Extreme terahertz magnon multiplication induced by resonant magnetic pulse pairs

Nonlinear interactions of spin-waves and their quanta, magnons, have emerged as prominent candidates for interference-based technology, ranging from quantum transduction to antiferromagnetic spintronics. Yet magnon multiplication in the terahertz (THz) spectral region represents a major challenge. Intense, resonant magnetic fields from THz pulse-pairs with controllable phases and amplitudes enable high order THz magnon multiplication, distinct from non-resonant nonlinearities such as the high harmonic generation by below-band gap electric fields. Here, we demonstrate exceptionally high-order THz nonlinear magnonics. It manifests as 7th-order spin-wave-mixing and 6th harmonic magnon generation in an antiferromagnetic orthoferrite. We use THz two-dimensional coherent spectroscopy to achieve high-sensitivity detection of nonlinear magnon interactions up to six-magnon quanta in strongly-driven many-magnon correlated states. The high-order magnon multiplication, supported by classical and quantum spin simulations, elucidates the significance of four-fold magnetic anisotropy and Dzyaloshinskii-Moriya symmetry breaking. Moreover, our results shed light on the potential quantum fluctuation properties inherent in nonlinear magnons.

First-in-Human Phase I Trial Combining Biologically Guided Radioimmunotherapy (RIT) Using a 90Y-Anti-CD25 Monoclonal Antibody (Mab) with CT-guided Total Marrow and Lymphoid Irradiation (TMLI) in Relapsed and Refractory (R/R) Acute Leukemia

PURPOSE/OBJECTIVE(S)

Patients with R/R acute leukemia after allogeneic hematopoietic cell transplant (alloHCT) have a dismal prognosis with 3-year survival rates of < 20%. To improve outcomes, innovative targeted forms of organ sparing radiotherapy, such as tumor-specific RIT and TMLI, are needed to dose escalate with acceptable toxicities, especially in patients ≥ age 60 years who cannot tolerate total body irradiation (TBI) / myeloablative regimens and who have a poor prognosis. CD25 is an ideal RIT target given its expression in acute leukemias, association with poor prognosis, and expression by leukemia stem cells. In this phase I trial (NCT05139004) we hypothesized that combining dose escalated 90Y-anti-CD25 RIT with fixed dose TMLI 12 Gy, fludarabine (flu), and melphalan (mel) in patients with R/R disease is safe and associated with acceptable toxicities.

MATERIALS/METHODS

The primary objective of this trial is to determine the maximum tolerated dose and recommended phase 2 dose of 90Y-anti-CD25 Mab (Day -15) with 12 Gy TMLI (1.5 Gy twice a day, days -8 to -5), flu (30 mg/m2/d days -5 to -2), and mel (100 mg/m2, day -2) in patients ≥ 60 years old or with a HCT-comorbidity index ≥ 2 and with R/R AML, ALL or myelodysplastic syndrome (MDS) scheduled to undergo alloHCT from a matched donor. TMLI mean organ dose constraints for kidney, lung and liver were 4 Gy. Planned dose levels of 90Y-anti-CD25 were 0.3, 0.4, and 0.5 mCi/kg. 111In-anti-CD25 (5 mCi) was co-infused followed by serial nuclear scans to assess dosimetry and biodistribution.

RESULTS

To date 5 patients (ages 31-74) with R/R AML have been treated. Marrow and circulating blasts ranged from 10-36% and 9-44%, respectively. For the 3 patients at 0.3 mCi/kg, follow-up ranged from 89-191+ days. 90Y/111In-anti-CD25 nuclear scans demonstrated persistent uptake in bone out to 144 hours, which was associated with a decline in circulating blasts. After combined RIT and TMLI, mean doses (Gy) to lungs ranged from 5.7-6.5, to kidneys from 7.5-8.2 and to liver from 7.2-11.6. No dose-limiting toxicities (DLT) were observed. All 3 patients achieved CR on day +30 bone marrow biopsies and 2 remained in CR on day +90 biopsies. Two patients have recently been treated at the 0.4 mCi/kg dose level. The results of patients treated at the higher dose levels will be provided.

CONCLUSION

Dose escalation by adding 90Y-anti-CD25 RIT at 0.3 mCi/kg to 12 Gy TMLI was safe, including in older patients, with no dose-limiting toxicities, mean critical organ doses lower than conventional myeloablative TBI, and encouraging response rates. The toxicity profile and dose estimates at 0.3 mCi/kg predict that the planned higher dose levels will also be feasible with acceptable toxicities. RIT and TMLI are complementary and when combined address the limitations of each modality. Combining these targeted therapies may be a superior strategy to intensify dose to leukemia compared to dose escalation of either modality alone.

Protective effect of Mucuna pruriens (L.) DC. var. pruriens seed extract on apoptotic germ cells in ethanolic male rats

Thai Mucuna pruriens (L.) DC. var pruriens (T-MP) seed containing levodopa (L-DOPA) and antioxidant capacity has been shown to improve sexual behavior and male reproductive parameters in rats treated with ethanol (Eth). However, its protective effect on testicular apoptotic germ cells has never been reported. This study aimed to investigate the potential effects of T-MP seed extract on expressions of caspase, proliferating cell nuclear antigen (PCNA), and dopamine D2 receptor (D2R) proteins in Eth rats. Thirty-six male Wistar rats were divided into four groups (9 animals/group), including control, Eth, T-MP150+Eth, and T-MP300+Eth, respectively. Control rats received distilled water, and Eth rats received Eth (3g/kg BW; 40%v/v). The T-MP groups were treated with T-MP seed extract at a dose of 150 or 300 mg/kg before Eth administration for 56 consecutive days. The results showed that the seminiferous tubule diameter and epithelial height were significantly increased in both T-MP treated groups compared to the Eth group. Additionally, the caspase-9 and -3, and PCNA expressions were decreased, but D2R expression was markedly increased in T-MP groups. It was concluded that T-MP seed extract could protect testicular apoptosis induced by Eth via changes in caspase, PCNA, and D2R protein expressions.

Abstract 2409: A synergistic effect of miR-21-5p inhibitor and PARP1 inhibitor to enhance the radiosensitivity of oral squamous cell carcinoma

Radiotherapy is one of the standard treatments for oral squamous cell carcinoma (OSCC). Radiotherapy damages cancer cells mainly by inducing DNA double-strand breaks, but some advanced OSCC can effectively repair DNA damages, resulting in radiotherapy resistance. TCGA data showed that miR-21-5p was highly expressed in advanced OSCC and correlated with prognosis. However, the involvement of miR-21-5p in OSCC’s response to radiotherapy and the underlying mechanism are still unclear. When treated with a miR-21-5p inhibitor, we found OSCC cell lines (SAS and CAL33) became more sensitive to X-ray radiation at 2Gy (the commonly used single-dose in conventional radiotherapy), which was supported by the evidence that more resident 53BP1-marked-foci for non-repaired DNA double strand breaks (1.61±0.54 folder more in SAS, 1.47±0.49 folder more in CAL33, n=4, p&lt;0.05) and less colony-forming capacity (14.62±2.36% in SAS, 18.65±4.32% in CAL33, n=3, p&lt;0.05) than untreated control cells were observed at 24hr after radiation. However, the expression of PARP1, a DNA damage sensor for recognizing DNA damage and facilitating DNA repair, was significantly increased (1.38±0.12, n=4, p&lt;0.05) in SAS cells treated with miR-21-5p inhibitor. In order to achieve a better tumor control, we tested the combined treatments with miR-21-5p inhibitor and PARP1 inhibitor (Olaparib) on SAS cells, which resulted in a synergistic effect in inhibition of the repair of DNA double strand breaks. The residual 53BP1 foci after 2Gy X-ray irradiation was increased 1.45±0.06 folder more when inhibiting both miR-21-5p and PARP1, while the colony-forming capacity of irradiated SAS cells was decreased by 39.55±5.89% (p&lt;0.0001) in the same conditions. This work provided novel insights on the molecular mechanism of miR-21-5p regulated cell response to radiotherapy, which may give rise to potential therapeutic strategy for treatment of advanced OSCC.

Citation Format: Lin Ma, Weitao Hu, Rui Fu, Anhui Wu, Qiangyong Deng, Qi Liu. A synergistic effect of miR-21-5p inhibitor and PARP1 inhibitor to enhance the radiosensitivity of oral squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2409.

Incidence and risk factors for major bleeding events in atrial fibrillation patients on direct oral anticoagulant therapy: data from the National Patient-Centered Clinical Research Network

Background

Direct oral anticoagulation (DOACs) prevent stroke in patients with atrial fibrillation (AF) and have a superior safety profile compared with vitamin K antagonists (VKA). Yet, better definition of incidence and risk factors for major bleeding associated with DOACs in clinical practice may be important given emerging stroke prevention technologies, both pharmacologic and nonpharmacologic.

Purpose

To describe the incidence of and risk factors for major bleeding in individuals with AF on DOAC therapy.

Methods

We reviewed electronic health record data for two patient cohorts with AF prescribed DOACs: (1) Duke University Health System (DUHS) (2010–2018) and (2) Sites within the Patient-Centered Clinical Research Network (PCORnet) (2015–2019) which had ≥6 years assimilated data from both inpatient and outpatient encounters (7 sites). In each cohort, we assessed the 5-year incidence of major bleeding events defined as hospitalization for intracranial hemorrhage, or hospitalization for gastro-intestinal bleeding or procedure to control bleeding accompanied by transfusion within ±7 days or death within 30 days. Multivariable Fine-Gray proportional hazards modeling in each cohort was performed to evaluate independent risk factors for major bleeding on DOAC therapy.

Results

The cohorts included 10,625 patients (DUHS) and 58,321 patients (PCORnet) with AF. Major bleeding events occurred within 5 years of diagnosis in 639 (7.9%) of DUHS patients and 2568 (6.6%) of PCORnet patients (Table 1). The DUHS model predicted time to first major bleeding event with a C-index of 0.756 (95% CI 0.737, 0.775) and the PCORNet model had a c-index of 0.745 (0.736, 0.755) (Table 2). Independent factors associated with major bleeding consistent across both models (p&lt;0.001 in PCORnet for all unless noted) were higher CHA2DS2-VASc scores, lower eGFR, anemia (HR per 1-point increase in hemoglobin up to 12 g/dL 0.79 [0.76, 0.82]), prior major bleeding (HR 2.70 [2.22, 3.30]), cancer (HR 1.23 [1.12, 1.36]), recent cardiac surgery (HR 0.70 [0.51, 0.97]; p=0.030), alcohol use (HR 1.56 [1.29, 1.88]), aspirin use (HR 1.44 [1.32, 1.57]), and selective serotonin reuptake inhibitor use (HR 1.30 [1.19, 1.42]).

Conclusions

Across a large and geographically diverse contemporary population, risk of bleeding on DOAC for stroke prevention in AF remains a frequent and important clinical problem. There is an unmet need for stroke prevention therapies with improved safety profiles. We identified risk factors for major bleeding events on DOAC therapy, some of which are not represented in traditional risk scores, which may inform shared decision making for stroke prevention.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Bayer Pharmaceuticals

Reduced dose, but not reduced risk: rates of inappropriate apixaban dose reduction and stroke and bleeding incidence

Introduction

Patients with atrial fibrillation (AF) should be prescribed standard-dose (5mg twice daily) apixaban for stroke prevention unless they meet 2 or more criteria: age ≥80, weight ≤60kg, and/or creatinine ≤1.5mg/dL, in which case a reduced-dose (2.5mg twice daily) is indicated. Despite this, some clinicians may also prescribe reduced-dose apixaban to patients who do not meet criteria for dose reduction, in an effort to reduce bleeding risk.

Purpose

To assess apixaban prescribing patterns in patients with AF based on dose reduction criteria and to characterize baseline demographics and incidence of ischemic stroke, major bleeding, and intracranial hemorrhage (ICH) for patients stratified by standard-dose, appropriately reduced-dose, and inappropriately reduced-dose apixaban.

Methods

Using pooled data from 8 large hospitals in PCORnet, a multicenter national healthcare research network, we assessed the standard and reduced-dose apixaban prescribing patterns for patients with AF, with additional stratification of patients prescribed 2.5mg based on presence or absence of 2+ criteria for dose reduction. We then assessed baseline characteristics and 5-year event rate of ischemic stroke, major bleeding, ICH and death.

Results

Of 45,947 patients with AF on apixaban and available dosing information, 38,861 (85%) were prescribed apixaban 5mg and 7086 (15%) were prescribed 2.5mg. Of patients prescribed apixaban 2.5mg, 4321 (61%) did not meet criteria for dose reduction. Patients on reduced dose apixaban were more likely to be female and have comorbidities such as heart failure, hypertension, and prior ischemic stroke. These trends were more pronounced for patients meeting dose adjustment criteria than those not meeting criteria (Table 1).

Unadjusted analyses found patients on 2.5mg of apixaban were significantly more likely to experience ischemic stroke, major bleeding, and all-cause death. Patients with 2+ dose reduction criteria on 2.5mg of apixaban had the highest rates of each event, but patients who were prescribed reduced dose without meeting criteria were also at elevated risk (Table 2).

Conclusion

Many patients prescribed reduced-dose apixaban do not meet criteria for dose reduction. Because patients prescribed reduced dose apixaban are older and have more cardiovascular risk factors, their incidence of stroke, major bleeding, and death exceeds that of full dose treated patients. These risks exist both for patients who do and do not meet criteria for dose reduction, suggesting potential under-treatment for the majority of dose-reduced patients.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Bayer

An evaluation of the outcome metric 'days alive and at home' in older patients after hip fracture surgery

'Days alive and at home' is a validated measure that estimates the time spent at home, defined as the place of residence before admission to hospital. We evaluated this metric in older adults after hip fracture surgery and assessed two follow-up durations, 30 and 90 days. Patients aged ≥ 70 years who underwent hip fracture surgery were identified retrospectively via hospital admission and government mortality records. Patients who successfully returned home and were still alive within 90 days of surgery were distinguished from those who were not. Regression models were used to examine which variables were associated with failure to return home and number of days at home among those who did return, within 90 days of surgery. We analysed the records of 825 patients. Median (IQR [range]) number of days at home within 90 days (n = 788) was 54 (0-76 [0-88]) days and within 30 days (n = 797) it was 2 (0-21 [0-28]) days. Out of these, 274 (35%) patients did not return home within 90 days and 374 (47%) within 30 days after surgery. Known peri-operative risk-factors such as older age, pre-operative anaemia and postoperative acute renal impairment were associated with failure to return home. This study supports days alive and at home as a useful patient-centred outcome measure in older adults after hip fracture surgery. We recommend that this metric should be used in clinical trials and measured at 90, rather than 30, postoperative days. As nearly half of this patient population did not return home within 30 days, the shorter time-period catches fewer meaningful events.

Senolytic agent Quercetin ameliorates intervertebral disc degeneration via the Nrf2/NF-κB axis

OBJECTIVE

Intervertebral disc degeneration (IDD) represents major cause of low back pain. Quercetin (QUE) is one of the approved senolytic agents. In this study, we evaluated the protective effects of QUE on IDD development and its underlying mechanism.

METHODS

Effects of senolytic agent QUE on the viability of nucleus pulposus cells (NPCs) were measured by CCK-8 assays and EdU staining. The senescence associated secreted phenotype (SASP) factors expressions were measured by qPCR, western blot, and ELISA; and NF-κB pathway was detected by immunofluorescence and western blot. Molecular docking was applied to predict the interacting protein of QUE; while Nrf2 was knocked down by siRNAs to confirm its role in QUE regulated senescence phenotype. X-ray, MRI, Hematoxylin-Eosin and Safranin O-Fast green staining were performed to evaluate the therapeutic effects of QUE on IDD in the puncture-induced rat model.

RESULTS

In in vitro experiments, QUE inhibited SASP factors expression and senescence phenotype in IL-1β-treated NPCs. Mechanistically, QUE suppressed IL-1β induced activation of the NF-κB pathway cascades; it was also demonstrated in molecular docking and knock down studies that QUE might bind to Keap1-Nrf2 complex to suppress NF-κB pathway. In vivo, QUE ameliorated the IDD process in the puncture-induced rat model.

CONCLUSIONS

Together the present work suggests that QUE inhibits SASP factors expression and senescence phenotype in NPCs and ameliorates the progression of IDD via the Nrf2/NF-κB axis, which supports senolytic agent QUE as a potential therapeutic agent for the treatment of IDD.

Time-to-Maximum of the Tissue Residue Function Improves Diagnostic Performance for Detecting Distal Vessel Occlusions on CT Angiography

BACKGROUND AND PURPOSE

Detecting intracranial distal arterial occlusions on CTA is challenging but increasingly relevant to clinical decision-making. Our purpose was to determine whether the use of CTP-derived time-to-maximum of the tissue residue function maps improves diagnostic performance for detecting these occlusions.

MATERIALS AND METHODS

Seventy consecutive patients with a distal arterial occlusion and 70 randomly selected controls who underwent multimodal CT with CTA and CTP for a suspected acute ischemic stroke were included in this retrospective study. Four readers with different levels of experience independently read the CTAs in 2 separate sessions, with and without time-to-maximum of the tissue residue function maps, recording the presence or absence of an occlusion, diagnostic confidence, and interpretation time. Accuracy for detecting distal occlusions was assessed using receiver operating characteristic analysis, and areas under curves were compared to assess whether accuracy improved with use of time-to-maximum of the tissue residue function. Changes in diagnostic confidence and interpretation time were assessed using the Wilcoxon signed rank test.

RESULTS

Mean sensitivity for detecting occlusions on CTA increased from 70.7% to 90.4% with use of time-to-maximum of the tissue residue function maps. Diagnostic accuracy improved significantly for the 4 readers (P < .001), with areas under the receiver operating characteristic curves increasing by 0.186, 0.136, 0.114, and 0.121, respectively. Diagnostic confidence and speed also significantly increased.

CONCLUSIONS

All assessed metrics of diagnostic performance for detecting distal arterial occlusions improved with the use of time-to-maximum of the tissue residue function maps, encouraging their use to aid in interpretation of CTA by both experienced and inexperienced readers. These findings show the added diagnostic value of including CTP in the acute stroke imaging protocol.

Burden of pneumococcal disease: 8-year retrospective analysis from a single centre in Hong Kong

PURPOSE

Streptococcus pneumoniae is a common pathogen involved in community-acquired pneumonia. Invasive pneumococcal disease is often associated with higher co-morbidity rates, but mortality-related findings have been inconclusive. This study investigated predictors of 30-day mortality and invasive pneumococcal disease.

METHODS

This retrospective analysis included adults with pneumococcal disease who were admitted to Pamela Youde Nethersole Eastern Hospital from 1 January 2011 to 31 December 2018. Demographics, microbiological characteristics, and outcomes were compared between 30-day survivors and non-survivors, and between patients with invasive disease and those with non-invasive disease. Intensive care unit (ICU) subgroup analysis was performed. The primary outcome was 30-day all-cause mortality; secondary outcomes were ICU and hospital mortalities, and ICU and hospital lengths of stay.

RESULTS

In total, 792 patients had pneumococcal disease; 701 survived and 91 (11.5%) died within 30 days. Notably, 106 (13.4%) patients had invasive pneumococcal disease and 170 (21.5%) patients received intensive care. Vasopressor use (odds ratio [OR]=4.96, P<0.001), chronic kidney disease (OR=3.62, P<0.001), positive urinary antigen test results (OR=2.57, P=0.001), and advanced age (OR=2.19, P=0.010) were independent predictors for 30-day mortality by logistic regression analysis. Among critically ill patients, chronic kidney disease (OR=4.64, P<0.001), higher APACHE IV score (OR=3.73, P=0.016), and positive urinary antigen test results (OR=2.94, P=0.008) were predictors for 30-day mortality. Logistic regression analysis revealed that chronic kidney disease (OR=3.10, P<0.001) was a risk factor for invasive pneumococcal disease.

CONCLUSION

Advanced age, vasopressor use, chronic kidney disease, and positive urinary antigen test results were independent predictors for 30-day mortality in patients with pneumococcal disease.

Liquid Chromatographic Determination of Major Organic Acids in Apple Juice and Cranberry Juice Cocktail: Collaborative Study

Twelve laboratories collaboratively studied a liquid chromatographic method for determination of quinic, malic, and citric acids in cranberry juice cocktail and apple juice. Samples are passed through a disposable silica cartridge, filtered, and directly injected into the chromatograph. The mobile phase is 0.2M KH2PO4 (pH 2.4). Two reverse phase columns are used, with UV detection at 214 nm. Six samples of cranberry juice cocktail and 6 samples of apple juice were sent to each collaborator. Repeatability and reproducibility coefficients of variation ranged from 1.2 to 7.6% and from 2.9 to 14.7%, respectively, for quinic, malic, and citric acid levels above 0.10%. The precision of the method is satisfactory. The method has been adopted official first action.

Imaging of spindle cell lipoma

AIM

To review the evaluation, diagnosis, and treatment of spindle cell lipoma (SCL) with emphasis on the location of these tumours and the spectrum of magnetic resonance imaging (MRI) and computed tomography (CT) appearances.

MATERIALS AND METHODS

The MRI and CT findings of 27 histopathologically proven SCLs were evaluated retrospectively. Imaging features evaluated included margins, percentage visible fat, MRI signal characteristics, oedema, and contrast enhancement patterns.

RESULTS

Patient ages ranged from 18 to 80 years with an average age of 56.5 years. Men were affected twice as frequently as women (M=18, F=9). SCLs ranged in size from 2 to 10 cm, with an average greatest dimension of 5.5 cm. Five lesions (19%) contained no visible fat on CT or MRI, and the leading differential diagnosis of high-grade soft-tissue sarcoma diagnosis was suggested by referring surgeons. Five lesions (19%) had <50% fatty areas, nine lesions (52%) demonstrated >50% but <90% fat at MRI or CT. Only three of 25 lesions (12%) had an appearance of a typical lipoma on unenhanced MRI sequences. All SCLs that were imaged with contrast medium (n = 18) demonstrated some degree of enhancement, with eight (44%) showing marked enhancement, four (22%) showing moderate, and six (33%) minimal enhancement.

CONCLUSION

SCLs have considerably variable imaging appearances and may have minimal or no visible fat at MRI or CT. Imaging features may make it difficult to distinguish this benign tumour from a potentially higher-grade malignant tumour.

ABCA1 transporter reduces amphotericin B cytotoxicity in mammalian cells

Amphotericin B (AmB) belongs to a group of polyene antibiotics commonly used in the treatment of systemic mycotic infections. A widely accepted mechanism of action of AmB is based on the formation of an oligomeric pore structure within the plasma membrane (PM) by interaction with membrane sterols. Although AmB binds preferentially to ergosterol, it can also bind to cholesterol in the mammalian PM and cause severe cellular toxicity. The lipid content and its lateral organization at the cell PM appear to be significant for AmB binding. Several ATP-binding cassette (ABC) transporters, including ABCA1, play a crucial role in lipid translocation, cholesterol redistribution and efflux. Here, we demonstrate that cells expressing ABCA1 are more resistant to AmB treatment, while cells lacking ABCA1 expression or expressing non-active ABCA1MM mutant display increased sensitivity. Further, a FLIM analysis of AmB-treated cells reveals a fraction of the antibiotic molecules, characterized by relatively high fluorescence lifetimes (> 6 ns), involved in formation of bulk cholesterol-AmB structures at the surface of ABCA1-expressing cells. Finally, lowering the cellular cholesterol content abolishes resistance of ABCA1-expressing cells to AmB. Therefore, we propose that ABCA1-mediated cholesterol efflux from cells induces formation of bulk cholesterol-AmB structures at the cell surface, preventing AmB cytotoxicity.

Autoregulation of RCO by Low-Affinity Binding Modulates Cytokinin Action and Shapes Leaf Diversity

Mechanisms through which the evolution of gene regulation causes morphological diversity are largely unclear. The tremendous shape variation among plant leaves offers attractive opportunities to address this question. In cruciferous plants, the REDUCED COMPLEXITY (RCO) homeodomain protein evolved via gene duplication and acquired a novel expression domain that contributed to leaf shape diversity. However, the molecular pathways through which RCO regulates leaf growth are unknown. A key question is to identify genome-wide transcriptional targets of RCO and the DNA sequences to which RCO binds. We investigate this question using Cardamine hirsuta, which has complex leaves, and its relative Arabidopsis thaliana, which evolved simple leaves through loss of RCO. We demonstrate that RCO directly regulates genes controlling homeostasis of the hormone cytokinin to repress growth at the leaf base. Elevating cytokinin signaling in the RCO expression domain is sufficient to both transform A. thaliana simple leaves into complex ones and partially bypass the requirement for RCO in C. hirsuta complex leaf development. We also identify RCO as its own target gene. RCO directly represses its own transcription via an array of low-affinity binding sites, which evolved after RCO duplicated from its progenitor sequence. This autorepression is required to limit RCO expression. Thus, evolution of low-affinity binding sites created a negative autoregulatory loop that facilitated leaf shape evolution by defining RCO expression and fine-tuning cytokinin activity. In summary, we identify a transcriptional mechanism through which conflicts between novelty and pleiotropy are resolved during evolution and lead to morphological differences between species.

Neural stem cells promote glioblastoma formation in nude mice

PURPOSE

Neural stem cells (NSCs) have been characterized with the ability of self-renewal and neurogenesis, which has inspired lots of studies to clarify the functions of NSCs in neural injury, ischemic stroke, brain inflammation and neurodegenerative diseases. We focused on the relationship of NSCs with glioblastoma, since we have discovered that recurrent glioblastomas were inclined to be derived from subventricular zone (SVZ), where NSCs reside. We want to clarify whether NSCs are involved in glioblastoma relapse.

METHODS

Immunocytochemistry was used to confirm the stemness of NSCs. The Cell Counting Kit-8 was used to measure the proliferation of cells. Migration abilities were examined by wound healing and transwell assays, and tumor formation abilities were confirmed in nude mice.

RESULTS

We found in experiments that NSCs promoted proliferation of a glioblastoma cell line-Ln229, the migration ability of Ln229 cells was motivated by co-cultured with NSCs. Tumor formation of Ln229 cells was also accelerated in nude mice when co-transplanted with NSCs. In immunohistochemistry, we found that the Sox2- and Ki67-positive cells were much higher in co-transplanted groups than that of control groups.

CONCLUSIONS

These results imply the potential role that NSCs play in speeding up tumor formation in the process of glioblastoma relapse, providing the basis for dealing with newly diagnosed glioblastoma patients, which may help postpone the recurrence of glioblastoma as far as possible through preprocessing the tumor-adjacent SVZ tissue.

Early internationalization of students in a German medical school in the former German Democratic Republic

The growing influence and importance of internationalization in higher education, especially in medical education, inspired anatomists at Columbia University New York, USA and at the Martin Luther University Halle-Wittenberg, Germany, to start a novel international preclinical collaboration project. As part of the anatomy dissection course a group of volunteer medical students from Halle dissected selected areas of the human body with the help of an English, illustrated, iPad-run dissection script (American Dissector). Meanwhile the rest of the students worked with a traditional German text-based dissector. Additionally, participating German students were matched with US students, with whom they connected via video-conferencing and discussed subjects like differences between their health care systems, structure and content of the anatomy course and the differences in their medical education systems. Questionnaires were sent for feedback and checklists confirmed dissection findings. Results indicated that the American Dissector was successfully shared internationally. The majority (62%) found it easier to find structures using the American Dissector compared to the standard dissector and also 62% needed the atlas two times less when using the American Dissector. Furthermore, students enjoyed their interaction with their international peers and the vast majority (77%) wished there were more interactions like this in the medical curriculum. This publication describes an approach to embed internationalization in the preclinical medical curriculum based in the gross anatomy course in a German Medical school, located in East Germany. Considering its history as a former German Democratic Republic faculty this is a meaningful step towardglobalization of medical education in this part of Germany.

Hospitalisation of adults with Down syndrome: lesson from a 10-year experience from a community hospital

BACKGROUND

Life expectancy of individuals with Down syndrome (DS) has improved significantly over the past decades. However, there are sparse data documenting the co-morbidities and hospitalisation of adult patients with DS in the literature. The aim of this study was to characterise the co-morbidities and pattern of hospitalisation in adult patients with DS during a 10-year period at the community hospital as well as to compare hospitalisation parameters with the general adult population during the same years.

METHOD

We reviewed the medical records of 81 hospitalisations from 37 patients with DS aged 21 to 68 years at Metrowest Medical Center during a 10-year period and compared with those of the general adult population during the same time. Co-morbidities were also described.

RESULTS

Adults with DS had a mean age at admission of 48.6 ± 8.8 years with the median length of stay of 3 days (interquartile range 4 days). Male patients were hospitalised longer than female patients (mean 5.0 vs. 2.8 days; P < 0.05), and patients who lived at home were admitted at earlier ages than those who came from residential healthcare facility (mean 41.5 vs. 52.2 years; P < 0.001). The most common cause of hospitalisation was pneumonia/aspiration syndrome (29.6%), and the most common co-morbidity was gastroesophageal reflux disease (GERD)/dysphagia (70.3%). Presence of GERD/dysphagia or seizure disorder was significantly associated with multiple admission and readmission within 1 month (P < 0.05). The mortality rate was 4.9%, and the rate of intensive care unit admission was 8.6%.

CONCLUSIONS

Our cohort did not show statistically significant different hospitalisation parameters such as inpatient mortality and average length of stay when compared with general adult population hospitalised at the same years. The care of adult patients with DS presents challenges in internal medicine due to its unique co-morbid profile and signifies the importance of multidisciplinary approach. In order to improve the care of this patient population, their co-morbidities, particularly GERD/dysphagia and seizure disorder, should be optimally managed and comprehensively addressed when patients are hospitalised.