An Unexpected Diagnosis Uncovered by Quantitative Molecular Findings: A Case Report.

A 74-year-old male presented with rectal pain; workup uncovered an anal mass, and a diagnosis of melanoma was rendered via histologic examination and immunohistochemical (IHC) studies. Droplet digital PCR (ddPCR)-based BRAF testing was performed and revealed the presence of BRAF V600E, which is a common targetable genetic alteration in melanoma. Interestingly, the ratio of mutant to wild-type copy number was low (0.3%), whereas tumor cell percentage on tissue slides was 90%. With additional workup, BRAF V600E IHC confirmed a very small subset of BRAF V600E-positive cells, and a next-generation sequencing (NGS) panel revealed a pathogenic KIT variant, p.L576P, with an allele frequency of 63%. It was initially hypothesized that the main driver of the melanoma was the KIT alteration, whereas a small subclone (not detected by NGS, which has a 5% limit of detection) was driven by the BRAF V600E detected by ddPCR. To determine whether there were morphologic differences between the 2 clones, a careful review of the histology was performed and revealed distinct morphology of the BRAF V600E-positive cells, including pale cytoplasm, nuclear grooves, and infiltrating eosinophils. Additional IHC workup of the BRAF V600E-positive cells showed coexpression of CD1a, Langerin, and S100, diagnostic of Langerhans cell histiocytosis (LCH). This diagnosis was unexpected and would have been missed without highly sensitive molecular testing; yet it is of clinical importance for the patient. This case raises interesting biology questions regarding the relationship between melanoma and LCH; moreover, it highlights the importance of integrating quantitative information in molecular data interpretation.

Quantitative sensory phenotyping in chronic neuropathic pain patients treated with unilateral L4-dorsal root ganglion stimulation.

BACKGROUND: In a previous study, we reported that selective dorsal root ganglion stimulation (DRGSTIM) at DRG level L4 promoted a favorable outcome for complex regional pain syndrome (CRPS) patients along with DRGSTIM-related changes of inflammatory biomarkers in blood and saliva. The impact on somatosensation is largely unknown. Herein, we assessed the quantitative sensory profile to quantify L4-DRGSTIM effects in CRPS patients. METHODS: Twelve refractory CRPS patients (4 female; 8 male; mean age 69 ± 9 years) received standardized quantitative sensory testing (QST) protocol at baseline and after 3 months of unilateral L4-DRGSTIM assessing nociceptive and non-nociceptive thermal and mechanical sensitivity of the knee affected by CRPS and the contralateral non-painful knee area. RESULTS: At baseline, CRPS subjects showed significantly increased thresholds for warmth, tactile and vibration detection (WDT, MDT and VDT) and exaggerated pain summation (WUR). After 3 months of unilateral L4-DRGSTIM all pain parameters exhibited trends towards normalization of sensitivity accumulating to a significant overall normalization for pain sensitivity (effect size: 0.91, p < 0.01), while with the one exception of WDT all non-nociceptive QST parameters remained unchanged. Overall change of non-nociceptive detection was negligible (effect size: 0.25, p > 0.40). Notably, reduction of pain summation (WUR) correlated significantly with pain reduction after 3 months of L4-DRGSTIM. CONCLUSIONS: Selective L4-DRGSTIM lowered ongoing pain in CRPS patients and evoked significant normalization in the pain domain of the somatosensory profile. Thermoreception and mechanoreception remained unchanged. However, larger randomized, sham-controlled trials are highly warranted to shed more light on effects and mechanisms of dorsal root ganglion stimulation on quantitative sensory characteristics. The study protocol was registered at the 15.11.2016 on German Register for Clinical Trials (DRKS ID 00011267). https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00011267.

Establishment of droplet digital PCR for the detection of Neisseria gonorrhoeae.

BACKGROUND: Infection with Neisseria gonorrhoeae in adults usually leads to vaginitis and acute urethritis, and infection through the birth canal in newborns can lead to acute neonatal conjunctivitis. In view of certain factors such as a high missed detection rate of N.gonorrhoeae from staining microscopy method, the time-consuming nature and limited sensitivity of bacterial culture method, complicated and inability of absolute quantification from the ordinary PCR method. METHODS: This study aims to establish a ddPCR system to detect N.gonorrhoeae in a absolute quantification, high specificity, high stability and accurate way. We selected the pgi1 gene as the target gene for the detection of N.gonorrhoeae. RESULTS: The amplification efficiency was good in the ddPCR reaction, and the whole detection process could be completed in 94 min. It has a high sensitivity of up to 5.8 pg/µL. With a high specificity, no positive microdroplets were detected in 9 negative control pathogens in this experiment. In addition, ddPCR detection of N.gonorrhoeae has good repeatability, and the calculated CV is 4.2 %. CONCLUSIONS: DdPCR detection technology has the characteristics of absolute quantification, high stability, high specificity and high accuracy of N.gonorrhoeae. It can promote the accuracy of the detecting of N.gonorrhoeae, providing a more scientific basis for clinical diagnosis and treatment.

[The objectification of ashi point diagnosis and treatment].

Ashi points play a significant role in the clinical localization and qualitative diagnosis of acupuncture, as well as in selecting acupoints along the meridians and applying tonifying or reducing techniques. This paper introduces the theoretical basis and existing technical methods of objectification of ashi point diagnosis and treatment. It proposes that using sensory quantitative testing to determine the temperature and tenderness thresholds of ashi points could help to identify the pathological characteristics of "cold" "heat" "deficiency" or "excess" of ashi points. In addition, the possibility of objectification of ashi point diagnosis-treatment plan is explored from three perspectives, precision of selection of ashi point therapy, objectification of effect evaluation of ashi point analgesia, and differentiation of the studies on ashi point analgesic mechanism, aiming to provide new research ideas for the modernization of traditional Chinese acupuncture.

Experimental Measurement of the Size of Gaps Required to Compromise Fit of an N95 Respirator.

OBJECTIVE: The effectiveness of filtering facepiece respirators such as N95 respirators is heavily dependent on the fit. However, there have been limited efforts to discover the size of the gaps in the seal required to compromise filtering facepiece respirator performance, with prior studies estimating this size based on in vitro models. In this study, we measure the size of leak necessary to compromise the fit of N95 respirators. METHODS: Two methods were used to create a gap of specific dimensions. A set of 3D-printed resin spacers and hollow steel rods were used to generate gaps in N95 respirators while worn on 2 participants. Occupational Safety and Health Administration (OSHA) quantitative fit testing methods were used to quantify mask performance with gaps between 0.4 and 2.9-mm diameters. RESULTS: Gap size was regressed against fit factor, showing that overall, the minimum gap size to compromise N95 performance was between 1.5 mm2 and 3 mm2. CONCLUSIONS: These findings suggest the fit of a N95 respirator is compromised by gaps that may be difficult to visually detect. The study also adds to the body of evidence supporting the routine use of quantitative fit testing to ensure that masks are well-fitting.

Rapid and accurate determination of carboxyl groups in carbon materials by headspace gas chromatography.

This paper reports a novel and rapid method for determining carboxyl groups in carbon materials by headspace gas chromatography (HS-GC). Taking carboxylated carbon nanotubes (CNTs) as an example, the experiment based on GC measurement of carbon dioxide (CO2) generated by complete reaction between carboxyl groups and sodium bicarbonate in a sealed vial, which showed that carboxyl groups in CNTs could be completely transformed into CO2 under the equilibrium temperature at 60 °C for 10 min. The relative standard deviation (RSD) of this method in the repeatability test was less than 1.52%, and the limit of quantitation (LOQ) for carboxyl content was 0.014 mmol/g in CNTs. More significantly, appropriate ultrasound of the sample before headspace injection could greatly improve the detection efficiency by reducing the equilibrium time. All in all, the HS-GC method provides an automated and accurate analysis for testing carboxyl groups in carbon materials, and it is of profound significance to develop a new way for quantitative research of carbon materials.

Skin testing for inhalant allergy.

BACKGROUND: Allergy is diagnosed by a combination of history, physical examination, and confirmatory testing. Modalities for testing include skin testing, in vitro assessment, and challenge testing of the conjunctiva or nasal mucosa. Challenge testing is primarily reserved for research. METHODS: A review of the literature on skin testing methods for inhalant allergic rhinitis was performed. RESULTS: Different forms of commonly used skin testing are available, including: individual prick; multiple prick; single, intradermal, and intradermal dilutional testing; and blended techniques. Each has inherent benefits and limitations. CONCLUSION: Skin testing remains a valid and in some cases superior means of identifying inhalant allergy. Skin-prick testing and intradermal testing are the primary categories, although different formats exist for each. Caution must be taken to avoid creating a serious systemic reaction by injecting an injudicious amount of antigen into the skin, or in skin testing a patient whose medication profile puts them at increased risk.