Myelin oligodendrocyte glycoprotein antibody titers by fixed cell-based assay: positive predictive value and impact of sample collection timing.

Introduction: In January 2023, our laboratory began performing serum myelin oligodendrocyte glycoprotein antibody (anti-MOG) titers by fixed cell-based assay (CBA). As a quality assurance (QA) assessment, we evaluated titer positive predictive value (PPV) as well as impact of sample collection timing on titers. Methods: Among patients who underwent antibody titers to distinguish between low-positive (<1:100) and clear-positive (≥1:100) anti-MOG, records were reviewed to classify results as true-positive (TP) or false-positive (FP) and facilitate PPV calculation. Timing of sample collection relative to administration of immunotherapy and symptom onset was determined for TP results. Results: Overall PPV of anti-MOG was 70/85 (82%). The PPV of low-positive anti-MOG was significantly lower than clear-positive anti-MOG (72% vs. 95%, p = 0.009). The difference in PPV between low-positive and clear-positive anti-MOG was significant among adults tested, but not children. Among patients with TP anti-MOG, the proportion who received immunotherapy prior to sample collection was significantly higher and median time from symptom onset to sample collection was significantly longer for low-positive compared to clear-positive results. Conclusion: Overall PPV of anti-MOG testing by fixed CBA was reasonably high. The PPV of low-positive anti-MOG was significantly lower than clear-positive anti-MOG. This was driven by the significantly lower PPV of low-positive anti-MOG in adults, possibly reflecting the lower prevalence of MOG antibody-associated disease among adults tested. Timing of sample collection relative to administration of immunotherapy and symptom onset may substantially impact titers, indicating that testing should ideally be performed prior to immunotherapy and close to time of attack.

Carbon-TiO2 Hybrid Quantum Dots for Photocatalytic Inactivation of Gram-Positive and Gram-Negative Bacteria.

Carbon-semiconductor hybrid quantum dots are classical carbon dots with core carbon nanoparticles doped with a selected nanoscale semiconductor. Specifically, on those with the nanoscale TiO2 doping, denoted as CTiO2-Dots, their synthesis and thorough characterization were reported previously. In this work, the CTiO2-Dots were evaluated for their visible light-activated antibacterial function, with the results showing the effective killing of not only Gram-positive but also the generally more resistant Gram-negative bacteria. The hybrid dots are clearly more potent antibacterial agents than their neat carbon dot counterparts. Mechanistically, the higher antibacterial performance of the CTiO2-Dots is attributed to their superior photoexcited state properties, which are reflected by the observed much brighter fluorescence emissions. Also considered and discussed is the possibility of additional contributions to the antibacterial activities due to the photosensitization of the nanoscale TiO2 by its doped core carbon nanoparticles.

Positive predictive value of myositis antibody line blot testing in patients with suspected idiopathic inflammatory myopathy.

INTRODUCTION/AIMS: Line blot (LB) is in widespread use for myositis antibody detection. Yet, studies of its positive predictive value (PPV) in patients with suspected idiopathic inflammatory myopathy (IIM), which would be of particular relevance to neuromuscular clinicians, are lacking. We aimed to determine the PPV of myositis antibody LB testing in patients with suspected IIM, and examine whether PPV was significantly impacted by intensity of antibody positivity. METHODS: This was a retrospective study of patients who underwent myositis antibody LB testing for suspected IIM between March 2019 and August 2022. RESULTS: Of 70 patients who underwent testing for suspected IIM and had positive myositis antibody LB results, 43 (61%) were female and the median age was 61 years (range: 10-83 years). Forty-four were classified as true-positives, yielding a PPV of 63%. The PPV of patients with weak-positive myositis antibody results (14/30, 47%) was significantly lower than the PPV of patients with moderate-positive or strong-positive myositis antibody results (30/40, 75%) (p = .02). DISCUSSION: Our study found that myositis antibody LB testing in patients with suspected IIM had a modest PPV, underscoring the need for antibody interpretation in the context of all available clinical and ancillary test data to avoid misdiagnosis. The significantly lower PPV in patients with weak-positive results emphasizes the particular importance of clinical correlation in such patients. Further study into the diagnostic performance of various LBs for myositis antibody detection is needed to inform their interpretation in clinical practice.

Evaluating yield and utilization of ganglioside antibody testing in clinical practice.

BACKGROUND AND OBJECTIVES: Ganglioside antibodies can help diagnose distinct acute and chronic inflammatory neuropathies including axonal variants of Guillain-Barre syndrome, Miller-Fisher syndrome (MFS), multifocal motor neuropathy, and chronic sensory ataxic neuropathies. Because ganglioside antibody testing may be routinely ordered in patients with suspected inflammatory neuropathy, we sought to evaluate its yield and utilization in clinical practice. METHODS: We performed a retrospective chart review of all patients at London Health Sciences Centre who underwent ganglioside antibody testing between April 2019 and August 2023. The disease phenotype was determined for each patient, and the proportion of all tests that yielded a true-positive result was calculated. Ganglioside antibody positivity was classified as a true-positive result if the disease phenotype was robustly associated with the detected ganglioside antibody and there was no other more likely diagnosis. RESULTS: We identified 92 patients who underwent ganglioside antibody testing. One patient (1%) was classified as having a true-positive result; this patient had GQ1b-IgG positivity with MFS. Among 92 patients tested, 20 patients (22%) had a disease phenotype that was considered to be robustly associated with ganglioside antibody positivity. CONCLUSIONS: The yield of ganglioside antibody testing in clinical practice is low. We found that this testing is frequently ordered in patients with disease phenotypes that are not robustly associated with ganglioside antibody positivity, indicating that suboptimal test utilization is a primary contributor to its low yield. Restricting ganglioside antibody testing to patients with characteristic disease phenotypes would be valuable to improving yield and utilization of this testing.

ATP promotes resident CD34+ cell migration mainly through P2Y2-Stim1-ERK/p38 pathway.

Extracellular adenosine triphosphate (ATP) is one of the most abundant biochemical constitutes within the stem cell microenvironment and is postulated to play critical roles in cell migration. However, it is unclear whether ATP regulates the cell migration of CD34+ vascular wall-resident stem/progenitor cells (VW-SCs) and participates in angiogenesis. Therefore, the biological mechanisms of cell migration mediated by ATP was determined by in vivo subcutaneous matrigel plug assay, ex vivo aortic ring assay, in vitro transwell migration assay, and other molecular methods. In the present study, ATP dose-dependently promoted CD34+ VW-SCs migration, which was more obviously attenuated by inhibiting or knocking down P2Y2 than P2Y6. Furthermore, it was confirmed that ATP potently promoted the migration of resident CD34+ cells from cultured aortic artery rings and differentiation into endothelial cells in matrigel plugs by using inducible lineage tracing Cd34-CreERT2; R26-tdTomato mice, whereas P2Y2 and P2Y6 blocker greatly inhibited the effect of ATP. In addition, ATP enhanced the protein expression of stromal interaction molecule 1 (STIM1) on cell membrane, blocking the calcium release-activated calcium (CRAC) channel with shSTIM1 or BTP2 apparently inhibited ATP-evoked intracellular Ca2+ elevation and channel opening, thereby suppressing ATP-driven cell migration. Moreover, extracellular signal-regulated protein kinase (ERK) inhibitor PD98059 and p38 inhibitor SB203580 remarkably inhibited ERK and p38 phosphorylation, cytoskeleton rearrangement, and subsequent cell migration. Unexpectedly, it was found that knocking down STIM1 greatly inhibited ATP-triggered ERK/p38 activation. Taken together, it was suggested that P2Y2 signaled through the CRAC channel mediated Ca2+ influx and ERK/p38 pathway to reorganize the cytoskeleton and promoted the migration of CD34+ VW-SCs.NEW & NOTEWORTHY In this study, we observed that the purinergic receptor P2Y2 is critical in the regulation of vascular wall-resident CD34+ cells' migration. ATP could activate STIM1-mediated extracellular Ca2+ entry by triggering STIM1 translocation to the plasma membrane, and knockdown of STIM1 prevented ERK/p38 activation-mediated cytoskeleton rearrangement and cell migration.

Pediatric Reference Value Profiling of Essential Trace and Toxic Elements in Healthy Children and Adolescents Using High-Resolution and Triple Quadrupole Inductively Coupled Plasma Mass Spectrometry.

BACKGROUND: Assessment of trace and toxic element status is important for the diagnosis and monitoring of several pediatric conditions. Elemental deficiency and toxicity have serious implications, particularly in pediatrics wherein risk is higher. Pediatric reference intervals (RIs) for trace elements and normal exposure limits for toxic elements are lacking on modern analytical systems. Herein, reference values were established for 13 plasma and 22 whole blood trace elements in the Canadian Laboratory Initiative on Pediatric Reference Intervals (CALIPER) cohort of healthy children and adolescents. METHODS: Approximately 320 healthy children and adolescents were recruited with informed consent. Trace elements were measured in whole blood and plasma samples using 2 technologies: (a) triple quadrupole inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) (n = 172) and (b) high-resolution sector field ICPMS (HR-SF-ICPMS) (n =161). RIs and normal exposure limits were then established according to Clinical and Laboratory Standards Institute guidelines. RESULTS: Of all elements assessed, none required sex partitioning and 8 required age partitioning (e.g., copper, manganese, and cadmium). Reference value distributions determined via ICP-MS/MS and HR-SF-ICPMS demonstrated excellent concordance, with few exceptions (e.g., molybdenum, cobalt, and nickel). CONCLUSIONS: These data represent the first study wherein pediatric RIs and normal exposure limits were derived simultaneously on 2 different clinically validated MS platforms which provide urgently needed data to inform clinical decision-making for trace elements in pediatrics. Study findings suggest some trace elements require age-specific consideration for appropriate interpretation. Highly concordant observations across the 2 analytical methods also demonstrate the comparability and reliability of results obtained on both platforms.

[Isolation, culture and validation of CD34+ vascular wall-resident stem cells from mice].

Vascular wall-resident stem cells (VW-SCs) play a critical role in maintaining normal vascular function and regulating vascular repair. Understanding the basic functional characteristics of the VW-SCs will facilitate the study of their regulation and potential therapeutic applications. The aim of this study was to establish a stable method for the isolation, culture, and validation of the CD34+ VW-SCs from mice, and to provide abundant and reliable cell sources for further study of the mechanisms involved in proliferation, migration and differentiation of the VW-SCs under various physiological and pathological conditions. The vascular wall cells of mouse aortic adventitia and mesenteric artery were obtained by the method of tissue block attachment and purified by magnetic microbead sorting and flow cytometry to obtain the CD34+ VW-SCs. Cell immunofluorescence staining was performed to detect the stem cell markers (CD34, Flk-1, c-kit, Sca-1), smooth muscle markers (SM22, SM MHC), endothelial marker (CD31), and intranuclear division proliferation-related protein (Ki-67). To verify the multipotency of the isolated CD34+ VW-SCs, endothelial differentiation medium EBM-2 and fibroblast differentiation medium FM-2 were used. After culture for 7 days and 3 days respectively, endothelial cell markers and fibroblast markers of the differentiated cells were evaluated by immunofluorescence staining and q-PCR. Furthermore, the intracellular Ca2+ release and extracellular Ca2+ entry signaling were evaluated by TILLvisION system in Fura-2/AM loaded cells. The results showed that: (1) High purity (more than 90%) CD34+ VW-SCs from aortic adventitia and mesenteric artery of mice were harvested by means of tissue block attachment method and magnetic microbead sorting; (2) CD34+ VW-SCs were able to differentiate into endothelial cells and fibroblasts in vitro; (3) Caffeine and ATP significantly activated intracellular Ca2+ release from endoplasmic reticulum of CD34+ VW-SCs. Store-operated Ca2+ entry (SOCE) was activated by using thapsigargin (TG) applied in Ca2+-free/Ca2+ reintroduction protocol. This study successfully established a stable and efficient method for isolation, culture and validation of the CD34+ VW-SCs from mice, which provides an ideal VW-SCs sources for the further study of cardiovascular diseases.

Carbon Dots: Classically Defined versus Organic Hybrids on Shared Properties, Divergences, and Myths.

Carbon dots are defined as small carbon nanoparticles with effective surface passivation via organic functionalization. The definition is literally a description of what carbon dots are originally found for the functionalized carbon nanoparticles displaying bright and colorful fluorescence emissions, mirroring those from similarly functionalized defects in carbon nanotubes. In literature more popular than classical carbon dots are the diverse variety of dot samples from "one-pot" carbonization of organic precursors. On the two different kinds of samples from the different synthetic approaches, namely, the classical carbon dots versus those from the carbonization method, highlighted in this article are their shared properties and apparent divergences, including also explorations of the relevant sample structural and mechanistic origins for the shared properties and divergences. Echoing the growing evidence and concerns in the carbon dots research community on the major presence of organic molecular dyes/chromophores in carbonization produced dot samples, demonstrated and discussed in this article are some representative cases of dominating spectroscopic interferences due to the organic dye contamination that have led to unfound claims and erroneous conclusions. Mitigation strategies to address the contamination issues, including especially the use of more vigorous processing conditions in the carbonization synthesis, are proposed and justified.

Positive Predictive Value of Anti-GAD65 ELISA Cut-Offs for Neurological Autoimmunity.

High anti-GAD65 levels associate with core manifestations of GAD65 neurological autoimmunity. ELISA cut-offs for high anti-GAD65 levels (>10,000 IU/ml in serum, >100 IU/ml in CSF) have been proposed that merit further evaluation. We reviewed patients who underwent anti-GAD65 ELISA for suspected autoimmune encephalitis and found values above these cut-offs to have a positive predictive value (PPV) for neurological autoimmunity of 88%. Anti-GAD65 values above proposed ELISA cut-offs have a reasonably high PPV for neurological autoimmunity in patients with suspected autoimmune encephalitis. Consideration of alternative diagnoses and corroboration with CSF can help flag potentially clinically irrelevant results and avoid patient misdiagnosis.

Development and validation of a nomogram for predicting pelvic lymph node metastasis and prognosis in patients with cervical cancer.

Objective: Cervical cancer (CC) is one of the main causes of death among gynecological malignancies. Patients with CC with lymph node metastasis (LNM) have poor prognoses. We investigated the risk factors and prognosis of LNM in patients with CC patients using data from the SEER database. Methods: We collected the information of cervical cancer patients registered in SEER database from 2010 to 2015. The dataset was divided into a training set and a validation set at a 7:3 ratio. LASSO regression analysis was used to evaluate risk factors for LNM in patients with CC. Using the results, we established a nomogram prediction model. C-index, ROC curves, calibration curves, decision curve analysis, and clinical impact curves were used to evaluate the prediction performance of the model. Results: We included 14,356 patients with CC in the analysis. Among these, 3997 patients were diagnosed with LNM. A training set (10,050 cases) and a validation set (4306 cases) were used for the following analysis. We established nomogram LNM prediction models for the patients with T1-2-stage CC. The C-indices for the internal and external validations of the prediction models were 0.758 and 0.744, respectively. In addition, we established a prognostic nomogram for all CC patients with LNM, and the internal and external validation C-indices were 0.763 and 0.737. Conclusion: We constructed a quantitative and visual predictive nomogram that predicted prognosis of patients with LNM in CC to provide clinicians with a reference for diagnosis and treatment.

Inactivation of Vesicular Stomatitis Virus with Light-Activated Carbon Dots and Mechanistic Implications.

The prevention of viral transmission is an important step to address the spread of viral infections. Using the enveloped vesicular stomatitis virus (VSV) as a model, this study explored the antiviral functions of the specifically designed and prepared carbon dots (CDots). The CDots were prepared using small carbon nanoparticles with surface functionalization-passivation by oligomeric polyethylenimine (PEI). The results indicated that the PEI-CDots were readily activated by visible light to effectively and efficiently inactivate VSVs under various combinations of experimental conditions (viral titer, dot concentration, and treatment time). The photodynamically induced viral structural protein degradation and genomic RNA degradation were observed, suggesting the mechanistic origins, leading to the inactivation of virus. The results suggested CDots as a class of promising broad-spectrum antiviral agents for disinfection of viruses.

Decrease of MYPT1 Is Critical for Impairment of NO-mediated Vasodilation in Mesenteric Artery of the Older Spontaneously Hypertensive Rats.

Nitric oxide (NO)-mediated vasodilatation is a fundamental response of vasculature, however, regulation of NO signaling pathway on resistance vessels in the older adult with hypertension is still unclear. The 16-week-spontaneously hypertensive rats (SHR), the 18-month-SHR (OldSHR), and the age-matched Wistar-Kyoto rats were used to study the changes of mesenteric resistance artery dilatation caused by sodium nitroprusside (SNP). After pre-vasoconstriction by norepinephrine (NE), the response of endothelium-denuded mesenteric artery ring to SNP was observed, and the changes in vascular response after pharmacological interventions of key nodes in the NO/sGC/cGMP/PKG1α signaling pathway were observed as well. RNA sequencing and functional enrichment analyses were used to provide information for conducting validation experiments. Vasodilation of NO in OldSHR was decreased, which significantly correlated with the reduction of PKG-mediated effect. Functional enrichment analysis of RNA sequencing showed that genes encoding important proteins such as sGC and MYPT1 (protein phosphatase 1 regulatory subunit 12A) were downregulated in OldSHR. Molecular biology validation results showed that mRNA expression of both α and ß subunits of sGC were reduced, while mRNA and protein expression of PKG1α were reduced in OldSHR. More importantly, the expression of MYPT1 and pS668-MYPT1 was significantly reduced in OldSHR, even under the treatment of SNP. The experiment also revealed an enhanced cAMP system in vasodilation in hypertension, while this function was completely lost in the OldSHR. Therefore, an NO-mediated decrease in vascular smooth muscle relaxation was found in the OldSHR. The dysfunction in cGMP-PKG signaling, in particular, decreased pS668-MYPT1 was mechanistically involved.

Exploration for the effect of renal function and renal replacement therapy on pharmacokinetics of remdesivir and GS-441524 in patients with COVID-19: A limited case series.

Remdesivir, an antiviral agent for the treatment of coronavirus disease 2019 (COVID-19), is metabolized intracellularly, with these metabolites eliminated predominantly in urine. Because of a lack of safety and pharmacokinetic (PK) data, remdesivir is not currently recommended for patients with estimated glomerular filtration rate less than 30 ml/min/1.73 m2 and those on hemodialysis. This study evaluated the PKs of remdesivir and its metabolite, GS-441524, in patients with COVID-19 who were and were not receiving renal replacement therapy (RRT). This study enrolled two patients with normal renal function, two with impaired renal function not receiving RRT, two receiving continuous RRT (CRRT), and three undergoing intermittent hemodialysis (IHD). Patients were administered 200 mg remdesivir on the first day, followed by 100 mg/day for 5-10 days. Serial blood samples were collected for PK analysis, and PK parameters were assessed by a noncompartmental method. Systemic exposure to remdesivir was higher in patients with impaired renal function and those receiving CRRT than in patients with normal renal function, but was similar in patients undergoing IHD and those with normal renal function. By contrast, systemic exposure to GS-441524 was highest in patients undergoing IHD, followed by patients with impaired renal function and those receiving CRRT, and lowest in patients with normal renal function. The PK profiles of remdesivir and GS-441524 varied according to renal function and RRT. The impact of PK changes of remdesivir and its metabolite on safety and efficacy should be considered when administering remdesivir to patients with COVID-19 with renal impairment.

Carbon "quantum" dots for bioapplications.

Carbon "quantum" dots or carbon dots (CDots) exploit and enhance the intrinsic photoexcited state properties and processes of small carbon nanoparticles via effective nanoparticle surface passivation by chemical functionalization with organic species. The optical properties and photoinduced redox characteristics of CDots are competitive to those of established conventional semiconductor quantum dots and also fullerenes and other carbon nanomaterials. Highlighted here are major advances in the exploration of CDots for their serving as high-performance yet nontoxic fluorescence probes for one- and multi-photon bioimaging in vitro and in vivo, and for their uniquely potent antimicrobial function to inactivate effectively and efficiently some of the toughest bacterial pathogens and viruses under visible/natural or ambient light conditions. Opportunities and challenges in the further development of the CDots platform and related technologies are discussed.

Visible Light-Activated Carbon Dots for Inhibiting Biofilm Formation and Inactivating Biofilm-Associated Bacterial Cells.

This study aimed to address the significant problems of bacterial biofilms found in medical fields and many industries. It explores the potential of classic photoactive carbon dots (CDots), with 2,2'-(ethylenedioxy)bis (ethylamine) (EDA) for dot surface functionalization (thus, EDA-CDots) for their inhibitory effect on B. subtilis biofilm formation and the inactivation of B. subtilis cells within established biofilm. The EDA-CDots were synthesized by chemical functionalization of selected small carbon nanoparticles with EDA molecules in amidation reactions. The inhibitory efficacy of CDots with visible light against biofilm formation was dependent significantly on the time point when CDots were added; the earlier the CDots were added, the better the inhibitory effect on the biofilm formation. The evaluation of antibacterial action of light-activated EDA-CDots against planktonic B. subtilis cells versus the cells in biofilm indicate that CDots are highly effective for inactivating planktonic cells but barely inactivate cells in established biofilms. However, when coupling with chelating agents (e.g., EDTA) to target the biofilm architecture by breaking or weakening the EPS protection, much enhanced photoinactivation of biofilm-associated cells by CDots was achieved. The study demonstrates the potential of CDots to prevent the initiation of biofilm formation and to inhibit biofilm growth at an early stage. Strategic combination treatment could enhance the effectiveness of photoinactivation by CDots to biofilm-associated cells.

Photoactivated Carbon Dots for Inactivation of Foodborne Pathogens Listeria and Salmonella.

Foodborne pathogens have long been recognized as major challenges for the food industry and repeatedly implicated in food product recalls and outbreaks of foodborne diseases. This study demonstrated the application of a recently discovered class of visible-light-activated carbon-based nanoparticles, namely, carbon dots (CDots), for photodynamic inactivation of foodborne pathogens. The results demonstrated that CDots were highly effective in the photoinactivation of Listeria monocytogenes in suspensions and on stainless steel surfaces. However, it was much less effective for Salmonella cells, but treatments with higher CDot concentrations and longer times were still able to inactivate Salmonella cells. The mechanistic implications of the observed different antibacterial effects on the two types of cells were assessed, and the associated generation of intracellular reactive oxygen species (ROS), the resulting lipid peroxidation, and the leakage of nucleic acid and proteins from the treated cells were analyzed, with the results collectively suggesting CDots as a class of promising photodynamic inactivation agents for foodborne pathogens. IMPORTANCE Foodborne infectious diseases have long been recognized as major challenges in public health. Contaminations of food processing facilities and equipment with foodborne pathogens occur often. There is a critical need for new tools/approaches to control the pathogens and prevent such contaminations in food processing facilities and other settings. This study reports a newly established antimicrobial nanomaterials platform, CDots coupled with visible/natural light, for effective and efficient inactivation of representative foodborne bacterial pathogens. The study will contribute to promoting the practical application of CDots as a new class of promising nanomaterial-based photodynamic inactivation agents for foodborne pathogens.

Neural Antibody Testing for Autoimmune Encephalitis: A Canadian Single-Centre Experience.

Neural antibodies have emerged as useful biomarkers in suspected autoimmune encephalitis. We reviewed results of neural antibody testing (anti-N-methyl D-aspartate receptor (NMDAR), leucine-rich glioma-inactivated protein (LGI1), contactin-associated protein-like 2 (CASPR2), α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR), γ-aminobutyric acid type B receptor (GABA(B)R), dipeptidyl-peptidase-like protein-6 (DPPX), IgLON family member 5 (IgLON5) and glutamic acid decarboxylase-65 (GAD65)) using cell-based assays (CBAs) and tissue indirect immunofluorescence (TIIF) at our centre. Our findings suggest increased clinical sensitivity of CBA compared to TIIF. However, this may come at some expense to clinical specificity, as evidenced by possible false-positive results when weak serum positivity by CBA was observed for certain antibodies (i.e. anti-NMDAR, CASPR2). In such cases, correlation with serum TIIF, as well as CSF CBA and TIIF, aids in identifying true-positive results.

On the myth of "red/near-IR carbon quantum dots" from thermal processing of specific colorless organic precursors.

Carbon dots were originally found and reported as surface-passivated small carbon nanoparticles, where the effective surface passivation was the chemical functionalization of the carbon nanoparticles with organic molecules. Understandably, the very broad optical absorptions of carbon dots are largely the same as those intrinsic to the carbon nanoparticles, characterized by progressively decreasing absorptivities from shorter to longer wavelengths. Thus, carbon dots are generally weak absorbers in the red/near-IR and correspondingly weak emitters with low quantum yields. Much effort has been made on enhancing the optical performance of carbon dots in the red/near-IR, but without meaningful success due to the fact that optical absorptivities defined by Mother Nature are in general rather inert to any induced alterations. Nevertheless, there were shockingly casual claims in the literature on the major success in dramatically altering the optical absorption profiles of "carbon dots" by simply manipulating the dot synthesis to produce samples of some prominent optical absorption bands in the red/near-IR. Such claims have found warm receptions in the research field with a desperate need for carbon dots of the same optical performance in the red/near-IR as that in the green and blue. However, by looking closely at the initially reported synthesis and all its copies in subsequent investigations on the "red/near-IR carbon dots", one would find that the "success" of the synthesis by thermal or hydrothermal carbonization processing requires specific precursor mixtures of citric acid with formamide or urea. In the study reported here, the systematic investigation included precursor mixtures of citric acid with not only formamide or urea but also their partially methylated or permethylated derivatives for the carbonization processing under conditions similar to and beyond those commonly used and reported in the literature. Collectively all of the results are consistent only with the conclusion that the origins of the observed red/near-IR optical absorptions in samples from some of the precursor mixtures must be molecular chromophores from thermally induced chemical reactions, nothing to do with any nanoscale carbon entities produced by carbonization.