Longitudinal Cognitive Decline in Patients With Mild Cognitive Impairment or Dementia Due to Alzheimer's Disease

Sensitive cognitive assessments accurately detect and track cognitive decline in Alzheimer's disease. The Cogstate battery was used to measure cognitive change in cognitively normal participants and in individuals with mild cognitive impairment and mild Alzheimer's disease enrolled in the Australian Imaging, Biomarker and Lifestyle Rate of Change Substudy. Over 18 months, verbal episodic memory performance declined for mild cognitive impairment and mild Alzeheimer's disease groups when compared to cognitively normal participants. Frequent assessments of episodic memory may facilitate early detection of cognitive decline due to Alzheimer's disease.

Efficacy and safety of ivermectin for the treatment of COVID-19: a systematic review and meta-analysis

BACKGROUND

Ivermectin became a popular choice for COVID-19 treatment among clinicians and the public following encouraging results from pre-print trials and in vitro studies. Early reviews recommended the use of ivermectin based largely on non-peer-reviewed evidence, which may not be robust. This systematic review and meta-analysis assessed the efficacy and safety of ivermectin for treating COVID-19 based on peer-reviewed randomized controlled trials (RCTs) and observational studies (OSs).

METHODS

MEDLINE, EMBASE and PubMed were searched from 1 January 2020 to 1 September 2021 for relevant studies. Outcomes included time to viral clearance, duration of hospitalization, mortality, incidence of mechanical ventilation and incidence of adverse events. RoB2 and ROBINS-I were used to assess risk of bias. Random-effects meta-analyses were conducted. GRADE was used to evaluate quality of evidence.

RESULTS

Three OSs and 14 RCTs were included in the review. Most RCTs were rated as having some concerns in regards to risk of bias, while OSs were mainly rated as having a moderate risk of bias. Based on meta-analysis of RCTs, the use of ivermectin was not associated with reduction in time to viral clearance, duration of hospitalization, incidence of mortality and incidence of mechanical ventilation. Ivermectin did not significantly increase incidence of adverse events. Meta-analysis of OSs agrees with findings from RCT studies.

CONCLUSIONS

Based on very low to moderate quality of evidence, ivermectin was not efficacious at managing COVID-19. Its safety profile permits its use in trial settings to further clarify its role in COVID-19 treatment.

PROTOCOL REGISTRATION

The review was prospectively registered in PROSPERO (CRD42021275302).

Enhancing titre and production stability of paenibacillin from Paenibacillus polymyxa by sequential drug resistance screening

AIMS

Paenibacillin is a naturally biosynthesized antimicrobial lantibiotic peptide which is produced by wild-type Paenibacillus polymyxa OSY-DF in low but detectable levels. The aim was to increase paenibacillin titre and production consistency through sequential drug resistance screening.

METHODS AND RESULTS

Spontaneous mutants of P. polymyxa OSY-DF were isolated by subjecting the bacterium to two rounds of screening for resistance to rifampicin, which targets RNA polymerase, and gentamicin, which targets ribosomes. Changes in antimicrobial production of the mutants were monitored using a bioassay method. A spontaneous mutant, P. polymyxa OSY-EC, capable of producing high paenibacillin titre, was selected and compared phenotypically to the wild-type strain. The mutant was found to produce paenibacillin at five-fold higher titre than the wild type. The mutant constantly produced paenibacillin while the wild type produced the antimicrobial agent variably. Fourier transformation mid-infrared spectroscopy revealed an interclass distance of 6·4 between the wild type and the mutant strain, suggesting significant phenotypic change during the mutation.

CONCLUSIONS

P. polymyxa OSY-EC, a spontaneous mutant capable of consistent production of high paenibacillin titre, was isolated from the wild type after sequential screening on rationally selected antibiotics.

SIGNIFICANCE AND IMPACT OF THE STUDY

The study will help make paenibacillin available for large-scale testing by interested researchers and industries seeking applications that improve food safety and quality.

A method of assessing essential amino acid availability from microbial and ruminally undegraded protein in lactating dairy cows

The objective of this study was to extend a stable isotope-based assessment of AA absorption from rumen-degradable protein (RDP) sources to include determination of essential AA (EAA) availability from microbial protein (MCP). To demonstrate the technique, a study using a 2 × 2 factorial arrangement of treatments applied in a repeated 4 × 4 Latin square design was undertaken. Factors were high and low rumen-degradable protein and high and low starch. Twelve lactating cows were blocked into 3 groups according to days in milk and randomly assigned to the 4 treatment sequences. Each period was 14 d in length with 10 d of adaption followed by 4 d of ruminal infusions of ¹⁵N-labeled ammonium sulfate. On the last day of each period, a ¹³C-labeled AA mixture was infused into the jugular vein over a 6-h period to assess total AA entry. Rumen, blood, urine, and milk samples were collected during the infusions. Ruminal bacteria and blood samples were assessed for AA enrichment. Total plasma AA absorption rates were derived for 6 EAA from plasma ¹³C AA enrichment. Absorption of 6 EAA from MCP was calculated from total AA absorption based on ¹⁵N enrichment in blood and rumen bacteria. Essential AA absorption rates from total protein, MCP, and rumen-undegradable protein were derived with standard errors of the mean of 6, 14, and 14%, respectively. An average of 45% of absorbed EAA were from MCP, which varied among 6 EAA and was interactively affected by starch and RDP in diets. Microbial AA availability measured by isotope dilution method increased with the high RDP diets and was unaffected by starch level, except for Met, which decreased with high starch. Microbial protein outflow, estimated from urinary purine derivatives, increased with RDP and was not significantly affected by starch. This was consistent with measurements from the isotope dilution method. Total AA absorption rates measured from isotope dilution were similar to estimates from CNCPS (v. 6.55), but a lower proportion of absorbed AA was derived from MCP for the former method. Compared with the isotope and CNCPS estimates, the Fleming model underestimated microbial EAA and total EAA availability. An average of 58% of the absorbed EAA was converted into milk, which varied among individual AA and was interactively affected by starch and RDP in diets. The isotope dilution approach is advantageous because it provides estimates of EAA availability for individual EAA from rumen-undegradable protein and MCP directly with fewer errors of measurement than can be achieved with intestinal disappearance methods.

Online Learning of Gait Models From Older Adult Data

This paper proposes a novel approach for online, individualized gait analysis, based on an adaptive periodic model of any gait signal. The proposed method learns a model of the gait cycle during online measurement, using a continuous representation that can adapt to inter- and intra-personal variability by creating an individualized model. Once the algorithm has converged to the input signal, key gait events can be identified based on the estimated gait phase and amplitude. The approach is implemented and tested on retirement home resident 6 min walk (6MW) data using wearable accelerometers at the ankle. The proposed approach converges within approximately four gait cycles and achieves 3% error in detecting initial swing events.11 An early version of this work was presented in [1]. A more extensive description of related work and an extended method, including optimization of learning rates, were added to this paper. Further, this paper applies and evaluates the method to a new and much larger gait dataset taken from older adults who each have a variety of medical conditions. Therefore, the experimental protocol was also updated and the results are entirely novel.

Abstract P1-08-05: Type 2 diabetes and survival outcomes among a multi-ethnic cohort of breast cancer patients

BACKGROUND: With increasing prevalence of type 2 diabetes, it has become one of the common comorbidities among breast cancer patients. Few contemporary studies have examined the effect of preexisting diabetes on survival outcomes in breast cancer patients. Furthermore, both breast cancer mortality and diabetes prevalence are higher in African American women compared to Caucasian women, yet data on whether diabetes can explain racial disparity in breast cancer mortality is scarce.

OBJECTIVE: To compare clinopathological characteristics and survival outcomes between breast cancer patients with and without co-existing diabetes, and to explore the contribution of diabetes to breast cancer survival differences between African Americans and Caucasians.

METHODS: We analyzed data from the Chicago Multiethnic Epidemiologic Breast Cancer Cohort (ChiMEC) comprising of 3170 histologically confirmed breast cancer patients diagnosed between 2004 and 2017. The cohort consists of 55% Caucasians, 38% African Americans, and 7% other ethnicities. Cox models were used to analyze data on several clinical outcomes.

Table 1 Unadjusted HR (95% CI)pAdjusted HR (95% CI)*pAll-cause mortality2.20 (1.65-2.92)<0.0011.79 (1.33-2.43<0.001Breast Cancer-specific mortality1.61 (1.06-2.44)0.0251.97 (1.27-3.05)0.002Non-breast cancer mortality3.14 (2.11-4.69)<0.0011.62 (1.06-2.47)0.025Time to recurrence1.18 (0.76-1.85)0.461.41 (0.89-2.25)0.15Recurrence-free survival1.73 (1.32-2.26)<0.0011.68 (1.27-2.22)<0.001*Adjusted for age, race, stage, hormone therapy, and chemotherapy

RESULTS: 245 patients (8%) in the cohort had co-existing diabetes at time of breast cancer diagnosis, with African Americans having highest prevalence (14%). Patients with diabetes were older (mean 66 vs. 56 years old) and had higher proportion of obesity (67% vs. 34%) and Charlson comorbidity index >2 (27% vs. 10%) than those without diabetes. The two groups were similar in terms of surgery, radiation, and hormonal therapy received, while patients with diabetes had slightly more advanced stage (15% vs. 10%). After adjusting for multiple prognostic factors, patients with diabetes had a 97% higher risk of dying from breast cancer and a 62% fold higher risk dying from other causes than patients without diabetes (Table). The two groups had no significant difference in risk of recurrence. In addition, the hazard ratio (HR) comparing African Americans with Caucasians was 2.35 (95% confidence interval [CI] 1.90-2.91), and it changed to 2.19 (95% CI 1.76-2.33) after the adjustment for diabetes.

CONCLUSIONS: Pre-existing diabetes among breast cancer patients was associated with higher risk of breast cancer specific and all-cause mortality. About 11% of racial disparities in breast cancer mortality could be attributed to higher difference in diabetes prevalence in African American patients. Further research investigating how pre-existing diabetes may influence breast cancer treatment and survival are warranted.

Citation Format: Neerukonda AR, Olopade OI, Huang E, Huo D. Type 2 diabetes and survival outcomes among a multi-ethnic cohort of breast cancer patients [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-08-05.

Radiocarbon constraints on the glacial ocean circulation and its impact on atmospheric CO2

While the ocean’s large-scale overturning circulation is thought to have been significantly different under the climatic conditions of the Last Glacial Maximum (LGM), the exact nature of the glacial circulation and its implications for global carbon cycling continue to be debated. Here we use a global array of ocean–atmosphere radiocarbon disequilibrium estimates to demonstrate a ∼689±53 ¹⁴C-yr increase in the average residence time of carbon in the deep ocean at the LGM. A predominantly southern-sourced abyssal overturning limb that was more isolated from its shallower northern counterparts is interpreted to have extended from the Southern Ocean, producing a widespread radiocarbon age maximum at mid-depths and depriving the deep ocean of a fast escape route for accumulating respired carbon. While the exact magnitude of the resulting carbon cycle impacts remains to be confirmed, the radiocarbon data suggest an increase in the efficiency of the biological carbon pump that could have accounted for as much as half of the glacial–interglacial CO₂ change.

Establishing the efficiency of the biological carbon pump is needed to constrain the impact of ocean circulation on the carbon cycle. Here, the authors compile a global array of ocean–atmosphere radiocarbon disequilibrium estimates and evaluate the strength of the carbon pump over the last glacial maximum.

Increased Frequency of BK Virus-Specific Polyfunctional CD8+ T Cells Predict Successful Control of BK Viremia After Kidney Transplantation

BACKGROUND

BK virus infection remains an important cause of loss of allograft function after kidney transplantation. We sought to determine whether polyfunctional T cells secreting multiple cytokines simultaneously, which have been shown to be associated with viral control, could be detected early after start of BK viremia, which would provide insight into the mechanism of successful antiviral control.

METHODS

Peripheral blood mononuclear cells collected during episodes of BK viral replication were evaluated by multiparameter flow cytometry after stimulation by overlapping peptide pools of BK virus antigen to determine frequency of CD8+ and CD4+ T cells expressing 1 or more cytokines simultaneously, as well as markers of T-cell activation, exhaustion, and maturation.

RESULTS

BK virus controllers, defined as those with episodes of BK viremia of 3 months or less, had an 11-fold increase in frequency of CD8+ polyfunctional T cells expressing multiple cytokines, as compared with patients with prolonged episodes of BK viremia. Patients with only low level BK viremia expressed low frequencies of polyfunctional T cells. Polyfunctional T cells were predominantly of the effector memory maturation subtype and expressed the cytotoxicity marker CD107a.

CONCLUSIONS

Noninvasive techniques for immune assessment of peripheral blood can provide insight into the mechanism of control of BK virus replication and may allow for future patient risk stratification and customization of immune suppression at the onset of BK viremia.

Application of Hyperbranched Block Copolymers as Templates for the Generation of Nanoporous Organosilicates

A general route to organic–inorganic hybrids with nanophase morphologies has been elaborated with the objective of ultimately generating nanoporosity in organosilicates. Hyperbranched block copolymers prepared by either the sequential or concurrent polymerization of an ABC monomer ( γ-( ∊-caprolactone) 2-bromo-2-dimethylpropionate) with a BCD monomer (2-hydroxyethyl methacrylate) were used as the macromolecular templates. The two monomers, each polymerizing by different chemistries, for example ring-opening polymerization and atom transfer radical polymerization, bear initiating centres that are targeted for the functionality located on the accompanying monomer. Consequentially, a branched polymer is obtained which avoids the traditional multistep procedures. The branching density was altered simply by the addition of the appropriate AB ( ∊-caprolactone) and/or CD (methyl methacrylate) comonomers. These polymers were readily soluble initially in the organosilicate prepolymer (methyl silsesquioxane), however, upon the onset of crosslinking, both the solubility parameters and molecular weight of the organosilicate (polymethylsilsesquioxane) change, causing the hyperbranched polymer to phase separate by a nucleation and growth process. The organic polymer was selectively removed by thermolysis, producing a nanoporous inorganic structure. The size and shape of the pores are identical to those of the initial hybrid morphology. A significant reduction in the dielectric constant was achieved by simply replacing a portion of the glass matrix with air, which has a dielectric constant of 1.0.

Exosomes from CIITA-transfected CT26 cells enhance anti- tumor effects

AIM

To study anti-tumor effects of exosomes from class II transactivator (CIITA) gene transfected CT26 cells.

METHODS

In this study, we established an MHC class II molecule-expressing murine colon cancer cell line (CT26-CIITA) by transduction of the CIITA gene. Immune effects in vitro and tumor protective results in vivo were tested and monitored.

RESULTS

Exosomes from CT26-CIITA cells were found to contain a high level of MHC class II protein. When loaded on dendritic cells (DCs), exosomes from CT26-CIITA cells significantly increased expression of MHC class II molecules, CD86 and CD80, as compared to exosomes from CT26 cells. In vitro assays using co-culture of immunized splenocytes and exosome-loaded DCs demonstrated that CIITA- Exo enhanced splenocyte proliferation and IFN-γ production of CD4+T cells, while inhibiting IL-10 secretion. In addition, compared to exosomes from CT26 cells, CT26-CIITA-derived exosomes induced higher TNF-α and IL-12 mRNA levels. A mouse tumour preventive model showed that CT26-CIITA derived exosomes significantly inhibited tumour growth in a dose-dependent manner and significantly prolonged the survival time of tumour- bearing mice.

CONCLUSION

Our findings indicate that CT26-CIITA-released exosomes are more efficient to induce anti-tumour immune responses, suggesting a potential role of MHC class II-containing tumour exosomes as cancer vaccine candidates.

Photoinduced doping in heterostructures of graphene and boron nitride

The design of stacks of layered materials in which adjacent layers interact by van der Waals forces has enabled the combination of various two-dimensional crystals with different electrical, optical and mechanical properties as well as the emergence of novel physical phenomena and device functionality. Here, we report photoinduced doping in van der Waals heterostructures consisting of graphene and boron nitride layers. It enables flexible and repeatable writing and erasing of charge doping in graphene with visible light. We demonstrate that this photoinduced doping maintains the high carrier mobility of the graphene/boron nitride heterostructure, thus resembling the modulation doping technique used in semiconductor heterojunctions, and can be used to generate spatially varying doping profiles such as p-n junctions. We show that this photoinduced doping arises from microscopically coupled optical and electrical responses of graphene/boron nitride heterostructures, including optical excitation of defect transitions in boron nitride, electrical transport in graphene, and charge transfer between boron nitride and graphene.