Timing of Biomarker Changes in Sporadic Alzheimer's Disease in Estimated Years from Symptom Onset

OBJECTIVE

A clock relating amyloid positron emission tomography (PET) to time was used to estimate the timing of biomarker changes in sporadic Alzheimer disease (AD).

METHODS

Research participants were included who underwent cerebrospinal fluid (CSF) collection within 2 years of amyloid PET. The ages at amyloid onset and AD symptom onset were estimated for each individual. The timing of change for plasma, CSF, imaging, and cognitive measures was calculated by comparing restricted cubic splines of cross-sectional data from the amyloid PET positive and negative groups.

RESULTS

The amyloid PET positive sub-cohort (n = 118) had an average age of 70.4 ± 7.4 years (mean ± standard deviation) and 16% were cognitively impaired. The amyloid PET negative sub-cohort (n = 277) included individuals with low levels of amyloid plaque burden at all scans who were cognitively unimpaired at the time of the scans. Biomarker changes were detected 15-19 years before estimated symptom onset for CSF Aβ42/Aβ40, plasma Aβ42/Aβ40, CSF pT217/T217, and amyloid PET; 12-14 years before estimated symptom onset for plasma pT217/T217, CSF neurogranin, CSF SNAP-25, CSF sTREM2, plasma GFAP, and plasma NfL; and 7-9 years before estimated symptom onset for CSF pT205/T205, CSF YKL-40, hippocampal volumes, and cognitive measures.

INTERPRETATION

The use of an amyloid clock enabled visualization and analysis of biomarker changes as a function of estimated years from symptom onset in sporadic AD. This study demonstrates that estimated years from symptom onset based on an amyloid clock can be used as a continuous staging measure for sporadic AD and aligns with findings in autosomal dominant AD. ANN NEUROL 2024;95:951-965.

Clinical validation of the PrecivityAD2 blood test: A mass spectrometry-based test with algorithm combining %p-tau217 and Aβ42/40 ratio to identify presence of brain amyloid

BACKGROUND

With the availability of disease-modifying therapies for Alzheimer's disease (AD), it is important for clinicians to have tests to aid in AD diagnosis, especially when the presence of amyloid pathology is a criterion for receiving treatment.

METHODS

High-throughput, mass spectrometry-based assays were used to measure %p-tau217 and amyloid beta (Aβ)42/40 ratio in blood samples from 583 individuals with suspected AD (53% positron emission tomography [PET] positive by Centiloid > 25). An algorithm (PrecivityAD2 test) was developed using these plasma biomarkers to identify brain amyloidosis by PET.

RESULTS

The area under the receiver operating characteristic curve (AUC-ROC) for %p-tau217 (0.94) was statistically significantly higher than that for p-tau217 concentration (0.91). The AUC-ROC for the PrecivityAD2 test output, the Amyloid Probability Score 2, was 0.94, yielding 88% agreement with amyloid PET. Diagnostic performance of the APS2 was similar by ethnicity, sex, age, and apoE4 status.

DISCUSSION

The PrecivityAD2 blood test showed strong clinical validity, with excellent agreement with brain amyloidosis by PET.

Regeneration of per- and polyfluoroalkyl substance-laden granular activated carbon using a solvent based technology

Per- and polyfluoroalkyl substances (PFAS) are a large class of chemicals widely used for many commercial and industrial applications and have resulted in contamination at sites across globally. Pump-and-treat systems, groundwater extraction, and ex situ treatment using granular activated carbon (GAC) are being implemented, either in full or pilot scale, to treat PFAS-impacted groundwater and drinking water. The only current method of regenerating spent GAC is to reactivate it at temperatures greater than 1000 °C, which requires large amounts of energy and is quite expensive. This research focused on development and demonstration of an effective GAC regeneration technology using a solvent-based method for PFAS-laden GAC used in water treatment. Two different organic solvents (ethanol and isopropyl alcohol) with 0.5% and 1.0% ammonium hydroxide (NH₄OH) as a base additive were tested to determine the most effective regenerant solution to remove PFAS from the contaminated GAC. Based on column tests using laboratory-contaminated GAC with perfluorooctanoic acid (PFOA) and perfluorooctanoic sulfonate (PFOS), the solvent-base mix (SBM) of ethanol with 0.5% NH₄OH was found to be the optimum performing regenerant solution. The GAC life span assessment showed that solvent-regenerated GAC performed similar to virgin GAC without losing its optimal performance of PFAS sorption. Further, the solvent-regenerated GAC showed optimal performance even after four cycles of solvent regenerations tested using the optimum SBM. Average percent removal in laboratory-contaminated GAC using the optimum SBM was 65% and 93% for PFOS and PFOA, respectively. Four field-spent GAC samples were also regenerated using the optimum SBM. Percent removal from these samples was found to be in range of 55%-68%. The type of GAC used, level of contamination and type of PFAS present, water type and quality, and the presence of co-contaminants may have influenced the removal capacity. Distillation experiments have shown that it is feasible to concentrate the spent solvent prior to disposal, which reduces the amount of PFAS-contaminated solvent waste produced in regeneration cycles.

Stimuli Response of Cationic Polymer Brush Prepared by ATRP: Application in Peptide Fractionation

Random cationic copolymer brushes composed of 2-(dimethylamino)ethyl methacrylate (DMAEMA) and N-isopropylacrylamide (NIPAAm) were synthesized using the atom transfer radical polymerization (ATRP) method. The effects of varying the monomer feed ratios (30:70 and 70:30 DMAEMA:NIPAAm) and polymerization times on the film height, morphology and stimuli response to pH of the brush were evaluated. While the polymerization time was found to have little influence on the properties of the brushes, the monomer feed ratios had a great impact. The 70 % DMAEMA polymer brush had similar height as the 30 % DMAEMA brush after 45 min; however, it had a greater response to pH and morphological change compared to the 30 % DMAEMA. The 70 % DMAEMA brush was used to demonstrate an efficient approach to alleviate the ion suppression effect in MALDI analysis of complex mixtures by effectively fractionating a binary mixture of peptides prior to MALDI-MS analysis.

Peptide/protein separation with cationic polymer brush nanosponges for MALDI-MS analysis

A cationic polymer nanobrush was synthesized, attached to a MALDI target, and used for the fractionation of peptides and proteins based on their pI, prior to analysis by MALDI-MS. The cationic polymer nanobrush was synthesized on a gold substrate by AIBN photoinitiated polymerization, using a 70:30 ratio of 2-aminoethyl methacrylate hydrochloride (AEMA):N-isopropylacrylamide (NIPAAM). This brush showed selectivity for adsorption of acidic peptides and proteins and allowed fractionation of simple two-component mixtures to be completed in less than 10 min. The brush-adsorbed biomolecules were recovered by treating the nanobrush with ammonium hydroxide, which effectively collapsed the brush, thereby releasing the trapped compounds for MALDI MS analysis. These results demonstrate that nanobrush can serve as a convenient platform for rapid fractionation of biomolecules prior to analysis by MALDI-MS.

Equine influenza immunity in the Special Restricted Area (Purple Zone) of New South Wales, Australia

The 2007 equine influenza (EI) outbreak in New South Wales (NSW) consisted of a central infected area that extended south from the lower New England Tableland, across the Hunter Valley, Central Coast and the Sydney basin, and a series of isolated clusters outside this area across rural NSW. The central area was assigned the status of a Purple Zone (Special Restricted Area, SRA) approximately 1 month after the outbreak commenced. Within this SRA, the eradication program's focus was to increase the proportion of horses immune to EI via vaccination, thus reducing the susceptible proportion to a level below the critical threshold for EI spread. An estimated 84-87% of all horse-owning premises achieved immunity to EI by the end of the outbreak. A high proportion (60-90%) of premises within most parts of the SRA became naturally infected with EI, and the rate of newly infected premises fell to low levels before EI vaccination commenced. Immunity to EI from very rapid natural spread appears to have been the most important factor in disease eradication within the SRA.

A Girl with Pervasive Developmental Disorder and Complex Chromosome Rearrangement Involving 8p and 10p

We report a 4-year-old girl with a de novo, apparently balanced complex chromosome rearrangement. She initially presented for assessment of velopharyngeal insufficiency due to hypernasal speech. She has distinctive facial features (long face, broad nasal bridge, and protuberant ears with simplified helices), bifid uvula, strabismus, and joint laxity. She is developmentally delayed, with language and cognitive skills approximately 2 SD below the mean expected for her age, and meets ADI, ADOS, and DSM-IV criteria for pervasive developmental disorder. She has poor eye contact, atypical communication and social interaction, repetitive behaviours and significant difficulties with processing sensory input. Her karyotype is characterized by the presence of two derivative chromosomes; 46,XX, der(8)(10pter- >10pl2.32::8p12- >8qter), der(l0)(8pter- >8p21.3::10p12.32- >10p11.23::8p21.3- > 8p12::10p11.23- >l0qter). The der(8) is a result of translocation of the segment 10p12.32-pter onto 8p12. The der(l0) has two 8p segments collectively from 8p12-pter in that the segment 8p21.3-pter is translocated onto 10p12.32 and the segment 8p12-p21.3 is inserted at 10p11.23. FISH analysis showed no microdeletion of the major locus at 22q11.2 nor for the minor locus at 10p13p14. This case suggests that aberrations at 8p12, 8p21.3, 10p11.23 and/or 10p12.32 may result in pervasive developmental disorder, associated with mild cognitive delay and specific facial anomalies.

Breaking the silence: women living with multiple sclerosis and urinary incontinence

This study examined women's understandings of living with multiple sclerosis (MS) and urinary incontinence and the challenges they have encountered in their day-to-day lives. As health-care professionals, we aimed to understand how people living with MS manage urinary incontinence. This paper reports the findings from a Participatory Action Research (PAR) group with four women, the researcher and two Continence Nurse Advisors (CNAs). The group met on five occasions between March and June 1999. The women's stories held personal and gendered meanings about living with MS and urinary incontinence. Four themes were derived from the transcripts: maintaining control; seeking understanding; avoiding shame; and good and bad days. The women and the CNAs benefited from an exchange of knowledge about living with MS and incontinence. The CNAs became sensitive to the women's experience and have been able to incorporate these understandings into their practice. By sharing our research we hope the findings may be more widely incorporated into sensitive health practice.

Improving the Quality of Reports of Meta-Analyses of Randomised Controlled Trials: The QUOROM Statement

BACKGROUND: The Quality of Reporting of Meta-analyses (QUOROM) conference was convened to address standards for improving the quality of reporting of meta-analyses of clinical randomised controlled trials (RCTs). METHODS: The QUOROM group consisted of 30 clinical epidemiologists, clinicians, statisticians, editors, and researchers. In conference, the group was asked to identify items they thought should be included in a checklist of standards. Whenever possible, checklist items were guided by research evidence suggesting that failure to adhere to the item proposed could lead to biased results. A modified Delphi technique was used in assessing candidate items. FINDINGS: The conference resulted in the QUOROM statement, a checklist, and a flow diagram. The checklist describes our preferred way to present the abstract, introduction, methods, results, and discussion sections of a report of a meta-analysis. It is organised into 21 headings and subheadings regarding searches, selection, validity assessment, data abstraction, study characteristics, and quantitative data synthesis, and in the results with <<trial flow>>, study characteristics, and quantitative data synthesis; research documentation was identified for eight of the 18 items. The flow diagram provides information about both the numbers of RCTs identified, included, and excluded and the reasons for exclusion of trials. INTERPRETATION: We hope this report will generate further thought about ways to improve the quality of reports of meta-analyses of RCTs and that interested readers, reviewers, researchers, and editors will use the QUOROM statement and generate ideas for its improvement. Copyright 2000 S. Karger GmbH, Freiburg

Improving the quality of reports of meta-analyses of randomised controlled trials: the QUOROM statement. QUOROM Group

BACKGROUND

The Quality of Reporting of Meta-analyses (QUOROM) conference was convened to address standards for improving the quality of reporting of meta-analyses of clinical randomised controlled trials (RCTs).

METHODS

The QUOROM group consisted of 30 clinical epidemiologists, clinicians, statisticians, editors, and researchers. In conference, the group was asked to identify items they thought should be included in a checklist of standards. Whenever possible, checklist items were guided by research evidence suggesting that failure to adhere to the item proposed could lead to biased results. A modified Delphi technique was used in assessing candidate items.

FINDINGS

The conference resulted in the QUOROM statement, a checklist, and a flow diagram. The checklist describes our preferred way to present the abstract, introduction, methods, results, and discussion sections of a report of a meta-analysis. It is organised into 21 headings and subheadings regarding searches, selection, validity assessment, data abstraction, study characteristics, and quantitative data synthesis, and in the results with 'trial flow', study characteristics, and quantitative data synthesis; research documentation was identified for eight of the 18 items. The flow diagram provides information about both the numbers of RCTs identified, included, and excluded and the reasons for exclusion of trials.

INTERPRETATION

We hope this report will generate further thought about ways to improve the quality of reports of meta-analyses of RCTs and that interested readers, reviewers, researchers, and editors will use the QUOROM statement and generate ideas for its improvement.

Biomedical publication for neurosurgery residents: a program and guide

One of the most pressing obligations in academic neurosurgery is the publication of clinical and basic science research results. Publication documents intellectual property and communicates findings among researchers working to improve neurosurgical treatment. It documents productivity, justifies funding for research, creates reputations, and builds careers. Nonetheless, the actual writing of reports is a skill often learned by osmosis in academic medicine. To give residents the tools necessary to negotiate the biomedical publication process successfully, we developed a publications program based on the premise that residents seeking an academic career must be prepared to generate publishable reports with maximum efficiency. The program consists of a "publication kit," a series of seminars, and one-on-one tutorials with academic biomedical editors that permit residents individually to improve the quality of their reporting. We describe this program, provide guidelines that can help residents write high-quality papers and publish their work more efficiently, and summarize important content regarding the framework for a successful paper, the elements of a conventional research report, brief guidelines for specific types of papers, reporting standards for clinical trials and meta-analyses, keys to citation in bibliographic indexes, and ethical and legal considerations related to research approval, confidentiality requirements, copyright law, permission to use previously published material, and conflict of interest. Residents who are able to view their work with a sharp critical focus and are educated about the standards of biomedical publication are better prepared to succeed in building a career in academic medicine.

[Improving the quality of reports of meta-analyses of randomized controlled trials: the QUOROM Statement]

BACKGROUND

The Quality of Reporting of Meta-analyses (QUOROM) Conference was convened to address standards for improving the quality of reporting of meta-analyses of clinical randomised controlled trials (RCTs).

METHODS

The QUOROM group consists of 30 clinical epidemiologists, clinicians, statisticians, editors, and researchers. In conference, the group was asked to identify items they thought should be included in a checklist of standards. Whenever possible, checklist items were guided by research evidence suggesting that failure to adhere to the item proposed could lead to biased results. A modified Delphi technique was used in assessing candidate items.

RESULTS

The conference resulted in the QUOROM statement, a checklist, and a flow diagram. The checklist describes our preferred way to present the abstract, introduction, methods, results, and discussion sections of a report of a meta-analysis. it is organized into 21 headings and subheadings regarding searches, selection, validity assessment, data abstraction, study characteristics, and quantitative data synthesis, and in the results with 'trial flow', study characteristics, and quantitative data synthesis; research documentation was identified for eight of the 18 items. The flow diagram provides information about both the numbers of RCTs identified, included, and excluded and the reasons for exclusion of trials.

INTERPRETATION

We hope this report will generate further thought about ways to improve the quality of reports of meta-analyses of RCTs and that interested readers, reviewers, researchers, and editors will use the QUOROM statement and generate ideas for its improvement.

Improving the quality of reports of meta-analyses of randomised controlled trials: the QUOROM statement. Quality of Reporting of Meta-analyses

BACKGROUND

The Quality of Reporting of Meta-analyses (QUOROM) conference was convened to address standards for improving the quality of reporting of meta-analyses of clinical randomised controlled trials (RCTs).

METHODS

The QUOROM group consisted of 30 clinical epidemiologists, clinicians, statisticians, editors, and researchers. In conference, the group was asked to identify items they thought should be included in a checklist of standards. Whenever possible, checklist items were guided by research evidence suggesting that failure to adhere to the item proposed could lead to biased results. A modified Delphi technique was used in assessing candidate items.

FINDINGS

The conference resulted in the QUOROM statement, a checklist, and a flow diagram. The checklist describes our preferred way to present the abstract, introduction, methods, results, and discussion sections of a report of a meta-analysis. It is organised into 21 headings and subheadings regarding searches, selection, validity assessment, data abstraction, study characteristics, and quantitative data synthesis, and in the results with "trial flow", study characteristics, and quantitative data synthesis; research documentation was identified for eight of the 18 items. The flow diagram provides information about both the numbers of RCTs identified, included, and excluded and the reasons for exclusion of trials.

INTERPRETATION

We hope this report will generate further thought about ways to improve the quality of reports of meta-analyses of RCTs and that interested readers, reviewers, researchers, and editors will use the QUOROM statement and generate ideas for its improvement.

[Improving the quality of reports on randomized controlled trials. Recommendations of the CONSORT Study Group]

This summary corresponds to the translation into Spanish of the Special Communication published in the Journal of the American Medical Association in August 1996, along with the editorial published in the same issue "How to report Randomized Controlled Trials. The Consort Statement". It describes the Consolidated Standards for Preparation of Controlled Clinical Trials, prepared by a work group made up of members of the SORT Group and of the Asilomar Work Group, along with the director of a magazine and the author of the report on a clinical trial. The work was carried out by means of a Delphi process and the result was a check list and a process diagram. The check list is made up of 21 items that mainly refer to methods, results and discussions on the report of a controlled clinical trial, identifying the necessary information in order to be able to evaluate the internal and external value of the report, judging the improvement to be positive for the patient, the editors and the reviewers of the magazines.

Ocular lens gap junctions: protein expression, assembly, and structure-function analysis

Recent advances in understanding lens fiber gap junction formation are reviewed. These include studies of junctional protein expression in the embryonic lens, and of age related changes affecting gap junction structure and composition in the adult lens. An in vitro assembly system based on detergent solubilized pore complexes and endogenous lipids has been developed to provide information on the molecular interactions involved in gap junction formation and to provide material for structure analysis. Important information on the electrical properties of lens gap junction channels is obtained using electrophysiological techniques including planar lipid bilayer analysis and patch clamping.

Gap junction formation during development of the mouse lens

We have identified a 60 kDa membrane protein (MP60) as a component of the mouse cortical lens fiber gap junction and a monoclonal antibody recognizing this protein has been used to establish the temporal and spatial patterns of gap junction formation during development of the mouse lens. The initial expression of MP60 during embryonic development of the mouse lens correlates with primary fiber elongation and is first seen on the luminal aspect of the extending cells. About 2 days after birth, the relatively large, antibody-positive macular structures characteristic of late embryonic fiber cells begin to disperse into progressively smaller structures within a centrally located region of the lens. This change in the staining pattern with antibody directed against MP60 is consistent with the dispersion of gap junction plaques as confirmed by freeze fracture analysis. Around 5 days after birth, the 60 kDa gap junctional protein in this central region of the lens undergoes a modification resulting in the alteration to the epitope for the monoclonal antibody and a consequent loss of immunorecognition. Our results suggest that gap junctions in the central region of the developing mouse lens undergo sequential changes in immunoreactivity which may reflect potentially distinct functional phases of intercellular communication.

Familial systemic lupus erythematosus: evidence for separate loci controlling C4 deficiency and formation of antibodies to DNA, nRNP, Ro and La

A family has been identified in the Canadian province of Prince Edward Island in which 2 sisters have systemic lupus erythematosus in a sibship of 14. Studies are reported on 11 of the siblings and 16 other family members. The affected siblings, and 4 other members of their sibship, are halfnull homozygotes for the C4A component of complement. We studied the distribution in family members of antibodies to ss and dsDNA, and to Ro(SSA), La(SSB), Sm and nRNP. Eight of 11 members of the affected sibship are antibody producers, compared to only 3 of 13 members of the parental generation. Our study provides further evidence for an association between null genes for C4A and familial lupus, and suggests, in an unusually large kindred, that several other genetic factors are involved in the production of antinuclear antibodies.

Arterial eicosanoid production following chronic exposure to a periarterial haematoma

Cisternal and lumbar cerebrospinal fluid obtained some days following a subarachnoid haemorrhage contains abnormally large quantities of various prostanoids; some may be partly the result of abnormal production by the cerebral arteries. The extra-arterial and intra-arterial production of 6 oxo PGF1 alpha (prostacyclin metabolite), PGE2, PGF2 alpha and TXB2 were measured in perfused rabbit common carotid arteries taken both from normal rabbits and from rabbits in which the arteries had been ensheathed by blood clot in vivo for 7 days using two techniques. Prostaglandin production by control arteries was highest during the first hour of perfusion but declined or increased marginally (PGE2) during the succeeding three hours. Arteries exposed to a periarterial haematoma for 7 days produced prostaglandins at a high rate throughout the 4 hours of study, and there was a progressive and marked increase in PGE2 production. The disproportionate increase in the cerebral vasoconstrictor PGE2 may reflect the inflammatory response which occurred in the adventitia of the vessels. Increased prostanoid production by cerebral arteries probably does contribute to the increased levels in CSF after subarachnoid haemorrhage.

Effects of subarachnoid haemorrhage on intracranial prostaglandins

Prostaglandins E2, F2 alpha, 6 oxo F1 alpha and thromboxane B2 increased in cisternal CSF following mock subarachnoid haemorrhage in dogs, particularly PGE2 (X25.5). Concentrations were increased also in lumbar CSF of five patients some 8 days after subarachnoid haemorrhage. Subarachnoid haemorrhage did not alter the production of prostaglandins by dog whole cortex or choroid plexuses in vitro, but production by pooled dissected cerebral arteries of PGE2 was increased and of 6 oxo F1 alpha was decreased. Intravenous indomethacin decreased prostaglandin production by cerebral tissues, and caused a marked decrease in the prostacyclin metabolite in CSF. The implications of our findings for the aetiology of cerebral vasospasm are discussed.