Impact of the COVID-19 pandemic on hematopoietic stem cell transplant programmes in Singapore

Background

Hematopoietic stem cell transplantation (HSCT) has been performed in Singapore since 1985. Currently, more than 100 transplants are performed annually across the public and private sectors. In 2020, the COVID-19 pandemic resulted in unprecedented disruptions to global healthcare systems, and Singapore was no exception. In particular, the field of HSCT faced additional, unique challenges aside from those borne by the healthcare system at large, and appropriate measures were necessary to ensure that HSCT remained available to patients who needed it.

Methods

The expert opinions of six hematologists from various institutions across Singapore were gathered through individual interviews and summarized. This was supplemented by a literature review on bone marrow donation and HSCT in Singapore.

Main Findings and Conclusion

In Singapore, the COVID-19 pandemic has had significant implications for HSCT, ranging from the implementation of additional infection control measures in hospitals to an accelerated rise in haploidentical transplants. Further research is required to better understand and quantify these impacts, improve existing processes, and investigate the effects of COVID-19 and its treatment modalities on patients with HSCT.

The role of coupled DNRA-Anammox during nitrate removal in a highly saline lake

Nitrate (NO₃^-) removal from aquatic ecosystems involves several microbially mediated processes, including denitrification, dissimilatory nitrate reduction to ammonium (DNRA), and anaerobic ammonium oxidation (anammox), controlled by slight changes in environmental gradients. In addition, some of these processes (i.e. denitrification) may involve the production of undesirable compounds such as nitrous oxide (N₂O), an important greenhouse gas. Saline lakes are prone to the accumulation of anthropogenic contaminants, making them highly vulnerable environments to NO₃^- pollution. The aim of this paper was to investigate the effect of light and oxygen on the different NO₃^- removal pathways under highly saline conditions. For this purpose, mesocosm experiments were performed using lacustrine, undisturbed, organic-rich sediments from the Pétrola Lake (Spain), a highly saline waterbody subject to anthropogenic NO₃^- pollution. The revised ¹⁵N-isotope pairing technique (¹⁵N-IPT) was used to determine NO₃^- sink processes. Our results demonstrate for the first time the coexistence of denitrification, DNRA, and anammox processes in a highly saline lake, and how their contribution was determined by environmental conditions (oxygen and light). DNRA, and especially denitrification to N₂O, were the dominant nitrogen (N) removal pathways when oxygen and/or light were present (up to 82%). In contrast, anoxia and darkness promoted NO₃^- reduction by DNRA (52%), combined with N loss by anammox (28%). Our results highlight the role of coupled DNRA-anammox, which has not yet been investigated in lacustrine sediments. We conclude that anoxia and darkness favored DNRA and anammox processes over denitrification and therefore to restrict N₂O emissions to the atmosphere.

HEMATOPOIETIC STEM CELL TRANSPLANT IN AGGRESSIVE T AND NK/T CELL LYMPHOMA - ROLE OF UPFRONT AUTOLOGOUS TRANSPLANT IN NODAL PERIPHERAL T-CELL LYMPHOMA

Aggressive T and NK/T-cell lymphoma are known to have a high risk of relapse and poor long-term prognosis. Hematopoietic stem cell transplantation has been performed as part of consolidation or salvage treatment. We retrospectively studied the outcomes of autologous (A) and allogeneic (allo) hematopoietic stem cell transplantation (SCT) in aggressive T and NK/T-cell lymphoma at our center between 2010 to 2020. Patients with nodal peripheral T-cell lymphoma (PTCL) that were younger than 65 years old who did not receive upfront autologous SCT (ASCT) at first complete remission were selected from our registry data for further comparison. Thirty-six patients underwent ASCT, and 16 patients underwent alloSCT. In the ASCT cohort, 18 patients with nodal PTCL who underwent upfront ASCT at first complete remission (upfront ASCT) were compared with 15 patients with nodal PTCL who were in first complete remission after single-line induction but did not receive ASCT. The two-year progression-free survival (PFS) and overall survival (OS) rates for the ASCT cohort were 58% and 73%, respectively. The two-year PFS and OS for the alloSCT cohort were 47% (P=0.35, P=0.02, respectively). Twenty-four patients who received SCT at first remission (21 ASCT and three alloSCT) had a two-year PFS and OS of 75% and 89%, respectively. In comparison, 28 patients who received SCT at relapse/refractory (15 ASCT and 13 alloSCT) had a two-year PFS and OS of 40% and 50%, respectively (P=0.047, P=0.024, respectively). Patients in complete remission prior to transplantation (n=42) had a two-year PFS and OS of 59% and 73%, respectively. In contrast, patients in partial remission prior to transplantation (n=10) had a two-year PFS and OS of 40% and 48%, respectively (p>0.05). Non-relapse mortality occurred in 6% and 43% of ASCT and AlloSCT, respectively. Multivariate analysis revealed that EBV-positivity at diagnosis indicated poorer PFS. EBV-positivity at diagnosis and more than two prior lines of treatment at transplant were associated with poorer OS. For nodal PTCL, the two-year PFS and OS were 79% and 100% for the upfront ASCT cohort and 78% and 92% for the non-upfront ASCT cohort, respectively (p>0.05). Hematopoietic SCT is a feasible treatment option for aggressive T and NK/T-cell lymphoma. Patients who underwent SCT at first remission had better survival rates than those who underwent SCT at relapse/refractory. Nevertheless, due to the limited sample size of the current study, the role of upfront ASCT in patients with nodal PTCL who achieved first complete remission remains unclear.

Genomic landscape of neutrophilic leukemias of ambiguous diagnosis

Chronic neutrophilic leukemia (CNL), atypical chronic myeloid leukemia (aCML), and myelodysplastic/myeloproliferative neoplasms, unclassifiable (MDS/MPN-U) are a group of rare and heterogeneous myeloid disorders. There is strong morphologic resemblance among these distinct diagnostic entities as well as a lack of specific molecular markers and limited understanding of disease pathogenesis, which has made diagnosis challenging in certain cases. The treatment has remained empirical, resulting in dismal outcomes. We, therefore, performed whole-exome and RNA sequencing of these rare hematologic malignancies and present the most complete survey of the genomic landscape of these diseases to date. We observed a diversity of combinatorial mutational patterns that generally do not cluster within any one diagnosis. Gene expression analysis reveals enrichment, but not cosegregation, of clinical and genetic disease features with transcriptional clusters. In conclusion, these groups of diseases represent a continuum of related diseases rather than discrete diagnostic entities.

Introducing the H2020 AQUACROSS project: Knowledge, Assessment, and Management for AQUAtic Biodiversity and Ecosystem Services aCROSS EU policies

The AQUACROSS project was an unprecedented effort to unify policy concepts, knowledge, and management of freshwater, coastal, and marine ecosystems to support the cost-effective achievement of the targets set by the EU Biodiversity Strategy to 2020. AQUACROSS aimed to support EU efforts to enhance the resilience and stop the loss of biodiversity of aquatic ecosystems as well as to ensure the ongoing and future provision of aquatic ecosystem services. The project focused on advancing the knowledge base and application of Ecosystem-Based Management. Through elaboration of eight diverse case studies in freshwater and marine and estuarine aquatic ecosystem across Europe covering a range of environmental management problems including, eutrophication, sustainable fisheries as well as invasive alien species AQUACROSS demonstrated the application of a common framework to establish cost-effective measures and integrated Ecosystem-Based Management practices. AQUACROSS analysed the EU policy framework (i.e. goals, concepts, time frames) for aquatic ecosystems and built on knowledge stemming from different sources (i.e. WISE, BISE, Member State reporting within different policy processes, modelling) to develop innovative management tools, concepts, and business models (i.e. indicators, maps, ecosystem assessments, participatory approaches, mechanisms for promoting the delivery of ecosystem services) for aquatic ecosystems at various scales of space and time and relevant to different ecosystem types.

The effect of hypoxia and flow decrease in macroinvertebrate functional responses: A trait-based approach to multiple-stressors in mesocosms

River ecosystems are most often subject to multiple co-occurring anthropogenic stressors. Mediterranean streams are particularly affected by water scarcity and organic loads that commonly lead to a simultaneous reduction in flow and increasing depletion of dissolved oxygen. In the present study, the single and combined effects of water scarcity (flow velocity reduction) and dissolved oxygen depletion were used to evaluate alterations of drifting macroinvertebrates on a channel mesocosm system, by employing a multiple trait-based approach. Our main findings confirmed that the impact of the two combined stressors can be implicated in alterations of ecosystem functions as result of the changes in proportions of biological traits. Overall, our results showed that, individually, flow velocity reduction and a severe oxygen depletion promoted a shift in community traits. In more detail, biological traits describing the dispersal of organisms and their respiration showed the strongest responses. The respiration mode responded to low flow with drift increase of gill breathers and decrease of individuals with tegument, whereas dispersal was clearly affected by the combination of stressors. Resistance through eggs was higher with the single effect of flow reduction, while swimmers´ relative abundance increased in individuals that drift after exposure to the combination of stressors. Thus, while flow reduction alone is expected to specifically filter out the gill breathers and the egg producers, the combination of stressors will impact more drastically organism's dispersal and swimmers. Such changes in biological traits can result in variations in ecosystem functioning through, for example, local changes in biomass, secondary production, stream metabolism as well as resulting in biodiversity losses or alterations of its distribution patterns.

Computer-based quantification of the Achilles tendon thickness in sequential B-mode ultrasound images: a study of feasibility and reliability

INTRODUCTION

Assessment of the Achilles tendon thickness (ATT) using B-mode ultrasound is a common technique for clinical evaluation of chronic mid-part tendinosis. Currently used image-based assessment is limited by relatively high inter- and intra-observer variability. In this study, it was tested whether a new sequence-based automated assessment of ATT provides more reliable and reproducible results than the standard image-based procedure.

MATERIALS AND METHODS

A total of 118 non-operated tendons of 59 healthy subjects (44, range 28-50 years) were analysed using an automated image based as well as a newly developed automated sequence-based method. Correlation and agreement of both methods were evaluated. The root mean square deviation (RMSD) and a Bland-Altman analysis were performed to highlight observer (n = 18 tendons) as well as reader (n = 40 tendons) dependent variabilities of both methods.

RESULTS

A strong correlation was found between image and sequence-based ATT assessment (p = 0.92). The Bland-Altman analysis showed a good agreement between both methods (mean difference 0.0018, 95 % CI: -0.046; 0.05). In repetitive examinations, sequence-based analysis showed a significant reduction concerning reader- and observer-dependent variability compared to image-based assessment. The RMSD for repetitive sequence-based measurements was approximately 0.3 mm (compared to 0.6 mm for image-based measurement), respectively.

CONCLUSIONS

The study shows sequence-based automated assessment of ATT being clearly superior to the standard image-based procedure. The new method provides a clear reduction of reader as well as observer-dependent variability. Due to the decreased scattering of measurement data sequence-based measurement seems especially valuable for quantification of small tendon thickness changes such as exercise-induced hypertrophy.

[Prostate cancer in Luxembourg from 1982 to 2006. Incidence and mortality. Survival of a hospital cohort]

Prostate cancer incidence has tripled in Luxembourg as in many other western countries. From 1982 to 2006, new cases increased from 80 to 309 per year, while the incidence (world stand.pop.) rose from 29.5 to 85 per 100 000 men. Since 1991 prostate cancer is the most frequent male cancer in Luxembourg, exceeding colo-rectal, lung and stomach cancer. Prostate cancer deaths have diminished from 64 in 1982 to 45 in 2006. This represents less than 10% of male cancer related deaths; it represents the third most frequent cancer death, behind lung and colo-rectal cancers. Annual mortality rate has decreased from 29 to 10 per 100 000 men during the same period, this difference between incidence and mortality is explained on the one hand by the widespread use of PSA since the 1990's and on the other hand by a better local control as well as a multidisciplinary approach of advanced disease. The increase of the incidence is particularly important in the 60 to 70 age group, while for men older than 70, the peak incidence was reached in 2002. A lowering of the age at diagnosis is confirmed by the 5-year age group analysis. The hospital cohort consists of 628 patients from the urological department of the Centre Hospitalier de Luxembourg diagnosed with prostate cancer between 1st January 1982 and 31st December 2006; follow-up ended 31st December 2011. During this period, age at diagnosis decreased from 71.5 to 68.9 years whereas the proportion of localized clinical stages increased from 44 to 70%. Median PSA dropped from 14.5 to 9 ng/ml. Furthermore the analysis of cancer specific mortality confirms the negative effects of an advanced clinical stage (10-year survival: 90% for localized disease, 60% for advanced disease) or a high PSA level at diagnosis (10-year survival: 97% if PSA < 4 ng/nl, 94% if 4 < PSA < 10, and 72% if PSA > 10 ng/ml), as well as a poor differentiation (60% 10-year survival compared to 90% for differentiated tumors). Kaplan-Meier curves show that long term surveillance is necessary as even tumors with a good initial prognosis may relapse after 10-12 years.

How do long-term development and periodical changes of river-floodplain systems affect the fate of contaminants? Results from European rivers

In many densely populated areas, riverine floodplains have been strongly impacted and degraded by river channelization and flood protection dikes. Floodplains act as buffers for flood water and as filters for nutrients and pollutants carried with river water and sediment from upstream source areas. Based on results of the EU-funded "AquaTerra" project (2004-2009), we analyze changes in the dynamics of European river-floodplain systems over different temporal scales and assess their effects on contaminant behaviour and ecosystem functioning. We find that human-induced changes in the hydrologic regime of rivers have direct and severe consequences on nutrient cycling and contaminant retention in adjacent floodplains. We point out the complex interactions of contaminants with nutrient availability and other physico-chemical characteristics (pH, organic matter) in determining ecotoxicity and habitat quality, and draw conclusions for improved floodplain management.

[Projection of the number of multiple sclerosis patients in Germany]

For determining the prevalence of multiple sclerosis (MS) in Germany, the outcomes of several epidemiological studies are available. If these rates are transferred to Germany as a whole, figures result of 67,000 to 138,000 MS patients in all. The differing prevalence rates may be caused by various problems in finding patients, the epidemiological area, and different population structures. To avoid these difficulties, a new approach for calculating the number of patients with diagnosed MS was chosen based on representative samples taken from the groups of physicians involved in MS treatment. The disadvantage of this approach is that it does not allow any questioning of the diagnosis. Projecting the results in this way and their subsequent compilation--taking "double treatments" into consideration--showed a total of 122,000 patients with diagnosed multiple sclerosis in Germany. This figure corresponds to a prevalence rate of 149.1 per 100,000 inhabitants and is within the range found by Poser et al. [19]: 127 per 100,000 excluding the diagnostic category "possible multiple sclerosis" and 170 per 100,000 including it.

[Prostatic cancer in the Grand Duchy of Luxembourg. Role of PSA]

We reviewed the trends in prostate cancer incidence and mortality in Luxembourg between 1983 and 1995 to discuss the importance of total and free PSA in early detection. The study was performed on all the new cases recorded by the National Cancer Registry (Registre Morphologique des Tumeurs). Total and free PSA were measured with the automated Immulite System (DPC, Los Angeles) using a chemoluminescent immunometric assay. The performance of free-to-total serum PSA was analysed by a hospital based study of 113 patients (55 PC, 58 BPH). The age standardized incidence rate increased from 29.3/100,000 in 1983 to 71.5/100,000 in 1995. Mortality rates only changed slightly. The widespread use of PSA testing from 1988 on is probably the main cause of this incidental increase; however no major changes in the age-specific-incidence have been found suggesting the absence of a systematic screening policy by the PSA. The superiority of free-to-total serum PSA ratio in discriminating between cancer and benign condition was confirmed. Early health-conscious man over 50 should be proposed prostate cancer screening by digital rectal examination and PSA. However a systematic screening policy cannot been recommended since a benefit in survival after early treatment has not yet been proven.

[Renal adenocarcinoma and radical nephrectomy]

74 cases of radical nephrectomy for adenocarcinoma are reported. The authors review the clinical aspects and the accuracy of imaging and insist on fortuitous detection of early stages by ultrasound. Survival is studied with regard to tumor stage, transfusion and cell type.

Culture and selection of somatic hybrids using an auxotrophic cell line

Protoplast fusions between Nicotiana tabacum and N. paniculata and between N. tabacum and N. sylvestris were obtained by polyethylene glycol and Ca(NO3)2 treatment. The protoplasts of one parent originated from cell suspensions, while the protoplasts of the other originated from leaf mesophyll. The heterokaryons were detectable by their intermediate phenotype, namely the green chloroplasts from mesophyll and the dense cytoplasm from suspension cells. They were isolated with micropipettes immediately after fusion using a micromanipulator and were transferred into a protoplast suspension of an auxotrophic cell line serving as a nursery. This mutant is not able to utilize nitrate and had to be supplemented with amino acids. The somatic hybrids were selected by a stepwise reduction of the supplements, which caused the death of the mutant cell colonies, while the autotrophic somatic hybrids continued to grow. The hybrid character of the selected colonies was confirmed by isoenzyme investigations.