Alethea Rea

Relationships between Breastfeeding Patterns and Maternal and Infant Body Composition over the First 12 Months of Lactation

Breastfeeding has been implicated in the establishment of infant appetite regulation, feeding patterns and body composition (BC). A holistic approach is required to elucidate relationships between infant and maternal BC and contributing factors, such as breastfeeding parameters. Associations between maternal and breastfed term infant BC (n = 20) and feeding parameters during first 12 months of lactation were investigated. BC was measured at 2, 5, 9 and/or 12 months postpartum with ultrasound skinfolds (US; infants only) and bioimpedance spectroscopy (infants and mothers). 24-h milk intake (MI) and feeding frequency (FFQ) were measured. Higher FFQ was associated with larger 24-h MI (p ≤ 0.003). Higher 24-h MI was associated with larger infant fat mass (FM) (US: p ≤ 0.002), greater percentage FM (US: p ≤ 0.008), greater FM index (FMI) (US: p ≤ 0.001) and lower fat-free mass index (FFMI) (US: p = 0.015). Lower FFQ was associated with both larger FFM (US: p ≤ 0.001) and FFMI (US: p < 0.001). Greater maternal adiposity was associated with smaller infant FFM measured with US (BMI: p < 0.010; %FM: p = 0.004; FMI: p < 0.011). Maternal BC was not associated with FFQ or 24-h MI. These results reinforce that early life is a critical window for infant programming and that breastfeeding may influence risk of later disease via modulation of BC.

Stock Selection with Principal Component Analysis

We propose a stock selection method that is based on a variable selection method used with principal component analysis. We applied our method to stocks in the ASX200 and show that a portfolio of as little as 15 stocks can closely replicate the behaviour of the index. We show that the number of stocks required to form a diversified portfolio is not constant across time but varies with market conditions.

Transition from Laparoscopy to Retroperitoneoscopy for Live Donor Nephrectomy - A Case Control Study

Introduction Laparoscopic donor nephrectomy has become the standard of care due to multiple benefits. Transperitoneal laparoscopic (TLDN) approach is currently being widely adopted in most transplant centres. However, a systematic review has shown that an alternative retroperitoneoscopic (RLDN) approach is associated with fewer complications due to the anatomical advantage by avoidance of manipulation of the intraperitoneal organs. There was limited data available in assessing the learning curve for transition to RLDN. The aims of this study were to compare the outcomes of RLDN and TLDN by a case control study. The learning curve for transition from TLDN to RLDN was analyzed. Materials and Methods From Dec 2012, the authors have changed the surgical technique for live donor nephrectomy from TLDN to RLDN after a mentorship. Sixty two cases of live donor nephrectomy have been performed by RLDN up to Oct 2017. For an efficient analysis, another 60 cases of live donor nephrectomy by TLDN were included retrospectively in this study. Data on patient demographics, peri-operative parameters, analgesia consumption, pain scores and kidney graft function were collected and analyzed. Statistical analyses were performed with a student’s t-test or Mann-Whitney test. A CUSUM analysis was also performed to explore the learning curve by setting the mean operative goal time of TLDN as a target. Results All these 122 donor nephrectomies were successful with no conversion to open surgery. There was no blood transfusion, readmission or mortality. There were no post-operative complications which were graded over Clavien II. The kidney graft function was comparable in both groups. The follow-up period ranged from 2 to 86 months. The CUSUM analysis demonstrated that approximately 30 cases are required for the surgeon to be proficient in the transition from TLDN to RLDN. Conclusion RLDN is a safe approach with comparable results to TLDN. It has an anatomical advantage as it avoids manipulating the intraperitoneal organs and retains a virgin abdomen and hence translates to a lower peri-operative complication risk. The learning curve of transitioning from TLDN to RLDN of about 30 cases is acceptable.

Transition from laparoscopic to retroperitoneoscopic approach for live donor nephrectomy

BackgroundLaparoscopic donor nephrectomy has become the standard of care due to multiple benefits. Currently, there are various techniques employed with two different approaches: transperitoneal (TLDN) or retroperitoneoscopic (RLDN) approach. There is a lack of data to determine which technique is superior, although the RLDN offers an anatomical advantage by avoidance of manipulation of the intraperitoneal organs. The aims of this study were to explore the merits of RLDN to TLDN and assess the learning curve of transition from TLDN to RLDN.MethodsFrom January 2010 to February 2017, 106 live donor nephrectomies were performed: 56 by TLDN and 50 by RLDN. Data on patient demographics, perioperative parameters, analgesic consumption, pain scores, and kidney graft function were collected and analysed. Data were compared with a Student’s t test or Mann–Whitney test. A CUSUM analysis was performed to investigate the learning curve.ResultsAll live donor nephrectomies were successful with no conversion to open surgery. There was no blood transfusion, readmission, or mortality. No postoperative complications were graded over Clavien II. Kidney function was comparable in both groups. The follow-up period ranged from 3 to 78 months.ConclusionRetroperitoneoscopic live donor nephrectomy is a safe approach with comparable results to TLDN. RLDN has an anatomical advantage as it avoids manipulating the intraperitoneal organs and retains a virgin abdomen and hence translates to a lower perioperative complication risk.

Hourly Breast Expression to Estimate the Rate of Synthesis of Milk and Fat

Objective measurement of the rate of synthesis of breast milk and fat in breastfeeding mothers requires test-weighing of each breastfeed and the measurement of each expression from each breast over 24 h, with the collection of milk samples before and after each breastfeed and expression. We sought an abbreviated technique for measuring these rates of synthesis. Participants completed a 24-h breastfeeding milk profile, and expressed their breasts on arrival at the research room and each hour thereafter for 3 h (4 expressions). The hourly rate of milk synthesis, as measured by the yield of milk from the fourth expression, was closely related to the hourly rate of milk synthesis calculated from the 24-h milk profile. The hourly rate of fat synthesis, calculated from the fat content of small samples of the first and last milk expressed during the fourth expression, was different from the rate of fat synthesis calculated from the fat content and volumes of all the breastfeeds and expressions during the 24-h milk profile. The study confirms the use of an abbreviated technique to measure the rate of breast milk synthesis, but is not reliable as a measure of the rate of fat synthesis for an individual.

Human Milk Casein and Whey Protein and Infant Body Composition over the First 12 Months of Lactation

Human milk (HM) influences infant feeding patterns and body composition (BC). This small proof-of concept longitudinal study investigated relationships between infant/maternal BC and HM casein, whey and total protein during the first 12 months of lactation. BC of breastfeeding dyads (n = 20) was measured at 2 (n = 15), 5 (n = 20), 9 (n = 19), and/or 12 (n = 18) months postpartum with ultrasound skinfolds (infants) and bioimpedance spectroscopy (infants/mothers). Proteins concentrations and 24-h milk intake were measured and calculated daily intakes (CDI) determined. Higher maternal weight, body mass index, fat-free mass, fat-free mass index, and fat mass index were associated with higher concentration of whey protein (p ≤ 0.034, n = 20). There were no associations between infant BC and concentrations of all proteins, and CDI of whey and total protein. Higher CDI of casein were associated with lower infant fat-free mass (p = 0.003, n = 18) and higher fat mass (p < 0.001), fat mass index (p = 0.001, n = 18), and % fat mass (p < 0.001, n = 18) measured with ultrasound skinfolds. These results show a differential effect of HM casein on development of infant BC during the first year of life, suggesting that there is a potential to improve outcome for the infant through interventions, such as continuation of breastfeeding during the first 12 months of life and beyond, which may facilitate favourable developmental programming that could reduce risk of non-communicable diseases later in life.

Human Milk Adiponectin and Leptin and Infant Body Composition over the First 12 Months of Lactation

Human milk (HM) adipokines may influence infant feeding patterns, appetite regulation, and body composition (BC). The associations between concentrations/calculated daily intakes (CDI) of HM adipokines in the first 12 months postpartum and maternal/term infant BC, and infant breastfeeding parameters were investigated. BC of breastfeeding dyads (n = 20) was measured at 2, 5, 9, and/or 12 months postpartum with ultrasound skinfolds (infants) and bioimpedance spectroscopy (infants/mothers). 24-h milk intake and feeding frequency were measured along with whole milk adiponectin and skim and whole milk leptin (SML and WML) and CDI were calculated. Statistical analysis used linear regression/mixed effects models; results were adjusted for multiple comparisons. Adipokine concentrations did not associate with infant BC. Higher CDI of adiponectin were associated with lower infant fat-free mass (FFM; p = 0.005) and FFM index (FFMI; p = 0.009) and higher fat mass (FM; p < 0.001), FM index (FMI; p < 0.001), and %FM (p < 0.001). Higher CDI of SML were associated with higher infant FM (p < 0.001), FMI (p < 0.001), and %FM (p = 0.002). At 12 months, higher CDI of WML were associated with larger increases in infant adiposity (2–12 month: FM, p = 0.0006; %FM, p = 0.0004); higher CDI of SML were associated with a larger decrease in FFMI (5–12 months: p = 0.0004). Intakes of HM adipokines differentially influence development of infant BC in the first year of life, which is a critical window of infant programming and may potentially influence risk of later disease via modulation of BC.

Measuring the impact of genetic knowledge on intentions and attitudes of the community towards expanded preconception carrier screening

Background Preconception carrier screening (PCS) provides the potential to empower couples to make reproductive choices before having an affected child. An important question is what factors influence the decision to use or not use PCS. Methods We analysed the relationship between knowledge, attitudes and intentions to participate in PCS using logistic regression in 832 participants in Western Australia. Results Two-thirds of participants said they would take the test, with 92% of these supporting screening for diseases reducing the lifespan of children and infants. Those who had good genetic knowledge were seven times more likely to intend to use PCS (p≤0.001), while those with high genetic knowledge were four times more likely to (p=0.002) and raised concerns such as insurance and confidentiality. Decreasing genetic knowledge correlated positively with religiosity and apprehension (p≤0.001), which correlated negatively with intention to use PCS (p≤0.001). Increasing genetic knowledge correlated positively with factors representing positive attitudes (p≤0.001), which correlated positively with intention to use PCS (p≤0.001). Many participants with good genetic knowledge nevertheless answered questions that tested understanding incorrectly. 80% of participants stated they would prefer to access the test through their general practitioners and 30% would pay up to

Comparison of physical and biological properties of CardioCel® with commonly used bioscaffolds

A200. Conclusions Knowledge is instrumental in influencing participation. Having good genetic knowledge may not be enough to understand core concepts of PCS and may impact informed decision-making. This study recommends that continuous education of health professionals and thus the community, in PCS is crucial to reduce misconceptions.

Visualization of a stock market correlation matrix

OBJECTIVES Durability of bioscaffolds cross-linked with glutaraldehyde and used in cardiovascular surgery is limited by biomechanical instability, calcification and reduced biocompatibility. This study compares CardioCel®, a bovine pericardial scaffold engineered via the ADAPT® process to ensure optimized biostability and biocompatibility, with the commonly used bioscaffolds. METHODS Bovine pericardial scaffolds, cross-linked with 0.6% glutaraldehyde (XenoLogiX™, PeriGuard®), dye-mediated photo-oxidized (PhotoFix™) and a non-crosslinked porcine scaffold (CorMatrix®), were compared with CardioCel (decellularized, cross-linked with 0.05% monomeric glutaraldehyde, detoxified) by thermal stability and mechanical tests. Biocompatibility and calcification were assessed in a juvenile subcutaneous rat model at 6 and 12 weeks. RESULTS CardioCel displayed significantly higher (P < 0.01) cross-link stability (77.99 ± 0.64 °C) than CorMatrix (57.88 ± 0.22 °C) and PhotoFix (53.96 ± 0.41 °C). Tensile strength of CardioCel (8.31 ± 3.36 MPa) was comparable with XenoLogiX (11.00 ± 5.43 MPa, P = 0.734), PeriGuard (16.44 ± 6.69 MPa, P = 0.136), PhotoFix (7.10 ± 6.11, P = 0.399) and CorMatrix (9.75 ± 2.61, P = 0.204). XenoLogiX and PeriGuard recorded the highest Youngs modulus (67.01 ± 30.36 vs 95.67 ± 45.91 MPa), while CardioCel (50.21 ± 19.92 MPa) was comparable with CorMatrix (36.78 ± 10.47 MPa, P = 0.204) and PhotoFix (33.50 ± 10.24, P = 0.399). CorMatrix displayed a significantly (P < 0.05) greater stiffness (4.74 ± 0.77 MPa) at 10% strain than PeriGuard (3.73 ± 1.79 MPa), PhotoFix (1.59 ± 0.40 MPa) and CardioCel (3.39 ± 0.83 MPa). Differences in extractable calcium did not reach significance; however, the inorganic phosphorus content of PhotoFix (21.3 ± 9.0 µg/mg) was higher than CardioCel (11.35 ± 0.76 µg/mg, P = 0.004) or PeriGuard (10.7 ± 2.18 µg/mg, P = 0.002) at 12 weeks. CardioCel underwent a typical mild host-graft response with fibroblast infiltration and remodelling. Foreign body reactions were visible in both XenoLogiX and PeriGuard, with isolated fibroblast infiltration. PhotoFix showed severe inflammation and 2 implants were completely degraded at 12 weeks. CONCLUSIONS CardioCel demonstrated optimized physical properties, minimal mineralization potential and superior biocompatibility. These results may benefit the long-term performance of this bioscaffold for cardiovascular surgery. The favourable characteristics of the comparator products were counterbalanced by less desirable features that may have negative implications on durability and performance when used in cardiovascular procedures.