Red Blood Cells' Area Deformation as the Origin of the Photoplethysmography Signal.

The origin of the photoplethysmography (PPG) signal is a debatable topic, despite plausible models being addressed. One concern revolves around the correlation between the mechanical waveform's pulsatile nature and the associated biomechanism. The interface between these domains requires a clear mathematical or physical model that can explain physiological behavior. Describing the correct origin of the recorded optical waveform not only benefits the development of the next generation of biosensors but also defines novel health markers. In this study, the assumption of a pulsatile nature is based on the mechanism of blood microcirculation. At this level, two interconnected phenomena occur: variation in blood flow velocity through the capillary network and red blood cell (RBC) shape deformation. The latter effect was qualitatively investigated in synthetic capillaries to assess the experimental data needed for PPG model development. Erythrocytes passed through 10 µm and 6 µm microchannel widths with imposed velocities between 50 µm/s and 2000 µm/s, according to real scenarios. As a result, the length and area deformation of RBCs followed a logarithmic law function of the achieved traveling speeds. Applying radiometric expertise on top, mechanical-optical insights are obtained regarding PPG's pulsatile nature. The mathematical equations derived from experimental data correlate microcirculation physiologic with waveform behavior at a high confidence level. The transfer function between the biomechanics and the optical signal is primarily influenced by the vasomotor state, capillary network orientation, concentration, and deformation performance of erythrocytes.

CMV and HIV Coinfection in Women from a Region in Eastern Europe.

(1) Background: Human cytomegalovirus (CMV) infection is one of the most frequent opportunistic infections in immunosuppressed patients. Romania has one of the highest incidences of patients living with human immunodeficiency virus (HIV) which determines an immunosuppressive state. The aim of this study was to establish the prevalence of CMV infection among women living with HIV in Southeastern Romania and also to evaluate and correlate antiretroviral therapy (ART) with CD4 level and CMV disease evolution. (2) Methods: Seventy women living with HIV from Southeastern Romania were screened for CMV infection using antigen quantification. Of these, 50 were included in the study. First, the patients filled out a questionnaire regarding social conditions and other associated diseases. Then, we explored the statistical correlations between the data and HIV status, CD4+ cell counts, viral load, and antiretroviral therapy (ART). (3) Results: Median age of the patients was 33 years. Twenty-nine cases were diagnosed with HIV after sexual life beginning and 21 before. Most of the patients had a CD4 level over 200 cells/µL. ART duration in the CD4 under 200 cells/µL group was a bit longer than that in the CD4 over 200 cells/µL group. Forty-one patients had undetectable viremia. CD4 average value in the lot of patients with undetectable viremia was 704.71 cells/µL and in the lot with detectable viremia was 452.44 cells/µL. Viremia values correlated negatively with CD4 level. A positive correlation between IgG CMV values and ART therapy length was identified. A negative significant correlation between values of IgG CMV and values of CD4 was identified. CD4 value correlated negatively with IgG CMV values and with CMV avidity. (4) Conclusions: IgG CMV values had a weak positive correlation with ART therapy length, and a negative statistically significant correlation with values of CD4. CMV avidity has a negative correlation with CD4 value.

Clinical and Biological Risk Factors Associated with Increased Mother-to-Child Transmission of HIV in Two South-East HIV-AIDS Regional Centers in Romania.

Background and Objectives: The occurrence of human immunodeficiency virus (HIV) infection in children in Romania has been reported since 1989. This retrospective study was aimed at assessing clinical and biological risk factors for mother-to-child transmission (MTCT) of HIV in two HIV-acquired immune deficiency syndrome (AIDS) Regional Centers (RCs), Constanta and Craiova in Romania. Materials and Methods: During the study period (2008-2019), 408 HIV-positive pregnant women, 244 from Constanta RC and 164 from Craiova RC who attended antenatal visits, were included. All HIV-positive pregnant women were under combined antiretroviral therapy (cART) during pregnancy and childbirth, being followedup with their infants up to 18 months after delivery. We investigated the clinical as well as biological risk factorsassociated with increased MTCT of HIV. Results: Comparing different variables of HIV-positive pregnant women from the two HIV-AIDS CRs, we find that there are significant differences between the mean value of hemoglobin, CD4 level, environmental area, marital and amniotic membranes status, and HIV patient stage in the last trimester of pregnancy (p < 0.05), but without any differences in mother's mean age, education level, type of delivery, breastfeeding, the duration of cART administration, HIV viral load, and survival rate. Conclusions: In 408 HIV-positive pregnant women followed up at two HIV-AIDS RCs in Romania, the most important clinical and biological risk factors associated with increased MTCT of HIV are represented by anemia, CD4 level, and HIV patient stage.

Parental environmental tobacco smoking and the prevalence of respiratory diseases in primary school children.

INTRODUCTION: The inhaling tobacco smoke to which a child is exposed, in a home environmental area, could affect respiratory system. MATERIAL AND METHODS: The aim of the study consists in detecting the prevalence of respiratory diseases in home exposure to secondhand smoke among primary school children. A 6-month prospective case-control study based on questionnaire survey was carried out among school children of "Spiru Haret" Primary School, Medgidia, Romania, with absences for respiratory diseases, related to exposure to parental passive smoking, in their home environmental. 136 school children and their families informed, consented to complete the questionnaire and were surveyed for respiratory diseases and domestic environmental tobacco smoking, from the 1st of October, 2011 to the 31st March, 2012. The method consists in collecting data about any respiratory illness events, correlating them with the questionnaire --reports of parental smoking in home environmental. RESULTS: Participants were divided in 88 cases exposed to SHS (E) and 48 controls without exposure (NE). The most sick children with more than one episode of respiratory illness were among cases (n = 61/88; 69.31% vs 19/48; 39.58%; OR = 3.45; RR = 1.62; chi2 = 12.25; p < 0.0008). The most important source of parental passive smoking is the father (n = 67/88; 76.13%), being a single parent in most of the cases (n = 46/88; 57.95%). The prevalence of bronchial asthma was 0.34% in cases, being related with prenatal maternal smoking exposure (1.11%). CONCLUSION: The prevalence of respiratory diseases is higher among children with environmental parental tobacco exposure, in particular, smoking father.