to 50 ng/ml. Apo-E levels were measured using Human Apolipoprotein E (Apo-E) ELISA Kit . This assay has an improved functional assay sensitivity of 0.23 ng/ml and results range from 0.5 to 200 ng/ml. Data analysisU test for nonparametric data where appropriate, chi-square or Fisher exact test for testing the significance of percentages were used. Continuous data with normal distribution are given as mean±standard deviation, otherwise as median. Values are also given as the n and percent. Student t-test for testing the significance of mean for independent continuous scale data and Mann-Whitney P<0.05 was considered as significant. All statistical analyses were performed with SPSS version 17.0 .ROC analysis was conducted to calculate sensitivity and specificity of Apo-E and procalcitonin. In this study, 33 neonates with mean age of 55.72±26.80 days referring with jaundice were evaluated. HIDA scan was performed in 31 patients and results were indicative of extrahepatic biliary atresia (EHBA) in 26 (83.9%), suspected atresia in 1 (3.2%) and no atresia in 4 (12.9%). Among 33 patients, only 22 underwent diagnostic laparatomy and cholangiography during laparatomy, this showed atresia in 13 (59.1%). Twenty-six patients who had liver biopsy and pathologic findings showed EHBA in 16 (61.6%), neonatal hepatitis in 9 (34.6%) and paucity in 1 (3.8%). The missing cases are due to disagreement of parents for further imaging or invasive evaluations.  Final diagnosis was made according to imaging studies, laboratory and laparatomy findings; 18 patients were defined to have EHBA and 15 patients had other causes including neonatal hepatitis in 12, paucity in 1, α1-Antitrypsin deficiency in 1 and inborn error of metabolism (IEM) in 1 patient.  Baseline findings between patients with and without EHBA are shown in Besides total and direct bilirubin, all other laboratory findings were higher in patients with extrahepatic atresia; however, only Gamma-glutamyl transpeptidase and alkaline phosphatase (ALP) had statistically significant difference.r=0.37, P=0.03), SGPT  and Gamma-glutamyl transpeptidase , as well as inverse correlation between procalcitonin and Gamma GT . The inverse correlation between Apo-E and procalcitonin was not significant . We also found positive correlation between Apo-E levels and weight at admission  and between procalcitonin levels and age at jaundice onset .  We evaluated the correlation between Apo-E and procalcitonin with laboratory findings and found significant positive correlation between Apo-E and SGOT (P=0.05) with cut-point of 0.735 ng/ml. The sensitivity, specificity, positive and negative predictive value (PPV and NPV) of procalcitonin in differentiating cases with and without extrahepatic biliary atresia with cut-point of 0.735 ng/ml was 67%, 61%, 69% and 59%, respectively. Procalcitonin levels in extrahepatic biliary atresia group were between 0.28 and 1.2 in 17 cases and 13 in a female infant which had cholangitis and died after 69 days. The range of procalcitonin in the other group was between 0.47 and 4.52. Procalcitonin was 4.52 in a female neonate with severe sepsis. Due to the lower levels of procalcitonin in extrahepatic biliary atresia group, ROC curve analysis was used to define cut-point of procalcitonin in diagnosing cases with and without extrahepatic biliary atresia . AUC wasP=0.06). Although not significant, the evaluated cut-point was 61.25 ng/ml. The calculated sensitivity, specificity, PPV and NPV was 67%, 67%, 71% and 67%, respect-tively. We also used ROC curve to define probable cut-points for Apo-E in diagnosing extrahepatic biliary atresia from other causes of jaundice . Area un[22-24]. While idiopathic neonatal hepatitis and EHBA are the major causes of neonatal cholestasis, EHBA must be managed operatively as soon as possible; the preferred treatment of less common metabolic and other causes is medical[23].  Distinguishing between different underlying etiologies of neonatal cholestasis is of great importance because the plan of treatment could literally vary. Late referral of infants with neonatal cholestasis is considered to be one of the main problems in dealing with these patients; especially in developing countriesSimilarly, most EHBA cases in our study more likely have been referred late, but the difference was not significant. [25].  As the previous study by Nemati and colleagues, in our study it was also shown that HIDA scan although is very sensitive in diagnosis of EHBA, its positive predictive value was low[26]. Among 18 neonates with EHBA, nine underwent Kasai portoenterostomy, one died due to severe cholangitis and for the other eight liver transplantation was recommended because of liver cirrhosis due to late referral and late diagnosis.  More than 80% of cases with EHBA, who undergo Kasai portoenterostomy before 60th day of life become jaundice-free, as compared to 20-35% that were operated later. In the infants with successful biliary drainage, a 15-year survival of 87% has been shown. Many modalities and markers are proposed for this purpose. We evaluated different laboratory findings and observed that although most markers were higher in EHBA, only Gamma-glutamyl transpeptidase and ALP had statistically significant difference. Similarly, Chu and colleagues[29] showed that SGOT, SGPT, ALP and Gamma-glutamyl transpeptidase were higher in biliary atresia; however, in this study total and conjugated bilirubin was also higher.  Since immediate portoentrostomy may prevent further potentially fatal consequence of EHBA, it is very critical to differentiate EHBA from other causes of cholestatic jaundice Among these modalities, due to previous reports we suspected that Apo-E and procalcitonin levels could distinguish between EHBA and other causes. We found positive correlation between Apo-E and Gamma-glutamyl transpeptidase and inverse correlation between procalcitonin and Gamma-glutamyl transpeptidase. It is known that procalcitonin levels increase by age, as we observed a positive correlation between procalcitonin levels and age at jaundice onset. [30]. PCT has been proposed as a marker of bacterial sepsis in critically ill patients. PCT is a precursor of calcitonin and a 116 amino acids protein. In healthy persons, PCT levels are barely detectable. It is believed that hepatic cells are potential sources for PCT[31]. Due to the potential role of hepatic cells in producing PCT, it is possible that PCT increase in different liver diseases could differentiate these diseases especially biliary tract involvement. It was previously reported that acute alcoholic hepatitis and acute viral hepatitis on cirrhotic background without proven bacterial infection induce mild elevation of serum PCT levels. However, in another study, there was no statistical correlation between PCT serum levels and the presence of biliary obstruction on ERCP findings[34].  Over the past two decades, the body of literature on the clinical usefulness of procalcitonin in adults has grown rapidly. However, the use of PCT in pediatric populations is less evaluated and is mostly studied for severe infection and sepsis diagnosis21 evaluated serum procalcitonin in children with hepatic disease. They observed that procalcitonin level was low in viral infection and toxic liver injury, and was moderately elevated in 50% of children with an autoimmune process. These bring up the possible role for procalcitonin in distinguishing between different liver diseases including neonatal cholestatic disease. In this study, sensitivity, specificity, PPV and NPV of procalcitonin in differentiating EHBA from other cases was 67%, 61%, 69% and 59%, respectively. Our findings are indicative of the role of procalcitonin, but the low sensitivity and specificity as well as low PPV and NPV question its utility.  As mentioned before, there are few studies evaluating PCT levels in diseases other than sepsis in infants. Korczowski indicating that Apo-E levels increase in biliary atresia, especially EHBA. Similar to these findings, in our study Apo-E levels were significantly higher in EHBA patients in comparison to other causes of neonatal cholestasis. The sensitivity, specificity, PPV and NPV of Apo-E in distinguishing between these was 67%, 67%, 71% and 67%, respectively. Apo-E with slightly better PPV and NPV seems to be a better marker than PCT in diagnosing EHBA cases. However, both markers have low sensitivity and specificity which limits their diagnostic use. The possible role of various apolipoproteins is mentioned previously. Unlike PCT, Apo-E has been previously studied in various liver diseases and in neonatal cholestasisOur findings show that both PCT and Apo-E have relative accuracy in diagnosing EHBA cases; we could not rely on these markers for diagnosis of EHBA, however, combinations of these biomarkers with other markers and imaging tests could improve their accuracy and may help for rapid and accurate diagnosis of EHBA. However, further studies should be performed to define the exact level of significance and to confirm these findings.


A major component driving cross-country fertility differences in the developed world is differences in the probability of having additional children among those who have one. Why do people stop at having only one child? We hypothesize that the experience of the transition to parenthood is an important determinant of further fertility. Analyzing longitudinal data from Germany, we find that the experience during the transition to parenthood, as measured by changes in subjective well-being, predicts further parity progression. A drop in well-being surrounding first birth predicts a decreased likelihood of having another child. The association is particularly strong for older parents and those with higher education: these characteristics may be related to the ability or willingness to revise fertility plans based on prior experiences. Parents’ experience with the first birth is an important and understudied factor in determining completed family size, and policy-makers concerned about low fertility should pay attention to factors that influence the well-being of new parents. Period fertility declined in much of the developed world to below-replacement levels in the late twentieth century. By the early twenty-first century, more than one-half of the world’s population lived in countries with below-replacement fertility Wilson . DespiteResearch has identified several important social and demographic determinants of low period fertility. The rise of individualistic values and the increase of women into the paid labor force have led to low levels of desired and actual fertility  groups, although the expected pattern is ambiguous. On the one hand, parenting experiences might be more critical in determining final parity for high-SES or older parents, perhaps because of a greater absolute opportunity cost of unpleasant physical consequences of pregnancy or parenting for high-SES working parents or those who are more advanced in their career , described in detail in the Data section, is the longest data set in the world that includes panel information about both subjective well-being and fertility behavior. Using these data, we are able to analyze how an overall measure of well-being changes annually for new parents and how these changes predict further parity progression. We measure life satisfaction before a first birth and over a long period to observe parity progression, as well as many other factors that affect progression to second birth, such as changes in partnership status and employment.German fertility can be characterized by persistent low fertility. The period total fertility rate (TFR) has been below 1.5 since 1983. For a period of four years following the unification of East and West Germany in 1990, the TFR dropped below 1.3. There is also important regional variation. In West Germany, the TFR has been very stable, between 1.4 and 1.5, since the 1980s. However, in East Germany, the TFR declined from about 2.0 in 1980 to 1.5 in 1990, and fell below 0.8 after the unification in the early 1990s. By 2010, the TFR in East Germany climbed back to the West German level of approximately 1.4  the levels of parental life satisfaction over the transition to parenthood, (2) the gain in well-being in anticipation of a first birth, and (3) the drop in parental well-being from before to after a first birth. Based on the theories of learning and planned behavior, we hypothesize that higher levels of parental well-being over the course of transition to parenthood, greater gains in well-being leading up to birth, and smaller drops in well-being after a birth will be associated with a higher hazard of a second birth.Second, we examine whether there are sex differences in the importance of the pattern of subjective well-being over the transition to parenthood. We hypothesize that the experiences during the transition to parenthood will be a stronger predictor of progression to a second child for women than for men because women experience the birth physically, are much more likely to take leave after the birth, and may have more power in a couple’s fertility decisions given disagreement.Third, we examine whether parental well-being around a first birth is a stronger predictor of parity progression for highly educated parents than for those with less education, and for those with high age at first birth than for those with a lower age at first birth, net of other factors. The direction of this interaction is ambiguous, depending on whether the absolute or relative costs of temporarily dropping out of the labor force are more costly for highly or less-educated workers.We use data from the German Socio-Economic Panel Study (SOEP), a nationally representative longitudinal study of private households run by the German Institute for Economic Research (DIW Berlin). Every year, nearly 11,000 households and more than 20,000 persons are interviewed. The data provide information on all household members, consisting of Germans living in the old (West) and new (East) German states, foreigners, and recent immigrants to Germany. The SOEP was started in 1984, with the East German states added in 1991. Wave-to-wave reinterview response rates for the SOEP have been consistently above 90 %, in line with other national panel studies such as the PSID, HRS, and BHPS Frick ; and surN = 2,301). After excluding 111 respondents who reported having their first two children in one interview (twins or two singleton births within a year) and excluding another 174 respondents because of missing data on key variables , our sample consists of 2,016 persons who experienced first births during the follow-up, 58 % of whom were observed to have a second birth over an average follow-up of 9.0 years (range 2–15) after a first birth.Our analysis draws on survey waves from 1984 to 2010. Because the focus is on the parental well-being trajectory from before having children through having a birth and how that influences further parity progression, we exclude people who already had a child at first interview or who remained childless throughout the study period. We include in our analytical sample individuals whom we observe from three years before a first birth through at least two years after the first birth  and the minimum level of life satisfaction after the birth (measured in the year the child is reported and the year after the birth is reported). This is a continuous measure that ranges from 0 if there is no drop or a gain, to 9, the maximum drop we observe in the data. This measure captures the issues raised by new parents who reported that the most common high is just before or just after the child arrives and that the most common low is during the first year after birth  to 10 (completely satisfied). This is a distal measure of overall positive well-being. Although this measure does not capture respondents’ overall experience of having a child, it is preferable to direct questions about childbearing because it is considered taboo for new parents to say negative things about a new child. We examine whether three aspects of respondents’ subjective well-being during the transition to parenthood are associated with a second birth, net of other important factors:We test whether changes in well-being matter more for three subgroups: men versus women, younger versus older first-time parents, and more- versus less-educated parents. Age at first birth is measured as age in the first interview following the birth, and coded as less than 30 years or 30 years and older. Educational attainment at the time of first birth is also measured in the interview following the first birth and coded as less than 12 years (59 % of the sample) or 12 or more years. Our results were robust to alternative coding schemes for education. We control for variables that have been shown in previous research to also be associated with progression from parity 1 to 2. We control for country of origin with a dummy variable for whether the person was German-born (or had migrated to Germany before 1949), or immigrated to Germany in 1949 or later. A dummy variable is included for whether the respondent lived in the former East or West German states in the interview following the first birth. We also control for three time-varying variables measured annually at each interview. Partnership status measures whether the respondent was married or cohabiting, or whether the respondent was unpartnered. Household income at each interview is measured on a log scale. Labor force participation measures whether respondents were working in the last week before the survey.We begin with a brief overview of the characteristics of respondents at the time of their first birth, by whether they go on to have a second during the period of observation. Then, to better understand how changes in parental well-being around the first birth shape the progression to a second birth, we model the likelihood of having a second birth using event history methods. Respondents enter the model—that is, are included in the population at risk for experiencing a second birth—the year of the first birth and are censored at the second birth, exit from or end of the survey, or 15 years after the first birth, whichever comes first. We use a Cox proportional hazard model to estimate the relative hazard of a second birth. Cox regression models use the time to an event to estimate the relationship between observed covariates and the rate of occurrence of the event, taking into account that not all respondents will undergo the event and that some observations will be censored before the event occurs.hi(t) represents the hazard, or instantaneous rate of second birth for an individual i at time t. The function λ0(t) is the nonparametric baseline hazard function, which can take any form and is the same for all individuals. The baseline hazard is shifted by the measures of parental well-being (Wi); the time-invariant characteristics of age at first birth, gender, education at first birth (Xi); and time-varying measures of partnership status, household income, and labor force participation (Zit). In testing the proportional hazards assumptions, we found that region and nativity interact with time (Ri). Therefore, these interactions are included in the multivariate models (RiT). In the last part of the analysis, we test whether the drop in parental well-being is similarly important for men and women, by age at first birth, and by educational attainment. We test these with a series of interaction terms among sex, age at first birth or education, and measures of the experience of the transition to parenthood (WiXi). The coefficients (B) are estimated coefficients.We estimate the following model:Table Respondents who have a second child are also more likely to have had their first child at a younger age, to have been partnered at the time of the first child, to have been immigrants, and to have lived in West Germany than in East Germany. There are no significant differences in observed final parity by sex, educational attainment, labor force status, or household income in the year before a first birth Table .Table p < .10). To test for nonlinearity, in Model 4 we examine differences in the size of the life satisfaction drop around a first birth, comparing those with no drop, and a drop of one, two, and three or more units. The point estimates suggest that the hazard declines monotonically with the drop of life satisfaction, although only for those with a drop of three or more units in well-being around a first birth is the hazard of a second birth significantly lower (Model 4) . To translate these hazard ratios into parity progression, we present in Fig. Models 3 and 4 test two specifications of the drop in well-being from just before to after a first birth. The results of these models, as well as the bivariate analysis on life satisfaction drop, consistently support the hypothesis that a drop in well-being is associated with lower hazard of a second birth. Model 3 includes the drop as a continuous variable; a one-unit increase in the size of the drop is associated with a 4 % lower hazard of a second birth, and the coefficient is marginally significant p < .0. To tesBecause the degree to which respondents experience a drop in well-being from before to after a first birth appears to be important in predicting further parity progression, we examine the predictors of the well-being drop around first birth. Table Last, we examine whether the subjective experience of a first birth matters more or less for different subgroups: men and women, those with high and low education, and those with a high and low age at first birth. Table We conducted several robustness checks. First, we estimated results with various lengths of follow-up and found similar results when analyzing respondents for 5, 8, and 10 years after reporting a first birth. Second, we examined whether the results would change when controlling for the sex of the child: they did not. Both men and women seem to have lower drops in well-being after having a daughter rather than a son, but the sex of the first child is not associated with parity progression. Third, we ran the analysis excluding those who reported a second child in the first or second year after reporting a first child, when the drop was being measured. The sample was much smaller, and power was reduced, leading to lower levels of statistical significance, but the results yielded patterns and coefficients that were similar to those reported earlier. Fourth, we estimated models that control for period effects by using year-of-interview dummy variables. In these models, none or only one of the 21 dummy variables was statistically significant at the .05 level, so we did not include these in the final models. Last, we tested whether the results held for both the former West and East German states and found the same patterns as the results reported earlier in this article. However, the smaller samples led to less statistical power and more varied estimates.A standing puzzle in demography is why fertility in many developed countries is so far below replacement level. Recent answers focus on fecundity impairments brought on by postponement of fertility, the high opportunity cost of childbearing, and partnership dissolution (Bongaarts Fertility research can benefit from incorporating an element of learning about parenthood. Prior research has used the macro perspective to analyze how childbearing spreads within a population (Myrskylä and Goldstein Subjective well-being changes after a first birth may also be important for the TFR. We used parity progression rates for the 1959 birth cohort in Germany (Kreyenfeld How relevant are these findings for other low-fertility countries? In part, this depends on the size of the childless population, which dictates the proportion of the population at risk of the transition from parity 1 to 2. Childlessness among German women increased from 11 % of the 1935–1939 birth cohort to 22 % for the 1965–1969 birth cohort, the latest for which childlessness can be calculated without forecasting (Kreyenfeld and Konietzka In testing for heterogeneous effects of the transition to parenthood on fertility behavior, we found that the drop in well-being around the transition to parenthood was a stronger predictor of not having a second birth for highly educated parents and those who waited longer to have a first child. We propose four possible reasons for this finding. First, highly educated parents may not enjoy the mundane tasks of parenting Newman . High-SEThis analysis has limitations. First, our analysis describes the predictors and consequences of changes in overall life satisfaction for parity progression, but it cannot speak to the underlying mechanisms that determine parents’ difficulty with the transition to parenthood. These factors, such as the ease of the birth experience, level of exhaustion during the first year, and relationship stress, are not available in our survey data and are better suited to qualitative work, such as that by Newman . TherefoDespite these limitations, this article presents evidence that parents’ subjective experience of a first birth is an important and understudied factor in determining final family size. An immediate follow-up question stemming from our results is whether policy could influence the subjective well-being of new parents. In 2007, Germany implemented several new policies that were aimed at supporting new parents, and preliminary evidence suggests that these policies may have positively influenced parental well-being (Myrskylä and Margolis


This year, National Birth Defects Prevention Month focuses on how common, costly, and critical birth defects are in the United States. Birth defects are relatively common, affecting one in every 33 infants born in the United States each year, or approximately 120,000 infants  (http://www.cdc.gov/birthdefects.Health-care professionals can help prevent many other birth defects by encouraging women of childbearing age to manage health conditions and adopt healthy behaviors before becoming pregnant, including not drinking alcohol  or using


Vallecular cyst is a rare cause of stridor in neonates, which may present as a life threatening airway obstruction. Here, we report a preterm infant with a congenital vallecular cyst who presented with stridor and respiratory distress that developed immediately after birth. She was successfully treated with endoscopic marsupialization.  A female infant, weighing 2020 grams born to a healthy 35-year-old mother at 33 weeks of gestation, was referred because of stridor and respiratory distress developed immediately after birth. On physical examination, she had cyanosis, inspiratory stridor, and tachypnea with suprasternal and subcostal retractions. During intubation, a laryngeal cystic mass at the base of the tongue was noted. Tracheal intubation was done. A flexible fiberoptic nasopharyngolaryngoscopy was performed by the otorhinolaryngologist, which showed a cystic mass arising from laryngeal and lingual mucosa of left epiglottis and obliterating pyriform sinus. Magnetic resonance imaging (MRI) scan revealed a 21x25x18 mm uniloculated cystic mass located behind the tongue; it filled the oropharynx and extended up to the epiglottis . On day 3, a diagnostic direct laryngoscopy was performed initially, which confirmed a cystic mass in the vallecula; endoscopic marsupialization of the cyst was done . The neonate required intubation for one-week postoperatively, though the postoperative period was uneventful.Histopathological analysis revealed a cyst lined by non-keratinizing squamous epithelium with evidence of chronic inflammation in fibrous tissue. There was no evidence of recurrence at follow-up after one year.Vallecular cyst is thought to occur as a consequence of either ductal obstruction of mucous glands or an embryologic malformation and presents as inspiratory stridor, respiratory distress, apnea, cyanosis and hoarse cry [1-7]. Majority of affected infants develop symptoms within the first week of life . Our patient developed stridor and respiratory distress immediately after birth and upper airway obstruction was detected during tracheal intubation. Feeding difficulties and failure to thrive may be the presenting symptoms in older children . Flexible fiberoptic endoscopy is the most helpful diagnostic tool in the diagnosis of vallecular cysts . It allows immediate dynamic assessment of the larynx in a bedside setting. MRI is a valuable imaging method to determine the extent and content of the lesion . Thyroglossal cyst, thyroid remnant cyst, dermoid cyst, cystic hygroma, hemangioma, lymphangioma, teratoma should be considered in the differential diagnosis of vallecular cyst . Direct laryngoscopy under general anesthesia is the major diagnostic tool for confirming the diagnosis of vallecular cyst . Prenatal diagnosis of vallecular cyst with ultrasonography and MRI has been reported and earlier diagnosis allows planning perinatal management [10]. Surgical cyst excision is the treatment of choice for vallecular cysts. Aspiration of the cyst is not advocated because of its high recurrence rate but cyst aspiration may offer prompt relief of upper airway obstruction . Endoscopic marsupialization is the recommended surgical approach in infants . Extirpation of the cyst with external approach is preferred for treatment of recurrent cysts but it is more invasive than marsupialization and sometimes requires tracheotomy . Hoarseness and dysphagia are complications of external approach. Long-term prognosis of vallecular cyst is generally good with minimal recurrence rate .Source of Support: NilConflict of Interest: Nil


Electroporation is gaining its importance in everyday clinical practice of cancer treatment. For its success it is extremely important that coverage of the target tissue, i.e. treated tumor, with electric field is within the specified range. Therefore, an efficient tool for the electric field monitoring in the tumor during delivery of electroporation pulses is needed. The electric field can be reconstructed by the magnetic resonance electric impedance tomography method from current density distribution data. In this study, the use of current density imaging with MRI for monitoring current density distribution during delivery of irreversible electroporation pulses was demonstrated.Using a modified single-shot RARE sequence, where four 3000 V and 100 μs long pulses were included at the start, current distribution between a pair of electrodes inserted in a liver tissue sample was imaged. Two repetitions of the sequence with phases of refocusing radiofrequency pulses 90° apart were needed to acquire one current density image. For each sample in total 45 current density images were acquired to follow a standard protocol for irreversible electroporation where 90 electric pulses are delivered at 1 Hz.2 to 13 kA/m2 and that direction of the current path did not change with repeated electric pulses significantly.Acquired current density images showed that the current density in the middle of the sample increased from first to last electric pulses by 60%, i.e. from 8 kA/mThe presented single-shot RARE-based current density imaging sequence was used successfully to image current distribution during delivery of short high-voltage electric pulses. The method has a potential to enable monitoring of tumor coverage by electric field during irreversible electroporation tissue ablation. One such application, which is also a topic of this study, is the use of CDI to monitor current density distribution in the sample during delivery of electric pulses in IRE. In previous studies [in situ using MREIT. ECT and IRE are not really different in voltage and current amplitude but in pulse repetition frequency and most of all in number of pulses delivered. Since MREIT algorithms depend on the quality of the measured current density distribution, a new CDI sequence, optimized for currents delivered by electroporation pulses used in IRE, is needed. Therefore, the aim of this study was to develop a new CDI sequence that would enable monitoring of current density distribution during application of electric pulses with parameters that are commonly used in IRE tissue ablation procedures, i.e. repetition rate of approximately 1 Hz and an amplitude of 3000 V [MREIT is enabled by Current Density Imaging (CDI), an MRI modality designed to detect electric currents via temporal change of magnetic field that is induced by the currents . In CDI, studies ,13-15 wef 3000 V ,27.c tin the sequence and to the signal-to-noise ratio (SNR) of the magnitude image obtained by the sequence. The relation follows from the phase-based detection of CDI. Namely, in CDI current density is calculated using Ampere's law from a known magnetic field change due to applied electric current pulses. The magnetic field change is measured from the image phase shift that is proportional to ct, while the error of the measured magnetic field change (standard deviation of the measured phase shift) is inversely proportional to SNR. Therefore, CDI sensitivity is proportional to c · SNRt. In most cases, i.e. for all spin-echo based imaging sequences, image signal decays exponentially with the time between signal excitation and its acquisition. If it is also assumed that this time is approximately equal to c tthen it follows that SNR is proportional to exp(-ct/T2) and CDI sensitivity to c texp(-ct/T2); here T2 is the spin-spin relaxation time of the sample. As presented in Figure c t= T2, which is also most favorable condition for performance of CDI experiments. In the case electroporation monitoring by CDI, the electric pulses are so short that T2 relaxation factor in the CDI sensitivity formula is equal to unity so that the sensitivity is proportional only to the duration of applied electric pulses  which ensures ethical standards of slaughtering procedure and is in compliance with European Union Council directive on the protection of animals at the time of slaughter or killing (93/119/EC). Temperature of the liver tissue was maintained at 4°C before the beginning of experiment when they were allowed to heat up to the room temperature, while time between slaughtering and the experiment was between 24 and 120 hours. Tissues were sectioned in cylindrical and flat shaped samples with a diameter of 21 mm and height of 4 mm in order to fit into an acrylic glass container designed for CDI experiments. Two self-built cylindrically shaped platinum-iridium electrodes with a diameter of 1 mm were inserted in the tissue. The distance between the electrodes was 14 mm. The sequence of 90 high voltage electric pulses with an amplitude of 3000 V and a duration of 100 μs at a repetition rate of 1 Hz were delivered between the electrodes. Electric pulses were delivered using customized Cliniporator Vitae  pulse generator. The electric pulse generator has 6 independently controlled and electrically insulated outputs each providing rectangular pulses with amplitudes up to 3000 V and 50 A maximum current. The generator is also capable of measuring the output voltage at 3 % precision. The current of electric pulses was measured with an oscilloscope  using a current probe  clamped around a wire connecting an electrode and the electric pulse generator. All experiments were repeated three times. The sample was replaced with a fresh one after each IRE pulse series delivery to ensure identical initial conditions in all electroporation experiments.Proposed method of measuring current density distribution during IRE therapy was evaluated on Two-shot RARE pulse sequence for monitoring IRE was performed on a 2.35 T horizontal bore small animal MRI scanner. The scanner was based on an Oxford superconducting magnet , an Apollo NMR/MRI spectrometer  and MRI probes for MR microscopy . The gradient hardware was able to deliver gradient pulses of up to 250 mT/m at the switching time of 200 μs. The spectrometer had several programmable TTL outputs that serve for a control of peripheral devices, one of these was used to trigger electroporation pulses on the electric pulse generator synchronously with the imaging sequence. Parameters of the sequence were the following: field of view 30 mm, imaging matrix 64 by 64, RARE factor 64, slice thickness 4 mm, echo time 2.64 ms, and repetition time 1 s. Centric sampling ordering of k-space lines was used to maximize CDI sensitivity.ex vivo an electric current density was established inside the tissue. After each pair of successive electric pulses an electric current density distribution was successfully acquired by means of CDI two-shot RARE pulse sequence. Figure 2) was established around the electrodes during the application of first two pulses whereas during the last two pulses this area has expanded towards the area between the electrodes. The direction of current path did not change with repeated electric pulses significantly, it only got more focused to the direct path between the electrodes. Thus, the current density in 10 × 10 pixels large area in the center of the tissue increased from the first to last electric pulses by 30%, i.e. from 6.6±0.3 kA/m2 to 8.6±0.4 kA/m2.When the tissue was exposed to a sequence of 90 electroporation pulses, i.e. a standard IRE sequence, A comparison of measured electric current by means of the current probe and reconstructed electric current by means of CDI for one of the examples is shown on Figure c t= T2, unfortunately, in practice most biomedical applications of CDI are such that there is a demand for either application of very short and high current pulses or very long and low current pulses. The first case is associated with CDI applications in monitoring electroporation pulses which are considered in more detail in this work, while the second case is associated with attempts to image physiological currents which are low due to low conductivity of biological tissues and also due to low voltages that living systems can bear if applied externally or possess inherently [T2 relaxation of biological tissues, which is of the order of 100 ms. Only one 100 μs pulse is four times shorter than what was used in our previous experiments on the same test sample where four 100 μs were delivered in intervals of 100 μs, i.e. 5 kHz pulse repetition frequency [SNR of the image, which can be done by increasing imaging slice thickness or decreasing images resolution. Another option would be to perform experiments in a higher field magnet. Namely, image signal in theory increases approximately proportionally with the magnetic field squared. Alternatively, delivery of IRE sequence of pulses in another schedule could be considered, e.g. 4 or up to 10 pulses at high pulse repetition frequency.While, as shown in Figure herently . The mosherently ,32. The requency . Our preResults presented in Figure in vivo IRE the current can reach up to 50 A [in vivo IRE would therefore enable measurement of current density distributions with even better SNR than one presented in this study. In Figure Electric current was also measured by means of a current probe. In Figure  to 50 A  due to eex vivo, however, its application in vivo seems feasible and will be our next research step. It is expected that such application would require only minor modifications of the experimental setup. Most of them will be associated with more difficult positioning of the electrodes in terms of their alignment along the direction of the static field and their interdistance. Namely, in this study one of few ideal electrode arrangement was used that do not require sample reorientation in the magnet to extract 2D current distribution. In the arrangement, the exposed parts of the electrodes were positioned in a plane perpendicular to the B0 field, while the electrodes were parallel to the B0 field. For the arrangement, the only nonzero current induced magnetic field component in the plane has B0 direction (it is perpendicular to the plane) and is therefore easy to detect. These conditions are often difficult to meet, especially in in vivo experiments where positioning of the electrodes is more difficult and the sample has a complex geometry. The sample reorientation in the magnet is a major limitation of CDI experiments, especially when performed in vivo, and is usually avoided by using electrode arrangements that do not require sample reorientation  in the magnet.CDI is the most important component of monitoring the electroporation process by means of MREIT since it provides current density distribution to MREIT algorithms for reconstruction of electric field distribution. Until now, CDI sequences could only be applied for acquiring current density distributions during delivery of electric pulses with repetition rate of 5 kHz and the whole acquisition took around 20 sec. New CDI sequence presented in this study is able to monitor current density distribution during the delivery of electric pulses with the repetition rate of 1 Hz and the acquisition time is shortened to a few seconds, thus new sequence can provide current density distribution every two pulses which provides opportunity for observation of current density distribution and electric field distribution during the IRE procedure. New CDI sequence was tested on a tissue sample Monitoring of electroporation process through reconstruction of electric field distribution by means of MREIT was until now limited to only electroporation applications with an electric pulse repetition rate in the range of kHz, such as ECT, due to the frequency limitation of CDI sequences. The new CDI sequence widens the range of electroporation applications, including those with electric pulse repetition rate of around 1 Hz, as for example IRE tissue ablation. Determining current density after each pair of pulses would not only provide electric field determination but also enable follow-up of electric field distribution and electrical conductivity during the delivery of clinically relevant IRE sequence providing potentially important information that would allow interventional radiologist to monitor electroporation during intervention and perform corrective intervention if necessary.The presented single-shot RARE-based CDI sequence shows that current distribution imaging during delivery of short high-voltage electric pulses is feasible. As the sequence requires only two short electric pulses repeated in an interval of approximately 1 s, sequential imaging of current distribution during delivery of the IRE electric pulse train is possible. The method could potentially enable monitoring of tumor coverage by electric field during IRE tissue ablation.AC - alternating currentCDI - current density imagingECT - elctrochemotherapyIRE - irreversible electroporationMREIT - magnetic resonance electrical impedance tomographyMRI - magnetic resonance imagingRARE - rapid acquisition with relaxation enhancementRF - radiofrequencyThe authors declare that they have no competing interests.IS designed and programmed the modified CDI sequence that was used in this study and drafted the manuscript, MK prepared the tissue sample, calculate CDI images and drafted the manuscript, DM conceived and coordinated the study. All authors read and approved the final manuscript.


T(E) onto a single curve. This offers a unique method that can be used to predict electrocaloric behavior beyond the limits of present measurement ranges or in regions where data are not yet available.A combination of theoretical and first-principles computational methods, along with experimental evidence from the literature, were used to predict the existence of a scaling law for the electrocaloric temperature change in antiferroelectric materials. We show that the temperature change scales quadratically with electric field, allowing a simple transformation to collapse the set of Δ One example is the existence of the inverse (negative) ECE in PbZrO310The electrocaloric (ECE) effect has received much attention in recent years following the discovery of giant ECE in some ferroelectrics1234567SM(T). This in turn leads to scaling, which is usually understood as the collapse of the set of ΔSM(T) curves associated with different magnetic field changes. Here SM and T are the magnetic entropy and temperature, respectively. The underlying cause of such behavior is the universality associated with critical phenomena that also serves as a foundation for theoretical derivationsThe subject of scaling laws for the magnetic entropy change in magnetocaloric materials has received much attention in recent years123 for a wide range of temperatures and electric fields; ii) predict the existence of a scaling law for electrocaloric ΔT in this material; iii) establish the origin of such an unexpected finding; and iv) demonstrate the relevance of our findings to the experimental measurements reported in the literature.Unlike magnetic materials, ferroelectrics and antiferroelectrics usually exhibit first order or first-order-like phase transitions. Naively, this seems to rule out the possibility to observe universal behavior or scaling laws. Indeed, we are not aware of any reports of scaling behavior of electrocaloric entropy or temperature change. The purpose of this article is to use a combination of macroscopic themodynamics and first-principles-based direct computations in order to: i) study the intrinsic electrocaloric effect in antiferroelectric PbZrOP, E and CE are the macroscopic polarization, electric field, and volumetric heat capacity, respectively. Under low electric fields, the polarization in antiferroelectrics (and nonpolar phases of ferroelectrics) can be written as P = εε0E, where ε is the dielectric constant. This allows us to rewrite the Maxwell relation as 310T) is rather small compared to T, which allows us to further approximate the Maxwell relation as T0 is the temperature before the application of the electric field. Integrating the differential equation under the assumption of constant heat capacity1T(E) onto a single curve. Indeed, one can choose a control curve T(E) curves can now be collapsed onto the control curve by using the transformation T/T ≪ 1 and electric fields that do not significantly affect C. As long as these requirements are met the collapse of ΔT(E) curves should occur for any linear dielectric. Note, that in ferroelectric phase the polarization is P = Pspont + εε0E, where Pspont is the spontaneous polarization. Therefore, the transformation T(T) on the same curve.We begin by considering ECE in antiferroelectrics from the thermodynamics point of view. The Maxwell relation predicts that T(E) dependencies can be collapsed onto a single curve. Note that our atomistic ECE simulations utilize the direct method to obtain caloric temperature change16Next we test the findings from the macroscopic thermodynamics against the predictions from first-principles direct ECE simulations. More precisely, we aim to establish whether the ECE temperature change is indeed quadratic in the electric field, and whether the points from different Δ3 that is modeled by a 16 × 16 × 16 supercell periodic along all three Cartesian directions. The total energy of the supercell is given by the first-principles effective Hamiltonian of Ref. 3 Hamiltonian includes dipole-dipole interactions, short-range interactions, on-site self energies, elastic energy, coupling energy between the degrees of freedom and the interaction between the local modes and electric field. The Hamiltonian correctly reproduces many of the electrical and thermodynamical properties of PbZrO33 behavior under pressure. Prior to ECE computations, the simulated sample was annealed from 1200 K to 5 K in steps of 5 K using the canonical Monte Carlo simulations. Thus equilibrated supercells were used in direct simulations of the ECE in the framework of the adiabatic Monte Carlo approach proposed in refs T was found for the different orientations of the electric field. The electrocaloric temperature was computed as a function of the applied field.We simulate bulk PbZrOP(T) dependencies given in 3 thin films319To estimate the electric fields associated with an antiferroelectric (AFE) to ferroelectric (FE) phase transition we compute the field-cooled T as a function of the applied electric field. In agreement with experimental measurements10T below the Curie point and a positive ΔT above the Curie point (946 K in computations). Remarkably, the electrocaloric ΔT obtained from the direct computations demonstrate a quadratic dependence on the electric field, in agreement with the predictions from thermodynamics and the experimental measurements of ref. T is quadratic in the electric field in the entire range of temperatures and electric fields associated with the AFE phase of PbZrO3. It should be noted that macroscopic thermodynamics predicts the quadratic dependence of ΔT on E for any dielectric in the low field limit. This is in agreement with the recent experimental measurements on relaxor ferroelectric ceramicsWe first focus on the ECE in the AFE phase and, therefore, apply electric fields of up to 1500 kV/cm. T(T) dependencies for a few select fields along with a prediction from the quadratic fit to the ΔT(E) data. We notice that the ECE remains negative for all temperatures below the Curie point and increases in magnitude as the transition temperature approaches. Above the Curie point the ECE is positive. The data are in qualitative agreement with the experimental results of ref. T(T) is continuous at the Curie temperature, while computationally there exist some discontinuities. These discontinuities are due to the thermal and electric hysteresis associated with the first-order phase transition in bulk PbZrO3.T(T) dependencies onto a single curve. We choose data for the field 1400 kV/cm for the control curve because the PbZrO3 remains AFE below this field and exhibits electrocaloric ΔT that is quadratic in the electric field. The data for other fields (given in T(T) in antiferroelectrics predicted from the macroscopic thermodynamics. It should be noted that our computations suggest that in defect-free PbZrO3 the scaling behavior occurs for all the fields below the critical field associated with the AFE-FE phase transition.Next we turn to the possibility of collapsing the electrocaloric Δgiven in  are thenT for the electric fields and temperatures for which the data are not available or for ranges of fields and temperatures that may be difficult to obtain in experiments, particularly when materials fabrication has not been optimized. T in PbZrO3 from the direct experimental measurements of ref. T(T) for the fields of 20, 40, 80, 100 and 150 kV/cm. The predictions are shown by the lines in 3 thin filmsT(T) in antiferroelectrics.One of the advantages of the scaling law is the possibility of predicting the electrocaloric ΔT/T ≪ 1 and C ≈ constant, as well as the absence of spontaneous polarization. This scenario can be realized in nonpolar phases of electric and magnetic materials. Indeed, universal scaling was observed in nonpolar phases (above the Curie point) of magnetic materials with both second and first-order phase transitionsThe existence of the scaling law in a material with a first-order phase transition is a rather striking result. Indeed, it was demonstrated in magnetism that magnetic materials that undergo first-order phase transition do not follow the universal scaling in their polar phasesP(E) and ΔT(E) dependencies from one such simulation. The initial application of the electric field in the AFE phase of PbZrO3 (region 1–2 in the figure) results in a temperature decrease (negative ECE). Further increasing the electric field (region 2–3) induces a first-order AFE-FE phase transition and results in an irreversible temperature increase. In the ferroelectric phase (region 3–4–5) the material’s response to the electric field changes dramatically. The electrocaloric ΔT now increases with the electric field (positive ECE). Positive ECE in the FE phase of antiferroelectric thin films was previously reported in ref. T is linear in the electric field, unlike the AFE regime where ΔT is quadratic in the field. Upon the FE-AFE transition (region 5–6) the material experiences a second irreversible temperature increase due to the structural phase transition. Finally, PbZrO3 reenters the regime associated with the negative ECE on returning into the AFE phase (region 6–7). Our computational data demonstrate that the field induced AFE-FE phase transition is associated with irreversible heating, a change in the sign of ECE, and departure from the quadratic dependence of the electrocaloric ΔT on the electric field. The latter point signals that the scaling law will no longer be obeyed. Interestingly, this finding seems to suggest another possible application of the scaling law model. In such an application a failure of an AFE material to follow the scaling law indicates the presence of minority FE phases.The existence of the scaling law is predicted in the AFE phase of antiferroelectrics. It is instructive to verify that the scaling law breaks down upon a field induced transition into a FE phase. To address this, we simulate the application of electric fields that are larger than the critical field associated with the AFE-FE phase transition. T(T) in antiferroelectrics. The existence of such a law was computationally demonstrated in antiferroelectric PbZrO3 from first-principles-based simulations. Application of the scaling model to experimental data from the literature provided further evidence for the existence of the scaling law for low-field electrocaloric ΔT(T). Potential applications of the scaling law include extrapolation to temperatures and fields for which data are not available, screening of novel materials performance, and the detection of minority phasesIn summary, on the basis of macroscopic thermodynamics we proposed the scaling law for low-field electrocaloric ΔHow to cite this article: Lisenkov, S. et al. Scaling law for electrocaloric temperature change in antiferroelectrics. Sci. Rep.6, 19590; doi: 10.1038/srep19590 (2016).