Observaciones en el mundo real sobre la efectividad del sistema flash de monitorización de glucosa en la práctica clínica en Chile / Real-world observations of the effectiveness of the flash glucose monitoring in clinical practice in Chile

OBJETIVO: Evaluar el tiempo en rango de glucosa y su asociación con otras medidas del control glicémico establecidas por el consenso internacional del tiempo en rango en usuarios de vida real del sistema flash de monitorización de glucosa FreeStyle LibreTM en Chile. MÉTODOS: Se analizaron los datos provenientes de la base de datos Freestyle Libre™ entre diciembre de 2014 y enero de 2022. Las lecturas se dividieron en 10 grupos (deciles) del mismo tamaño (cada decil contenía aproximadamente 498 usuarios) en función del tiempo en rango. Para cada decil se calculó la media de determinaciones diarias, el promedio de glucosa, la HbA1c, la desviación estándar de glucosa, el coeficiente de variación de la glucosa, el tiempo en rango, el tiempo de glucosa (porcentaje) por encima de 250 mg/dL (TA250), el tiempo de glucosa (porcentaje) por encima de 180 mg/dL (TA180), el tiempo por debajo (porcentaje) de 70 mg/dL (TB70) y el tiempo por debajo (porcentaje) de 54 mg/dL (TB54). RESULTADOS: Desde diciembre de 2014 hasta enero de 2022 hubo 4984 lectores. El grupo con el mayor tiempo en rango mostró significativamente una menor glucosa promedio que el grupo con el tiempo en rango más bajo (decil 1: media 248,3 mg/dL, decil 10: media 113,2 mg/L, diferencia ­135,1 mg/dL, p<0.05). Asimismo, el mayor tiempo en rango se asoció con una menor desviación estándar (decil 1: media 93,7mg/dL, decil 10: media 26,7mg/L, diferencia: -67,0 mg/ dL, p<0,05), menor coeficiente de variación (decil 1: media 37,8%, decil 10: media 23,3%, diferencia: -14,5%, p<0,05), menor TA250 (decil 1: media 46,5%, decil 10: media 0,2%, diferencia: -46,3%, p<0.05), menor TA180 (decil 1: media 73,9%, decil 10: media 3,8%, diferencia: -70,1%, p<0.05), menor TB70 (decil 5: mediana 6,13%, decil 10: mediana 1,70%, diferencia: -4,43%, p<0.05) y menor TB54 (decil 5: mediana 1,79%, decil 10: mediana 0,12%, diferencia: -1,67%, p<0.05). El mayor tiempo en rango se asoció también significativamente con más determinaciones diarias (decil 1: media 11,4, decil 10: media 16,6, diferencia: 5,2, p<0,05). La frecuencia media de las determinaciones entre todos los lectores fue de 14,7 determinaciones diarias. CONCLUSIONES: En los pacientes con diabetes en Chile, el empleo del sistema flash de monitorización demuestra la asociación entre el mayor tiempo en rango, la reducción de la variabilidad de la glucosa y un menor riesgo de hiperglucemias e hipoglicemias y también con un mayor compromiso.

OBJECTIVE: To evaluate glucose time in range and its association with other metrics of glucose control established by the International Consensus on TIR amongst real-life patients using the Flash Glucose Monitoring system FreeStyle LibreTM in Chile. METHODS: Data from the Freestyle Libre™ database between December 2014 and January 2022 were analyzed. Readers were divided into 10 groups (deciles) of the same size (each decile had approximately 498 users) according to time in range. For each decile of time in range, the mean of daily scans, average glucose, estimated HbA1c, glucose standard deviation, glucose coefficient of variation, time in range, glucose time (percentage) above 250 mg/dL (TA250), and glucose time (percentage) above 180 mg/dL (TA180), and the median of glucose time (percentage) below 70 mg/dL (TB70) and glucose time (percentage) below 54 mg/dL (TB54), were calculated. RESULTS: From December 2014 to January 2022, there were 4984 readers. The group with the highest TIR showed significantly lower average glucose than the group with the lowest TIR (decile 1: mean 248.3 mg/dL, decile 10: mean 113.2 mg/L, difference: ­135.1 mg/dL, p<0.05). In addition, more time in range was associated with a lower glucose standard deviation (decile 1: mean 93.7 mg/dL, decile 10: mean 26.7 mg/L, difference: -67.0 mg/dL, p<0.05), lower glucose coefficient of variation (decile 1: mean 37.8%, decile 10: mean 23.3%, difference: -14.5%, p<0.05), lower TA250 (decile 1: mean 46.5%, decile 10: mean 0.2%, difference: -46.3%, p<0.05),lower TA180 (decile 1: mean 73.9%, decile 10: mean 3.8%, difference: -70.1%, p<0.05), lower TB70 (decile 5: median 6.13%, decile 10: median 1.70%, difference: -4.43%, p<0.05) and lower TB54 (decile 5: median 1.79%, decile 10: median 0.12%, difference: -1.67%, p<0.05). Greater TIR was also associated with significantly more daily scans (decile 1: mean 11.4, decile 10: mean 16.6, difference: 5.2, p<0.05). Mean scan frequency amongst all readers was 14.7 daily scans. CONCLUSIONS: In patients with diabetes from Chile, the use of the flash glucose monitoring system demonstrates the association between greater TIR, reduced glucose variability, and reduced risk of hyperglycemia and hypoglycemia, and also its association with greater engagement.

Relación del volumen de agua corporal total, el extracelular, y preeclampsia. Revisión narrativa de la literatura / Relation of total and extracellular body water and preeclampsia. Literature review

RESUMEN La preeclampsia es una importante causa de mortalidad materna mundial, identificar de manera temprana las gestantes con riesgo de desarrollarla, es una medida preventiva de gran impacto. La medición del agua corporal se ha documentado desde 1994, y desde 2015 se demostró su relación con el riesgo de desarrollar preeclampsia. Por lo anterior se realizó una revisión de la relación del agua corporal y la preeclampsia hasta junio de 2019, con 17 artículos seleccionados. Producto de la revisión se concluyó que la medición del agua corporal en gestantes podría detectar la aparición de preeclampsia para establecer un seguimiento estricto temprano a las mujeres con mayor riesgo de presentarla. Estas mediciones se realizan con métodos sencillos, no invasivos y de bajo costo, como la impedancia eléctrica por análisis espectral. Sin embargo, se requieren estudios con mayor rigor metodológico para el estudio de una prueba diagnóstica como la que se propone. MÉD.UIS.2021;34(2): 49-60.

ABSTRACT Preeclampsia is an important cause of maternal mortality worldwide. Early identification of pregnant women at risk of developing it is a preventive measure of great impact. Body water measurement has been documented since 1994, and since 2015 it was stablished its relationship with risk of developing preeclampsia. Therefore, a review of the relationship between body water and preeclampsia was carried out until June 2019, with 17 papers selected. As a result of the review, it was concluded that the measurement of body water in pregnant women could detect the appearance of preeclampsia to establish a strict early follow-up of women with a higher risk of presenting it. These measurements are made with simple, non-invasive and low-cost procedure, such as electrical impedance by spectral analysis. However, studies with greater methodological rigor are required for the study of a diagnostic test such as the one proposed. MÉD.UIS.2021;34(2): 49-60.

Hidratación en el síndrome urémico hemolítico / Hydration in hemolytic uremic syndrome

El síndrome urémico hemolítico asociado a diarrea es precedido por una gastroenteritis por Escherichia coli productora de toxina Shiga. Se recomiendan medidas de sostén, especialmente, la restricción hídrica para evitar la sobrecarga cardiopulmonar. Sin embargo, la expansión de volumen con líquidos isotónicos, en el período prodrómico o síndrome urémico hemolítico establecido, es segura y eficaz, reduce los requerimientos de diálisis, los días de internación y de terapia intensiva, los eventos neurológicos y la hiponatremia.Por ello, se propone, bajo supervisión nefrológica y/o garantizando el acceso a un centro de alta complejidad a corto plazo, hidratar a todo paciente sin signos de sobrecarga cardiopulmonar, independientemente de su función renal, con expansión inicial de volumen. Luego, si se logra una diuresis adecuada, no dializarlo (excepto que presente un trastorno metabólico/electrolítico intratable médicamente) y continuar la hidratación con una solución isotónica de dextrosa al 5 % para una adecuada hidratación y diuresis.

Diarrhea-associated hemolytic uremic syndrome is preceded by gastroenteritis due to Shiga toxin-producing Escherichia coli. Support measures are recommended, specifically, fluid restriction to avoid cardiopulmonary overload. However, in the prodromal period or with established hemolytic uremic syndrome, volume expansion with isotonic fluids is safe and effective, and reduces the need for dialysis, the length of hospital and intensive care stay, neurological events, and hyponatremia.Therefore, when nephrological monitoring is available and/or short-term access to a tertiary care hospital is guaranteed, it is suggested to hydrate patients with no signs of cardiopulmonary overload, regardless of their renal function, with initial volume expansion. Afterwards, if an adequate urine output is achieved, the patient should not be dialyzed (except if they have a medically intractable metabolic/electrolyte disorder) and hydration should be continued with an isotonic solution containing 5 % dextrose for adequate hydration and urine output.

Preliminary observation on imbalance degree of impedance in extracellular fluid of cells in the twelve meridians in healthy subjects / 中国针灸

OBJECTIVE@#To calculate the imbalance degree (IBD) of left-right meridian (IBD-LRM), IBD of exterior-interior meridian (IBD-EIM) and IBD of hand-foot meridians (IBD-HFM) of impedance in extracellular fluid of cells in twelve meridians of healthy subjects, so as to provide foundation for meridian diagnosis.@*METHODS@#A total of 31 healthy volunteers were enrolled and bioelectrical impedance spectroscopy (BIS) was applied. The constant current (from 1 to 100 kHz, 200 μA) was connected into the bilateral twelve meridians through two excitation electrodes with a distance of 10 cm. Two measuring electrodes, with an interval of 5 cm, were set in between the two excitation electrodes to collect the voltage amplitude and phase. The Cole-Cole curve fitting was used to calculate the impedance of extracellular fluid of cells in the twelve meridians; the IBD-LRM, IBD-EIM and IBD-HFM as well as their absolute values were calculated.@*RESULTS@#The impedance of extracellular fluid in the left side was higher than that in right side in the large intestine meridian, the small intestine meridian and the bladder meridian (<0.05, <0.01). The mean value of IBD-LRM of extracellular fluid was (4.0±1.4) %; the mean value of absolute value of IBD-LRM was (15.0±1.1) %; the maximum absolute value of IBD-LRM was the bladder meridian. The mean value of IBD-EIM was (3.3±1.0) %; the mean value of absolute value of IBD-EIM was (17.9±1.6) %; the maximum absolute value of IBD-EIM was the bladder meridian and the kidney meridian. The impedance of extracellular fluid of hand meridian, hand meridian and hand meridian were lower than those of foot meridians. The mean value of IBD-HFM was (-2.6±1.1) %; the mean value of absolute value of IBD-HFM was (19.7±1.7) %; the maximum absolute value of IBD-HFM was meridian; the imbalance of meridians was greater than meridians. There were significant differences in impedance of extracellular fluid between left and right and between hands and feet (<0.05, <0.01).@*CONCLUSION@#The extracellular fluid of left-right meridians of healthy subjects is different, but the absolute value of IBD is low; the mean value of exterior meridian and interior meridian is very close, and the absolute value of IBD is medium; the impedance of the foot meridians are greater than the hand meridians, and the absolute value of IBD is relatively high.

Discovery of a new division system in brain and the regionalized drainage route of brain interstitial fluid / 北京大学学报(医学版)

Brain extracellular space (ECS) is a narrow, irregular space, which provides immediate living environment for neural cells and accounts for approximately 15%-20% of the total volume of living brain. Twenty-five years ago, as an interventional radiologist, the author was engaged in investigating early diagnosis and treatment of cerebral ischemic stroke, and the parameters of brain ECS was firstly derived and demonstrated during the study of the permeability of blood-brain barrier (BBB) and its diffusion changes in the cerebral ischemic tissue. Since then, the author and his team had been working on developing a novel measuring method of ECS: tracer-based magnetic resonance imaging (MRI), which could measure brain ECS parameters in the whole brain scale and make the dynamic drainage process of the labelled brain interstitial fluid (ISF) visualized. By using the new method, the team made a series of new findings about the brain ECS and ISF, including the discovery of a new division system in the brain, named regionalized ISF drainage system. We found that the ISF drainage in the deep brain was regionalized and the structural and functional parameters in different interstitial system (ISS) divisions were disparate. The ISF in the caudate nucleus could be drained to ipsilateral cortex and finally into the subarachnoid space, which maintained the pathway of ISF-cerebrospinal fluid (CSF) exchange. However, the ISF in the thalamus was eliminated locally in its anatomical division. After verifying the nature of the barrier structure between different drainage divisions, the author proposed the hypothesis of "regionalized brain homeostasis". Thus, we demonstrated that the brain was protected not only by the BBB, which avoided potential exogenous damage through the vascular system, but was also protected by an internal ISF drainage barrier to avoid potentially harmful interference from other ECS divisions in the deep brain. With the new findings and the proposed hypothesis, an innovative therapeutic method for the treatment of encephalopathy with local drug delivery via the brain ECS pathway was established. By using this new administration method, the drug was achieved directly to the space around neurons or target regions, overwhelming the impendence from the blood-brain barrier, thus solved the obstacles of low efficiency in traditional drug investigation. At present, new methods and discoveries developed by the author and his team have been widely applied in several frontier fields including neuroscience, new drug research and development, neurodevelopment aerospace medicine, clinical encephalopathy treatment,new neural network modeling and so on.

Temporary acceleration of interstitial fluid drainage in excited brain region induced by movement / 北京大学学报(医学版)

OBJECTIVE@#To investigate the changes of brain interstitial fluid (ISF) induced by movement.@*METHODS@#Twenty mature male Sprague-Dawley rats were randomly divided into two groups: control group and movement group. Electrophysiological neurons in caudate nuclear of additional five rats were recorded and the differences analyzed between under anesthesia and by movement. In the control group, the rats were anesthetized using isoflurane continuously during the experiment process. In the meantime the magnetic tracer was injected into the center of the caudate nucleus and multi-period magnetic resonance scanning was performed at several time points until high signal intensity invisible in the images. In the movement group, the rats were anesthetized for the injection of the tracer, and the first post-injection magnetic resonance scanning was performed. Then the rats were waken and allowed moving voluntarily for 20 minutes. The rats were anesthetized again and multi-period magnetic resonance scanning was performed until the experiment ended. NanoDetect system (Version 1.2, MRI lab, Beijing, China) was used to measure the parameters on ISF, which included the weighed signal intensity (weighed ΔSI) , the term predicting the amount of the tracer, and half-time of the tracer. In movement group, the weighed ΔSI at the time points of pre-movement and 10, 40, 70, 130, and 190 minutes after movement were calculated respectively. In control group, the weighed ΔSI at the same time points also were measured. The weighed ΔSI and half-time were compared between the two groups.@*RESULTS@#The electrophysiological recording and data analysis showed significant difference in the local field potential of Caudate Nucleus between under anesthesia and by movement. The weighed ΔSI (unit: ΔSI×mm3) values of the two groups, presented by movement group vs. control group, were as followings, 60 257.1±23 069.2 vs. 61 072.0±19 547.3 at pre-move, 83 624.3±21 475.7 vs. 71 218.1±12 586.5 at 10 min after movement, 57 336.0±36 243.4 vs. 69 756.1±13 306.0 at 40 min after movement, 43 705.9±10 246.3 vs. 55 443.2±20 733.3 at 70 min after movement, 7 734.9±2 645.2 vs. 8 967.6±2 007.3 at 130 min after movement and 2 497.3±987.5 vs. 3 013.2±1 760.8 at 190 min after movement. Moreover, at 40 min after movement, the weighed ΔSI of movement group was significantly reduced compared with control group (P<0.05). The half-time was not significantly different [(104.3±54.1) min vs. (113.4±47.3) min, P>0.05].@*CONCLUSION@#ISF drainage of caudate nuclear can be acclerated temporarily by movement.

Study on calculation method of internal and external fluid capacity of human cells based on bioimpedance spectroscopy / 生物医学工程学杂志

Bioelectrical impedance measurement technology is a non-invasive detection technology for extracting human physiological and pathological information. The analysis method of the relationship between bioimpedance and human physiological parameters is an important part of this technology. In order to calculate the internal and external liquid volume of human cells more accurately, based on the Moissl equation for calculating the internal and external fluid volume of human cells, a segmented human bioimpedance spectrum measurement model and an improved calculation method of intracellular and external fluid capacity were proposed. The measurement and calculation experiments of the intracellular and extracellular fluid volume before and after the human body's water intake were designed and compared with the Moissl calculation method. The results show that the improved calculation method can calculate the intracellular and extracellular fluid volumes more effectively, and the relative error is less than 5%, which may provide new ideas or more accurate methods for the analysis of human body components, facilitating the diagnosis and treatment of diseases.

Cerebrospinal Fluid Levels of β-Amyloid 40 and β-Amyloid 42 are Proportionately Decreased in Amyloid Positron-Emission Tomography Negative Idiopathic Normal-Pressure Hydrocephalus Patients

BACKGROUND AND PURPOSE: Cerebrospinal fluid (CSF) biomarkers of Alzheimer's disease (AD) could be misleading in idiopathic normal-pressure hydrocephalus (iNPH). We therefore investigated the CSF biomarkers in 18F-florbetaben amyloid-negative positron-emission tomography (PET) [amyloid PET(−)] iNPH, amyloid-positive PET [amyloid PET(+)] AD, and cognitively normal (CN) subjects. METHODS: Ten amyloid PET(+) AD patients (56.7±5.6 years old, mean±standard deviation), 10 amyloid PET(−) iNPH patients (72.8±4.5 years old), and 8 CN subjects (61.2±6.5 years old) were included. We measured the levels of β-amyloid (Aβ)40, Aβ42, total tau (t-tau) protein, and phosphorylated tau (p-tau) protein in the CSF using enzyme-linked immunosorbent assays. RESULTS: The level of Aβ42 and the Aβ42/Aβ40 ratio in the CSF were significantly lower in AD than in iNPH or CN subjects. The Aβ40 level did not differ significantly between AD and iNPH (p=1.000), but it did between AD and CN subjects (p=0.032). The levels of both t-tau and p-tau were higher in AD than in iNPH or CN subjects. The levels of Aβ42, Aβ40, t-tau, and p-tau were lower in iNPH than in CN subjects, but there was no significant difference after controlling for age. CONCLUSIONS: Our results suggest that the mechanism underlying low CSF Aβ levels differs between amyloid PET(−) iNPH and amyloid PET(+) AD subjects. The lower levels of all CSF biomarkers in iNPH patients might be due to reduced clearances from extracellular fluid and decreased brain metabolism of the periventricular zone in iNPH resulting from glymphatic dysfunction.

Comparison among ACR1997, SLICC and the new EULAR/ACR classification criteria in childhood-onset systemic lupus erythematosus

Abstract Background: To date there are no specific classification criteria for childhood-onset systemic lupus erythematosus (cSLE). This study aims to compare the performance among the American College of Rheumatology (ACR) 1997, the Systemic Lupus International Collaborating Clinics criteria (SLICC) and the new European League Against Rheumatism (EULAR)/ACR criteria, in a cSLE cohort. Methods: We conducted a medical chart review study of cSLE cases and controls with defined rheumatic diseases, both ANA positive, to establish each ACR1997, SLICC and EULAR/ACR criterion fulfilled, at first visit and 1-year-follow-up. Results: Study population included 122 cSLE cases and 89 controls. At first visit, SLICC criteria had higher sensitivity than ACR 1997 (89.3% versus 70.5%, p < 0.001), but similar specificity (80.9% versus 83.2%, p = 0.791), however performance was not statistically different at 1-year-follow-up. SLICC better scored in specificity compared to EULAR/ACR score ≥ 10 at first visit (80.9% versus 67.4%, p = 0.008) and at 1-year (76.4% versus 58.4%, p = 0.001), although sensitivities were similar. EULAR/ACR criteria score ≥ 10 exhibited higher sensitivity than ACR 1997 (87.7% versus 70.5%, p < 0.001) at first visit, but comparable at 1-year, whereas specificity was lower at first visit (67.4% versus 83.2%, p = 0.004) and 1-year (58.4% versus 76.4%, p = 0.002). A EULAR/ACR score ≥ 13 against a score ≥ 10, resulted in higher specificity, positive predictive value, and cut-off point accuracy. Compared to SLICC, a EULAR/ACR score ≥ 13 resulted in lower sensitivity at first visit (76.2% versus 89.3%, p < 0.001) and 1-year (91% versus 97.5%, p = 0.008), but similar specificities at both assessments. When compared to ACR 1997, a EULAR/ACR total score ≥ 13, resulted in no differences in sensitivity and specificity at both observation periods. Conclusions: In this cSLE population, SLICC criteria better scored at first visit and 1-year-follow-up. The adoption of a EULAR/ACR total score ≥ 13 in this study, against the initially proposed ≥10 score, was most appropriate to classify cSLE. Further studies are necessary to address if SLICC criteria might allow fulfillment of cSLE classification earlier in disease course and may be more inclusive of cSLE subjects for clinical studies.

Role of aquaporin-4 in the change of interstitial fluid drainage in Alzheimer's disease / 北京大学学报(医学版)

OBJECTIVE@#To observe the characteristics of the interstitial fluid (ISF) drainage in the Alzheimer's disease (AD) rats through magnetic resonance imaging (MRI) tracer gadolinium-diethylene triamine pentacetic acid (Gd-DTPA)spread in the brain extracellular space (ECS) and to discuss the role of aquaporin-4 (Aqp4) in the AD.@*METHODS@#Wild type SD rats (300-350 g) and Aqp4 gene knock out (Aqp4-/-) SD rats (300-350g) were divided into Sham group, AD group, Aqp4-/--Sham group and Aqp4-/--AD group. Sham group and Aqp4-/--Sham group were injected with saline by intraperitoneal each day for 6 weeks, and the AD group and Aqp4-/--AD group were injected with D-galactose by intraperitoneal each day for 6 weeks. MRI tracer Gd-DTPA (10 mmol/L, 2 μL) was injected into the hippocampus of the rats. MRI scan was performed at the end of 0.5 h, 1.5 h, 1 h, 2 h, and 3 h to observe the dynamic distribution of the Gd-DTPA in the hippocampus and the diffusion rate D*, clearance rate k' and half-life t1/2 measured.@*RESULTS@#The diffusion rate D* in Sham group was (2.66±0.36)×10-6 mm2/s, the diffusion rate D* in AD group was (2.72±0.62)×10-6 mm2/s, the diffusion rate D* in Aqp4-/--Sham group was (2.75±0.47)×10-6 mm2/s, the diffusion rate D* in Aqp4-/--AD group was (2.802±0.55)×10-6 mm2/s, and there was no statistically significant difference in the four groups (One-Way ANOVA, P>0.05).The clearance rate k' in Sham group was (4.57±0.14)×10-4/s, the clearance rate k' in AD group was (3.68±0.22)×10-4/s, the clearance rate k' in Aqp4-/--Sham group was (3.17±0.16)×10-4/s, the clearance rate k' in Aqp4-/--AD group was (2.59±0.19)×10-4/s, and there was significant difference in the four groups (One-Way ANOVA, P<0.05). The half-life t1/2 in Sham group was (0.67±0.12) h, the half-life t1/2 in AD group was (0.88±0.08) h, the half-life t1/2 in Aqp4-/--Sham group was (1.12±0.15) h, the half-life t1/2 in Aqp4-/--AD group was (1.58±0.11) h, and there was significance difference in the four groups(one-way ANOVA,P<0.05).@*CONCLUSION@#The ISF drainage is slow after AD and the loss of Aqp4 in the AD makes the ISF drainage obviously slow down, Aqp4 plays an important role in AD to remove the metabolism of waste out of the brain.

Understanding Qi Running in the Meridians as Interstitial Fluid Flowing via Interstitial Space of Low Hydraulic Resistance / 中国结合医学杂志

Qi, blood and the meridians are fundamental concepts in Chinese medicine (CM), which are components of the human body and maintain physiological function. Pathological changes of qi, blood and meridians may lead to discomfort and disease. Treatment with acupuncture or herbal medicine aims to regulate qi and blood so as to recover normal function of the meridians. This paper explores the nature of qi as well as compares and correlates them with the structures of the human body. We propose a conceptualization of qi as being similar to the interstitial fluid, and the meridians as being similar to interstitial space of low hydraulic resistance in the body. Hence, qi running in the meridians can be understood as interstitial fluid flowing via interstitial space of low hydraulic resistance.

Hydrogen peroxide inhibits Ca²⁺ efflux through plasma membrane Ca²⁺-ATPase in mouse parotid acinar cells

Intracellular Ca²⁺ mobilization is closely linked with the initiation of salivary secretion in parotid acinar cells. Reactive oxygen species (ROS) are known to be related to a variety of oxidative stress-induced cellular disorders and believed to be involved in salivary impairments. In this study, we investigated the underlying mechanism of hydrogen peroxide (H₂O₂) on cytosolic Ca²⁺ accumulation in mouse parotid acinar cells. Intracellular Ca²⁺ levels were slowly elevated when 1 mM H₂O₂ was perfused in the presence of normal extracellular Ca²⁺. In a Ca²⁺-free medium, 1 mM H₂O₂ still enhanced the intracellular Ca²⁺ level. Ca²⁺ entry tested using manganese quenching technique was not affected by perfusion of 1 mM H₂O₂. On the other hand, 10 mM H₂O₂ induced more rapid Ca²⁺ accumulation and facilitated Ca²⁺ entry from extracellular fluid. Ca²⁺ refill into intracellular Ca²⁺ store and inositol 1,4,5-trisphosphate (1 µM)-induced Ca²⁺ release from Ca²⁺ store was not affected by 1 mM H₂O₂ in permeabilized cells. Ca²⁺ efflux through plasma membrane Ca²⁺-ATPase (PMCA) was markedly blocked by 1 mM H₂O₂ in thapsigargin-treated intact acinar cells. Antioxidants, either catalase or dithiothreitol, completely protected H₂O₂-induced Ca²⁺ accumulation through PMCA inactivation. From the above results, we suggest that excessive production of H₂O₂ under pathological conditions may lead to cytosolic Ca²⁺ accumulation and that the primary mechanism of H₂O₂-induced Ca²⁺ accumulation is likely to inhibit Ca²⁺ efflux through PMCA rather than mobilize Ca²⁺ ions from extracellular medium or intracellular stores in mouse parotid acinar cells.

Artificial Pancreas: A Concise Review / 임상당뇨병

Artificial pancreas is a technique developed to automatically control blood glucose in people with diabetes by providing an endocrine function instead of a healthy pancreas. The technique was developed for the replacement of insulin secretion deficiencies among various exocrine and endocrine functions of the pancreas and is mainly used for people with type 1 diabetes or those who need intensive insulin treatment. This review briefly summarizes the working principles, components, recent clinical research, and future perspectives of artificial pancreas.

Hydrogen peroxide attenuates refilling of intracellular calcium store in mouse pancreatic acinar cells

Intracellular calcium (Ca²⁺) oscillation is an initial event in digestive enzyme secretion of pancreatic acinar cells. Reactive oxygen species are known to be associated with a variety of oxidative stress-induced cellular disorders including pancreatitis. In this study, we investigated the effect of hydrogen peroxide (H₂O₂) on intracellular Ca²⁺ accumulation in mouse pancreatic acinar cells. Perfusion of H₂O₂ at 300 µM resulted in additional elevation of intracellular Ca²⁺ levels and termination of oscillatory Ca²⁺ signals induced by carbamylcholine (CCh) in the presence of normal extracellular Ca²⁺. Antioxidants, catalase or DTT, completely prevented H₂O₂-induced additional Ca²⁺ increase and termination of Ca²⁺ oscillation. In Ca²⁺-free medium, H₂O₂ still enhanced CCh-induced intracellular Ca²⁺ levels and thapsigargin (TG) mimicked H₂O₂-induced cytosolic Ca²⁺ increase. Furthermore, H₂O₂-induced elevation of intracellular Ca²⁺ levels was abolished under sarco/endoplasmic reticulum Ca²⁺ ATPase-inactivated condition by TG pretreatment with CCh. H₂O₂ at 300 µM failed to affect store-operated Ca²⁺ entry or Ca²⁺ extrusion through plasma membrane. Additionally, ruthenium red, a mitochondrial Ca²⁺ uniporter blocker, failed to attenuate H₂O₂-induced intracellular Ca²⁺ elevation. These results provide evidence that excessive generation of H₂O₂ in pathological conditions could accumulate intracellular Ca²⁺ by attenuating refilling of internal Ca²⁺ stores rather than by inhibiting Ca²⁺ extrusion to extracellular fluid or enhancing Ca²⁺ mobilization from extracellular medium in mouse pancreatic acinar cells.

Comparison of Glucose Area Under the Curve Measured Using Minimally Invasive Interstitial Fluid Extraction Technology with Continuous Glucose Monitoring System in Diabetic Patients

BACKGROUND: Continuous glucose monitoring (CGM) is reported to be a useful technique, but difficult or inconvenient for some patients and institutions. We are developing a glucose area under the curve (AUC) monitoring system without blood sampling using a minimally invasive interstitial fluid extraction technology (MIET). Here we evaluated the accuracy of interstitial fluid glucose (IG) AUC measured by MIET in patients with diabetes for an extended time interval and the potency of detecting hyperglycemia using CGM data as a reference. METHODS: Thirty-eight inpatients with diabetes undergoing CGM were enrolled. MIET comprised a pretreatment step using a plastic microneedle array and glucose accumulation step with a hydrogel patch, which was placed on two sites from 9:00 AM to 5:00 PM or from 10:00 PM to 6:00 AM. IG AUC was calculated by accumulated glucose extracted by hydrogel patches using sodium ion as standard. RESULTS: A significant correlation was observed between the predicted AUC by MIET and CGM in daytime (r=0.76) and nighttime (r=0.82). The optimal cutoff for the IG AUC value of MIET to predict hyperglycemia over 200 mg/dL measured by CGM for 8 hours was 1,067.3 mg·hr/dL with 88.2% sensitivity and 81.5% specificity. CONCLUSION: We showed that 8-hour IG AUC levels using MIET were valuable in estimating the blood glucose AUC without blood sampling. The results also supported the concept of using this technique for evaluating glucose excursion and for screening hyperglycemia during 8 hours in patients with diabetes at any time of day.

Liposuction in the Treatment of Lipedema: A Longitudinal Study

BACKGROUND: Lipedema is a condition consisting of painful bilateral increases in subcutaneous fat and interstitial fluid in the limbs with secondary lymphedema and fibrosis during later stages. Combined decongestive therapy (CDT) is the standard of care in most countries. Since the introduction of tumescent technique, liposuction has been used as a surgical treatment option. The aim of this study was to determine the outcome of liposuction used as treatment for lipedema. METHODS: Twenty-five patients who received 72 liposuction procedures for the treatment of lipedema completed a standardized questionnaire. Lipedema-associated complaints and the need for CDT were assessed for the preoperative period and during 2 separate postoperative follow-ups using a visual analog scale and a composite CDT score. The mean follow-up times for the first postoperative follow-up and the second postoperative follow-up were 16 months and 37 months, respectively. RESULTS: Patients showed significant reductions in spontaneous pain, sensitivity to pressure, feeling of tension, bruising, cosmetic impairment, and general impairment to quality of life from the preoperative period to the first postoperative follow-up, and these results remained consistent until the second postoperative follow-up. A comparison of the preoperative period to the last postoperative follow-up, after 4 patients without full preoperative CDT were excluded from the analysis, indicated that the need for CDT was reduced significantly. An analysis of the different stages of the disease also indicated that better and more sustainable results could be achieved if patients were treated in earlier stages. CONCLUSIONS: Liposuction is effective in the treatment of lipedema and leads to an improvement in quality of life and a decrease in the need for conservative therapy.

Emerging Roles of Lymphatic Vasculature in Immunity

The lymphatic vasculature has been regarded as a passive conduit for interstitial fluid and responsible for the absorption of macromolecules such as proteins or lipids and transport of nutrients from food. However, emerging data show that the lymphatic vasculature system plays an important role in immune modulation. One of its major roles is to coordinate antigen transport and immune-cell trafficking from peripheral tissues to secondary lymphoid organs, lymph nodes. This perspective was recently updated with the notion that the interaction between lymphatic endothelial cells and leukocytes controls the immune-cell migration and immune responses by regulating lymphatic flow and various secreted molecules such as chemokines and cytokines. In this review, we introduce the lymphatic vasculature networks and genetic transgenic models for research on the lymphatic vasculature system. Next, we discuss the contribution of lymphatic endothelial cells to the control of immune-cell trafficking and to maintenance of peripheral tolerance. Finally, the physiological roles and features of the lymphatic vasculature system are further discussed regarding inflammation-induced lymphangiogenesis in a pathological condition, especially in mucosal tissues such as the gastrointestinal tract and respiratory tract.

Cardiopulmonary effects of thiopental versus propofol as an induction agent prior to isoflurane anesthesia in chair trained rhesus macaques (Macaca mulatta) / 한국실험동물학회지

The purpose of this study was to evaluate the effects of thiopental versus propofol on cardiopulmonary functions, when used as an induction agent prior to isoflurane anesthesia in rhesus monkeys. Eight healthy rhesus monkeys weighing 3.72 to 5.7 kg, 4-5 years old, were used in the study. Anesthesia was induced with thiopental or propofol intravenous injection, and then maintained with isoflurane in oxygen for 45 minutes. Cardiopulmonary measurements were obtained before and 5, 15, 30, 45, and 60 minutes after induction. The induction doses of thiopental and propofol were 19.41±0.54 and 9.33±1.02 mg/kg, respectively. In both groups, the values of heart rate, respiratory rate, temperature, systolic blood pressure, mean blood pressure, diastolic blood pressure, pH, and lactate were decreased, while the values of partial pressure of carbon dioxide, partial pressure of oxygen, total carbon dioxide, bicarbonate, oxygen saturation, and base excess in the extracellular fluid were increased, as compared with baseline. Systolic blood pressure was significantly lower in thiopental group compare to propofol group. Induction time was very short in both agents but not revealed a significant difference between both groups. However, recovery time was extremely faster in the propofol group. Our results demonstrated that propofol provides a minor suppression in systolic arterial blood pressure than thiopental sodium. In addition, propofol have a fast recovery effect from the anesthesia as well. Furthermore, it is suggested that thiopental sodium could also be used to induce anesthesia instead of propofol, despite slight more suppression of cardiopulmonary function compared to thiopental sodium.

Evaluation of a Novel Glucose Area Under the Curve (AUC) Monitoring System: Comparison with the AUC by Continuous Glucose Monitoring

BACKGROUND: Management of postprandial hyperglycemia is a key aspect in diabetes treatment. We developed a novel system to measure glucose area under the curve (AUC) using minimally invasive interstitial fluid extraction technology (MIET) for simple monitoring of postprandial glucose excursions. In this study, we evaluated the relationship between our system and continuous glucose monitoring (CGM) by comparing glucose AUC obtained using MIET with that obtained using CGM for a long duration. METHODS: Twenty diabetic inpatients wearing a CGM system were enrolled. For MIET measurement, a plastic microneedle array was applied to the skin as pretreatment, and hydrogels were placed on the pretreated area to collect interstitial fluid. Hydrogels were replaced every 2 or 4 hours and AUC was predicted on the basis of glucose and sodium ion levels. RESULTS: AUC predicted by MIET correlated well with that measured by CGM (r=0.93). Good performances of both consecutive 2- and 4-hour measurements were observed (measurement error: 11.7%±10.2% for 2 hours and 11.1%±7.9% for 4 hours), indicating the possibility of repetitive measurements up to 8 hours. The influence of neither glucose fluctuation nor average glucose level over the measurement accuracy was observed through 8 hours. CONCLUSION: Our system showed good relationship with AUC values from CGM up to 8 hours, indicating that single pretreatment can cover a large portion of glucose excursion in a day. These results indicated possibility of our system to contribute to convenient monitoring of glucose excursions for a long duration.