Advances in experimental medicine and biology最新文献

Acute infectious diarrhea (AID) is one of the most common diseases in pediatric age with relevant burden both in high and in low-income countries. Thanks to their direct action on enterocyte functions and indirect actions on the mucosal and systemic immune system and on intestinal microbiome, probiotics are an ideal intervention to treat AID in childhood. However, their efficacy is strictly related to strains and indications, and practitioners should take this information into account in clinical practice. This chapter summarizes the main mechanisms of action of probiotics in AID, with a focus on proof of efficacy supporting their use in prevention and treatment of childhood AID. The use of selected strains in appropriate doses is strongly recommended by guidelines of AID, based on compelling proofs of efficacy and safety. At present, therapy with probiotics of AID is probably the strongest indication for probiotic use in medicine. Their role in prevention of AID is however questionable in healthy population, whereas it should be considered in at-risk population. Evidence for prevention of diarrhea in day-care centers and communities is lacking, but consistent evidence supports efficacy in prevention of hospital acquired diarrhea. Finally, this chapter presents novelties on this topic, in particular the role of rotavirus immunization on probiotics effectiveness and the effect of probiotics and postbiotics on Covid-associated diarrhea.Overall: AID is the most convincing area for probiotic use in children with gastrointestinal disorders, and effective strains should be used early on after onset of symptoms.

Gum chewing is used in orofacial therapy to improve oral functions, such as a patient's chewing ability, bite force, tongue pressure, and lip closure strength. However, its effects on masseter muscle oxygen dynamics and muscle activity may vary with the hardness and features of the gum base. Therefore, when considering gum chewing for therapeutic purposes, it is essential to select gum of an appropriate hardness. This study aimed to elucidate the impact of gum hardness differences on masseter muscle tissue oxygen dynamics and muscle activity. We conducted a 120-s gum chewing study using three types of gum with different hardness levels on 11 healthy adult males. Each patient's masseter muscle tissue oxygen dynamics, muscle activity, and heart rate were measured, and the extent of masseter fatigue was assessed using a visual analogue scale (VAS). Per our findings, as gum hardness increased, significant reductions in oxygen saturation (StO₂) and significant increases in deoxyhaemoglobin (Deoxy-Hb) concentrations were observed in masseter muscle tissue oxygen dynamics. Likewise, muscle activity, heart rate, and muscle fatigue (according to VAS) also increased significantly as gum hardness increased. The findings of this study reveal that increasing gum base hardness not only affects masseter muscle tissue oxygen dynamics but also increases muscle activity, masseter fatigue, and heart rate. When selecting gum for orofacial therapy involving gum chewing exercises, it is crucial to choose the appropriate gum.

The purpose of this study was to examine the effects on prefrontal cortex (PFC) activity of listening to pleasant sounds (PS) while walking, gum chewing (GCh), or performing the dual task of walking and gum chewing at the same time (walking + GCh). A total of 11 healthy adult male volunteers participated in the study (mean age: 29.54 ± 3.37). The block design of the trial consisted of a 30-sec rest, a 60-sec task (target task or control task), and a 30-sec rest. There were three target task conditions: walking, GCh, and the dual task. All of these were performed while listening to PS. The control condition was rest (no exercise) while listening to PS. The outcomes measured and measurements used were PFC activity using two-channel near-infrared spectroscopy and participant self-evaluation of the pleasantness of the experience using the visual analogue scale (VAS). Compared to the control condition, there was significantly greater PFC activation during the GCh and the walking + GCh tasks. Compared to the control condition, GCh and walking + GCh showed significantly greater activation on the VAS measure. In conclusion, listening to PS while GCh or walking + GCh increases PFC activity in the lower central region and induces positive emotional change.

Background: Tissue mimicking optical phantoms are commonly used to calibrate or validate the performance of near-infrared spectroscopy or tomography. Human tissue is not only irregular in shape, but also exhibits dynamic behaviour, which can cause changes in optical properties. However, existing phantoms lack complex structures and/or continuously varying optical properties.

Aim: The project aimed to design, fabricate and characterise a novel phantom system for testing near-infrared imaging devices.

Material and methods: We designed a dynamic tissue-mimicking phantom platform which features arbitrary internal shapes and variable optical properties. The solid part of phantom was made of silicone material with absorbing and scattering properties similar to the brain. We printed a semi-ellipsoidal sphere (a major axis = 20 mm and a minor axis = the third axis = 12 mm) using a water-soluble material polyvinyl alcohol (PVA). The shape was placed at the depth of 5 mm in the silicone bulk. The desired internal hollow structure was formed after curing and submerging the phantom in water. The liquid part contained dyes and Intralipid. The optical properties within the internal shape were adjusted by injecting the liquid solutions of varying dye concentrations with a syringe pump at a constant rate. The phantom was measured by a frequency domain near-infrared spectroscopy (FD NIRS) and imaged by a time domain near-infrared optical tomography (TD NIROT).

Results and discussion: A dynamic phantom system with a complex internal structure and varying optical properties was created. Changes in light intensity were detected by the FD NIRS. The internal structure of this phantom was accurately recovered by NIROT image reconstruction.

Conclusion: We successfully developed a novel phantom system with an internal complex shape and continuously adjustable optical properties. This phantom was accurately imaged using NIROT, and the changing light intensity was detected by NIRS. It is a valuable tool for validating optical technologies.

Recent studies revealed that excessive supplemental oxygen, such as inhaled 100% O₂, damages various organ functions in post-cardiac arrest (CA) patients. Optimal indicators of supplemental oxygen are therefore important to prevent hyperoxic organ injuries. In this study, we evaluated a hyperoxic pulmonary injury and assessed the association between alveolar-arterial oxygen difference (AaDO₂) and a degree of lung oedema. In this study, we focused on the hyperoxia-induced lung injury and its association with changes of gas-exchange parameters in post-CA rats. Rats were resuscitated from 10 min of asphyxial CA and stratified into two groups: those with inhaled 100% O₂ (CA-FiO₂ 1.0) and those with 30% O₂ (CA-FiO₂ 0.3). We prepared a sham surgery group for comparison (sham-FiO₂ 0.3). After 2 h, animals were sacrificed, and the lung wet-to-dry (W/D) weight ratio was measured. We collected blood gas results and measured the ratio of partial pressure arterial oxygen and fraction of inspired oxygen (p/f ratio), and calculated AaDO₂. The lung W/D ratio in the CA-FiO₂ 1.0 group (5.8 ± 0.26) was higher than in the CA-FiO₂ 0.3 (4.6 ± 0.42) and sham-FiO₂ 0.3 groups (4.6 ± 0.38, p < 0.01). There was a significant difference in AaDO₂ between CA-FiO₂ 1.0 (215 ± 49.3) and, CA-FiO₂ 0.3 (36.8 ± 32.3), and sham-FiO₂ 0.3 groups (49.0 ± 20.5, p < 0.01). There were also significant changes in pH and blood lactate levels in the early phase among the three groups. AaDO₂ showed the strongest correlation with W/D ratio (r = 0.9415, p < 0.0001), followed by pH (r = -0.5131, p = 0.0294) and p/f ratio (r = -0.3861, p = 0.1135). Hyperoxic injury might cause the pulmonary oedema after CA. Measuring respiratory quotient (RQ) in rodents enabled an accurate calculation for AaDO₂ at a variety level of inhaled O₂. Given that AaDO₂ measurement is non-invasive, we therefore consider AaDO₂ to be a potentially optimal indicator of post-CA hyperoxic pulmonary injury.

We measured changes in blood flow and oxygenation in the brachioradialis muscle using near-infrared spectroscopy (NIRS) during reversal of rocuronium-induced muscle relaxation with administration of sugammadex in patients (n = 25) under general anaesthesia, to investigate whether reversal of muscle relaxant-induced muscle relaxation increases oxygen metabolism in skeletal muscle under general anaesthesia. NIRS measurements, including oxy-haemoglobin (Hb), deoxyHb, total Hb concentration, tissue oxygen index, and various cardiopulmonary parameters, were recorded at four timepoints: T0 (baseline), 3 min before sugammadex administration; T1, immediately before sugammadex administration; T2, at complete recovery of muscle contractility; and T3, 3 min after T2. All measured values at each timepoint were compared using multiple comparison tests. The median values (quartile deviation; QD) (μmol/L) of oxyHb and deoxyHb at T0, T1, T2, and T3 were 0, -0.01 (0.14), -1.15 (0.54), and -1.52 (0.54), and 0, 0.11 (0.06), 0.86 (0.5), and 1.36 (0.61), respectively. The levels of oxyHb were significantly lower and those of deoxyHb were significantly higher at T2 and T3 when compared to those at T1, respectively (P < 0.01). There were no significant changes in other measurements. These results suggest that reversal of rocuronium-induced muscle relaxation by sugammadex slightly increases oxygen metabolism in the brachioradialis muscle. This study might support the clinical finding that administration of neuromuscular blockers decreases whole body oxygen consumption in patients receiving mechanical ventilation under general anaesthesia.

Mild hyperthermia at 39-43 °C for 30-60 min is applied locoregionally to improve the oxygenation status of recurrent breast cancers, thus enhancing the efficacy of radio-, chemo-, and immunotherapy. In this context, estimated (or even conflicting) data are often used in computational modelling of tumour oxygenation and simulation of O₂ transport. In this chapter, we present information that may help to improve adjuvant thermotherapy delivered immediately prior to radiotherapy of recurrent breast cancers. Data are preferentially derived from clinical investigations; in some cases, measurements in experimental breast cancers are included.The biophysical properties presented for healthy, mostly postmenopausal, human breast (composite glandular-adipose-fibrous tissue) measured under normothermic (NT) conditions and in therapeutically heated breast cancers include tissue water content and tissue density. In general, averaged values of parameters reported for NT conditions are higher in breast cancers than in normal breast tissue, i.e., all ratios breast cancer/normal breast are >1. Mean values observed in breast cancers during mild hyperthermia (mHT) are consistently higher than those in NT tumours. Parameters determining convective transports in healthy breast tissue and breast cancer include blood flow rates, blood volume, exchanging water space, arterio-venous shunt flow, interstitial fluid flow rate, interstitial fluid pressure, microvascular permeability, interstitial hydraulic conductivity, and interstitial flow velocity. In general, averaged values of parameters measured under NT conditions are higher in breast cancers than in healthy breast. Except for interstitial fluid pressure, these values increase upon mHT treatment of cancers. Prime factors determining and describing the oxygenation status of the healthy breast, and in NT- versus mHT-treated breast cancers, include: oxygen (O₂) delivery rates, O₂- extractions, O₂- consumption rates, subepidermal microvascular HbO₂, tissue oxygen solubility, oxygen diffusion coefficients, mean O₂ partial pressures pO₂, hypoxic fractions HF <5 mmHg, oxygen enhancement ratio, and mitochondrial ROS production. With the exception of the mean pO₂, O₂ extraction rate and tissue O₂ saturation all parameters listed are distinctly higher in breast cancers under NT conditions compared to normal breast. Mild hyperthermia results in therapeutically relevant improvements of the oxygenation status of cancers and enhances mitochondrial ROS production, thus improving radiosensitivity. Note: The oxygenation status of the healthy (postmenopausal) breast is very similar to that of the normal human subcutis.

Problematic smartphone use (PSU) is common among young people and linked to poor academic performance. However, how PSU affects learning processes remains unclear. This study investigated the influence of auditory cue stimulation during a reading task on the mental workload and prefrontal brain activity of young individuals with PSU. Sixteen university students with PSU and 14 healthy controls (HC) performed a silent reading task, during which fake notification sounds were introduced. Their mental workload was assessed using the NASA Task Load Index (NASA-TLX), and prefrontal brain activity was measured using functional near-infrared spectroscopy (fNIRS). The results of the NASA-TLX suggest that the PSU group experienced greater frustration than the HC group. The fNIRS results showed that in the right medial prefrontal region of the HC group, O₂Hb levels increased following cue stimulation, whereas no change was observed in the PSU group. Moreover, in the HC group, HHb levels in the left lateral prefrontal region decreased after cue stimulation. The findings of the present study demonstrate that university students with PSU experience frustration and exhibit deactivation in the prefrontal regions associated with the executive control network during silent reading in realistic learning situations.

This chapter provides an overview of how international students in the United States used media and interpersonal channels to communicate with family, friends, and each other during the COVID-19 pandemic. The chapter starts by discussing the challenges of international students during the health pandemic. It then provides a review of the role of media during a crisis. Factors influencing media use during the COVID-19 crisis include culture, personality, and time spent in a foreign country. Finally, the chapter ends by providing suggestions for how universities can better equip their international offices to deal with international students during challenging times such as the COVID-19 pandemic.

Recent advances in neonatal intensive care have improved the survival rates of extremely low-birth-weight infants (ELBWIs). However, there has been no obvious improvement in the proportion of survivors without sequelae. Therefore, the development of appropriate management methods for ELBWIs in the neonatal intensive care unit is important to improve outcomes. In this study, we utilised time-domain near-infrared spectroscopy (TD-NIRS) for deep brain monitoring in premature infants in the clinical setting and measured the heads of three ELBWIs once weekly using a TD-NIRS system in transmittance mode. We found that optical signals transmitted through the head were detectable in all ELBWIs. We also confirmed that the total haemoglobin concentration and tissue oxygen saturation decreased in the first month after birth, while the reduced scattering coefficient was not correlated with postmenstrual age. We anticipate that this TD-NIRS technique will be useful for clinical assessment of deep brain tissues for appropriate management of cerebral circulation of ELBWIs in the neonatal intensive care unit.