Biomedical subjects

Jenny Liu

Publications and source records attributed to Jenny Liu.

6 recordsLinked to original sources

PubMed2025

Profile of the BREATHE cohort for risk-based breast screening in Singapore.

The BREAst screening Tailored for HEr (BREATHE) study was established to pilot a personalised, risk-based breast cancer screening programme for a multi-ethnic Asian population. Between October 2021 and December 2023, 4592 women aged 35-59 were enrolled (73% response rate). Follow-up from February 2022 to June 2024 included 4112 participants (8.6% loss to follow-up). Data collected encompassed demographics, lifestyle factors, reproductive risks, breast cancer awareness, screening behaviours, programme satisfaction, mammography outcomes (density and recall status), and genotype data. Above-average breast cancer risk increased with age: 2% in women aged 35-39, 31% in 40-49, and 42% in 50-59. Findings suggests that women valued the knowledge of their breast cancer risk and were motivated to attend mammography. The BREATHE study confirms the feasibility and acceptability of a personalised risk-based screening programme in a multi-ethnic Asian population, highlighting the value of tailored protocols to improve early detection and outcomes. Further details are available in the study protocol and online at https://blog.nus.edu.sg/breathe/ .

Humans↗

PubMed2025

Impact of personalised risk predictions on breast cancer risk perceptions: insights from the BREATHE study.

OBJECTIVE: Biennial mammography screening is well-established for women aged 50 and above, but guidelines for younger women are less clear. Risk-based screening may provide women with key information to make informed decisions about their breast cancer risk and screening. This study examines how predicted breast cancer (BC) risk shapes women's perception and confidence in risk prediction. METHODS: Women aged 35 to 59 years were recruited for a prospective multi-centre cohort and stratified into above-average, average, or below-average BC risk categories based on genetic and non-genetic risk factors. Perceived risk was assessed at enrolment and after participants were informed of their predicted risk. We used ordinal models to identify predictors of perceived risk and logistic regression to examine the relationship between changes in perceived risk and confidence in the risk prediction. RESULTS: At enrolment, 43% and 47% of 4112 participants perceived their BC risk pre-result as low or average, respectively. Thirty-five percent adjusted their perceived risk to align more closely with their predicted risk. Predictors of perceived risk post-result: perceived risk pre-result, predicted risk, ethnicity and having regular menstruation. Participants who underestimated their BC risk were nearly eight times more likely to have low confidence in the accuracy of their predicted risk (OR for underestimation vs. accurate perception: 7.94 [95% CI 5.60-11.28]). Predictors of perceived risk post-result: perceived risk pre-result, predicted risk, ethnicity and having regular menstruation. Confidence in risk prediction was lowest when women's perceived risk pre-result was lower than their predicted risk (OR-2 vs 0 [95%CI] 5.06 [3.67 to 6.97]). CONCLUSION: Many women underestimated their BC risk, and their initial perceptions were influenced by the knowledge of their predicted risk. Women who underestimated their risk had less confidence in their predicted risk scores.

Humans↗

PubMed2007

Impact of left atrial appendage exclusion on left atrial function.

OBJECTIVES: We sought to investigate the short-term and midterm effects of left atrial appendage exclusion on left atrial function. Left atrial appendage exclusion is considered a possible therapeutic option for stroke prevention in patients with atrial fibrillation. Favorable outcomes have encouraged widespread use of left atrial appendage exclusion for cardiac surgical patients-even for patients in sinus rhythm who have stroke risk factors; however, the chronic effects on left atrial function of left atrial appendage exclusion are unclear. METHODS: Nineteen mongrel dogs (29.7 +/- 5.2 kg) in sinus rhythm were studied. The Doppler signals from the pulmonary venous flow, transmitral flow, and tissue Doppler imaging of mitral annular motion were obtained before and after left atrial appendage exclusion. Dogs were evaluated in the same manner at 7 days (n = 2), 30 days (n = 7), or 90 days (n = 10) after left atrial appendage exclusion. RESULTS: Except for a significant increase in early diastolic transmitral flow velocity after left atrial appendage exclusion (P = .01), no significant differences were found in any parameters related to the transmitral flow and tissue Doppler imaging measurements throughout follow-up. The systolic components of pulmonary venous flow at follow-up revealed a significant reduction relative to baseline (peak systolic velocity P < .0001, systolic velocity-time integral P < .0001), despite the lack of significant changes in left atrial pressure, left ventricular volume, and stroke volume. CONCLUSION: Left atrial appendage exclusion may affect left atrial reservoir function in the short-term and midterm periods. Further long-term studies with more clinically relevant models are needed.

Animals↗

PubMed2006

Evaluation of a novel device for left atrial appendage exclusion: the second-generation atrial exclusion device.

BACKGROUND: The left atrial appendage is a frequent source of thromboemboli in patients with atrial fibrillation. Exclusion of the left atrial appendage may reduce the risk of stroke in patients with atrial fibrillation. The atrial exclusion device, previously developed to perform left atrial appendage exclusion on a beating heart, was modified to accommodate different anatomic patterns of the human left atrial appendage and to ensure uniform pressure and occlusion. The purpose of this study was to evaluate this second-generation atrial exclusion device during a midterm period in a canine model. METHODS: Ten mongrel dogs (mean weight 28.9 +/- 4.6 kg) were used in this study. The atrial exclusion device, constructed from two parallel and rigid titanium tubes and two nitinol springs with a knit-braided polyester fabric, was implanted at the base of the left atrial appendage through a left thoracotomy on a beating heart using a specially designed delivery tool. Dogs were evaluated at 30 days (n = 4) and 90 days (n = 6) by epicardial echocardiography, left atrial and coronary angiography, gross pathology, and histologic inspection. RESULTS: Device implantation was performed without complications in all dogs. Complete left atrial appendage exclusion without device migration or hemodynamic instability was confirmed, and there was no damage to the left circumflex artery or pulmonary artery. Macroscopic and microscopic assessments revealed favorable biocompatibility during midterm follow-up. CONCLUSION: The atrial exclusion device enabled rapid, reliable, and safe exclusion of the left atrial appendage. Clinical application may provide a new therapeutic option for reducing the risk of stroke in patients with atrial fibrillation.

Animals↗

PubMed2001

Molecular basis for interaction between Icap1 alpha PTB domain and beta 1 integrin.

Icap1 alpha is a 200-amino acid protein that binds to the COOH-terminal 13 amino acids ((786)AVTTVVNPKYEGK(798)) of the integrin beta(1) subunit. Alanine scanning mutagenesis of this region revealed that Val(787), Val(790), and (792)NPKY(795) are critical for Icap1 alpha binding. The NPXY motif is a known binding substrate for phosphotyrosine binding (PTB) domain proteins. The sequences of Icap1 alpha, residues 58--200, and the beta(1) integrin, residues 786-797, were aligned to the available PTB-peptide structures to generate a high quality structural model. Site-directed mutagenesis showed that Leu(135), Ile(138), and Ile(139) of Icap1 alpha, residues predicted by the model to be in close proximity to (792)NPKY(795), and Leu(82) and Tyr(144), residues expected to form a hydrophobic pocket near Val(787), are required for the Icap1 alpha-beta(1) integrin interaction. These findings indicate that Icap1 alpha is a PTB domain protein, which recognizes the NPXY motif of beta(1) integrin. Furthermore, our date suggest that an interaction between Val(787) and the hydrophobic pocket created by Leu(82) and Tyr(144) of Icap1 alpha forms the basis for the specificity of Icap1 alpha for the beta(1) integrin subunit.

3T3 Cells↗

PubMedDate not supplied

Progress in the development of the DexAide right ventricular assist device.

The DexAide right ventricular assist device (RVAD) is an implantable centrifugal pump modified from the CorAide left ventricular assist device. As previously published, in vitro performance testing of the DexAide RVAD has met design criteria, and the nominal operating condition of 4 l/min and 20 mm Hg pressure rise was achieved at 2,000 rpm, with a power consumption of 1.9 watts. In vivo studies in 14 calves have demonstrated acceptable hemodynamic characteristics. The calf inflow cannula design is still evolving to minimize depositions on the cannula observed in most experiments. Fitting studies were performed in 5 cadavers and 2 patients to reconfigure the cannulae for use in humans. The design and development of external electronics have been completed for the stand-alone RVAD system, and verification tests are under way in preparation for preclinical tests. Work on the external electronics design for the biventricular assist system is ongoing. In conclusion, the initial in vitro and in vivo studies have demonstrated acceptable hemodynamic characteristics of the DexAide RVAD. The design and development of the external electronic components for the stand-alone RVAD system have been completed. The calf inflow cannula is being redesigned, and chronic in vivo tests are under way.

Animals↗