Acute ventilatory restriction in children after weaning off inhaled nitric oxide: relation to rebound pulmonary hypertension

Objective: To assess the interaction between pulmonary hemodynamics and respiratory mechanics during acute pulmonary hypertension. Patients: Ventilated and paralysed children treated with inhaled nitric oxide because of post-operative pulmonary hypertension. Interventions: Weaning of inhaled nitric oxide. Measurements: Air flow and airway pressure, calculation of dynamic respiratory system compliance and respiratory system resistance for each breath by multiple linear regression. Results: In four patients, increases in pulmonary arterial pressure from 26.1 to 56.7 mmg (p < 0.001) during weaning off nitric oxide were associated with decreases in tidal volume (from 9.7 → 8.2 ml/kg, p < 0.01) and reductions in dynamic respiratory system compliance (from 0.52 → 0.34 cmH₂0/ml/kg, p < 0.001), while respiratory system resistance was unchanged. Conclusions: Impaired ventilation during acute pulmonary hypertension is predominantly related to a reduction in respiratory system compliance. Received: 26 March 1998 Final revision received: 9 June 1998 Accepted: 30 July 1998     

以一氧化氮为例浅析中医学“气”本质的研究思路

"气"作为中医学的一个基本概念,在病因病机阐述、临床诊断、治疗方法确定、方药选择、养生指导等多方面被广泛应用,但至今对于其本质的研究并未取得实质性进展。究其原因主要在于未能将具体的、物质的气完全从哲学概念中剥离出来。为此笔者作了初步探索,提出了气本质研究应当遵循的三大原则。并以一氧化氮为例,对三大原则进行了分析。同时笔者也初步提出了气本质的物质基础与一氧化氮密切相关,为中医气本质研究提供一个全新思路。     

Physiology of the normal heart

The mechanical events of the cardiac cycle provide the circulation with normal cardiac output and blood pressure. This requires an appropriate venous return, regulation of outflow resistance, a normal myocardial contractile state and heart rate control, together with an adequate supply of oxygenated blood via the coronary circulation. Other neural influences contribute to cardiac regulation, including natriuretic peptides and the renin–angiotensin system. The atria and ventricles are richly supplied with adrenergic nerves that may augment cardiac function, particularly with increased cardiac output during exercise. Inhibitory vagal fibres are largely confined to the sinus and atrioventricular nodes. Exercise causes increased sympathetic outflow, with a decrease in peripheral vascular resistance and increased cardiac output, heart rate, systolic blood pressure and venous return. Regular rhythmic exercise has a training effect, which enhances cardiac performance. This is important for the maintenance of many aspects of cardiovascular health.     

Effects Of Endothelin-1 On Intracellular Tetrahydrobiopterin Levels In Vascular Tissue

Objective: Tetrahydrobiopterin (BH4) is the essential cofactor of endothelial nitric oxide synthase (eNOS) and intracellular levels of BH4 is regulated by oxidative stress. The aim of this paper was to describe the influence of exogenous endothelin-1 on intracellular BH4 and its oxidation products dihydrobiopterin (BH2) and biopterin (B) in a wide range of vascular tissue.

Design: Segments of internal mammary artery (IMA) and human saphenous vein (SV) from 41 patients undergoing elective surgery were incubated in ET-1 (0.1?μM). Aorta and lung from transgenic mice overexpressing ET-1 in the endothelium (ET-TG) were analysed with regards to intracellular biopterin levels. Human umbilical vein endothelial cells (HUVEC) were incubated in ET-1 (0.1?μM) and intracellular biopterin levels were analysed. From 6 healthy women undergoing caesarean section, subcutaneous fat was harvested and the resistance arteries in these biopsies were tested for ET-mediated endothelial dysfunction.

Results: In HUVEC, exogenous ET-1 (0.1?μM) did not significantly change intracellular BH4, 1.54?±?1.7 vs 1.68?±?1.8?pmol/mg protein; p?=?.8. In IMA and SV, exogenous ET-1(0.1?μM) did not change intracellular BH4 n?=?10, p?=?.4. In aorta from wild type vs ET-TG mice there was no significant difference in intracellular BH4 between the groups: 1.3?±?0.49 vs 1.23?±?0.3?pmol/mg protein; p?=?.6. In resistance arteries (n?=?6) BH4 together with DTE (an antioxidant) was not able to prevent ET-mediated endothelial dysfunction.

Conclusion: ET-1 did not significantly alter intracellular tetrahydrobiopterin levels in IMA, SV, HUVEC or aorta from ET-TG mice. These findings are important for future research in ET-1 mediated superoxide production and endothelial dysfunction.     

Mechanisms and biomarkers of immune quiescence in kidney transplantation

This review discusses the current understanding of biomarkers of immune quiescence based on reviews of published literature in kidney transplant operational tolerance and mechanistic studies based on a better characterization of the stable, well-functioning renal allograft.     

LyP-1-conjugated Fe3O4 nanoparticles suppress tumor growth by magnetic induction hyperthermia

To find a promising drug carrier to suppress tumor using magnetic induction hyperthermia (MIH) and targeted therapy, two superparamagnetic iron oxide nanoparticles (SPIONs) coated with polyethylene glycol (PEG) and LyP-1, respectively, were prepared and compared. The particle size ranges of PEG-SPIONs and LyP-1-SPIONs were 10–15 nm, and 15–20 nm, respectively. In FTIR spectra, PEG-SPIONs and LyP-1-SPIONs had strong peaks between 575 and 1630 cm^?1. Specifically, the PEG-SPIONs mainly has peaks in 581 and 1630 cm^?1. The LyP-1-SPIONs mainly had peaks in 575, 1050 and 1625 cm^?1. The contents of Fe₃O₄ in the PEG-SPIONs and LyP-1-SPIONs were about 94.24 and 89.26%, respectively. The iron contents in the MCF-7 and CT-26 cells were 33.1 ± 1.8 and 27.9 ± 0.95 pg, respectively, after co-incubation with LyP-1-SPIONs for 8 h. The LyP-1-SPIONs accumulated in the nucleus of MCF-7 cells while PEG-SPIONs in cytoplasma. In vitro, after 30 days we can found the tumor almost stopped to grow in Group LyP-1-SPIONs. LyP-1-SPIONs are promising in treating cancer as they accumulated in the nucleus of MCF-7 cells which expressed p32 and almost stopped tumor growth by combined MIH and targeted therapy.     

Mechanisms underlying blood pressure reduction by dietary inorganic nitrate

Nitric oxide (NO) importantly contributes to cardiovascular homeostasis by regulating blood flow and maintaining endothelial integrity. Conversely, reduced NO bioavailability is a central feature during natural ageing and in many cardiovascular disorders, including hypertension. The inorganic anions nitrate and nitrite are endogenously formed after oxidation of NO synthase (NOS)‐derived NO and are also present in our daily diet. Knowledge accumulated over the past two decades has demonstrated that these anions can be recycled back to NO and other bioactive nitrogen oxides via serial reductions that involve oral commensal bacteria and various enzymatic systems. Intake of inorganic nitrate, which is predominantly found in green leafy vegetables and beets, has a variety of favourable cardiovascular effects. As hypertension is a major risk factor of morbidity and mortality worldwide, much attention has been paid to the blood pressure reducing effect of inorganic nitrate. Here, we describe how dietary nitrate, via stimulation of the nitrate‐nitrite‐NO pathway, affects various organ systems and discuss underlying mechanisms that may contribute to the observed blood pressure‐lowering effect.     

Acceleration of wound healing by a porous collagen/silk fibroin scaffold carrying zinc oxide nanoparticles北大核心

BACKGROUND: Anti-infective ability determine the success or failure of skin grafting. It is one of the commonly used methods to enhance the anti-infective ability of implants by compounding antibacterial materials with scaffolds. OBJECTIVE:To investigate the effect of porous collagen/silk fibroin scaffolds carrying zinc oxide nanoparticles against infection and inflammation, and to evaluate its effect on wound healing. METHODS: Thirty-two Sprague-Dawley rats with a full-thickness wound on the back skin were randomly divided into two groups. In experimental groiup, porous collagen/silk fibroin scaffolds containing zinc oxide nanoparticles were implanted, while only collagen/silk fibroin scaffolds were implanted in control group. Wound healing was compared between the two groups by measuring residual wound area at 1, 2, 4, 8 weeks post implantation. Hematoxylin-eosin and interleukin 6 immumohistochemical staining were performed at 1, 2, 4 weeks post implantation to observe wound morphology and inflammatory reactions. Meanwhile, expression of interleukin 6 and interleukin 1β was detected by real-time PCR. RESULTS AND CONCLUSION: (1) At 2, 4, 8 weeks post implantation, significantly increased healing rate was observed in the experiment group compared with the control group (P<0.05). (2) Findings from the hematoxylin-eosin staining showed that obvious inflammatory cell infiltration was observed in the control group, but less inflammation with vigorous growth of granulation tissues on the wound surface occurred in the experimental group at 1 week after implantation. Then, the wound repair was basically completed in the experimental group presenting with complete and compact epidermal tissue structure, while scar formation with no skin cover was found in the control group at 4 weeks after implantation. (3) Findings from the interleukin 6 immumohistochemical staining showed that there was interleukin 6 positive expression in both two groups to different extents; at 4 weeks after implantation, the expression of interleukin 6 was remarkably reduced in the control group, but it was still a strong positive expression, while week positive expression of interleukin 6 was observed in the experimental group. (4) Compared with the control group, the mRNA expression of interleukin 6 and interleukin 1β was both lower in the experimental group at 1, 2, 4 weeks after implantation, but there was a significant difference between the two groups at 1 and 2 weeks after implantation (P<0.05). Overall, the porous collagen/silk fibroin scaffold carrying zinc oxide nanoparticles can effectively reduce inflammations following skin injury, and accelerate skin wound healing. © 2018, Journal of Clinical Rehabilitative Tissue Engineering Research. All rights reserved.     

Evaluation of biofilm formation ability in different Candida strains and anti-biofilm effects of Fe3O4-NPs compared with Fluconazole: an in vitro study

Objective

Biofilm formation ability is one of the major virulence factors contributing to the pathogenesis of Candida species. Biofilms produced by Candida spp. cause complicated treatments and contribute to increasing unpleasant mortality rates. Nanoparticles of Fe₃O₄ (Fe₃O₄-NPs) are considered due to their magnetic and biochemical properties, as well as their low costs. The purpose of present study was to determine biofilm formation ability in different Candida strains and evaluation of anti-biofilm effect of Fe₃O₄-NPs compared with FLC.