人血脑屏障体外实验模型的建立及缺氧-复氧对其通透性的影响

目的建立人血脑屏障体外实验模型，并探讨缺氧-复氧对血脑屏障模型通透性的影响。 方法将分离、纯化的人脑微血管内皮细胞（HB-MVEC）在细胞插入器上培养至汇合状态，以液面试漏试验确定血脑屏障模型的形成，并通过形态学检查、跨内皮细胞电阻（TEER）测定和辣根过氧化物酶（HRP）通透率对血脑屏障模型进行鉴定；以未达汇合状态的HB-MVEC及培养至汇合状态的人脐静脉内皮细胞（HUVEC）作为对照。观察缺氧-复氧处理（缺氧2h和复氧1、2、4、8、24h）和缺氧-复氧时存在白细胞激活产物（缺氧2h后在有白细胞激活产物存在情况下复氧1h）对血脑屏障模型通透性的影响，以及前列腺素E、α1抗胰蛋白酶和丹参单体764-3对血脑屏障模型的保护作用。各项实验均观察3孔细胞。 结果HB-MVEC在细胞插入器培养至汇合状态后，液面试漏试验呈阳性；扫描电镜观察显示细胞间无间隙，透射电镜检查证实细胞间存在紧密连接。血脑屏障模型、未达汇合状态HB-MVEC和HUVEC的TEER分别为（46.0±1.3）、（30.8±1.4）、（7.5±2.1）Ω/cm^2；向细胞插入器内加入含HRP的培养基培养1h后，HRP通透率分别为0.17%±0.03%、0.26%±0.04%和0.94%±0.07%；缺氧2h和复氧1、2、4、8、24h HRP通透率分别为3.97%±0.94%、6.06%±0.75%、7.17%±0.18%、7.96%±0.47%、8.57%±0.62%、10.37%±0.78%。血脑屏障模型缺氧2h后在有白细胞激活产物的情况下复氧1h，其HRP通透率为8.87%±0.76%，明显高于无白细胞激活产物组（7.20%±0.87%）；而前列腺素E、α1抗胰蛋白酶和丹参单体764-3能够减弱这种情况下的血脑屏障模型通透性增加，3组的HRP通透率分别为7.08%±0.89%，6.01%±0.57%和5.53%±0.62%。 结论应用HB-MVEC可以构建血脑屏障体外模型，缺氧-复氧明显增加血脑屏障模型的通透性，前列腺素E、α1抗胰蛋白酶和丹参单体764-3具有保护血脑屏障     

NF-κB subunits are differentially distributed in cells of lumbar dorsal root ganglia in naïve and diabetic rats

Mesenchymal stem cells (MSCs) hold much promise for cell therapy for neurological diseases such as cerebral ischemia and Parkinson's disease. Intravenously administered MSCs accumulate in lesions within the brain parenchyma, but little is known of the details of MSC transmigration across the blood-brain barrier (BBB). To study MSC transmigration across the BBB, we developed an in vitro culture system consisting of rat brain microvascular endothelial cells (BMECs) and bone marrow-derived MSCs using Transwell or Millicell culture inserts. Using this system, we first investigated the influence of the number of MSCs added to the upper chamber on BMEC barrier integrity. The addition of MSCs at a density of 1.5 × 10⁵ cells/cm² led to disruption of the BMEC monolayer structure and decreased barrier function as measured by the transendothelial electrical resistance (TEER). When applied at a density of 1.5 × 10⁴ cells/cm², neither remarkable disruption of the BMEC monolayers nor a significant decrease in TEER was observed until at least 12 h. After cultivation for 24 h under this condition, MSCs were found in the subendothelial space or beneath the insert membrane, suggesting that MSCs transmigrate across BMEC monolayers. Time-lapse imaging revealed that MSCs transmigrated across the BMEC monolayers through transiently formed intercellular gaps between the BMECs. These results show that our in vitro culture system consisting of BMECs and MSCs is useful for investigating the molecular and cellular mechanisms underlying MSC transmigration across the BBB.     

Differential effects of hydrocortisone and TNFalpha on tight junction proteins in an in vitro model of the human blood-brain barrier

Homeostasis of the central nervous system (CNS) microenvironment is maintained by the blood–brain barrier (BBB) which regulates the transport of molecules from blood into brain and back. Many disorders change the functionality and integrity of the BBB. Glucocorticoids are being used sucessfully in the treatment of some disorders while their effects on others are questionable. In addition, conflicting results between clinical and experimental experience using animal models has arisen, so that the results of molecular studies in animal models need to be revisited in an appropriate in vitro model of the human BBB for more effective treatment strategies. Using the human brain microvascular endothelial cell line hCMEC/D3, the influence of glucocorticoids on the expression of barrier constituting adherens junction and tight junction transmembrane proteins (VE-cadherin, occludin, claudins) was investigated and compared to other established BBB models. In hCMEC/D3 cells the administration of glucocorticoids induced expression of the targets occludin 2.75 ± 0.04-fold and claudin-5 up to 2.32 ± 0.11-fold, which is likely to contribute to the more than threefold enhancement of transendothelial electrical resistance reflecting barrier tightness. Our analyses further provide direct evidence that the GC hydrocortisone prevents endothelial barrier breakdown in response to pro-inflammatory stimuli (TNFα administration), which could be demonstrated to be partly based on maintenance of occludin levels. Our studies strongly suggest stabilization of BBB function as a mode of GC action on a molecular level in the human brain vasculature.     

Quantification of head sweating during rest and exercise in the heat

The head’s capacity for evaporative heat loss is important for design of protective helmets for use in hot environments. This study quantified head sweating rate (m _sw) in eight males during rest and exercise at three metabolic rates (338 ± 36, 481 ± 24, 622 ± 28 W) in hot-dry (HD: 45 °C, 21 % RH) and hot-wet (HW: 35 °C, 69 % RH) conditions (matched at 31.6 °C WBGT), which were counterbalanced. Heads were shaved, and surface area was (458 ± 61 cm²) measured by 3D scanner. For measurement of head m _sw, dry air was passed through a sealed helmet, whereas for forearm m _sw a capsule (15.9 cm²) was ventilated with ambient air. Evaporation rate was determined from the increase in vapor pressure in the exiting air. Whole-body sweat loss was calculated from the change in nude weight plus fluid intake and corrected for respiratory fluid losses. Head m _sw increased (p = 0.001) with metabolic rate, and was lower (p = 0.018) in HD (0.4 ± 0.2 mg cm^?2 min^?1 at rest to 1.1 ± 0.6 mg cm^?2 min^?1 at 622 W), compared to HW (0.5 ± 0.3–1.4 ± 0.8 mg cm^?2 min^?1). Forearm m _sw increased (p < 0.001) with metabolic rate, but was higher (p = 0.002) in HD (0.4 ± 0.3–1.4 ± 0.7 mg cm^?2 min^?1) than HW (0.1 ± 0.1–1.1 ± 0.3 mg cm^?2 min^?1). Whole-body sweat loss was not significantly different (p = 0.06) between HD (647 ± 139 g m^?2 h^?1) and HW (528 ± 189 g m^?2 h^?1). This study demonstrates the importance of the head for evaporative heat loss, particularly for populations who wear protective clothing which can impair vapor transfer from the skin.     

An Instrumented Mouthguard for Measuring Linear and Angular Head Impact Kinematics in American Football

The purpose of this study was to evaluate a novel instrumented mouthguard as a research device for measuring head impact kinematics. To evaluate kinematic accuracy, laboratory impact testing was performed at sites on the helmet and facemask for determining how closely instrumented mouthguard data matched data from an anthropomorphic test device. Laboratory testing results showed that peak linear acceleration (r ² = 0.96), peak angular acceleration (r ² = 0.89), and peak angular velocity (r ² = 0.98) measurements were highly correlated between the instrumented mouthguard and anthropomorphic test device. Normalized root-mean-square errors for impact time traces were 9.9 ± 4.4% for linear acceleration, 9.7 ± 7.0% for angular acceleration, and 10.4 ± 9.9% for angular velocity. This study demonstrates the potential of an instrumented mouthguard as a research tool for measuring in vivo impacts, which could help uncover the link between head impact kinematics and brain injury in American football.     

Walker 256 tumour cells increase substance P immunoreactivity locally and modify the properties of the blood–brain barrier during extravasation and brain invasion

It is not yet known how tumour cells traverse the blood–brain barrier (BBB) to form brain metastases. Substance P (SP) release is a key component of neurogenic inflammation which has been recently shown to increase the permeability of the BBB following CNS insults, making it a possible candidate as a mediator of tumour cell extravasation into the brain. This study investigated the properties of the BBB in the early stages of tumour cell invasion into the brain, and the possible involvement of SP. Male Wistar rats were injected with Walker 256 breast carcinoma cells via the internal carotid artery and euthanised at 1, 3, 6 and 9 days post tumour inoculation. Culture medium-injected animals served as controls at 1 and 9 days. Evidence of tumour cell extravasation across the BBB was first observed at 3 days post-inoculation, which corresponded with significantly increased albumin (p < 0.05) and SP immunoreactivity (p < 0.01) and significantly reduced endothelial barrier antigen labelling of microvessels when compared to culture medium control animals (p < 0.001). By day 9 after tumour cell inoculation, 100 % of animals developed large intracranial neoplasms that had significantly increased albumin in the peri-tumoral area (p < 0.001). The increased SP immunoreactivity and altered BBB properties at 3 days post-inoculation that coincided with early tumour invasion may be indicative of a mechanism for tumour cell extravasation into the brain. Thus, extravasation of tumour cells into the brain to form cerebral metastases may be a SP-mediated process.     

Palatine tonsil volume estimation using different methods after tonsillectomy

This study was carried out to measure the volume of the palatine tonsil in otorhinolaryngology outpatients with complaints of adenotonsillar hypertrophy and chronic tonsillitis who had undergone tonsillectomy. To date, no study has investigated palatine tonsil volume using different methods and compared with subjective tonsil size in the literature. For this purpose, we used three different methods to measure palatine tonsil volume. The correlation of each parameter with tonsil size was assessed. After tonsillectomy, palatine tonsil volume was measured by Archimedes, Cavalieri and Ellipsoid methods. Mean right–left palatine tonsil volumes were calculated as 2.63 ± 1.34 cm³ and 2.72 ± 1.51 cm³ by the Archimedes method, 3.51 ± 1.48 cm³ and 3.37 ± 1.36 cm³ by the Cavalieri method, and 2.22 ± 1.22 cm³ and 2.29 ± 1.42 cm³ by the Ellipsoid method, respectively. Excellent agreement was found among the three methods of measuring volumetric techniques according to Bland–Altman plots. In addition, tonsil grade was correlated significantly with tonsil volume.     

Development of a High-Throughput Magnetic Separation Device for Malaria-Infected Erythrocytes

This study describes a non-dilutive high-gradient magnetic separation (HGMS) device intended to continuously remove malaria-infected red blood cells (iRBCs) from the circulation. A mesoscale prototype device with disposable photo-etched ferromagnetic grid and reusable permanent magnet was designed with a computationally-optimized magnetic force. The prototype device was evaluated in vitro using a non-pathogenic analog for malaria-infected blood, comprised of 24% healthy RBCs, 6% human methemoglobin RBCs (metRBCs), and 70% phosphate buffer solution (PBS). The device provided a 27.0 ± 2.2% reduction of metRBCs in a single pass at a flow rate of 77 μL min^?1. This represents a clearance rate over 380 times greater throughput than microfluidic devices reported previously. These positive results encourage development of a clinical scale system that would economize time and donor blood for treating severe malaria.     

Clinical significance of circulating tumor cells from lung cancer patients using microfluidic chip

Circulating tumor cells (CTCs) exist in the peripheral blood and have an important role in the disease development, tumor metastasis and clinical surveillance, especially in the process of metastasis. However, the technology of detecting CTCs still had a large challenge since they were rare in the peripheral blood. Here, we developed a size-based microfluidic chip, which contained array and filter channel array that could enrich CTCs from blood samples more quickly and conveniently. Combined with clinical specimen, we analyzed CTCs in 200 lung cancer patients by this microfluidic chip. The microfluidic device has high specificity and sensitivity in detecting CTCs (86.0% sensitivity and 98% specificity). Furthermore, the number of CTCs showed a increasing trend according to the stage of the disease (the mean number of I stage 5.0 ± 5.121 versus II stage 8.731 ± 6.36 versus III stage 16.81 ± 9.556 versus IV stage 28.72 ± 17.39 cells/mL, P < 0.05). The number of CTCs was concurrent with the condition of pathological type and metastasis patients. Compared to conventional markers like CEA, CY211, SCC, CTCs showed a higher positive rate in diagnosed patients. The advanced microfluidic device could capture tumor cells without reliance on cell surface expression markers and provide a fast, convenient, economical method in detecting CTCs, thereby offering potential to design effective and individualized cancer therapies.     

Pilot Randomized Controlled Trial of Omega-3 and Individual–Family Psychoeducational Psychotherapy for Children and Adolescents With Depression

The goal of this study is to evaluate feasibility and estimate effect sizes of omega-3 fatty acids (Ω3), individual-family psychoeducational psychotherapy (PEP), their combination, and moderating effects of maternal depression and psychosocial stressors in youth with depression. In a pilot 2 × 2 randomized controlled trial, 72 youth (ages 7–14; 57% Caucasian, 57% male) with major depression, dysthymia, or depression not otherwise specified were randomized to 12 weeks of Ω3, PEP+placebo, Ω3+PEP, or placebo. Ω3 versus placebo was double-masked. Evaluators masked to condition assessed depressive severity at baseline (randomization) and at 2, 4, 6, 9, and 12 weeks using the Children’s Depression Rating Scale–Revised. Side effects were either absent or mild. PEP was administered with 74% fidelity. Remission was 77%, Ω3+PEP; 61%, PEP+placebo; 44%, Ω3; 56%, placebo. Intent-to-treat analyses found small to medium effects of combined treatment (d = .29) and Ω3 monotherapy (d = .42), but negligible effect for PEP+placebo (d < .10), all compared to placebo alone. Relative to placebo, youth with fewer social stressors responded better to Ω3 (p = .04), PEP (p = .028), and their combination (p = .035), and those with maternal depression responded better to PEP (p = .020) than did those without maternal depression. Remission rates were favorable compared to other studies of psychotherapy and comparable to an existing randomized controlled trial of Ω3; results warrant further evaluation in a larger sample. Ω3 was well tolerated. Active treatments show significantly more placebo-controlled depression improvement in the context of maternal depression and fewer stressors, suggesting that they may benefit depression with a more endogenous than environmental origin.     

Hyperbaric oxygen preconditioning ameliorates blood-brain barrier damage induced by hypoxia through modulation of tight junction proteins in an in vitro model

AimTo explore the effects of hyperbaric oxygen preconditioning (HBOP) on the permeability of blood-brain barrier (BBB) and expression of tight junction proteins under hypoxic conditions in vitro.MethodsA BBB in vitro model was constructed using the hCMEC/D3 cell line and used when its trans-endothelial electrical resistance (TEER) reached 80-120 Ω · cm² (tested by Millicell-Electrical Resistance System). The cells were randomly divided into the control group cultured under normal conditions, the group cultured under hypoxic conditions (2%O₂) for 24 h (hypoxia group), and the group first subjected to HBOP for 2 h and then to hypoxia (HBOP group). Occludin and ZO-1 expression were analyzed by immunofluorescence assay.ResultsNormal hCMEC/D3 was spindle-shaped and tightly integrated. TEER was significantly reduced in the hypoxia (P = 0.001) and HBOP group (P = 0.014) compared to control group, with a greater decrease in the hypoxia group. Occludin membranous expression was significantly decreased in the hypoxia group (P = 0.001) compared to the control group, but there was no change in the HBOP group. ZO-1 membranous expression was significantly decreased (P = 0.002) and cytoplasmic expression was significantly increased (P = 0.001) in the hypoxia group compared to the control group, although overall expression levels did not change. In the HBOP group, there was no significant change in ZO-1 expression compared to the control group.ConclusionHyperbaric oxygen preconditioning protected the integrity of BBB in an in vitro model through modulation of occludin and ZO-1 expression under hypoxic conditions.Ischemic tolerance is an endogenous protective mechanism that refers to the ability of a sublethal stimulus to induce tolerance to a subsequent lethal ischemic injury. It was first demonstrated in neuronal cells of the gerbil hippocampus (1), after which it has aroused a considerable interest as a possible therapeutic modality for ischemic brain diseases. However, to expose patients to brief periods of ischemia is both impractical and unsafe. Chemical preconditioning substances that can induce ischemic tolerance, such as endotoxins, cytokines, metabolic inhibitors, potassium, chloride, and neurotoxin 3-nitro-propionic acid (1-5) have also been investigated but were found to have limited clinical application due to toxicity and side effects.A variety of experimental models of cerebral ischemia have found that hyperbaric oxygen preconditioning (HBOP) induces ischemic tolerance and attenuates cerebral injury (6-17). Its protective effect is also visible in other conditions leading to oxidative stress, with final anti-apoptotic result, as well as modulation of neutrophin and immune systems (6-17).The blood-brain barrier (BBB), a highly selective permeability barrier, consists of tight junctions (TJ) between capillary endothelial cells, the basal lamina, pericytes, and astrocyte end-feet (18). It plays an important role in maintaining cerebral homeostasis by restricting molecular movement from the cerebral capillaries to the brain tissue. BBB breakdown can result in a vasogenic edema, hemorrhage, and neuronal cell death, all of which can contribute to the pathophysiology of cerebral ischemic diseases (19). TJs between cerebral endothelial cells are formed by complex interactions of cytoskeletal proteins and tight junction proteins (TJPs), including claudins, occludin, zonula occludens (ZO), and cingulin (20). TJPs increase endothelial electrical resistance and decrease paracellular permeability (21). Changes in their expression can lead to the loss of BBB integrity and BBB breakdown (22).HBOP has been associated with reduced brain edema, decreased infarct volume, and improved neurological function (6-17), but it is not clear whether it directly affects the BBB, particularly TJPs expression. This should be clarified in order to find new therapeutic strategies to attenuate BBB permeability in cerebral ischemic disorders. Therefore, the aim of this study was to examine the HBOP effect on hypoxia-induced BBB breakdown in vitro and the changes of occludin and ZO-1 expression.     

大鼠脑微血管内皮细胞的原代培养及其生物学行为初步探讨

本文旨在探讨建立稳定的大鼠原代脑微血管内皮细胞的培养方法,并对其血脑屏障特性进行初步研究。通过匀浆、葡聚糖高速梯度离心提取大鼠脑皮层微血管段,用胶原酶消化后,在37℃,5%CO2孵箱中进行原代及传代细胞培养,以跨内皮阻抗值分析其血脑屏障特性随传代次数的改变。结果证明:原代培养后7～10d沿微血管段生成单层"铺路石"样细胞,经VIII因子证实95%以上的培养细胞是血管内皮细胞,通过传代可以进一步纯化,得到稳定的脑微血管内皮细胞系,原代培养的脑微血管内皮细胞表现出很强的屏障特性,与内皮细胞株之间有显著差异,随着传代次数的增加脑微血管内皮细胞的跨内皮阻抗减弱。以上结果表明,采用匀浆、梯度离心、胶原酶消化是获取大鼠脑微血管内皮细胞稳定的方法,原代培养的脑微血管内皮细胞是研究血脑屏障的最佳技术手段。     

Volumetric growth of the lungs in human fetuses: an anatomical,hydrostatic and statistical study

Purpose

The prenatal assessment of lung volume is becoming increasingly important in determining survival in both preterm infants and newborns affected by pulmonary hypoplasia. This study aimed to examine the lung volumes in the human fetus at varying gestational ages.

Materials and methods

Using anatomical, hydrostatic (water displacement according to Archimedes’ patent) and statistical methods (one-way ANOVA test for paired data and post-hoc Bonferroni test, Kolmogorov–Smirnov test, Levene’s test, Student’s t test, regression analysis), volumes of the right and left lungs were measured in 67 human fetuses of both sexes (35 males, 32 females) aged 16–25 weeks, derived from spontaneous abortions and stillbirths.

Results

No male–female differences concerning the right and left pulmonary volumes were found. The mean volume of the right lung increased from 1.43 ± 0.25 to 8.45 ± 2.66 cm³, according to the cubic function y = –1.592 + 0.0007 × age³ ± 0.851 (R ² = 0.84). The volumetric growth of the left lung, from 1.24 ± 0.22 to 6.78 ± 3.03 cm³, followed the cubic model y = –1.110 + 0.0005 × age³ ± 0.794 (R ² = 0.78). The total pulmonary volume increased from 2.67 ± 0.47 to 15.22 ± 5.58 cm³, in accordance with the cubic model y = –2.729 + 0.0012 × age³ ± 1.598 (R ² = 0.83). The mean volumes of the right and left lungs accounted for 54.9 ± 2.0 and 45.1 ± 2.0 %, respectively, of the total lung volume.

Conclusions

No sex differences are found between the lung volumes in the fetus. The growth of fetal lung volume follows a three-degree polynomial function. Throughout the analyzed period the two lungs grow proportionately to each other, with the volumetric predominance of the right lung. The lung volumes in the fetus are of great relevance in the evaluation of the normal pulmonary growth and the diagnosis of pulmonary hypoplasia.     

High Content Evaluation of Shear Dependent Platelet Function in a Microfluidic Flow Assay

The high blood volume requirements and low throughput of conventional flow assays for measuring platelet function are unsuitable for drug screening and clinical applications. In this study, we describe a microfluidic flow assay that uses 50 μL of whole blood to measure platelet function on ~300 micropatterned spots of collagen over a range of physiologic shear rates (50–920 s^?1). Patterning of collagen thin films (CTF) was achieved using a novel hydrated microcontact stamping method. CTF spots of 20, 50, and 100 μm were defined on glass substrates and consisted of a dense mat of nanoscale collagen fibers (3.74 ± 0.75 nm). We found that a spot size of greater than 20 μm was necessary to support platelet adhesion under flow, suggesting a threshold injury size is necessary for stable platelet adhesion. Integrating 50 μm CTF microspots into a multishear microfluidic device yielded a high content assay from which we extracted platelet accumulation metrics (lag time, growth rate, total accumulation) on the spots using Hoffman modulation contrast microscopy. This method has potential broad application in identifying platelet function defects and screening, monitoring, and dosing antiplatelet agents.     

Conservative Exposure Predictions for Rapid Risk Assessment of Phase-Separated Additives in Medical Device Polymers

A novel approach for rapid risk assessment of targeted leachables in medical device polymers is proposed and validated. Risk evaluation involves understanding the potential of these additives to migrate out of the polymer, and comparing their exposure to a toxicological threshold value. In this study, we propose that a simple diffusive transport model can be used to provide conservative exposure estimates for phase separated color additives in device polymers. This model has been illustrated using a representative phthalocyanine color additive (manganese phthalocyanine, MnPC) and polymer (PEBAX 2533) system. Sorption experiments of MnPC into PEBAX were conducted in order to experimentally determine the diffusion coefficient, D = (1.6 ± 0.5) × 10^?11 cm²/s, and matrix solubility limit, C _s = 0.089 wt.%, and model predicted exposure values were validated by extraction experiments. Exposure values for the color additive were compared to a toxicological threshold for a sample risk assessment. Results from this study indicate that a diffusion model-based approach to predict exposure has considerable potential for use as a rapid, screening-level tool to assess the risk of color additives and other small molecule additives in medical device polymers.     

Effects of microfluidic channel geometry on leukocyte rolling assays

Microfluidic cell adhesion assays have emerged as a means to increase throughput as well as reduce the amount of costly reagents. However as dimensions of the flow chamber are reduced and approach the diameter of a cell (D_c), theoretical models have predicted that mechanical stress, force, and torque on a cell will be amplified. We fabricated a series of microfluidic devices that have a constant width:height ratio (10:1) but with varying heights. The smallest microfluidic device (200 μm ×20 μm) requires perfusion rates as low as 40 nL/min to generate wall shear stresses of 0.5 dynes/cm². When neutrophils were perfused through P-selectin coated chambers at equivalent wall shear stress, rolling velocities decreased by approximately 70 % as the ratio of cell diameter to chamber height (D_c/H) increased from 0.08 (H?=?100 μm) to 0.40 (H?=?20 μm). Three-dimensional numerical simulations of neutrophil rolling in channels of different heights showed a similar trend. Complementary studies with PSGL-1 coated microspheres and paraformaldehyde-fixed neutrophils suggested that changes in rolling velocity were related to cell deformability. Using interference reflection microscopy, we observed increases in neutrophil contact area with increasing chamber height (9–33 %) and increasing wall shear stress (28–56 %). Our results suggest that rolling velocity is dependent not only on wall shear stress but also on the shear stress gradient experienced by the rolling cell. These results point to the D_c/H ratio as an important design parameter of leukocyte microfluidic assays, and should be applicable to rolling assays that involve other cell types such as platelets or cancer cells.     

Age-related volumetric changes in pancreas: a stereological study on computed tomography

Purpose

(1) To explore age-related changes in the volume of the pancreas on computed tomography (CT) images calculated by the method of Cavalieri. (2) To investigate the relationship between these changes and body mass index (BMI), gender, abdominal diameter, abdominal skinfold thickness.

Methods

We retrospectively reviewed abdominal CT examinations of 272 adults between the ages of 20–88 years. There were seven groups of patients, with 40 patients (only ninth decade has 32 patients) for each decade.

Results

Pancreatic volume (PV) was found to be 63.68 ± 15.08 cm³ in females, 71.75 ± 15.99 cm³ in males (mean value of both groups, 67.71 ± 16.03 cm³). Maximum value of PV was found in the fourth decade in females, males and also for mean of both groups (73.50, 84.21 and 78.85 cm³, respectively). PV remained constant until ~60 years of age. Thereafter, it gradually decreased in both genders. There was a negative correlation between PV and age (p < 0.001, r: ?0.473). We found positive correlation between PV and BMI, sagittal abdominal diameter (SAD), transverse abdominal diameter (TAD), anterior subcutaneous adipose tissue thicknesses (ASAT), posterior subcutaneous adipose tissue thicknesses (PSAT), bilateral subcutaneous adipose tissue thicknesses (BSAT).

Conclusions

Quantitative data may allow clinicians to better estimate age-related PV changes and help them in decision making.     

Glioma targeted delivery strategy of doxorubicin-loaded liposomes by dual-ligand modification

The blood-brain barrier (BBB) is the protective parclose of brain safety, but it is also the main obstacle of the drug delivery to cerebral parenchyma, which hamper therapy for brain diseases. In this work, a glioma targeted drug delivery system was developed through loading doxorubicin into Angiopep-2 and TAT peptide dual-modified liposomes (DOX-TAT-Ang-LIP). Low-density lipoprotein receptor-related protein-1 (LRP1) was one receptor overexpressed on both BBB and glioma cytomembranes. Angiopep-2, a specific ligand of LRP1, exhibited high LRP1 binding efficiency. Additionally, TAT could penetrate through cell membranes without selectivity via an unsaturated pathway. To avoid the receptor saturation of Angiopep-2, TAT was also conjugated on the surface of liposomes, providing that the liposomes not only have effective BBB penetrating effect, but also have the glioma targeting function. The prepared DOX liposomes appeared good stability and narrow dispersity in serum with a diameter of 90 nm, and exhibited sustained DOX release behaviors. The conjunctions of Angiopep-2 and TAT were confirmed by ¹H NMR spectra. The BBB model, cellular uptake observations, antiproliferation study, and the cell ultrastructure analyses suggested that DOX-TAT-Ang-LIP could not only penetrate through BBB via transcytosis, but also concentrate in glioma, then enter into glioma cells and finally result in the necrosis of glioma cells.     

Impact of acute whole-body cold exposure with concurrent isometric handgrip exercise on aortic pressure waveform characteristics

Purpose

Adverse cardiovascular events are more prevalent during winter and in people that exercise/work in cold temperatures. Since pulse wave analysis indices, aortic systolic blood pressure (ASBP), augmentation index (AIx), and wasted left ventricular pressure energy (ΔE _w), are stronger predictors of cardiovascular events and myocardial performance than brachial blood pressure (BP), we sought to evaluate the aortic hemodynamic responses during cold exposure with concurrent isometric handgrip exercise (IHG).

Methods

In a crossover randomized fashion, 20 healthy normotensive men (22.1 ± 2 years) were evaluated, by means of radial applanation tonometry, inside an environmental chamber in the supine position at cold (4 °C) and temperate (24 °C) conditions. Following a 30-min equilibration period, measurements were performed during pre-exercise baseline (REST), in the last 90 s of a 3-min IHG at 30 % maximal voluntary contraction, and 3 min immediately after the finalization of IHG bout (recovery, REC).

Results

At REST, brachial systolic BP (BSBP) (12 ± 2 mmHg; P < 0.01), ASBP (14 ± 3 mmHg; P < 0.01), AIx (11 ± 3 %; P < 0.05), and ΔE _w (737 ± 128 dynes s/cm²; P < 0.01) were higher in 4 °C compared to 24 °C trial. Compared to REST, IHG significantly increased (P < 0.01) BSBP, ASBP, AIx, and ΔEw, while BSBP and ASBP remained elevated during REC (P < 0.01). Compared to REST and temperate, AIx (11 ± 3 %) and ΔE _w (793 ± 145 dynes s/cm²; P < 0.01) were higher during IHG and cold, while BSBP and ASBP were elevated during REC and cold. AIx and ΔE _w returned to REST values in both trials, but AIx (11 ± 4 %; P < 0.05) and ΔE _w (656 ± 132 dynes s/cm²; P < 0.05) were higher in the cold.

Conclusions

Cold exposure with concurrent IHG induces a significant increase in aortic hemodynamic markers, which may evoke adverse cardiovascular events.     

A microdevice for parallelized pulmonary permeability studies

We describe a compartmentalized microdevice specifically designed to perform permeability studies across a model of lung barrier. Epithelial cell barriers were reproduced by culturing Calu-3 cells at the air-liquid interface (AIC) in 1 mm² microwells made from a perforated glass slide with an embedded porous membrane. We created a single basolateral reservoir for all microwells which eliminated the need to renew the growth medium during the culture growth phase. To perform drug permeability studies on confluent cell layers, the cell culture slide was aligned and joined to a collection platform consisting in 35 μL collection reservoirs connected at the top and bottom with microchannels. The integrity and functionality of the cell barriers were demonstrated by measurement of trans-epithelial electrical resistance (TEER), confocal imaging and permeability assays of ¹⁴C-sucrose. Micro-cell barriers were able to form confluent layers in 1 week, demonstrating a similar bioelectrical evolution as the Transwell systems used as controls. Tight junctions were observed throughout the cell-cell interfaces, and the low permeability coefficients of ¹⁴C-sucrose confirmed their functional presence, creating a primary barrier to the diffusion of solutes. This microdevice could facilitate the monitoring of biomolecule transport and the screening of formulations promoting their passage across the pulmonary barrier, in order to select candidates for pulmonary administration to patients.