移植气管软骨再生的实验

目的 研究同种异体移植气管软骨的再生能力。方法 将供体犬气管置于受体犬腹腔内，以带蒂大网胞包绕，分别在术后1，2，3，4，5，6，7，8及12wk时，共9个时间段将移植段气管取出作病理及透射电镜检查，部分标本软骨用^3H-TDR(^3H-脱氧胸苷）标记，行放射自显影检查。结果 软骨再生存在于移植后的各个时间段的气管软骨膜下，其再生的程度与良好的血液循环有关。结论 同种异体气管移植，血液循环充分建立的条件下，软骨具有良好的再生能力。     

Mucus Transport and Surface Damage After Endotracheal Intubation and Tracheostomy. An Experimental Study in Pigs

The effects on mucus transport of different grades of tracheal injury produced experimentally by an intubation tube were studied in 26 pigs. Two of them were not intubated and served as controls, while the rest were anaesthetized and either intubated or tracheostomized, or both, and ventilated for approximately 4.5 h. They were then killed and the trachea and larynx were immediately removed and placed in a specially designed chamber at 3 7^oG and 85 % relative humidity. Cardio-green dye was deposited caudally in the trachea as a mucus marker. The mucus transport was observed macroscopically and the ultrastructure of the tracheal wall at the region of mucus arrest was studied by light microscopy and scanning and transmission electron microscopy. In non-intubated pigs the mucus was transported to the posterior larynx. The ciliated epithelium was usually intact along the pathway where cardio-green-stained mucus had travelled. In pigs which had been intubated and/or tracheostomized, mucus transport stopped completely at different levels of the trachea. The damage to the ciliated epithelium varied; in some animals there was almost none at all and in others there was a patchy loss of a large proportion of the cilia, or complete lack of cilia. Lesions which also included epithelial cells were often seen. Tracheal injury due either to a cuffed endotracheal tube or to a tracheostomy tube, with destruction of epithelium and cilia, causes a barrier to mucus transport, leading to arrest and accumulation of mucus further down in the airway. We were unable, however, to demonstrate a direct correlation between grade of damage and tendency to mucus arrest.     

ENDOTHELIUM-DERIVED RELAXING FACTOR RELEASED FROM CULTURED CELLS: DIFFERENTIATION FROM NITRIC OXIDE

1. Endothelium-derived relaxing factor (EDRF) is an extremely labile mediator thought to be identical to nitric oxide (NO). 2. A cascade superfusion technique was used to bioassay EDRF released from bovine aortic endothelial cells grown to confluence on microcarrier beads. 3. Bradykinin (1-100 nmol/l), infused through a 1 cm column of endothelial cells on microcarriers, released an EDRF-like substance that caused relaxations of de-endothelialized strips of rabbit aorta (precontracted with phenylephrine). These relaxations diminished on successive tissues in the cascade, when compared with those produced by glyceryl trinitrate as a stable standard. 4. Haemoglobin (1 mumol/l), infused directly over the bioassay tissues, abolished bradykinin-induced relaxations and these were restored within 5 min after removal of haemoglobin. The infusion did not affect the relaxations produced by glyceryl trinitrate in this system. 5. Methylene blue (20 mumol/l) inhibited bradykinin-induced relaxations when infused over the rabbit aortae, and reduced those relaxations produced by glyceryl trinitrate. The effects of bradykinin, but not glyceryl trinitrate, were partially restored after removing methylene blue. 6. These data are consistent with the known effects of these compounds on the activity of NO, and on EDRF in isolated blood vessels. 7. The activity of EDRF (released by bradykinin) was compared directly with NO on strips of guinea-pig trachea (de-epithelialized) interposed in cascade between two rabbit aortae; all strips were precontracted with histamine and phenylephrine. 8. A submaximal dose of NO that matched the relaxation produced by EDRF on the uppermost aorta, caused relaxation of the trachea, but EDRF had no effect on this tissue. In addition, the NO-induced relaxation of the lower aorta was greater than that produced by EDRF. 9. These data indicate that EDRF does not have identical biological activity to NO. EDRF could contain an NO moiety attached to a carrier molecule that is bound and stabilized in tracheal tissue.     

小儿气管和支气管固定标本的观测

本文测量45例小儿气管、支气管长度和管径,气管软骨环数目,气管嵴下角度以及气管颈段与胸腺的关系,从应用解剖学角度,对小儿气管切开术套管的选择提供了形态学依据。     

The relationship between interstitial fluid pressure and volume in rat trachea

A change of interstitial fluid volume (IFV) will normally change the interstitial fluid pressure (P_if) so as to counteract further fluid movement across the capillaries and changes in IFV. Contrary to this, several acute inflammatory reactions in the trachea are associated with increased negativity of P_if, which will interstitial fluid balance in the trachea, interstitial compliance (ΔIFV/ΔP_if) was measured in pentobarbital anaesthetized rats. IFV was measured as the plasma equivalent extravascular distribution space of [⁵¹Cr]EDTA. P_if was measured in the same animal with sharpened glass pipettes (diameter 3–6 μm) connected to a servocontrolled counterpressure system. In dehydration (30 mL saline i.v., n=10) interstitial compliance was 0.083 mL g dry wt^-1 mmHg^-1. Since control IFV was 1.046 mL g dry wt^-1 (n=10) the interstitial compliance is 8% of IFV per mmHg. In overhydration (30 mL NaCl, n=10) and dextran anaphylaxis (1 mL dextran 70, n=10) compliance remained the same for the first 15% increase in IFV and then increased several-fold since P_if did not increase more than 2 mmHg above control level. The increased negativity of P_if by -10 mmHg associated with acute inflammation will require a reduction of IFV by 80% when interstitial compliance is 8% per mmHg. A more likely explanation is therefore that structural rearrangements are responsible for the events leading to increased negativity of P_if in acute inflammation.     

扎普司特和谷胱甘肽翻转豚鼠离体气管对硝普钠的耐受性

上皮完整或去上皮的豚鼠离体气管以300 μmol·L^-1硝普钠(SNP)预处理1 h,使SNP对抗乙醋甲胆碱气管收缩作用的剂量反应曲线右移1.3-1.5 倍, 最大舒张率下降41%-58%,形成SNP气管松弛作用的耐受性. 8-溴环鸟苷酸可模拟SNP在豚鼠离体气管形成的SNP耐受性, 谷胱甘肽(1 mmol·L^-1)及环核苷酸磷酸二酯酶(PDE) Ⅴ抑制剂扎普司特(30 μmol·L^-1)均可部分翻转SNP 的气管松弛作用耐受性,而蛋白合成抑制剂环己酰亚胺(10 μmol·L^-1)对SNP的耐受性无预防作用.结果表明SNP可产生豚鼠离体气管松弛耐受性, 这可能是由于气管平滑肌中环鸟苷酸(cGMP)积聚而下调鸟苷酸环化酶(GC)活性和上调PDEⅤ活性.     

HISTAMINE AND CARBACHOL CONTRACTILE RESPONSES IN PROXIMAL AND DISTAL AIRWAYS OF THE RABBIT

Airway preparations from the trachea, main bronchi, subsegmental bronchi and the parenchyma of rabbits were studied. The proximal airways, the trachea and main bronchi, were less sensitive to histamine than the distal airways of the subsegmental bronchi and lung parenchymal strip. The proximal airways were more sensitive to carbachol than the distal airways. These results may assist in the interpretation of airway responses in vivo.     

Changes in venous flow and intra tracheal flow in fetal breathing movements

Using pulsed Doppler ultrasound combined with a real-time B-mode image, changes in the central venous blood flow and tracheal fluid flow were recognized during fetal breathing movements. The blood flow in the umbilical vein was increased with fetal inspiration in which the abdominal wall of fetus moved inward, and decreased with expiration in which the abdominal wall moved outward. Velocity in the fetal vena cava revealed a complex blood flow, in accordance with both fetal cardiac motions and breathing movements. The tracheal flow velocity during fetal breathing was measured at a maximum of 40 cm s-1 and the flow volume was estimated at a maximum of 6 ml breath-1 in the matured fetus.     

Pharmacology of B-HT 920 in some Isolated Smooth Muscles of the Guinea-pig

Abstract: The effects of B-HT 920 were investigated on four isolated preparations from the guinea-pig, namely the aorta, trachea, ileum and vas deferens. The latter three preparations were studied during electrical field stimulation, which induced contractions by activating cholinergic neurones (trachea and ileum) or adrenergic neurones (vas deferens), respectively. Comparative studies were also made with clonidine and noradrenaline. In ileum and trachea B-HT 920 was almost equipotent with noradrenaline to inhibit the electrically induced contractions. In these tissues, B-HT 920 also displayed almost the same maximal effect as noradrenaline. Clonidine also inhibited the contractions in ileum and trachea; the drug was slightly more potent than noradrenaline. However, in contrast to the intrinsic activity of B-HT 920 that of clonidine was only submaximal. In vas deferens both B-HT 920 and clonidine induced inhibition of contractions on electrical field stimulation at low concentrations. In this organ, both drugs were capable of inducing complete inhibition of the contractile response. In aorta B-HT 920 as well as clonidine were only weak agonists in comparison to noradrenaline. The α₂-blocker, yohimbine, completely blocked the effect of B-HT 920 in ileum at low concentrations (1 × 10^?7 M). Remarkably, however, the inhibitory action of B-HT 920 in trachea was only marginally affected even by high concentrations of yohimbine (1 × 10^?6 M). It is suggested from the present results that B-HT 920 can induce inhibition of both cholinergic and adrenergic neurotransmission presumably by inducing selective stimulation of prejunctional α₂-receptors. In fact, the selectivity of B-HT 920 seems to be comparable to that of clonidine for the α₂-receptor. However, the mode of action of B-HT 920 in trachea may be somewhat uncertain since its effect was not inhibited by yohimbine.