优化两步输注美罗培南联合参麦注射液对重症感染患者血清感染指标、细菌清除率和T淋巴细胞亚群的影响

目的:探讨优化两步输注美罗培南联合参麦注射液对重症感染患者血清感染指标、细菌清除率和T淋巴细胞亚群的影响。方法:选取2017年1月-2018年10月在我院重症医学科(ICU)住院的153例重症感染患者,按随机数字表法将患者分为传统输注美罗培南组(A组,54例)、优化两步输注美罗培南组(B组,49例)、优化两步输注美罗培南联合参麦注射液组(C组,50例)。比较治疗后三组患者的总体疗效、血清感染指标和T淋巴细胞亚群水平及不良反应发生情况。结果:B组、C组的临床有效率、细菌清除率、28天生存率高于A组(P<0.05);B组、C组机械通气时间、ICU住院时间、总住院时间少于A组,且C组少于B组(P<0.05);治疗后B组、C组CD3⁺、CD4⁺、CD4⁺/CD8⁺高于A组,且C组高于B组(P<0.05);B组、C组CD8⁺、白细胞计数(WBC)、降钙素原(PCT)、C-反应蛋白(CRP)水平低于A组,且C组低于B组(P<0.05)。三组患者不良反应发生率比较无差异(P>0.05)。结论:优化两步输注美罗培南联合参麦注射液治疗重症感染患者疗效确切,可提高细菌清除率,改善患者免疫状态,促进患者康复。     

Plasminogen activator activity is inhibited while neuroserpin is up‐regulated in the Alzheimer disease brain

Amyloid‐beta plaques are a pathological hallmark of Alzheimer’s disease. Several proteases are known to cleave/remove amyloid‐beta, including plasmin, the product of tissue plasminogen activator cleavage of the pro‐enzyme plasminogen. Although plasmin levels are lower in Alzheimer brain, there has been little analysis of the plasminogen activator/plasmin system in the brains of Alzheimer patients. In this study, zymography, immunocapture, and ELISAs were utilized to show that tissue plasminogen activator activity in frontal cortex tissue of Alzheimer patients is dramatically reduced compared with age‐matched controls, while tissue plasminogen activator and plasminogen protein levels are unchanged; suggesting that plasminogen activator activity is inhibited in the Alzheimer brain. Analysis of endogenous plasminogen activator inhibitors shows that while plasminogen activator inhibitor‐1 and protease nexin‐1 levels are unchanged, the neuroserpin levels are significantly elevated in brains of Alzheimer patients. Furthermore, elevated amounts of tissue plasminogen activator‐neuroserpin complexes are seen in the Alzheimer brain, and immunohistochemical studies demonstrate that both tissue plasminogen activator and neuroserpin are associated with amyloid‐beta plaques in Alzheimer brain tissue. Thus, neuroserpin inhibition of tissue plasminogen activator activity leads to reduced plasmin and may be responsible for reduced clearance of amyloid‐beta in the Alzheimer disease brain. Furthermore, decreased tissue plasminogen activator activity in the Alzheimer brain may directly influence synaptic activity and impair cognitive function.     

Daytime grazing and assimilation rates of planktonic copepods Acanthodiaptomus denticornis and Cyclops vicinus vicinus. Comparison of spatial and resource utilisation by rotifers and cladoceran communities in a eutrophic lake

The clearance rates of ¹⁴ carbon-labelled Chlamydomonas sp. by the copepodite and adult stages of the 2 dominant species of Copepoda were studied in eutrophic Lake Aydat. They varied from 30 to 3,007 µl ind^–1 h^–1 for Acanthodiaptomus denticornis (mean = 600 µl ind^–1 h^–1) and from 20 to 1,133 µl ind^–1 h^–1 for Cyclops vicinus (mean = 340 µl ind^–1 h^–1). Their maximum assimilation efficiencies were 58% and 50%, respectively. These populations collectively could consume the available food in 4 days during September (maximum daily grazing rate = 24%). Mean individual clearance rates could be ranked Acanthodiaptomus denticornis > Ceriodaphnia quadrangula > Chydorus sphaericus > Daphnia longispina > Cyclops vicinus vicinus > Bosmina longirostris > K. cochlearis > K. quadrata and Kellicottia longispina. Like cladocerans and rotifers, the copepods living in this eutrophic lake can feed at low oxygen concentrations.     

Hand‐held,clinical dual mode ultrasound ‐ photoacoustic imaging of rat urinary bladder and its applications

Urinary bladder imaging is critical to diagnose urinary tract disorders, and bladder cancer. There is a great need for safe, non‐invasive, and sensitive imaging technique which enables bladder imaging. Photoacoustic imaging is a rapidly growing imaging technique for various biological applications. It can be combined with clinical ultrasound imaging system for hand‐held, dual modal ultrasound‐photoacoustic real‐time imaging. Structural (bladder wall) and functional (accretion of nanoparticles) bladder imaging is shown here with combined ultrasound and photoacoustic imaging in rats. Photoacoustic images of bladder wall is shown using black ink as the contrast agent. Chicken tissues were stacked on the abdomen of the animal to demonstrate the feasibility of photoacoustic imaging till a depth of 2 cm. Also, the feasibility of photoacoustic imaging for a common bladder disorder, vesicoureteral reflux is studied using urinary tract mimicking phantom. It is also shown that a clinical ultrasound system can be used for photoacoustic imaging of non‐invasive clearance study of gold nanorods from circulation by monitoring the gradual accumulation of the gold nanorods in the bladder. The time taken for accumulation of nanorods in the bladder can be used as an indicator of the clearance rate of the nanoparticle circulation from the body.      

2型糖尿病患者代谢清除率与血清游离脂肪酸的相关性

目的:探讨2型糖尿病(type 2 diabetes mellitus,T2DM)患者代谢清除率(metabolic clearance rate,MCR)与血清游离脂肪酸(nonesterified fatty acid,NEFA)、甘油三酯(triglyceride,TG)和胆固醇的相关性。方法:选择2014年10月至2016年12月我院收治的127例T2DM患者,测量患者身高、体重,并计算身体质量指数(BMI),进行口服糖耐量试验、胰岛素释放试验,检测血清脂质的水平。将T2DM患者按MCR值分为低MCR组(63例)、高MCR组(64例),比较两组间临床指标的差异,评价MCR、HOMA-IR与变量间的相关性。结果:T2DM患者BMI、TG、空腹血糖和糖化血红蛋白(Hb A1C)均高于参考值;T2DM患者低MCR组Hb A1C、空腹血糖、总胆固醇(total cholesterol,TC)、TG、低密度脂蛋白胆固醇(LDL-C)和NEFA明显升高(P0.05),高密度脂蛋白胆固醇(HDL-C)明显降低(P0.05);相关分析显示:MCR与HDL-C呈显著正相关(P0.05,r=0.215),与TC、TG、LDL-C、Hb A1C、NEFA均呈显著负相关(P0.05;r=-0.191,-0.380,-0.216,-0.587,-0.356)。结论:2型糖尿病患者MCR降低,与Hb A1C与血清NEFA水平呈负相关。MCR不仅能评价胰岛素抵抗,而且能反映机体糖脂代谢水平。     

Hematopoietic cells as site of first-pass catabolism after subcutaneous dosing and contributors to systemic clearance of a monoclonal antibody in mice

The neonatal Fc receptor (FcRn) has been demonstrated to contribute to a high bioavailability of monoclonal antibodies (mAbs). In this study, we explored the cellular sites of FcRn-mediated protection after subcutaneous (SC) and intravenous (IV) administration. SC absorption and IV disposition kinetics of a mAb were studied in hFcRn transgenic (Tg) bone marrow chimeric mice in which hFcRn was restricted to radioresistant cells or hematopoietic cells. SC bioavailabilities close to 90% were observed in hFcRn Tg mice and chimeric mice with hFcRn expression in hematopoietic cells, whereas SC bioavailabilities were markedly lower when FcRn was missing in hematopoietic cells. Our study demonstrates: 1) FcRn in radiosensitive hematopoietic cells is required for high SC bioavailability, indicating first-pass catabolism after SC administration by hematopoietic cells; 2) FcRn-mediated transcytosis or recycling by radioresistent cells is not required for high SC bioavailability; and 3) after IV administration hematopoietic and radioresistent cells contribute about equally to clearance of the mAb. A pharmacokinetic model was devised to describe a mixed elimination via radioresistent and hematopoietic cells from vascular and extravascular compartments, respectively. Overall, the study indicates a relevant role of hematopoietic cells for first-pass clearance of mAbs after SC administration and confirms their role in the overall clearance of mAbs.     

In Vivo Assessment of Dopamine Uptake in Rat Medial Prefrontal Cortex: Comparison with Dorsal Striatum and Nucleus Accumbens

Abstract: In vivo electrochemistry was used to characterize dopamine clearance in the medial prefrontal cortex and to compare it with clearance in the dorsal striatum and nucleus accumbens. When calibrated amounts of dopamine were pressure-ejected into the cortex from micropipettes adjacent to the recording electrodes, transient and reproducible dopamine signals were detected. The local application of the selective uptake inhibitors GBR-12909, desipramine, and fluoxetine before the application of dopamine indicated that at the lower recording depths examined (2.5–5.0 mm below the brain surface), locally applied dopamine was cleared from the extracellular space primarily by the dopamine transporter. The norepinephrine transporter played a greater role at the more superficial recording sites (0.5–2.25 mm below the brain surface). To compare clearance of dopamine in the medial prefrontal cortex (deeper sites only), striatum, and nucleus accumbens, varying amounts of dopamine were locally applied in all three regions of individual animals. The signals recorded from the cortex were of greater amplitude and longer time course than those recorded from the striatum or accumbens (per picomole of dopamine applied), indicating less efficient dopamine uptake in the medial prefrontal cortex. The fewer number of transporters in the medial prefrontal cortex may be responsible, in part, for this difference, although other factors may also be involved. These results are consistent with the hypothesis that regulation of dopaminergic function is unique in the medial prefrontal cortex.     

Pharmacokinetic Analysis of Free Radicals by in vivo BCM (Blood Circulation Monitoring)-ESR Method

In pharmacokinetic studies, a variety of analytical method including radioisotopic detection and HPLC (high performance liquid chromatography) has been used. In the present investigation, we developed in vivo BCM (Blood Circulation Monitoring)-ESR method, which is a new technique with a conventional X-band ESR spectrometer for observing stable free radicals in the circulating blood of living rats under anaesthesia. Both 5-(PROXYL derivatives) and 6-(TEMPO derivatives) membered nitroxide spin probes with various types of substituent functional group were used. After physicochemical properties of the spin probes such as hyperfine coupling constant (A-value), g-value and partition coefficient as well as chemical stability of the compounds in the fresh blood were obtained, the in vivo BCM-ESR method was performed in normal rats. Several pharmacokinetic parameters such as half-life of the probes, distribution volume, total body clearance and mean residence time were obtained and discussed in terms of their chemical structures. In addition, clearance of a spin probe was related to the urine concentration. The BCM-ESR method was found to be very useful to observe free radicals at the real time. By time-dependent ESR signal decay of spin probes, pharmacokinetic parameters were obtained.     

Calcium-dependent antigen binding as a novel modality for antibody recycling by endosomal antigen dissociation

The pH-dependent antigen binding antibody, termed a recycling antibody, has recently been reported as an attractive type of second-generation engineered therapeutic antibody. A recycling antibody can dissociate antigen in the acidic endosome, and thus bind to its antigen multiple times. As a consequence, a recycling antibody can neutralize large amounts of antigen in plasma. Because this approach relies on histidine residues to achieve pH-dependent antigen binding, which could limit the epitopes that can be targeted and affect the rate of antigen dissociation in the endosome, we explored an alternative approach for generating recycling antibodies. Since calcium ion concentration is known to be lower in endosome than in plasma, we hypothesized that an antibody with antigen-binding properties that are calcium-dependent could be used as recycling antibody. Here, we report a novel anti-interleukin-6 receptor (IL-6R) antibody, identified from a phage library that binds to IL-6R only in the presence of a calcium ion. Thermal dynamics and a crystal structure study revealed that the calcium ion binds to the heavy chain CDR3 region (HCDR3), which changes and possibly stabilizes the structure of HCDR3 to make it bind to antigen calcium dependently (PDB 5AZE). In vitro and in vivo studies confirmed that this calcium-dependent antigen-binding antibody can dissociate its antigen in the endosome and accelerate antigen clearance from plasma, making it a novel approach for generating recycling antibody.