Hearables: feasibility of recording cardiac rhythms from single in-ear locations

The ear is well positioned to accommodate both brain and vital signs monitoring, via so-called hearable devices. Consequently, ear-based electroencephalography has recently garnered great interest. However, despite the considerable potential of hearable based cardiac monitoring, the biophysics and characteristic cardiac rhythm of ear-based electrocardiography (ECG) are not yet well understood. To this end, we map the cardiac potential on the ear through volume conductor modelling and measurements on multiple subjects. In addition, in order to demonstrate real-world feasibility of in-ear ECG, measurements are conducted throughout a long-time simulated driving task. As a means of evaluation, the correspondence between the cardiac rhythms obtained via the ear-based and standard Lead I measurements, with respect to the shape and timing of the cardiac rhythm, is verified through three measures of similarity: the Pearson correlation, and measures of amplitude and timing deviations. A high correspondence between the cardiac rhythms obtained via the ear-based and Lead I measurements is rigorously confirmed through agreement between simulation and measurement, while the real-world feasibility was conclusively demonstrated through efficacious cardiac rhythm monitoring during prolonged driving. This work opens new avenues for seamless, hearable-based cardiac monitoring that extends beyond heart rate detection to offer cardiac rhythm examination in the community.

The calcium-to-phosphorous (Ca/P) ratio in the diagnosis of primary hyperparathyroidism and hypoparathyroidism: a multicentric study

PURPOSE

The diagnosis of primary hyperparathyroidism (PHPT) and chronic hypoparathyroidism (HypoPT) is still challenging, especially in patients asymptomatic or with non-classical phenotypes and for physicians not skilled in calcium-phosphorous (Ca-P) disorders. The serum calcium/phosphorous (Ca/P) ratio has been proposed as accurate index to identify PHPT, while it has never been tested in HypoPT. The aim of this study is to investigate the diagnostic power of the serum Ca/P ratio in the diagnosis of primary parathyroid dysfunctions (both PHPT and HypoPT) in a large series of data.

METHODS

A multicentric, retrospective, cross-sectional study (ClinicalTrials.gov: NCT03747029) was carried out including 432 PHPT patients and 217 HypoPT patients compared with 389 controls. Serum Ca, P, creatinine, parathyroid hormone and 25OH-vitamin D were collected. Serum Ca and P were expressed in mmol/L. Ca/P diagnostic performance was evaluated by receiver operating characteristic (ROC) curve, sensitivity, specificity and accuracy.

RESULTS

The Ca/P ratio was significantly higher in PHPT and lower in HypoPT patients than controls (p < 0.0001). At ROC curve analysis, the Ca/P ratio above 2.55 was defined to identify PHPT patients (sensitivity 85.7%, specificity 85.3%) and below 1.78 to identify HypoPT patients (sensitivity 88.2%, specificity 87.9%).

CONCLUSIONS

The Ca/P ratio is a highly accurate index to identify PHPT when Ca/P is above 2.55 and HypoPT when it is below 1.78. These results demonstrate the reliability of this index to rule in/out primary parathyroid dysfunctions and remark the importance of measuring serum P in clinical practice.

Subclassification of the "grey zone" of thyroid cytology; a retrospective descriptive study with clinical, cytological, and histological correlation

Undetermined thyroid cytology precludes any definitive distinction between malignant and benign lesions. Recently several classifications have been proposed to split this category into two or more cytological subcategories related to different malignancy risk rates. The current study was performed retrospectively to investigate the results obtained separating “undetermined” cytologic reports into two categories: “follicular lesion” (FL) and “atypia of undetermined significance” (AUS). Biochemical, clinical, and echographic features of each category were also retrospectively analyzed. Altogether, 316 undetermined fine-needle aspirated cytologies (FNACs) were reclassified as 74 FL and 242 AUS. Histological control leads to a diagnosis of carcinomas, adenomas, and nonneoplastic lesions, respectively, in 42.2%, 20%, and 37.8% of AUS and in 8.3%, 69.4%, and 22.2% of FL. Among biochemical, clinical, cytological, and echographic outcomes, altered thyroid autoantibodies, multiple versus single nodule, AUS versus FL, and presence of intranodular vascular flow were statistically significant to differentiate adenoma from carcinoma and from nonneoplastic lesions, whereas no significant differences were found between carcinomas and nonneoplastic lesions for these parameters. The results of this retrospective study show that undetermined FNAC category can further be subclassified in AUS and FL, the former showing higher malignancy rate. Further prospective studies are needed to confirm our results.

High Prevalence of B-RAF Mutation in Papillary Carcinoma of the Thyroid in North-East Italy

B-RAF V600E mutation is frequently observed in several tumors, including papillary thyroid carcinomas (PTCs), where it is considered of potential diagnostic and prognostic value. The reported prevalence of B-RAF mutation in PTCs in different Italian populations varies from 14% to 69%. The authors investigate the prevalence and utility of the B-RAF V600E mutation in a series of 91 fine needle aspiration biopsies (FNABs) of the thyroid and in 60 histologically proven PTCs in a well-defined north Italian population. In their series, the B-RAF mutation was detected in 43 (72%) PTCs and was more frequent in classic (34 out of 44, 77%) versus variant follicular PTCs (PTCVF; 9 out of 16, 56%). In all, 41 (46%) FNABs showed B-RAF mutation and corresponded to histologically proven PTCs (33 classic type and 8 PTCVF), which had been cytologically classified as malignant (28 cases), atypical/suspicious (10), inadequate (1), and benign (2). B-RAF mutations were never seen in non-PTC/ PTCVF FNAB cases, implying a 100% positive predictive value.These data demonstrate a high prevalence of B-RAF mutations in the present study population, underscoring the possibility of strong regional differences in B-RAF mutation prevalence in PTCs and further confirming its high diagnostic value on FNAB.

Identification of IgG-immunocomplex macroprolactin with an immunometric "sandwich" system: technical and clinical considerations

MacroPRL can be due either to anti-PRL autoantibodies IgG (IgG-macroPRL) or other PRL containing molecules without IgG-PRL immuncomplexes (nIgG-macroPRL), the composition of which is not fully clarified. The aims of this study were: a) testing a new immunometric assay, capable of recognising IgG-macroPRL, b) looking for any biological and/or clinical discrepancy between nlgG-macroPRL and IgG-macroPRL. Clinical, biological and neuroradiological data were recorded from 28 hyperprolactinemic women classified as macroprolactinemic on the basis of PRL recoveries after polyethylene glycol (PEG) precipitation <50% on a Roche Elecsys analyser. Fourteen sera with recoveries >70% were employed as controls for the IgG-macroPRL assay. An immunometric "sandwich" assay for IgG-macroPRL was performed employing an anti-PRL antibody to capture PRL and a second one binding and tracing the immunoglobulin G (IgG) component. For this purpose, 2 kits were simultaneously employed, the first for PRL assay and the second for Anti-Toxoplasma IgG assay. The procedure was applied to both DiaSorin LIAISON and Abbott AxSYM systems. IgG-macroPRL immunometric detection was obtained with DiaSorin LIAISON. Twenty out of 28 (72%) sera gave luminescent signal higher than the maximum control serum and were considered as IgG-macroPRL carriers. Our results confirm the high IgG-macroPRL prevalence in macroprolactinemia. No significant clinical differences appear between IgG and nIgG-macroPRL. Conversely, significantly higher PRL values (p =0,039) and lower recoveries (p = 0.001) were found in IgG-macroPRL. Further studies with reference methods, such as gel chromatography and human IgG (h-IgG) affinity columns, are needed to fully validate this IgG-macroPRL immunometric assay.

Macroprolactinemia: predictability on clinical basis and detection by PEG precipitation with two different immunometric methods

Prolactin (PRL) in human serum is present in three species: monomeric PRL (23 kDA), big PRL (50-60 kDa) and big, big PRL (bb-PRL or macroprolactinemia) of 150-170 kDa. Macroprolactin seems to be mainly composed of a molecule of monomeric PRL and an immunoglobulin G anti PRL. Its biological activity is considered low or absent, but it is measured, at various degrees, by the immunoassay method, thus causing diagnostic problems. Polyethylene Glycol (PEG) has been employed to precipitate macroprolactin, allowing its detection. This method is not applicable to all immunoassays for technical reasons. Our aim was to evaluate: 1) the predictability of macroprolactin on a clinical basis; 2) the possibility of applying PEG precipitation to Abbott AxSYM analyzer beside Roche Elecsys (already approved). We classified 34 hyperprolactinemic women, on a clinical and imaging basis, in four groups: A: functional hyperprolactinemia; B: pituitary lesions hyperprolactinemia; C: probably macroprolactinemia; D: unclassifiable hyperprolactinemia and a "control" group E of 19 healthy women. PRL was assayed, both with Elecsys and AxSYM, before and after PEG serum treatment. Eleven out of twelve group C, and 5/7 group D patients showed macroprolactinemia, against 1/7 in A and 1/8 in B. PEG was suitable for AxSYM only after the same treatment of the calibration standards, thus performing outcomes overlapping Elecsys. For clinical purposes, in the presence of macroprolactinemia, besides the recovery ratio, molar or ponderal monomeric PRL assay should be calculated.