Immune signature and therapeutic approach of natural killer cell in chronic liver disease and hepatocellular carcinoma.

Natural killer (NK) cells are one of the key members of innate immunity that predominantly reside in the liver, potentiating immune responses against viral infections or malignant tumors. It has been reported that changes in cell numbers and function of NK cells are associated with the development and progression of chronic liver diseases (CLDs) including non-alcoholic fatty liver disease, alcoholic liver disease, and chronic viral hepatitis. Also, it is known that the crosstalk between NK cells and hepatic stellate cells plays an important role in liver fibrosis and cirrhosis. In particular, the impaired functions of NK cells observed in CLDs consequently contribute to occurrence and progression of hepatocellular carcinoma (HCC). Chronic infections by hepatitis B or C viruses counteract the anti-tumor immunity of the host by producing the sheddases. Soluble major histocompatibility complex class I polypeptide-related sequence A (sMICA), released from the cell surfaces by sheddases, disrupts the interaction and affects the function of NK cells. Recently, the MICA/B-NK stimulatory receptor NK group 2 member D (NKG2D) axis has been extensively studied in HCC. HCC patients with low membrane-bound MICA or high sMICA concentration have been associated with poor prognosis. Therefore, reversing the sMICA-mediated downregulation of NKG2D has been proposed as an attractive strategy to enhance both innate and adaptive immune responses against HCC. This review aims to summarize recent studies on NK cell immune signatures and its roles in CLD and hepatocellular carcinogenesis and discusses the therapeutic approaches of MICA/B-NKG2D-based or NK cell-based immunotherapy for HCC.

Multifunctionality of Additively Manufactured Kelvin Foam for Electromagnetic Wave Absorption and Load Bearing.

Rationally engineered porous structures enable lightweight broadband electromagnetic (EM) wave absorbers for countering radar signals or mitigating EM interference between multiple components. However, the scalability of such structures has been hindered by their limited mechanical properties resulting from low density. Herein, an additively manufactured Kelvin foam-based EM wave absorber (KF-EMA) is reported that exhibits multifunctionality, namely EM wave absorption and light-weighted load-bearing structures with constant relative stiffness made possible using bending-dominated lattice structures. Based on tuning design parameters, such as the backbone structures and constituent materials, the proposed KF-EMA features a multilayered 3D-printed design with geometrically optimized KF structures made of carbon black-based backbone composites. The developed KF-EMA demonstrated an absorbance greater than 90% at frequencies ranging from 5.8 to 18 GHz (average EM wave absorption rates of 95.89% and maximum of 99.1% at 15.8 GHz), while the low-density structures of the absorber (≈200 kg m-3 ) still maintained a compression index between the stiffness and relative density (n = 2) under compression. The design strategy paves the way for using metamaterials as mechanically reinforced EM wave absorbers that enable multifunctionality by optimizing unit-cell parameters through a single and low-density structure.

Dexmedetomidine-induced hemodynamic instability in patients undergoing orthopedic upper limb surgery under brachial plexus block: a retrospective study.

BACKGROUND: Hemodynamic instability is a frequent adverse effect following administration of dexmedetomidine (DMED). In this study, we evaluated the incidence of DMED-induced hemodynamic instability and its predictive factors in clinical regional anesthesia practice. METHODS: One hundred sixteen patients who underwent orthopedic upper limb surgery under brachial plexus block with intravenous DMED administration were retrospectively identified. The primary outcome was the incidence of DMED-induced hemodynamic instability. The participants were allocated to a stable or unstable group by their hemodynamic instability status. Patients' characteristics were compared between the groups. The relationship between the potential risk factors and development of DMED-induced hemodynamic instability was analyzed with a logistic regression model. RESULTS: DMED-induced hemodynamic instability was observed in 14.7% of patients (17/116). The unstable group had more women than the stable group (76.5% vs. 39.4%, P = 0.010). When patients were classified into four subgroup according to body mass index (underweight, normal weight, overweight, and obesity), there was significant difference in the composition of the subgroups in the two groups (P = 0.008). In univariate analysis, female sex, obesity, and pre-existing hypertension were significant predictors of DMED-induced hemodynamic instability. Multivariate analysis demonstrated that female sex (adjusted OR 3.86, CI 1.09; 13.59, P = 0.036) and obesity (adjusted OR 6.41, CI 1.22; 33.57, P = 0.028) were independent predictors of DMED-induced hemodynamic instability. CONCLUSIONS: Female and obese patients are more likely to have hemodynamic instability following intravenous DMED administration in clinical regional anesthesia practice. This study suggests that DMED dose may be diminished to prevent hypotensive risk in these populations. TRIAL REGISTRATION: This article was retrospectively registered at WHO clinical trial registry platform (Trial number: KCT0005977 ).

The effect of an eye mask on midazolam requirement for sedation during spinal anesthesia: a randomized controlled trial.

BACKGROUND: Midazolam is frequently used for sedation during spinal anesthesia. However, external environmental factors, such as bright surgical lights, may hamper patient relaxation, which may lead to an increase in the dose of midazolam required and the likelihood of adverse drug effects. We investigated whether using an eye mask to block the external environment could reduce midazolam requirements during spinal anesthesia. METHODS: Participants aged 18-‒80 years, scheduled for elective surgery under spinal anesthesia, were randomly divided into a masked group (wearing eye masks during surgery, n = 20) and a control group (no mask, n = 18). The sedation level was assessed using a modified Observer Assessment of Alertness and Sedation (MOAA/S) scale. Midazolam (1 mg) was incrementally administered every 5 min until moderate sedation (MOAA/S score of 3) was achieved. The bispectral index (BIS) was monitored, and the onset and maintenance times of a BIS < 80 were recorded. RESULTS: The two groups had similar demographic characteristics. The midazolam requirements were significantly lower in the masked group than in the control group (2.8 mg vs. 3.7 mg, P = 0.024). However, the onset and maintenance times for a BIS < 80 were similar. In addition, there were no significant differences in the incidence of side effects or patient satisfaction between the two groups. CONCLUSIONS: Blocking the external environment with an eye mask during spinal anesthesia can reduce the requirement for sedatives, such as midazolam. TRIAL REGISTRATION: The trial was retrospectively registered with the Clinical Research Information Service (No. KCT0005528, 15/10/2020) entitled "Can we reduce an amount of sleeping pills just by blocking light?".

Diabetes Mellitus Promotes Smooth Muscle Cell Proliferation in Mouse Ureteral Tissue through the P-ERK/P-JNK/VEGF/PKC Signaling Pathway.

Background and objectives: The aim of our study was to evaluate the role of diabetes mellitus (DM) as a significant factor affecting spontaneous stone expulsion, as suggested by previous research. Materials and methods: We investigated the influence of DM on the ureter using a murine model. The mouse-model arm of this study used 20 15 -week-old mice, including 10 normal (control) mice and 10 DM mice. We measured the proximal, middle and distal ureteral smooth muscle thickness in each mouse and the differences among ureteral sections were analyzed. Mouse ureteral specimens were also analyzed via western blotting to detect relative protein expression of phosphor-extracellular signal regulated kinases (P-ERK), phosphor-C-Jun N-terminal kinase (P-JNK), vascular endothelial growth factor (VEGF), and protein kinase C (PKC), which are representative factors involved in cell regulation. Results: We observed significant hyperproliferation of ureteral smooth muscle in DM mice compared to normal mice, which may provoke reduced peristalsis. The ureteral smooth muscle of DM mice was significantly thicker than that of normal mice in all ureteral tissues: proximal (p = 0.040), mid (p = 0.010), and distal (p = 0.028). The relative protein expression of P-ERK (p = 0.005) and P-JNK (p = 0.001) was higher in the diabetic group compared to the normal group. Additionally, protein expression of VEGF (p = 0.002) and PKC (p = 0.001) were remarkably up-regulated in DM mice. Conclusions: Hyperproliferation of ureteral smooth muscle was observed in DM mice, but not in normal mice. The pathways mediated by P-ERK, P-JNK, VEGF, and PKC may play an important role in pathological ureteral conditions.

Unilateral Mastication Evaluated Using Asymmetric Functional Tooth Units as a Risk Indicator for Hearing Loss.

BACKGROUND: Some previous studies reported hearing ability can be reduced by impaired masticatory ability, but there has been little evidence reported of an association between hearing loss and unilateral mastication. Therefore, this study aimed to investigate the relationship between unilateral mastication (UM), estimated from individual functional tooth units (FTUs), and hearing loss in a representative sample of Korean adults. METHODS: The analyzed data were obtained from 1,773 adults aged 40-89 years who participated in Korean national survey. Hearing loss was defined as a pure-tone average of >25 dB at frequencies of 0.5, 1, 2, and 4 kHz in either ear. In each subject, UM was calculated as the difference in the sums of the FTU scores, which is an index of posterior tooth occlusion, on the two sides of the oral cavity. The scores were used to classify the UM into low, moderate, and high. The adjusted odds ratios (aORs) and their 95% confidence intervals (CIs) were calculated in multivariable logistic regression analyses. RESULTS: When controlling for sociodemographic factors, the aOR for hearing loss was 3.12 (95% CI, 1.21-8.03) for high UM relative to low UM. This association remained in a fully-adjusted model containing factors related to noise exposure (aOR 2.88; 95% CI, 1.12-7.46). CONCLUSION: Adults with high UM as measured using FTUs showed a higher occurrence of hearing loss than those with low UM.

Ginsenoside Rk1 Induces Apoptosis in Neuroblastoma Cells Through Loss of Mitochondrial Membrane Potential and Activation of Caspases.

Neuroblastoma (NB) is the most common childhood cancer, with a very poor prognosis. More than 60% of children with NB die within five years; therefore, a more effective therapy for NB is required. Although ginsenoside has been shown to significantly inhibit the growth of various cancers, the effect of ginsenoside Rk1 on neuroblastoma has not been known yet. Hence, we examined the anticancer effects of highly pure Rk1 on neuroblastoma cell lines. The apoptotic effects of Rk1 on neuroblastoma cells were examined using cell viability assay, flow cytometry and cell staining assay, and the change in gene expression levels were analysed using RT-PCR, western blots, and immunohistochemistry. The metastatic effect of Rk1 was monitored by wound healing assay, invasion and migration with Matrigels. Rk1 inhibited neuroblastoma cell viability dose-dependently. Rk1-induced apoptosis was investigated through nuclear condensation and mitochondrial membrane potential loss, and it showed that Rk1 can induce cell cycle arrest at the G0/G1 phase but also inhibit the metastatic ability of neuroblastoma cells. Moreover, Rk1 (30 mg/kg) injections markedly inhibited xenograft tumor growth. These findings demonstrate that Rk1 might be valuable in the development of anti-cancer agents for neuroblastoma treatment.

Association between age at asthma diagnosis and tooth loss.

OBJECTIVES: This study aimed to investigate the association between age at asthma diagnosis and tooth loss due to caries using data obtained from the Korean National Health and Nutrition Examination Survey. MATERIALS AND METHODS: A complex sample multivariable linear regression was used, and the results were analysed. Age at diagnosis and the number of teeth lost were set as independent and dependent variables, respectively. Among the total 65,973 subjects, 10,056 aged <12 years and 11,714 with missing values in dependent and independent variables were excluded. Asthmatic subjects were divided into the following age groups based on the age at diagnosis: 0-6 years, 7-12 years, 13-18 years, 19-28 years, and 29-64 years. In each analysis, the calibration was performed by adding covariates to each model. RESULTS: Compared with the no asthma group (ß = 0), the values of ß in asthmatic subjects belonging to the age groups 0-6 years (ß = 0.794, 0.521, 0.560) and 7-12 years (ß = 0.527, 0.407, 0.437) were high in all models. CONCLUSIONS: Our findings revealed significant increase in tooth loss due to caries after early asthma diagnosis at 0-6 years (ß = 0.560, p < .001) and 7-12 years (ß = 0.437, p < .001). Clinicians need to shift their perception of dental risks in young asthmatic patients and provide active oral health care to them.

Effects of integrated treatment with LED and microcurrent on muscle tone and stiffness in the calf muscle during moderate aerobic exercise.

[Purpose] This study aimed to investigate the effects of the therapeutic device combined with LED and microcurrent (MC) on muscle tone and stiffness in the calf muscle after its application during moderate aerobic exercise. [Subjects and Methods] Twenty healthy adult subjects were randomized to either the test group of the therapeutic device combined with LED and MC or the control group, and they walked on a 10%-sloped treadmill with a 5 km/hr speed for 30 minutes. Each of the subjects in the test group performed treadmill exercise with the therapeutic device attached to the edge of his or her calf muscle. After the exercise, the muscle tone and stiffness at the edge of the calf muscle were measured. [Results] With respect to the muscle tone, a statistically significant difference was found between the two groups only 5 minutes after the exercise. Concerning muscle stiffness, significant differences were shown between the two groups right after the exercise and 5 minutes after the exercise. [Conclusion] Integrated treatment with LED and MC on is considered helpful for lowering the muscle tone 5 minutes after the exercise, and for lowering the muscle stiffness right after the exercise and 5 minutes after the exercise.

Effects of measurement posture and stimulation intensity on the nociceptive flexion reflex (RIII reflex).

[Purpose] The purpose of this study was to examine the effects of the measurement posture and stimulation intensity on the nociceptive flexion reflex (RIII reflex). [Subjects and Methods] Thirty normal female adult subjects were selected for this study. Their RIII reflexes were measured in three positions and with three degrees of stimulation intensity. The measurement posture was randomly selected. The analysis items were the stimulation intensity of the induced RIII reflex, the amplitude of the RIII reflex, and the numeric rating scale (NRS). [Results] The study results showed statistically significant differences in the interaction effects between the measurement posture and the stimulation intensity. The NRS showed no statistically significant differences in the interaction effects but showed statistically significant differences in the main effect. The amplitude of the RIII reflex showed no statistically significant differences in the interaction effects and showed statistically significant differences only in the stimulation intensity. [Conclusion] The study results suggest that the RIII reflex may be influenced by the measurement posture and stimulation intensity.

Effects of body mass index on plantar pressure and balance.

[Purpose] To suggest physiotherapy programs and to determine foot stability based on the results of plantar pressure and spontaneity balance in the normal group and in the obesity group according to the body mass index (BMI). [Subjects and Methods] The plantar pressure and balance of 20 females college students in their 20s were measured according to their BMI. BMI was measured by using BMS 330. The peak plantar pressure was measured in a static position in the forefoot and hind-foot areas. To study balance, the spontaneity balance of each foot was measured on both stable and unstable surfaces. [Results] In terms of plantar pressure, no significant change was observed in the forefoot and hind-foot peak pressure. In terms of spontaneity balance, no significant difference in foot position interaction was observed on both stable and unstable surfaces, while a significant difference was observed in the foot position between the groups. [Conclusion] The index of hind-foot spontaneity balance was low, particularly in the obesity group. This meant significant hind-foot swaying. The forefoot body weight support percentage increased to reinforce the reduced spontaneity balance index.

Effects of galvanic vestibular stimulation on event related potentials.

[Purpose] The purpose of this study was to examine the effects of galvanic vestibular stimulation on event-related potentials. [Subjects and Methods] Forty normal female adult subjects were randomly distributed to a galvanic vestibular stimulation application group (20 subjects) and sham group (20 subjects). For galvanic vestibular stimulation application, a positive electrode was applied to the right mastoid process, and a negative electrode was applied to the left mastoid process; simulation was applied for 10 minutes. A test was conducted on the N100 and P300 components of the event-related potentials before and after galvanic vestibular stimulation. [Results] The N100 latency showed statistically significant differences in interaction effects between time and group in the F3, F4, Fz, and Pz areas. The P300 latency showed the same results in the Fp1 and Fp2 areas, the N100 amplitude showed the same results in the Fp2, Fz, and Pz areas; and the P300 amplitude showed the same results in the Pz area. [Conclusion] These results suggest that galvanic vestibular stimulation may play a positive role in the N100 and P300 components of the event-related potentials of the cerebral cortex related to decision-making in matching words with images.

300-MHz-repetition-rate, all-fiber, femtosecond laser mode-locked by planar lightwave circuit-based saturable absorber.

We show the implementation of fiber-pigtailed, evanescent-field-interacting, single-walled carbon nanotube (CNT)-based saturable absorbers (SAs) using standard planar lightwave circuit (PLC) fabrication processes. The implemented PLC-CNT-SA device is employed to realize self-starting, high-repetition-rate, all-fiber ring oscillators at telecommunication wavelength. We demonstrate all-fiber Er ring lasers operating at 303-MHz (soliton regime) and 274-MHz (stretched-pulse regime) repetition-rates. The 303-MHz (274-MHz) laser centered at 1555 nm (1550 nm) provides 7.5 nm (19 nm) spectral bandwidth. After extra-cavity amplilfication, the amplified pulse train of the 303-MHz (274-MHz) laser delivers 209 fs (178 fs) pulses. To our knowledge, this corresponds to the highest repetition-rates achieved for femtosecond lasers employing evanescent-field-interacting SAs. The demonstrated SA fabrication method, which is based on well-established PLC processes, also shows a potential way for mass-producible and lower-cost waveguide-type SA devices suitable for all-fiber and waveguide lasers.

Dosimetric Effects of Magnetic Resonance Imaging-assisted Radiotherapy Planning: Dose Optimization for Target Volumes at High Risk and Analytic Radiobiological Dose Evaluation.

Based on the assumption that apparent diffusion coefficients (ADCs) define high-risk clinical target volume (aCTVHR) in high-grade glioma in a cellularity-dependent manner, the dosimetric effects of aCTVHR-targeted dose optimization were evaluated in two intensity-modulated radiation therapy (IMRT) plans. Diffusion-weighted magnetic resonance (MR) images and ADC maps were analyzed qualitatively and quantitatively to determine aCTVHR in a high-grade glioma with high cellularity. After confirming tumor malignancy using the average and minimum ADCs and ADC ratios, the aCTVHR with double- or triple-restricted water diffusion was defined on computed tomography images through image registration. Doses to the aCTVHR and CTV defined on T1-weighted MR images were optimized using a simultaneous integrated boost technique. The dosimetric benefits for CTVs and organs at risk (OARs) were compared using dose volume histograms and various biophysical indices in an ADC map-based IMRT (IMRTADC) plan and a conventional IMRT (IMRTconv) plan. The IMRTADC plan improved dose conformity up to 15 times, compared to the IMRTconv plan. It reduced the equivalent uniform doses in the visual system and brain stem by more than 10% and 16%, respectively. The ADC-based target differentiation and dose optimization may facilitate conformal dose distribution to the aCTVHR and OAR sparing in an IMRT plan.

Comparison of VMAT-SABR treatment plans with flattening filter (FF) and flattening filter-free (FFF) beam for localized prostate cancer.

The purpose of this study is to investigate the feasibility of using a flattening filter-free (FFF) beam with an endorectal balloon for stereotactic ablative body radiotherapy (SABR) of clinically localized prostate cancer. We assessed plans of SABR with volumetric-modulated arc therapy (VMAT) that used a flattening filter (FF) beam and an FFF beam and compared the verification results of dosimetric quality assurance for all pretreatment plans. A total of 20 patients with prostate cancer were enrolled in the study. SABR plans using VMAT with two full arcs were optimized in the Eclipse treatment planning system. All plans prescribed 42.7 Gy in 7 fractions of 6.1 Gy each. Four SABR plans were computed for each patient: two with FF beams and two with FFF beams of 6 and 10 MV. For all plans, the cumulative dose-volume histograms (DVHs) for the target volumes and organs at risk (OARs) were recorded and compared. Pretreatment quality assurance (QA) was performed using the I'mRT MatriXX system and radiochromic EBT3 film to verify treatment delivery, and gamma analysis was used to quantify the agreement between calculations and measurements. In addition, total monitor units (MUs) and delivery time were investigated as technical parameters of delivery. All four plans achieved adequate dose conformity to the target volumes and had comparable dosimetric data. The DVHs of all four plans for each patient were very similar. All plans were highly conformal with CI < 1.05 and CN > 0.90, and the doses were homogeneous (HI = 0.08-0.15). Sparing for the bladder and rectum was slightly better with the 10 MV FF and FFF plans than with the 6 MV FF and FFF plans, but the difference was negligible. However, there was no significant difference in sparing for the other OARs. The mean agreement with the 3%/3 mm criterion was higher than 97% for verifying all plans. For the 2%/2 mm criterion, the corresponding agreement values were more than 90%, which showed that the plans were acceptable. The mean MUs and delivery time used were 1701 ± 101 and 3.02 ± 0.17 min for 6 MV FF, 1870 ± 116 and 2.01 ± 0.01 min for 6 MV FFF, 1471 ± 86 and 2.68 ± 0.14 min for 10 MV FF, and 1619 ± 101 and 2.00 ± 0.00 min for 10MV FFF, respectively. In the current study, the dose distributions of the prostate SABR plans using 6 and 10 MV FFF beams were similar to those using 6 and 10 MV FF beams. However, this study confirmed that SABR treatment using an FFF beam had an advantage with respect to delivery time. In addition, all pretreatment plans were verified as acceptable and their results were comparable. Therefore, the results of this study suggest that the use of an FFF beam for prostate SABR is a feasible and efficient technique, if carefully applied.

Development of municipal solid waste classification in Korea based on fossil carbon fraction.

UNLABELLED: Environmental problems and climate change arising from waste incineration are taken quite seriously in the world. In Korea, the waste disposal methods are largely classified into landfill, incineration, recycling, etc. and the amount of incinerated waste has risen by 24.5% from 2002. In the analysis of CO2emissions estimations of waste incinerators fossil carbon content are main factor by the IPCC. FCF differs depending on the characteristics of waste in each country, and a wide range of default values are proposed by the IPCC. This study conducted research on the existing classifications of the IPCC and Korean waste classification systems based on FCF for accurate greenhouse gas emissions estimation of waste incineration. The characteristics possible for sorting were classified according to FCF and form. The characteristics sorted according to fossil carbon fraction were paper, textiles, rubber, and leather. Paper was classified into pure paper and processed paper; textiles were classified into cotton and synthetic fibers; and rubber and leather were classified into artificial and natural. The analysis of FCF was implemented by collecting representative samples from each classification group, by applying the 14C method, and using AMS equipment. And the analysis values were compared with the default values proposed by the IPCC. In this study of garden and park waste and plastics, the differences were within the range of the IPCC default values or the differences were negligible. However, coated paper, synthetic textiles, natural rubber, synthetic rubber, artificial leather, and other wastes showed differences of over 10% in FCF content. IPCC is comprised of largely 9 types of qualitative classifications, in emissions estimation a great difference can occur from the combined characteristics according with the existing IPCC classification system by using the minutely classified waste characteristics as in this study. IMPLICATIONS: Fossil carbon fraction (FCF) differs depending on the characteristics of waste in each country; and a wide range of default values are proposed by the IPCC. This study conducted research on the existing classifications of the IPCC and Korean waste classification systems based on FCF for accurate greenhouse gas emissions estimation of waste incineration.

Effect of galvanic vestibular stimulation on movement-related cortical potential.

[Purpose] This study examined the effects of galvanic vestibular stimulation on motion-related cortical potential. [Subjects and Methods] Fourty healthy female adult subjects each received galvanic vestibular stimulation or sham treatment. For galvanic vestibular stimulation, the anode and cathode were applied to the right and left mastoid processes, respectively, for 10 minutes. Motion-related cortical potential was tested pre- and post-treatment. To measure motion-related cortical potential, surface electromyography signals were generated by 50 thumb abductions with electrode application on the abductor pollicis brevis of the left (i.e., non-dominant) hand. [Results] The negative slope cortical potential on the C3 area (i.e., dominant hand) and cortical negative slope and motor potential on the C4 area (i.e., non-dominant hand) showed significant interaction effects. The galvanic vestibular stimulation group showed an increased negative slope amplitude in the C3 area, and increased negative slope and motor potential amplitudes in the C4 area compared to the sham group. [Conclusion] Galvanic vestibular stimulation increases the negative slope and motor potential amplitudes of the homonymous brain cortex area, which controls hand function and motion-related cortical potential, and the negative slope amplitude of the opposite cortical area, thus activating the brain areas for hand function.

The relationship between serum progesterone concentration and anesthetic and analgesic requirements: a prospective observational study of parturients undergoing cesarean delivery.

BACKGROUND: In clinical practice, pregnant women have lower anesthetic requirements for general anesthesia than nonpregnant women. Although the hormonal changes such as progesterone associated with pregnancy may affect the minimum alveolar concentration of volatile anesthetics, the relationship between the anesthetic or analgesic requirements and progesterone level in full-term women has not been studied. In this study, we attempted to identify relationships between anesthetic or analgesic requirements and maternal serum concentrations of progesterone. METHODS: We studied 100 parturients >36 weeks' gestation who were scheduled for planned cesarean delivery under general anesthesia. Venous blood was collected to measure the maternal progesterone concentration. Anesthesia was induced with 4 to 5 mg/kg thiopental and 0.8 mg/kg rocuronium. During anesthetic maintenance, sevoflurane 0.5% to 2.0% and nitrous oxide 50% in oxygen were titrated based on arterial blood pressure, heart rate, and bispectral index value. Vital signs, bispectral index, end-tidal sevoflurane concentration, and sevoflurane consumption per hour were recorded. Visual analog scale pain scores and cumulative analgesic consumption were recorded at 2, 24, and 48 hours postoperatively. RESULTS: The mean serum progesterone concentration was 128.2 ± 83.0 ng/mL. There was a significant negative correlation between sevoflurane consumption per hour and serum progesterone concentration (Pearson correlation r = -0.26; 95% confidence interval, -0.44 to -0.05, P = 0.01). Cumulative analgesic consumption at postoperative hours 2 (r = -0.20, P = 0.05), 24 (r = -0.25, P = 0.02), and 48 (r = -0.28, P = 0.01) were correlated inversely with serum progesterone concentration. Women with high progesterone levels (higher than the median value) had lower sevoflurane consumption per hour (P = 0.02) and 48-hour postoperative cumulative analgesic consumption (P = 0.02) than women with low (below the median value) levels. CONCLUSIONS: The decreased anesthetic and analgesic requirements of near full-term parturients might partially depend on serum progesterone concentration.

Optimal nasopharyngeal temperature probe placement.

BACKGROUND: Although the nasopharynx is a commonly used temperature-monitoring site during general anesthesia, it is unknown whether the position of nasopharyngeal temperature probes placed blindly by anesthesia practitioners is optimal. The purposes of this study were (1) to determine where the nasopharyngeal mucosa is in closest proximity to the internal carotid artery (ICA) and (2) to evaluate the tip position of nasopharyngeal temperature probes that were placed by anesthesiology residents and nurse anesthetists. METHODS: In the first phase of the study, we reviewed enhanced axial computed tomography images of 100 patients to determine where the nasopharyngeal mucosa was in closest proximity to the left or the right ICA. The distance from this point to the nares was then measured in the sagittal image. In the second phase of the study, nasendoscopy was used to evaluate the positioning of nasopharyngeal temperature probes placed by anesthesiology residents (244 patients) or nurse anesthetists (116 patients). Malpositioned probes were repositioned to an optimal location, and the temperature differences were recorded. RESULTS: In the computed tomography images, the mucosa in closest proximity to the ICA was in the upper, mid-, and lower nasopharynx in 60%, 38%, and 2% of patients, respectively. The average distances between the ICA and the nasopharyngeal mucosa in the upper portion were significantly shorter than those in the lower portion (female: 9.4 vs 16.8 mm, P < 0.001; male: 12.4 vs 18.8 mm, P < 0.001). The average distances (95% prediction interval) from the nares to the upper portion of the nasopharynx through the inferior meatus were 9.1 (8.1-10.2) cm in females and 9.7 (8.6-10.8) cm in males. Temperature probes were correctly positioned in the upper or mid-nasopharynx by residents and nurses in 43% (95% confidence interval [CI], 37%-49%) and 41% (95% CI, 36%-50%), respectively. When the probe was inadvertently placed in the nasal cavity, the median (95% CI) temperature difference from the upper nasopharynx was 0.2°C (0.15°C-0.25°C). CONCLUSIONS: The closest portion of the nasopharyngeal mucosa to the ICA is within the upper or mid-nasopharynx. The depth from the nares to the upper one-third of the nasopharynx is approximately 10 cm. Less than half of nasopharyngeal temperature probes placed blindly by practitioners were optimally positioned.

A study on N2O measurement characteristics using photoacoustic spectroscopy (PAS).

N2O, which is emitted mainly from nitrogen decomposition via bacteria, livestock manure, agricultural fertilizer use, fossil fuel combustion and waste incineration, is classified as a substance that causes significant destruction of the ozone layer. The N2O measurement methods for these emission sources may be divided into chromatography, optical, and electrical current measurements. Chromatography has been widely utilized for analyzing N2O. However, up until now, few studies have been conducted on N2O using photoacoustic spectroscopy. Therefore, this study aimed to evaluate performance of photoacoustic spectroscopy in this regard based on laboratory and field test results. The repeatability of photoacoustic spectroscopy was measured at 1.12%, which is lower than the repeatability of 3.0% suggested by the ISO 1564 standard, so, it has shown an excellent repeatability. The detection limit was determined to be 0.025 ppm, and the response time was confirmed to be 3 min and 26 s. The results of comparison between these measurements and GC show that the latter has superior accuracy, but mobility and convenience are superior for PAS. On the contrary, GC has a continuous measurement limitation, but PAS makes it possible to conduct continuous measurements. Therefore, PAS can be extremely useful to confirm the characteristics of N2O emissions and to quantify their amount.