NAMPT-Driven M2 Polarization of Tumor-Associated Macrophages Leads to an Immunosuppressive Microenvironment in Colorectal Cancer

Nicotinamide phosphoribosyltransferase (NAMPT) is a metabolic enzyme with key roles in inflammation. Previous studies have examined the consequences of its upregulated expression in cancer cells themselves, but studies are limited with respect to its role in the other cells within the tumor microenvironment (TME) during colorectal cancer (CRC) progression. Using single-cell RNA sequencing (scRNA-seq) data, it is founded that NAMPT is highly expressed in SPP1+ tumor-associated macrophages (TAMs), a unique subset of TAMs associated with immunosuppressive activity. A NAMPThigh gene signature in SPP1+ TAMs correlated with worse prognostic outcomes in CRC patients. The effect of Nampt deletion in the myeloid compartment of mice during CRC development is explored. NAMPT deficiency in macrophages resulted in HIF-1α destabilization, leading to reduction in M2-like TAM polarization. NAMPT deficiency caused significant decreases in the efferocytosis activity of macrophages, which enhanced STING signaling and the induction of type I IFN-response genes. Expression of these genes contributed to anti-tumoral immunity via potentiation of cytotoxic T cell activity in the TME. Overall, these findings suggest that NAMPT-initiated TAM-specific genes can be useful in predicting poor CRC patient outcomes; strategies aimed at targeting NAMPT may provide a promising therapeutic approach for building an immunostimulatory TME in CRC progression.

Cellular senescence is associated with the spatial evolution toward a higher metastatic phenotype in colorectal cancer

In this study, we explore the dynamic process of colorectal cancer progression, emphasizing the evolution toward a more metastatic phenotype. The term "evolution" as used in this study specifically denotes the phenotypic transition toward a higher metastatic potency from well-formed glandular structures to collective invasion, ultimately resulting in the development of cancer cell buddings at the invasive front. Our findings highlight the spatial correlation of this evolution with tumor cell senescence, revealing distinct types of senescent tumor cells (types I and II) that play different roles in the overall cancer progression. Type I senescent tumor cells (p16INK4A+/CXCL12+/LAMC2-/MMP7-) are identified in the collective invasion region, whereas type II senescent tumor cells (p16INK4A+/CXCL12+/LAMC2+/MMP7+), representing the final evolved form, are prominently located in the partial-EMT region. Importantly, type II senescent tumor cells associate with local invasion and lymph node metastasis in colorectal cancer, potentially affecting patient prognosis.

The LKB1-TSSK1B axis controls YAP phosphorylation to regulate the Hippo-YAP pathway

The Hippo pathway's main effector, Yes-associated protein (YAP), plays a crucial role in tumorigenesis as a transcriptional coactivator. YAP's phosphorylation by core upstream components of the Hippo pathway, such as mammalian Ste20 kinase 1/2 (MST1/2), mitogen-activated protein kinase kinase kinase kinases (MAP4Ks), and their substrate, large tumor suppressor 1/2 (LATS1/2), influences YAP's subcellular localization, stability, and transcriptional activity. However, recent research suggests the existence of alternative pathways that phosphorylate YAP, independent of these core upstream Hippo pathway components, raising questions about additional means to inactivate YAP. In this study, we present evidence demonstrating that TSSK1B, a calcium/calmodulin-dependent protein kinase (CAMK) superfamily member, is a negative regulator of YAP, suppressing cellular proliferation and oncogenic transformation. Mechanistically, TSSK1B inhibits YAP through two distinct pathways. Firstly, the LKB1-TSSK1B axis directly phosphorylates YAP at Ser94, inhibiting the YAP-TEAD complex's formation and suppressing its target genes' expression. Secondly, the TSSK1B-LATS1/2 axis inhibits YAP via phosphorylation at Ser127. Our findings reveal the involvement of TSSK1B-mediated molecular mechanisms in the Hippo-YAP pathway, emphasizing the importance of multilevel regulation in critical cellular decision-making processes.

SRSF7 downregulation induces cellular senescence through generation of MDM2 variants

Alternative splicing (AS) enables a pre-mRNA to generate different functional protein variants. The change in AS has been reported as an emerging contributor to cellular senescence and aging. However, it remains to be elucidated which senescent AS variants are generated in and regulate senescence. Here, we observed commonly down-regulated SRSF7 in senescent cells, using publicly available RNA-seq datasets of several in vitro senescence models. We further confirmed SRSF7 deregulation from our previous microarray datasets of time-series replicative senescence (RS) and oxidative stress-induced senescence (OSIS) of human diploid fibroblast (HDF). We validated the time-course changes of SRSF mRNA and protein levels, developing both RS and OSIS. SRSF knockdown in HDF was enough to induce senescence, accompanied by p53 protein stabilization and MDM2 variants formation. Interestingly, expression of MDM2 variants showed similar patterns of p53 expression in both RS and OSIS. Next, we identified MDM2-C as a key functional AS variant generated specifically by SRSF7 depletion. Finally, we validated that MDM2-C overexpression induced senescence of HDF. These results indicate that SRSF7 down-regulation plays a key role in p53-mediated senescence by regulating AS of MDM2, a key negative regulator of p53, implying its critical involvement in the entry into cell senescence.

Unveiling Hypothalamic Molecular Signatures via Retrograde Viral Tracing and Single-Cell Transcriptomics

Despite the importance of hypothalamic neurocircuits in regulating homeostatic and survival-related behaviors, our understanding of the intrinsic molecular identities of neural components involved in these complex multi-synaptic interactions remains limited. In this study, we constructed a Cre recombinase-dependent pseudorabies virus (PRVs) capable of crossing synapses, coupled with transcriptome analysis of single upstream neurons post-infection. By utilizing this retrograde nuclear Connect-seq (nuConnect-seq) approach, we generated a single nuclei RNA-seq (snRNA-seq) dataset of 1,533 cells derived from the hypothalamus of CRH-IRES-Cre (CRH-Cre) mice. To ensure the technical validity of our nuConnect-seq dataset, we employed a label transfer technique against an integrated reference dataset of postnatal mouse hypothalamus comprising 152,524 QC-passed cells. The uniqueness of our approach lies in the integration of diverse datasets for validation, providing a more nuanced diversity of hypothalamic cell types. The presented validated dataset may deepen our understanding of hypothalamic neurocircuits and underscore the essential role of comprehensive integrated transcriptomic data for technical validity.

Mid-old cells are a potential target for anti-aging interventions in the elderly

The biological process of aging is thought to result in part from accumulation of senescent cells in organs. However, the present study identified a subset of fibroblasts and smooth muscle cells which are the major constituents of organ stroma neither proliferative nor senescent in tissues of the elderly, which we termed "mid-old status" cells. Upregulation of pro-inflammatory genes (IL1B and SAA1) and downregulation of anti-inflammatory genes (SLIT2 and CXCL12) were detected in mid-old cells. In the stroma, SAA1 promotes development of the inflammatory microenvironment via upregulation of MMP9, which decreases the stability of epithelial cells present on the basement membrane, decreasing epithelial cell function. Remarkably, the microenvironmental change and the functional decline of mid-old cells could be reversed by a young cell-originated protein, SLIT2. Our data identify functional reversion of mid-old cells as a potential method to prevent or ameliorate aspects of aging-related tissue dysfunction.

Integrative multi-omics and systems bioinformatics in translational neuroscience: A data mining perspective

Bioinformatic analysis of large and complex omics datasets has become increasingly useful in modern day biology by providing a great depth of information, with its application to neuroscience termed neuroinformatics. Data mining of omics datasets has enabled the generation of new hypotheses based on differentially regulated biological molecules associated with disease mechanisms, which can be tested experimentally for improved diagnostic and therapeutic targeting of neurodegenerative diseases. Importantly, integrating multi-omics data using a systems bioinformatics approach will advance the understanding of the layered and interactive network of biological regulation that exchanges systemic knowledge to facilitate the development of a comprehensive human brain profile. In this review, we first summarize data mining studies utilizing datasets from the individual type of omics analysis, including epigenetics/epigenomics, transcriptomics, proteomics, metabolomics, lipidomics, and spatial omics, pertaining to Alzheimer's disease, Parkinson's disease, and multiple sclerosis. We then discuss multi-omics integration approaches, including independent biological integration and unsupervised integration methods, for more intuitive and informative interpretation of the biological data obtained across different omics layers. We further assess studies that integrate multi-omics in data mining which provide convoluted biological insights and offer proof-of-concept proposition towards systems bioinformatics in the reconstruction of brain networks. Finally, we recommend a combination of high dimensional bioinformatics analysis with experimental validation to achieve translational neuroscience applications including biomarker discovery, therapeutic development, and elucidation of disease mechanisms. We conclude by providing future perspectives and opportunities in applying integrative multi-omics and systems bioinformatics to achieve precision phenotyping of neurodegenerative diseases and towards personalized medicine.

Deleterious Mechanical Deformation Selects Mechanoresilient Cancer Cells with Enhanced Proliferation and Chemoresistance

Cancer cells in secondary tumors are found to form metastases more efficiently as compared to their primary tumor counterparts. This is partially due to the unfavorable microenvironments encountered by metastasizing cancer cells that result in the survival of a more metastatic phenotype from the original population. However, the role of deleterious mechanical stresses in this change of metastatic potential is unclear. Here, by forcing cancer cells to flow through small capillary-sized constrictions, it is demonstrated that mechanical deformation can select a tumor cell subpopulation that exhibits resilience to mechanical squeezing-induced cell death. Transcriptomic profiling reveals up-regulated proliferation and DNA damage response pathways in this subpopulation, which are further translated into a more proliferative and chemotherapy-resistant phenotype. These results highlight a potential link between the microenvironmental physical stresses and the enhanced malignancy of metastasizing cancer cells which may be utilized as a therapeutic strategy in preventing the metastatic spread of cancer cells.

An integrated single-cell transcriptomic dataset for non-small cell lung cancer

As single-cell RNA sequencing (scRNA-seq) has emerged as a great tool for studying cellular heterogeneity within the past decade, the number of available scRNA-seq datasets also rapidly increased. However, reuse of such data is often problematic due to a small cohort size, limited cell types, and insufficient information on cell type classification. Here, we present a large integrated scRNA-seq dataset containing 224,611 cells from human primary non-small cell lung cancer (NSCLC) tumors. Using publicly available resources, we pre-processed and integrated seven independent scRNA-seq datasets using an anchor-based approach, with five datasets utilized as reference and the remaining two, as validation. We created two levels of annotation based on cell type-specific markers conserved across the datasets. To demonstrate usability of the integrated dataset, we created annotation predictions for the two validation datasets using our integrated reference. Additionally, we conducted a trajectory analysis on subsets of T cells and lung cancer cells. This integrated data may serve as a resource for studying NSCLC transcriptome at the single cell level.

Cancer-associated fibroblast-derived secreted phosphoprotein 1 contributes to resistance of hepatocellular carcinoma to sorafenib and lenvatinib

BACKGROUND

Cancer-associated fibroblasts (CAFs) play an important role in the induction of chemo-resistance. This study aimed to clarify the mechanism underlying CAF-mediated resistance to two tyrosine kinase inhibitors (TKIs), sorafenib and lenvatinib, and to identify a novel therapeutic target for overcoming TKI resistance in hepatocellular carcinoma (HCC).

METHODS

We performed a systematic integrative analysis of publicly available gene expression datasets and whole-transcriptome sequencing data from 9 pairs of CAFs and para-cancer fibroblasts isolated from human HCC and para-tumor tissues, respectively, to identify key molecules that might induce resistance to TKIs. We then performed in vitro and in vivo experiments to validate selected targets and related mechanisms. The associations of plasma secreted phosphoprotein 1 (SPP1) expression levels before sorafenib/lenvatinib treatment with progression-free survival (PFS) and overall survival (OS) of 54 patients with advanced HCC were evaluated using Kaplan-Meier and Cox regression analysis.

RESULTS

Bioinformatic analysis identified CAF-derived SPP1 as a candidate molecule driving TKI resistance. SPP1 inhibitors reversed CAF-induced TKI resistance in vitro and in vivo. CAF-derived SPP1 activated rapidly accelerated fibrosarcoma (RAF)/mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) through the integrin-protein kinase C-alpha (PKCα) signaling pathway and promoted epithelial-to-mesenchymal transition (EMT). A high plasma SPP1 level before TKI treatment was identified as an independent predictor of poor PFS (P = 0.026) and OS (P = 0.047) in patients with advanced HCC after TKI treatment.

CONCLUSIONS

CAF-derived SPP1 enhances TKI resistance in HCC via bypass activation of oncogenic signals and EMT promotion. Its inhibition represents a promising therapeutic strategy against TKI resistance in HCC. Moreover, plasma SPP1 level before TKI treatment represents a potential biomarker for treatment response prediction.

p15INK4B is an alternative marker of senescent tumor cells in colorectal cancer

Senescent tumor cells are nonproliferating tumor cells which are closely related to cancer progression by secreting senescence-related molecules, called senescence-associated secreting phenotypes. Therefore, the presence of senescent tumor cells is considered a prognostic factor in various cancer types. Although senescence-associated β-galactosidase staining is considered the best marker for detection of senescent tumor cells, it can only be performed in fresh-frozen tissues. p16^INK4A, a cyclin-dependent inhibitor, has been used as an alternative marker to detect senescent tumor cells in formalin-fixed paraffin-embedded tissues. However, other reliable markers to detect senescent tumor cells is still lacking. In the present study, using public single-cell RNA-sequencing data, we found that p15^INK4B, a cyclin-dependent kinase inhibitor, is a novel marker for detection of senescent tumor cells. Moreover, p15^INK4B expression was positively correlated with that of p16^INK4A in colorectal cancer tissues. In in vitro studies, mRNA expression of p15^INK4B was increased together with that of p16^INK4A in H₂O₂- and therapy-induced cancer senescence models. However, the mRNA level of p15^INK4B did not increase in the oncogene-induced senescence model in primary colonic epithelial cells. In conclusion, p15^INK4B is a potential alternative marker for detection of senescent tumor cells together with conventional markers in advanced stages of colorectal cancer.

Transcriptional Heterogeneity of Cellular Senescence in Cancer

Cellular senescence plays a paradoxical role in tumorigenesis through the expression of diverse senescence-associated (SA) secretory phenotypes (SASPs). The heterogeneity of SA gene expression in cancer cells not only promotes cancer stemness but also protects these cells from chemotherapy. Despite the potential correlation between cancer and SA biomarkers, many transcriptional changes across distinct cell populations remain largely unknown. During the past decade, single-cell RNA sequencing (scRNA-seq) technologies have emerged as powerful experimental and analytical tools to dissect such diverse senescence-derived transcriptional changes. Here, we review the recent sequencing efforts that successfully characterized scRNA-seq data obtained from diverse cancer cells and elucidated the role of senescent cells in tumor malignancy. We further highlight the functional implications of SA genes expressed specifically in cancer and stromal cell populations in the tumor microenvironment. Translational research leveraging scRNA-seq profiling of SA genes will facilitate the identification of novel expression patterns underlying cancer susceptibility, providing new therapeutic opportunities in the era of precision medicine.

Pro-metastatic and mesenchymal gene expression signatures characterize circulating tumor cells of neuroblastoma patients with bone marrow metastases and relapse

Existing marker-based methods of minimal residual disease (MRD) determination in neuroblastoma do not effectively enrich for the circulating disease cell population. Given the relative size differential of neuroblastoma tumor cells over normal hematogenous cells, we hypothesized that cell size-based separation could enrich circulating tumor cells (CTCs) from blood samples and disseminated tumor cells (DTCs) from bone marrow aspirates (BMA) of neuroblastoma patients, and that their gene expression profiles could vary dynamically with various disease states over the course of treatment. Using a spiral microfluidic chip, peripheral blood of 17 neuroblastoma patients at 3 serial treatment timepoints (diagnosis, n=17; post-chemotherapy, n=11; and relapse, n=3), and bone marrow samples at diagnosis were enriched for large intact circulating cells. Profiling the resulting enriched samples with immunohistochemistry and mRNA expression of 1490 cancer-related genes via NanoString, 13 of 17 samples contained CTCs displaying cytologic atypia, TH and PHOX2B expression and/or upregulation of cancer-associated genes. Gene signatures reflecting pro-metastatic processes and the neuroblastoma mesenchymal super-enhancer state were consistently upregulated in 7 of 13 samples, 6 of which also had metastatic high-risk disease. Expression of 8 genes associated with PI3K and GCPR signaling were significantly upregulated in CTCs of patients with bone marrow metastases versus patients without. Correspondingly, in patients with marrow metastases, differentially-expressed gene signatures reflected upregulation of immune regulation in bone marrow DTCs versus paired CTCs samples. In patients who later developed disease relapse, 5 genes involved in immune cell regulation, JAK/STAT signaling and the neuroblastoma mesenchymal super-enhancer state (OLFML2B, STAT1, ARHGDIB, STAB1, TLR2) were upregulated in serial CTC samples over their disease course, despite urinary catecholamines and bone marrow aspirates not indicating the disease recurrences. In summary, using a label-free cell size-based separation method, we enriched and characterized intact circulating cells in peripheral blood indicative of neuroblastoma CTCs, as well as their DTC counterparts in the bone marrow. Expression profiles of pro-metastatic genes in CTCs correlated with the presence of bone marrow metastases at diagnosis, while longitudinal profiling identified persistently elevated expression of genes in CTCs that may serve as novel predictive markers of hematogenous MRD in neuroblastoma patients that subsequently relapse.

Human pluripotent stem cell-derived myogenic progenitors undergo maturation to quiescent satellite cells upon engraftment

Human pluripotent stem cell (hPSC)-derived myogenic progenitor cell (MPC) transplantation is a promising therapeutic approach for a variety of degenerative muscle disorders. Here, using an MPC-specific fluorescent reporter system (PAX7::GFP), we demonstrate that hPSC-derived MPCs can contribute to the regeneration of myofibers in mice following local injury and in mice deficient of dystrophin (mdx). We also demonstrate that a subset of PAX7::GFP MPCs engraft within the basal lamina of regenerated myofibers, adopt a quiescent state, and contribute to regeneration upon reinjury and in mdx mouse models. This subset of PAX7::GFP MPCs undergo a maturation process and remodel their molecular characteristics to resemble those of late-stage fetal MPCs/adult satellite cells following in vivo engraftment. These in-vivo-matured PAX7::GFP MPCs retain a cell-autonomous ability to regenerate and can repopulate in the niche of secondary recipient mice, providing a proof of principle for future hPSC-based cell therapy for muscle disorders.

Multi-omic analysis of selectively vulnerable motor neuron subtypes implicates altered lipid metabolism in ALS

Amyotrophic lateral sclerosis (ALS) is a devastating disorder in which motor neurons degenerate, the causes of which remain unclear. In particular, the basis for selective vulnerability of spinal motor neurons (sMNs) and resistance of ocular motor neurons to degeneration in ALS has yet to be elucidated. Here, we applied comparative multi-omics analysis of human induced pluripotent stem cell-derived sMNs and ocular motor neurons to identify shared metabolic perturbations in inherited and sporadic ALS sMNs, revealing dysregulation in lipid metabolism and its related genes. Targeted metabolomics studies confirmed such findings in sMNs of 17 ALS (SOD1, C9ORF72, TDP43 (TARDBP) and sporadic) human induced pluripotent stem cell lines, identifying elevated levels of arachidonic acid. Pharmacological reduction of arachidonic acid levels was sufficient to reverse ALS-related phenotypes in both human sMNs and in vivo in Drosophila and SOD1G93A mouse models. Collectively, these findings pinpoint a catalytic step of lipid metabolism as a potential therapeutic target for ALS.

PPARγ Targets-Derived Diagnostic and Prognostic Index for Papillary Thyroid Cancer

Simple Summary

Through targeted next-generation sequencing of thyroid cancer-related genes in monozygotic twins with papillary thyroid cancer (PTC), we identified common variants of the gene encoding peroxisome proliferator activated receptor gamma (PPARG). Notably, the expression levels of PPARγ target genes were frequently deregulated in PTC compared to benign tissues and were closely associated with disease-specific survival (DSS) outcomes in a TCGA-PTC cohort. Machine learning-powered personalized scoring index comprising 10 PPARγ targets, termed as PPARGi, achieved a near-perfect accuracy in distinguishing cancers from benign tissues, and further identified a small subpopulation of patients at high-risk across different profiling platforms.

Abstract

In most cases, papillary thyroid cancer (PTC) is highly curable and associated with an excellent prognosis. Yet, there are several clinicopathological features that lead to a poor prognosis, underscoring the need for a better genomic strategy to refine prognostication and patient management. We hypothesized that PPARγ targets could be potential markers for better diagnosis and prognosis due to the variants found in PPARG in three pairs of monozygotic twins with PTC. Here, we developed a 10-gene personalized prognostic index, designated PPARGi, based on gene expression of 10 PPARγ targets. Through scRNA-seq data analysis of PTC tissues derived from patients, we found that PPARGi genes were predominantly expressed in macrophages and epithelial cells. Machine learning algorithms showed a near-perfect performance of PPARGi in deciding the presence of the disease and in selecting a small subset of patients with poor disease-specific survival in TCGA-THCA and newly developed merged microarray data (MMD) consisting exclusively of thyroid cancers and normal tissues.

A flexible multiplexed immunosensor for point-of-care in situ wound monitoring

Chronic wounds arise from interruption of normal healing due to many potential pathophysiological factors. Monitoring these multivariate factors can provide personalized diagnostic information for wound management, but current sensing technologies use complex laboratory tests or track a limited number of wound parameters. We report a flexible biosensing platform for multiplexed profiling of the wound microenvironment, inflammation, and infection state at the point of care. This platform integrates a sensor array for measuring inflammatory mediators [tumor necrosis factor-α, interleukin-6 (IL-6), IL-8, and transforming growth factor-β1], microbial burden (Staphylococcus aureus), and physicochemical parameters (temperature and pH) with a microfluidic wound exudate collector and flexible electronics for wireless, smartphone-based data readout. We demonstrate in situ multiplexed monitoring in a mouse wound model and also profile wound exudates from patients with venous leg ulcers. This technology may facilitate more timely and personalized wound management to improve chronic wound healing outcomes.

Distinct mRNAs in Cancer Extracellular Vesicles Activate Angiogenesis and Alter Transcriptome of Vascular Endothelial Cells

Simple Summary

Cancer extracellular vesicles (EVs) are implicated in various processes of cancer development, with most of the EV-induced changes attributed to EV proteins and microRNAs. However, the knowledge about the cancer EV-mRNAs remains limited. Here, we have assessed the mRNAs of 61 diverse oncogenes and found half of them, including VEGFA and SNAIL1/2, are abundant in cancer EVs while absent in non-tumorigenic cell-derived EVs. Fluorescent trafficking shows the EV VEGFA mRNAs are translatable after being internalized by the recipient cell. Concomitantly, the cancer EVs induced VEGFA-dependent angiogenesis and upregulated epithelial-mesenchymal transition-related genes. Our findings reveal that the EV-mRNA profile can reflect the cell malignancy, and the intercellular transfer of these mRNAs can contribute toward tumor angiogenesis.

Abstract

Cancer-derived extracellular vesicles (EVs) have been demonstrated to be implicated in various processes of cancer development, with most of the EV-induced changes attributed to EV-proteins and EV-microRNAs. However, the knowledge about the abundance of cancer EV-mRNAs and their contribution to cancer development remain elusive. Here, we show that mRNAs prevail in cancer EVs as compared with normal EVs, and cancer EVs that carry abundant angiogenic mRNAs activate angiogenesis in human umbilical vein endothelial cells (HUVECs). Specifically, of a gene panel comprising 61 hypoxia-targeted oncogenes, a larger proportion is harbored by cancer EVs (>40%) than normal EVs (14.8%). Fluorescent trafficking indicates cancer EVs deliver translatable mRNAs such as VEGFA to HUVECs, contributing to the activation of VEGFR-dependent angiogenesis and the upregulation of epithelial-mesenchymal transition-related and metabolism-related genes. Overall, our findings provide novel insights into EV-mRNAs and their role in angiogenesis, and has potential for diagnostic and therapeutic applications.

Single-Cell RNA Sequencing in Parkinson's Disease

Single-cell and single-nucleus RNA sequencing (sc/snRNA-seq) technologies have enhanced the understanding of the molecular pathogenesis of neurodegenerative disorders, including Parkinson's disease (PD). Nonetheless, their application in PD has been limited due mainly to the technical challenges resulting from the scarcity of postmortem brain tissue and low quality associated with RNA degradation. Despite such challenges, recent advances in animals and human in vitro models that recapitulate features of PD along with sequencing assays have fueled studies aiming to obtain an unbiased and global view of cellular composition and phenotype of PD at the single-cell resolution. Here, we reviewed recent sc/snRNA-seq efforts that have successfully characterized diverse cell-type populations and identified cell type-specific disease associations in PD. We also examined how these studies have employed computational and analytical tools to analyze and interpret the rich information derived from sc/snRNA-seq. Finally, we highlighted important limitations and emerging technologies for addressing key technical challenges currently limiting the integration of new findings into clinical practice.

Microfluidic studies of hydrostatic pressure-enhanced doxorubicin resistance in human breast cancer cells

Acquired multidrug resistance in tumors is a big challenge in cancer therapy. As an important physical stimulus in the tumor microenvironment, elevated interstitial fluid pressure has been reported to inhibit drug delivery and promote metastasis in solid tumors. However, the direct influence of this fluid pressure on anticancer drug resistance remains unclear. Here, we develop a pressurized in vitro circulating tumor cell (CTC) culture platform for anticancer drug screening. By using human breast cancer cell line MCF-7 and MDA-MB-231, we find that doxorubicin resistance can be increased by up to 2.5 times under 30 mmHg culture condition, through ABCC1 overexpression that reduces intracellular doxorubicin concentration. A similar chemoresistance change is also observed in clinical metastatic circulating tumor cells samples. These findings provide a new insight into the chemoresistance mechanism of metastatic human breast cancer cells and elucidate the significance of abnormal hydrostatic pressure in cancer progression.

Investigation of a Novel Decision Support Metric for Head and Neck Adaptive Radiation Therapy Using a Real-Time In Vivo Portal Dosimetry System

In adaptive radiation therapy of head and neck cancer, any significant anatomical changes observed are used to adapt the treatment plan to maintain target coverage without elevating the risk of xerostomia. However, the additional resources required for adaptive radiation therapy pose a challenge for broad-based implementation. It is hypothesized that a change in transit fluence is associated with volumetric change in the vicinity of the target and therefore can be used as a decision support metric for adaptive radiation therapy. This was evaluated by comparing the fluence with volumetric changes in 12 patients. Transit fluence was measured by an in vivo portal dosimetry system. Weekly cone beam computed tomography was used to determine volume change in the rectangular region of interest from condyloid process to C6. The integrated transit fluence through the region of interest on the day of the cone beam computed tomography scan was calculated with the first treatment as the baseline. The correlation between fluence change and volume change was determined. A logistic regression model was also used to associate the 5% region of interest volume reduction replanning trigger point and the fluence change. The model was assessed by a chi-square test. The area under the receiver-operating characteristic curve was also determined. A total of 46 pairs of measurements were obtained. The correlation between fluence and volumetric changes was found to be -0.776 (P value <.001). The negative correlation is attributed to the increase in the photon fluence transport resulting from the volume reduction. The chi-square of the logistic regression was found to be 17.4 (P value <.001). The area under the receiver-operating characteristic curve was found to be 0.88. Results indicate the change in transit fluence, which can be measured without consuming clinical resources or requiring additional time in the treatment room, can be used as a decision support metric for adaptive therapy.

Microfluidic tools for probing micro-culprits: Opportunities and challenges in microfluidic diagnostics

Microfluidics is a highly promising technology platform for cancer diagnosis. It will need a change of mindset among engineers, clinicians and regulators to fully embrace its potential.

Single-Cell Analysis of Circulating Tumor Cells: Why Heterogeneity Matters

Unlike bulk-cell analysis, single-cell approaches have the advantage of assessing cellular heterogeneity that governs key aspects of tumor biology. Yet, their applications to circulating tumor cells (CTCs) are relatively limited, due mainly to the technical challenges resulting from extreme rarity of CTCs. Nevertheless, recent advances in microfluidics and immunoaffinity enrichment technologies along with sequencing platforms have fueled studies aiming to enrich, isolate, and sequence whole genomes of CTCs with high fidelity across various malignancies. Here, we review recent single-cell CTC (scCTC) sequencing efforts, and the integrated workflows, that have successfully characterized patient-derived CTCs. We examine how these studies uncover DNA alterations occurring at multiple molecular levels ranging from point mutations to chromosomal rearrangements from a single CTC, and discuss their cellular heterogeneity and clinical consequences. Finally, we highlight emerging strategies to address key challenges currently limiting the translation of these findings to clinical practice.

Microfluidics for personalized drug screening of cancer

Resistance to targeted therapies is a major clinical challenge in cancer treatment. Despite technological advances, robust biomarkers or platforms predictive of treatment response are lacking owing to the inherent nature of complex genomic landscape of carcinoma. Nevertheless, recent efforts centred on performing direct drug screening on patient-derived cells through their ex vivo expansion and maintenance have enabled personalized stratification of treatment modalities. Microfluidics is one such technology that allows high-throughput drug screening through parallelization and automation using small-volume sample. In this review, we present recent microfluidic platforms that have been successfully applied for the maintenance and expansion of patient-derived tumor cells spanning diverse cancer types and sources (solid tumors or liquid biopsies (circulating tumor cells)) for personalized drug screening applications.

Compendiums of cancer transcriptomes for machine learning applications

There are massive transcriptome profiles in the form of microarray. The challenge is that they are processed using diverse platforms and preprocessing tools, requiring considerable time and informatics expertise for cross-dataset analyses. If there exists a single, integrated data source, data-reuse can be facilitated for discovery, analysis, and validation of biomarker-based clinical strategy. Here, we present merged microarray-acquired datasets (MMDs) across 11 major cancer types, curating 8,386 patient-derived tumor and tumor-free samples from 95 GEO datasets. Using machine learning algorithms, we show that diagnostic models trained from MMDs can be directly applied to RNA-seq-acquired TCGA data with high classification accuracy. Machine learning optimized MMD further aids to reveal immune landscape across various carcinomas critically needed in disease management and clinical interventions. This unified data source may serve as an excellent training or test set to apply, develop, and refine machine learning algorithms that can be tapped to better define genomic landscape of human cancers.

Low-dose anti-inflammatory combinatorial therapy reduced cancer stem cell formation in patient-derived preclinical models for tumour relapse prevention

Background

Emergence of drug-resistant cancer phenotypes is a challenge for anti-cancer therapy. Cancer stem cells are identified as one of the ways by which chemoresistance develops.

Method

We investigated the anti-inflammatory combinatorial treatment (DA) of doxorubicin and aspirin using a preclinical microfluidic model on cancer cell lines and patient-derived circulating tumour cell clusters. The model had been previously demonstrated to predict patient overall prognosis.

Results

We demonstrated that low-dose aspirin with a sub-optimal dose of doxorubicin for 72 h could generate higher killing efficacy and enhanced apoptosis. Seven days of DA treatment significantly reduced the proportion of cancer stem cells and colony-forming ability. DA treatment delayed the inhibition of interleukin-6 secretion, which is mediated by both COX-dependent and independent pathways. The response of patients varied due to clinical heterogeneity, with 62.5% and 64.7% of samples demonstrating higher killing efficacy or reduction in cancer stem cell (CSC) proportions after DA treatment, respectively. These results highlight the importance of using patient-derived models for drug discovery.

Conclusions

This preclinical proof of concept seeks to reduce the onset of CSCs generated post treatment by stressful stimuli. Our study will promote a better understanding of anti-inflammatory treatments for cancer and reduce the risk of relapse in patients.

A merged lung cancer transcriptome dataset for clinical predictive modeling

The Gene Expression Omnibus (GEO) database is an excellent public source of whole transcriptomic profiles of multiple cancers. The main challenge is the limited accessibility of such large-scale genomic data to people without a background in bioinformatics or computer science. This presents difficulties in data analysis, sharing and visualization. Here, we present an integrated bioinformatics pipeline and a normalized dataset that has been preprocessed using a robust statistical methodology; allowing others to perform large-scale meta-analysis, without having to conduct time-consuming data mining and statistical correction. Comprising 1,118 patient-derived samples, the normalized dataset includes primary non-small cell lung cancer (NSCLC) tumors and paired normal lung tissues from ten independent GEO datasets, facilitating differential expression analysis. The data has been merged, normalized, batch effect-corrected and filtered for genes with low variance via multiple open source R packages integrated into our workflow. Overall this dataset (with associated clinical metadata) better represents the diseased population and serves as a powerful tool for early predictive biomarker discovery.

An extracellular matrix-related prognostic and predictive indicator for early-stage non-small cell lung cancer

The prognosis and prediction of adjuvant chemotherapy (ACT) response in early-stage non-small cell lung cancer (NSCLC) patients remain poor in this era of personalized medicine. We hypothesize that extracellular matrix (ECM)-associated components could be potential markers for better diagnosis and prognosis due to their differential expression in 1,943 primary NSCLC tumors as compared to 303 normal lung tissues. Here we develop a 29-gene ECM-related prognostic and predictive indicator (EPPI). We validate a robust performance of the EPPI risk scoring system in multiple independent data sets, comprising a total of 2,071 early-stage NSCLC tumors. Patients are stratified according to the universal cutoff score based on the EPPI when applied in the clinical setting; the low-risk group has significantly better survival outcome. The functional EPPI gene set represents a potential genomic tool to improve patient selection in early-stage NSCLC to further derive the best benefits of ACT and prevent unnecessary treatment or ACT-associated morbidity.

Prognosis and prediction of adjuvant chemotherapy response in non-small cell lung cancer can have significant clinical impact. Here, the authors show that differential expression of a 29 extracellular matrix gene indicator, EPPI, can predict patient outcome.

Shape-controlled Pt nanocubes directly grown on carbon supports and their electrocatalytic activity toward methanol oxidation

Synthesis of shape-controlled Pt nanocrystals is substantial and important for enhancing chemical and electrochemical reactions. However, the removal of capping agents, shape-controlling chemicals, on Pt surfaces is essential prior to conducting the catalytic reactions. Here we report a facile one-pot synthesis of Pt nanocubes directly grown on carbon supports (Pt nanocubes/C) with modulating the kinetic reaction factors for shaping the nanocrystals, but without adding any capping agents for preserving the clean Pt surfaces. Well-dispersed Pt nanocubes/C shows enhanced activity and long-term stability toward methanol oxidation reaction compared to the commercial Pt/C catalyst.

Survival Benefit of Early Cancer Detection Through Regular Endoscopic Screening for De Novo Gastric and Colorectal Cancers in Korean Liver Transplant Recipients

BACKGROUND

De novo malignancy is not uncommon after liver transplantation (LT). Gastric cancer is one of the most common malignancies in both the Korean general population and LT recipients, and colorectal cancer prevalence is gradually increasing.

METHODS

Among 3690 adult recipients who underwent LT from January 1999 and December 2013, the screening patterns and prognosis of 26 cases of gastric cancer and 22 cases of colorectal cancer were analyzed.

RESULTS

For gastric cancer, the mean patient age was 54.6 ± 6.2 years at LT and 59.5 ± 6.7 years at cancer diagnosis, with a post-transplant interval of 60.2 ± 29.8 months. Patients were divided into regular (n = 18) and non-regular (n = 8) screening groups, with early cancer found in 14 and 0 patients; their 2-year survival rates after cancer diagnosis were 93.1% and 33.3% (P = .006), respectively. Endoscopic resection was successfully performed in 8 patients, all in the regular screening group. For colorectal cancer, the mean patient age was 53.3 ± 6.1 years at LT and 58.1 ± 6.7 years at cancer diagnosis, with a post-transplant interval of 54.3 ± 38.0 months. Patients were divided into regular (n = 19) and non-regular (n = 3) screening groups, with early cancer found in 12 and 0 patients; their 2-year survival rates after cancer diagnosis of 92.3% and 33.3% (P = .003), respectively. Endoscopic resection was successfully performed in 6 patients, all in the regular screening group.

CONCLUSIONS

LT recipients are strongly advised to undergo regular screening studies for various de novo malignancies, especially cancers common in the general population. Regular endoscopic screening contributes to the timely detection of gastric and colorectal cancers, improving post-treatment survival outcomes.

The psychometric properties of the Quantitative-Checklist for Autism in Toddlers (Q-CHAT) as a measure of autistic traits in a community sample of Singaporean infants and toddlers

Background

There is growing research evidence that subclinical autistic traits are elevated in relatives of individuals with autism spectrum disorder (ASD), continuously distributed in the general population and likely to share common etiology with ASD. A number of measures have been developed to assess autistic traits quantitatively in unselected samples. So far, the Quantitative-Checklist for Autism in Toddlers (Q-CHAT) is one of very few measures developed for use with toddlers as young as 18 months, but little is known about its measurement properties and factor structure.

Methods

The present study examined internal consistency, factor structure, test-retest stability, and convergent validity of the Q-CHAT in a sample of toddlers in Singapore whose caregivers completed the Q-CHAT at 18 (n = 368) and 24 months (n = 396).

Results

Three factors were derived accounting for 38.1 % of the variance: social/communication traits, non-social/behavioral traits, and a speech/language factor. Internal consistency was suboptimal for the total and speech/language scores, but acceptable for the social/communication and non-social/behavioral factor scores. Scores were generally stable between 18 and 24 months. Convergent validity was found with the Pervasive Developmental Disorders subscale of the Child Behavior Checklist (CBCL) completed by caregivers when their children were 24 months. Q-CHAT total scores in this sample were higher than those reported in other unselected samples from the UK.

Conclusions

The Q-CHAT was found to have a three-factor structure, acceptable internal consistency for its two main factor scores (social/communication and non-social/behavioral), normally distributed scores in an unselected sample, and similar structure and measurement properties as those reported in other published studies. Findings are discussed in relation to existing literature and future directions for the validation of the Q-CHAT.

Childhood intermittent exotropia from a different angle: does severity affect quality of life?

BACKGROUND

Few studies have explored the relationship between health-related quality of life (HRQOL) and clinical severity of childhood intermittent exotropia (IXT) measured by angle of deviation, control and stereoacuity.

METHODS

Sixty-eight consecutive children aged 5-17 years with childhood IXT who attended the paediatric eye clinic were recruited. One accompanying parent was recruited concurrently. Child, parent and proxy (parent about the child) HRQOL was measured using the IXT questionnaire (IXTQ). Angle of deviation, control and stereoacuity of the children were measured and correlated with IXTQ scores using Spearman's correlation coefficient and paired t test for differences in child and proxy IXTQ mean scores.

RESULTS

The mean age of the children was 9.0±2.6 years. Child HRQOL was not correlated to any strabismus measurements. Poorer parent HRQOL was correlated with poorer distance control (surgery subscale, r=-0.24 p=0.049), poorer near control (surgery subscale, r=-0.30, p=0.013), poorer office near control (mean, r=-0.24, p=0.047; psychological subscale, r=-0.27, p=0.025; surgery subscale, r=-0.28, p=0.020) and larger angle of deviation (psychological subscale, r=-0.30, p=0.013). Poorer proxy HRQOL was correlated with poorer home control (r=-0.28, p=0.022) and larger angle of deviation (r=0.33, p=0.0061).

CONCLUSIONS

It is difficult to predict child HRQOL based on clinical measurements. However, parent HRQOL tends to be worse with poorer control and larger angle of deviation. Perhaps HRQOL should be routinely assessed in clinic alongside clinical measurements in order to tailor management appropriately.

Synchronous gastric cancer in primary sporadic colorectal cancer patients in Korea

BACKGROUND AND AIMS

Colorectal cancer has been reported to be the malignancy most frequently associated with gastric cancer in Korea. The aim of this study was to define the frequency and clinical characteristics of synchronous gastric cancer detected at preoperative esophagogastroduodenoscopy (EGD) in colorectal cancer patients.

MATERIALS AND METHODS

This prospective study analyzed the EGD results from 1,542 consecutive colorectal cancer patients who underwent surgery from January 2003 to December 2005 at the Center for Colorectal Cancer, National Cancer Center, Korea.

RESULTS

Of the 1,542 cases, 1,155 (74.9%) underwent EGD at our center and 387 underwent EGD at other hospitals within 6 months before surgery. Of the 1,542 cases, synchronous gastric cancers were detected in 31 cases (2.0%). Of these 31 cases, 26 had early gastric cancer (EGC; 83.9%) and 5 had advanced gastric cancer. Ten (38.5%) of the 26 EGC cases were managed using endoscopic mucosal resection. Compared to colorectal cancer patients without synchronous gastric cancer, the group of patients with synchronous gastric cancer was older (65.5+/-9.6 vs 58.4+/-11.3 years, p=0.001) and had a greater proportion of males (77.4 vs 59.4%, p=0.043).

CONCLUSION

This study found that 2% of Korean sporadic colorectal cancer patients had synchronous gastric cancer. A preoperative EGD for colorectal cancer patients is likely to greatly assist in the diagnosis of synchronous gastric cancer at an early stage and the implementation of appropriate minimally invasive treatment.

Knockdown of polypyrimidine tract-binding protein suppresses ovarian tumor cell growth and invasiveness in vitro

Polypyrimidine tract-binding protein (PTB) is an RNA-binding protein with multiple functions in the regulation of RNA processing and IRES-mediated translation. We report here overexpression of PTB in a majority of epithelial ovarian tumors revealed by immunoblotting and tissue microarray (TMA) staining. By western blotting, we found that PTB was overexpressed in 17 out of 19 ovarian tumor specimens compared to their matched-normal tissues. By TMA staining, we found PTB expression in 38 out of 44 ovarian cancer cases but only in two out of nine normal adjacent tissues. PTB is also overexpressed in SV40 large T-antigen immortalized ovarian epithelial cells compared to normal human ovarian epithelial cells. Using doxycycline-inducible small interfering RNA technology, we found that knockdown of PTB expression in the ovarian tumor cell line A2780 substantially impaired tumor cell proliferation, anchorage-independent growth and in vitro invasiveness. These results suggest that overexpression of PTB is an important component of the multistep process of tumorigenesis, and might be required for the development and maintenance of epithelial ovarian tumors. Moreover, because of its novel role in tumor cell growth and invasiveness, shown here for the first time, PTB may be a novel therapeutic target in the treatment of ovarian cancer.

Universal newborn hearing screening in Singapore: the need, implementation and challenges

With about 1 in 1000 born with severe to profound hearing loss and about 5 in 1000 with lesser degrees of loss, congenital deafness is the commonest major birth defect. It is the recommended standard that hearing loss in newborns be detected by 3 months of age and intervention implemented by 6 months of age. Delayed detection and intervention may affect speech, language and psychosocial development, resulting in poor academic achievements. Universal newborn hearing screening (UNHS) is the only effective way of detecting all babies with hearing loss, within the recommended time frame. A survey in Singapore revealed that traditional childhood hearing screening programmes resulted in late detection (mean age, 20.8 months; range, 0 to 86 months) and late intervention (mean age, 42.4 months; range, 1 to 120 months). Increasingly, UNHS is becoming standard medical care in developed countries. In Singapore, UNHS has been implemented in all hospitals with obstetric services. Although a screening rate of more than 99% has been achieved in public hospitals, private hospitals have a screening rate of only about 77%. Parents' awareness and acceptance of early detection is still lacking, and this needs to be addressed by appropriate public education. Support from obstetricians and paediatricians will significantly contribute towards this objective. Effective programme management is essential; this includes the use of data management systems, the maintenance of a team of experienced screeners, and efficient coordination between screening and diagnostic services. Early detection of childhood deafness, together with early and effective intervention, maximises the chances of successful integration into mainstream education and society.

Long-term follow-up and outcome of extremely-low-birth-weight (ELBW) infants

INTRODUCTION

Modern day obstetric and neonatal care has dramatically increased the survival of the extremely-low-birth-weight (ELBW) neonates. As the limits of viability decrease, it is of paramount importance to have reliable data on long-term morbidity. Long-term follow-up of these high-risk survivors is thus becoming an integral part of neonatal intensive care units.

METHODS

Detailed Medline search and review of leading journal articles were done to assess the current data on long-term outcome of ELBW infants.

RESULTS

The developmental outcome of the ELBW infant is determined by a complex interaction of medical and environmental factors acting on a developmentally vulnerable premature brain. In early childhood, 13% to 37% of ELBW survivors have a significant delay in cognitive function while 7% to 17% have neurosensory impairment viz. cerebral palsy. Advances have been made in measuring functional outcome to assess the impact of ELBW births on long-term quality of life and skills for independent living. Measuring school age outcome is an important landmark in the longitudinal follow-up of ELBW infants and most reports show high rates of cognitive impairment as well as increased incidence of learning disability and school difficulties as well as behavioural problems. The ELBW adolescent and young adult continue to lag behind in academic achievement and cognitive score. However, more than half of the ELBW survivors function within the normal range of variability and their self-reported quality of life in adolescence continues to be comparable to that of their peers.

CONCLUSION

In managing ELBW infants, a holistic, systematic approach is needed to assess the degree and impact of impairment on their daily function and issues related to quality of life.

Eight-year outcome of very-low-birth-weight infants born in KK hospital

AIM

To determine the education, neurodevelopmental outcome and educational achievement of babies weighing < 1500 g at 8 years of age.

MATERIALS AND METHODS

This prospective study involved 171 of 202 survivors from KK Women's and Children's Hospital (KKWCH). Cognitive function was assessed using the Weschler Intelligence Scale for Children--version III (WISC-III).

RESULTS

Of these, 90.1% were in mainstream education and 1.2% were in home or religious schools. Special education programmes were recommended for 11.1% of children [24.4% of 56 extremely-low-birth-weight (ELBW) babies < 1000 g and 9.6% of 115 larger babies weighing 1000 to 1499 g]. Of these, only 7.8% eventually enrolled and 1.2% were not in any programme. In 136 children who had psychological assessments, the mean full-scale, verbal and performance intelligence scores were 87.0 +/- 17.7, 86.6 +/- 17.0 and 90.1 +/- 21.8 in ELBWs and 96.1 +/- 18.3, 93.3 +/- 15.7 and 100.0 +/- 17.5 in larger children, with the former having significantly lower scores than the latter (full scale: P = 0.02, 95% CI -18.23, -4.18; verbal: P = 0.04, 95% CI -13.8, -1.95; performance: P = 0.004, 95% CI -17.67, -3.35). 33.8% of the cohort, 49.0% of ELBWs and 25.3% of larger children had neurodevelopmental impairment (full scale score < 85 or in need of special education). Logistic regression analysis showed that birth weight < 1000 g, female sex, Chinese race, a non-intact family structure and bronchopulmonary dysplasia (BPD) were significant risk factors associated with neurodevelopmental impairment. 72.7% of children scored > or = 50% of total marks for English, Mathematics and second language. 14.1% had Band 4 (< 50% of total marks) in all 3 subjects. Logistic regression analysis showed that the only significant risk factors associated with adverse school performance in any of these three subjects were hypoglycaemia in the newborn period and impaired cognitive function.

CONCLUSION

The outcome of ELBWs is a major cause of concern. BPD and hypoglycaemia were the only perinatal factors that still exerted an influence on outcome at 8 years. Better methods of prediction of academic difficulty are critical for this high-risk group of children.

Effect of the mannose-binding Artocarpus integer lectin on the cellular proliferation of murine lymphocytes

The effect of the mannose-binding champedak (Artocarpus integer) lectin-M on the cellular proliferation of murine lymphocytes was investigated in this study. Our data demonstrated that the lectin was the main mitogenic component in the crude extract of the champedak seeds. It stimulated the proliferation of murine T cells at an optimal concentration of 2.5 microg/ml in a 3 day culture. Lectin-M appeared to be a T-cell mitogen as it does not induce significant DNA synthesis when cultured with spleen cells from the nude mouse. In the absence of T cells, the lectin was incapable of inducing resting B cells to differentiate into immunoglobulin secreting plasma cells.

Isolation of a mannose-binding and IgE- and IgM-reactive lectin from the seeds of Artocarpus integer

A mannose-binding lectin, termed champedak lectin-M, was isolated from an extract of the crude seeds of champedak (Artocarpus integer). On gel filtration chromatography, the lectin eluted in a single peak at elution volumes corresponding to 64 kDa. SDS-PAGE showed the mannose-binding lectin to be composed of 16.8 kDa polypeptides with some of the polypeptides being disulphide-linked to give dimers. When tested with all isotypes of immunoglobulins, champedak lectin-M demonstrated a selective strong interaction with human IgE and IgM, and a weak interaction with IgA2. The binding interactions of lectin-M were metal ion independent. The lectin was also shown to interact with horseradish peroxidase, ovalbumin, porcine thyroglobulin, human alpha1-acid glycoprotein, transferrin and alpha1-antitrypsin. It demonstrated a binding preference to Man alpha 1-3Man ligands in comparison to Man alpha 1-6Man or Man alpha 1-2Man.

Outcome of infants weighing 500-999 grams at birth in a Singapore hospital (1990-1993)

Over a 4-year period (1990-1993) 126 babies weighing 500-999 grams (0.39% of 32,362 livebirths) were born in the hospital that provides tertiary care. Seventy-eight babies (61.9%) were discharged alive. Survival rate (79.4% or 50/63) was higher in the larger babies (800-999 gm) than in the smaller babies (28/63 of the 500-799 gm or 44.4%, p = 0.0001). Survival rates among the 2 periods, 1990-91 (period 1) and 1992-93 (period 2) have also improved, from 44/74 or 59.5% to 34/52 or 65.4%, p = 0.62 (NS). Surfactant replacement therapy (SRT) has an impact on decreasing the mortality for babies < 1,000 gm. Only 35.3% (6/17) babies had SRT in 1993. Other perinatal factors are also contributing to a better outcome of these high risk babies. Neurodevelopmental outcome at 2 years of age of the 39 babies (50%) born in period 1 has been determined. Thirty-five percent (5/14) of the smaller babies and 28% (7/25) of the larger babies had MDI (Bayley Mental Developmental Index) of < 69. For cerebral palsy, it was 14% and 8% respectively; and for neurosensory disorder, 7% and 4% respectively. Some babies had a combination of 2 or 3 major impairments. It is estimated that 33% of babies who weighed less than 1,000 gm at birth had a disability. It was found that severe intraventricular haemorrhage (IVH) of grade III and IV correlated significantly with MDI of < 69 (p < 0.05). Severe IVH in period 2 (17.2%) did not differ significantly from that of period 1 (29.4%, p = 0.55).(ABSTRACT TRUNCATED AT 250 WORDS)

Aetiology of diarrhoea in Singapore

Stools from acute diarrhoea were investigated for bacterial and viral pathogens. In one study involving 63 young children in a paediatric ward, 70% of the stools were positive for the pathogens looked for of which 37% contained bacteria, 22% viruses and 11% mixed cultures of bacteria and viruses. In another study in which 130 watery stools from routine specimens of patients of all ages were investigated, 36% were positive for pathogens with 11% bacteria, 18% viruses and 7% mixed pathogens. The high incidence of bacterial diarrhoea in young children was attributed to gastroenteritis caused by Salmonella species. Salmonella and rotavirus were found the most common pathogens in bacterial and viral diarrhoeas, and the most susceptible age group was under 5 years-old.

Bronchopulmonary dysplasia in very low birthweight infants

Twenty-four (6%) of 375 infants with birthweights less than or equal to 1500g developed bronchopulmonary dysplasia (BPD); 16 (15%) of 107 in those less than or equal to 100g and 8 (3%) of 268 in those greater than 1000g. The incidence was 10% in those who required assisted ventilation. Perinatal asphyxia, significant respiratory distress, pulmonary interstitial emphysema and patent ductus arteriosus were statistically more common in BPD infants compared with the remaining 351 very low birthweight infants. Hyaline membrane disease was the primary respiratory disease in 54% of BPD infants. The mean durations of oxygen and ventilatory therapy were 68 days and 37 days respectively. Twenty-nine percent did not require more than 60% oxygen for over 24 hours. Only 38% required a peak airway pressure of over 30 cmH2O. Early postnatal growth was satisfactory on parenteral nutrition support. No perinatal factor was found to be predictive of death from BPD. The prolonged duration of hospital treatment has obvious implications to the psychosocial and economic costs of BPD.

Growth and development of very low birthweight infants recovering from bronchopulmonary dysplasia

Twenty four infants with birthweights less than or equal to 1500 g had bronchopulmonary dysplasia (BPD). Four died in the neonatal period and four in the postneonatal period-one had been discharged and was aged one year. Sixteen (67%) survived long term and were followed up until they were two years old. Common medical conditions included respiratory illnesses in 14 (88%) children and otitis media in 8 (50%). Eleven (69%) required hospital admission for an average of 5 times; total days in hospital averaged 27 days. The most common reasons for admission were bronchiolitis and bronchopneumonia. At two years 37% were below the 10th centile for weight, as were 25% for height: head circumferences were normal. Two children had cerebral palsy, two had developmental delay, two had multiple disabilities, and one had sensorineural deafness. Of the 24 BPD infants, 8 (33%) died, 7 (29%) survived with a disability (severe in one), and 9 (38%) had a normal neurodevelopmental outcome. From the available perinatal data it was not possible to predict late disabilities in BPD survivors.