Determinants of pulmonary blood volume. Effects of acute changes in pulmonary vascular pressures and flow

To examine the effects of pulmonary vascular pressures and flow on pulmonary blood volume (PBV), experiments were performed at constant heart rate and zone 3 conditions (mean left atrial pressure (LAP) above airway pressure) in six anesthetized, open-chest dogs. PBV was calculated as the product of electromagnetic aortic flow and pulmonary mean transit time for ascorbate, obtained without blood withdrawal by polarographic recording of aortic ascorbate changes. In three series of experiments LAP was raised similarly in three steps, from 4.5 to 14.8 mmHg: by mitral constriction which reduced pulmonary blood flow, by blood volume expansion which more than doubled pulmonary blood flow, or by a combination of the two procedures which kept pulmonary blood flow constant. In all three series, LAP and mean pulmonary arterial pressure (PAP) rose in proportion, but PBV was better correlated to PAP (r=0.87±0.02) than to LAP (r=0.66±0.09). These experiments suggest that PAP is the most important factor in determining PBV under zone 3 conditions, whether PAP is raised by increasing pulmonary blood flow or by mitral constriction.     

Transport of molecules across tumor vasculature

The vascular-extravascular exchange of fluid and solute molecules in a tissue is determined by three transport parameters (vascular permeability, P, hydraulic conductivity, L_p, and reflection coefficient, ); the surface area for exchange, A; and the transluminal concentration and pressure gradients. The transport parameters and the exchange area for a given molecule are governed by the structure of the vessel wall. In general, tumor vessels have wide interendothelial junctions; large number of fenestrae and transendothelial channels formed by vesicles; and discontinuous or absent basement membrane. While these factors favor movement of molecules across tumor vessels, high interstitial pressure and low microvascular pressure may retard extravasation of molecules and cells, especially in large tumors. These characteristics of the transvascular transport have significant implications in tumor growth, metastasis, detection and treatment.     

Effect of saline infusion on net reabsorption of endogenous sulfate relative to that of phosphate in intact and thyroparathyroidectomized rats

Clearance experiments have been performed to study the effects of saline infusion on the reabsorption of inorganic sulfate (SO₄) at endogenous levels. Adult female Sprague-Dawley rats on a standard diet were used. Both intact and thyroparathyroidectomized (TPTX) animals were infused with a 130 mmol/l sodium chloride solution at a low (0.15 ml/min) and a high (0.375 ml/min) rate. This increase of the infusion rate decreased the reabsorption of SO₄ in both groups of animals significantly. The fractional excretion of SO₄ in theintact rats increased from 9.9±5.6 to 18.4±3.6% (mean values±SD,p<0.001) and in theTPTX rats from 5.3±2.5 to 22.4±6.3% (p<0.001). It is concluded that endogenous parathyroid hormone has no major effect on the saline-induced inhibition of reabsorption of SO₄.This work was supported by a grant from the Deutsche Forschungsgemeinschaft (Fr 239/9-1)     

造血干/祖细胞的体外扩增培养研究

利用旋转壁式生物反应器(Rotating wall vessel,RWV)体外培养脐带血干细胞,使其大量扩增,以满足临床应用对造血干/祖细胞的数量与质量要求。从脐带血分离得到的单个核细胞(Mononuclear cells,MNC)在T-flask中培养24h,之后接种到RWV反应器中,培养200h。每24h细胞计数,测量培养基的pH和渗透压变化;在144h和197h测CD34 细胞含量并做CFU-GM半固体培养。有核细胞(Nucleated cells,NC)与CD34 细胞在第197h,分别扩增了435.5±87.6倍和32.7±15.6倍,CFU-GM(Colony-forming unit-granulocyte/macrophage)细胞扩增了21.7±4.9倍。整个培养过程中,RWV反应器中的pH和渗透压都保持在造血细胞最佳的扩增条件内,pH基本保持在7.2~7.4之间,渗透压基本保持在290~310mmol/kg之间。由于旋转壁式生物反应器(RWV)结构上的特殊性,可以保证细胞在悬浮流动的状态下生长,很好地模拟了脐带中的造血微环境,使脐带血造血干细胞在该反应器中短期内得到大量扩增。     

细胞因子组合对小鼠骨髓单核细胞的体外扩增作用

目的　了解细胞因子组合对小鼠骨髓单个核细胞的体外扩增作用。方法　采用SCF、IL 3、IL 6、GM CSF、G CSF和EPO等 6种细胞因子组合在体外扩增培养小鼠骨髓单个核细胞 5d后 ,收集培养细胞作体外半固体培养计数各不同阶段祖细胞数 ,并计数细胞总数 ,与未经扩增培养的细胞作比较以判断其扩增情况。结果　有核细胞总数扩增不显著 ,为 (1 .3 60± 0 .1 2 6)倍 ,但造血祖细胞却获得了明显扩增 ,其中CFU E达培养扩增前的 (7.0 4± 1 .2 6)倍 ,BFU E为 (4 .74± 1 .0 4)倍 ,CFU GM和CFU Cs则分别为 (1 .78± 0 .47)和 (1 .74± 0 .48)倍。由此可见 ,在此培养体系中以红系祖细胞的扩增最为显著。结论　小鼠骨髓单个核细胞在单纯细胞因子存在的扩增体系中具有一定的扩增其细胞总数和集落形成祖细胞数的能力 ,为进一步作体内实验判断其造血重建的功能奠定了理论基础。     

Skin expansion in burn patients: problems, rules and indications

Skin expansion in burn patients can be a useful method for secondary skin resurfacing, scar revision or facial remodelling. However, complications and problems occur more often in these patients than in any other. In this paper the incidence of complication in the first and second stages of expansion will be presented. Several rules will then be stated and we will clarify the indications for skin expansion in the treatment of hypertrophic scars, contractures, and post-burn destructions.Lecture given at the first State of the art course on burn reconstruction — Milano, May 1994     

Staged TRAM Breast Reconstruction: Combining the Advantages of Tissue Expansion with Surgical Delay

The TRAM flap has become the gold standard in breast reconstruction but suffers from the disadvantages of poor color match, different texture, and impaired sensation compared to the normal breast. This study reports on a two-stage procedure to address these problems. The first stage consists of insertion of a tissue expander and surgical delay of the TRAM flap. The second stage consists of removal of the tissue expander and transposition of a deepithelized TRAM flap into the tissue expanded cavity. (The capsule is excised.) Four cases of breast reconstruction are reported. The advantage of this procedure is that it offers the benefits of tissue expansion, viz., normal color match, texture, and sensation, and in addition, reconstruction is achieved with autologous tissue by a pedicled TRAM flap. The vascularity of the TRAM is enhanced by a surgical delay procedure.     

Labial skin-flap vaginoplasty using tissue expanders

In severe vaginal malformations, when the distance between the upper vaginal pouch and perineum is too long (6 cm or more), reconstruction of the vagina can be performed by colonic interposition or by long cutaneous flaps obtained by the tissue expansion technique. Two female adolescents were treated using expanded labial skin flaps. Dissection and anastomosis between the vaginal remnant and cutaneous tube was performed by the transtrigonal approach. Results were satisfactory at 2.5-year follow-up. In our opinion, expanded labial skin-flap vaginoplasty has three main advantages: (1) it permits the construction of a large, soft, well-vascularized neovagina using non-hair-bearing labial skin; (2) it obviates postoperative dilations and prevents delayed strictures; and (3) a transtrigonal approach permits an easy vaginal dissection and a careful, tension-free anastomosis.     

多功能通液仪的研制

介绍一种实用的多功能通液仪,主要用于输卵管、子宫、尿道、膀胱、胆管等器官的诊断治疗。阐述其系统功能、工作原理和软硬件设计。经临床使用,工作稳定,操作简便,成本低,应用广,具有很大的推广价值。     

颧骨缝牵张成骨过程中组织超微结构变化的研究

目的:观察天然骨缝牵张成骨过程中组织和细胞超微结构的变化。方法:对牵张成骨的缝区组织经过系列处理,进行超薄切片、透射电镜观察。结果:间充质细胞在牵引早期大量增生,并不断分化为成纤维细胞和成骨细胞,后2种细胞的超微结构显示出具有活跃的合成和分泌功能。1周标本成纤维细胞沿牵引力的长轴方向排列,胞核增大,在其周围包绕着发达并扩张的内质网系统;3周标本大量增生活跃的成骨细胞和成纤维细胞,成骨细胞核仁增大、粗面内质网扩张、核糖体丰富、线粒体增多、富含紧密排列的嵴;5、8周标本中骨细胞形成并发育成熟,骨基质逐渐矿化,清晰可见新形成的胶原纤维、哈氏管,以及骨基质矿化的过程。结论:三维牵张过程中,成纤维细胞、成骨细胞活跃,缝区形成新骨。