脱氧胆酸钠体系分离紫杉烷类化合物

以脱氧胆酸钠(SDC)为手性拆分剂,建立了紫杉醇、10-去乙酰基-紫杉醇、10-去乙酰基-7-表-紫杉醇、三尖杉宁碱、巴可亭Ⅲ、10-去乙酰基-巴可亭Ⅲ、10-去乙酰基-7-表-巴可亭Ⅲ等7种紫杉烷类化合物的胶束电动毛细管色谱分离方法.分离条件为67cm×75μm毛细管,分离电压25kv,温度25℃,UV检测器230nm,气动进样3s.缓冲液为脱氧胆酸50mm,Tris-HCl140mm,MeOH20%,pH8.5.     

Effects of cardiogenic edema fluid on ion and fluid transport in the adult lung

We have previously shown that cardiogenic pulmonary edema fluid (EF) increases Na(+) and fluid transport by fetal distal lung epithelia (FDLE) (Rafii B, Gillie DJ, Sulowski C, Hannam V, Cheung T, Otulakowski G, Barker PM and O'Brodovich H. J Physiol 544: 537-548, 2002). We now report the effect of EF on Na(+) and fluid transport by the adult lung. We first studied primary cultures of adult type II (ATII) epithelium and found that overnight exposure to EF increased Na(+) transport, and this effect was mainly due to factors other than catecholamines. Plasma did not stimulate Na(+) transport in ATII. Purification of EF demonstrated that at least some agent(s) responsible for the amiloride-insensitive component resided within the globulin fraction. ATII exposed to globulins demonstrated a conversion of amiloride-sensitive short-circuit current (I(sc)) to amiloride-insensitive I(sc) with no increase in total I(sc). Patch-clamp studies showed that ATII exposed to EF for 18 h had increased the number of highly selective Na(+) channels in their apical membrane. In situ acute exposure to EF increased the open probability of Na(+)-permeant ion channels in ATII within rat lung slices. EF did increase, by amiloride-sensitive pathways, the alveolar fluid clearance from the lungs of adult rats. We conclude that cardiogenic EF increases Na(+) transport by adult lung epithelia in primary cell culture, in situ and in vivo.     

Effects of arterial pressure on lung capillary pressure and edema after microembolism

The effect of increased arterial pressure (Pa) on microvessel pressure (Pc) and edema following microvascular obstruction (100-micron glass spheres) was examined in the isolated ventilated dog lung lobe pump perfused with blood. Lobar vascular resistance (PVR) increased 2- to 10-fold following emboli when either Pa or flow was held constant. Microbead obstruction increased the ratio of precapillary to total PVR from 0.60 +/- 0.05 to 0.84 +/- 0.02 (SE) or to 0.75 +/- 0.06 (n = 6), as determined by the venous occlusion and the isogravimetric capillary pressure techniques, respectively. Isogravimetric Pc (5.0 +/- 0.7) did not differ from Pc obtained by venous occlusion (3.8 +/- 0.2 Torr, n = 6). After embolism, Pc in constant Pa decreased from 6.2 +/- 0.3 to 4.4 +/- 0.3 Torr (n = 16). In the constant-flow group, embolism doubled Pa while Pc increased only 40% (6.7 +/- 0.6 to 9.2 +/- 1.4 Torr, n = 6) with no greater edema formation than in the constant Pa groups. These data indicate poor transmission of Pa to filtering capillaries. Microembolism, even when accompanied by elevated Pa and increased flow velocity of anticoagulated blood of low leukocyte and platelet counts, caused little edema. Our results suggest that mechanical effects alone of lung microvascular obstruction cause minimal pulmonary edema.     

A synthesis of interstitial fluid regulation and lymph formation.

The interstitial fluid spaces are filled with a mat of collagen fibers, and the interstices of this mat contain a mucopolysaccharide gel ground substance. Both the collagen fibers and the gel are elastic structures that can be expanded or compacted. In the expanded state the collagen fibers are pushed far apart and pockets of free fluid develop witin the gel. In the compacted state the elastic recoil of the compressed collagen fibers and gel reticular fibrillae seems to cause suction on the fluid within the tissue spaces, thus creating a subatmospheric pressure. Measurements of interstitial fluid pressure using a perforated capsule method indicate that this is normally slightly negative (subatmospheric) in most soft tissues. However, even very slight extra filtration of fluid into the tissue spaces increases the interstitial fluid pressure toward more positive values, which in turn increases lymph flow. The increased lymph flow then decreases the interstitial fluid volume and pressure back toward normal because of two mechanism, 1) direct removal of fluid from the tissue spaces in the lymph, and 2) removal of protein from the interstitial fluid in the lymph, thus decreasing the interstitial fluid colloid osmotic pressure and allowing more effective osmosis of fluid directly from the interstitial spaces back into the capillaries.     

Influence of microtubule-associated proteins on the differential effects of paclitaxel and docetaxel

Microtubules are complex structures arising in part from the polymerization of tubulin dimers. Tubulin binds to a wide range of drugs which have been used as probes for tubulin conformation and assembly properties. There is some evidence that taxol and taxotere have differing effects on tubulin conformation. Previous work has shown that MAP2 and Tau, although they both induce microtubule assembly, have qualitatively different effects on tubulin's behavior. Since most microtubulesin vivo are likely to be associated with MAPs, we decided to characterize the differential effects of MAP2, Tau, taxol, and taxotere on tubulin polymerization with the aim of understanding the mechanisms through which these agents stimulate microtubule assembly. Furthermore, the inhibitive effect of calcium has been used to elucidate the ability of the two drugs to force tubulin assembly. These observations suggest that docetaxel, in addition to its greater efficiency in tubulin assembly, may have the capacity to differently alter certain classes of microtubules. Tau and MAP2 accessory proteins may represent important cofactors modulating the effects of taxoids.     

Relationship of fluid filtration to lung vascular pressure during edema

Effect of edema on the relationship between rate of fluid filtration and vascular pressure was studied in ventilated isolated dog lung lobes blood-perfused at constant flow. Constant rate of lobe weight gain (S), representing transvascular fluid flux, was obtained at different venous pressures (Pv) as Pv was increased stepwise from 2 to 40 and then similarly decreased from 40 to 2 Torr (n = 6). In another group (n = 6), edema was maximized by reversing the sequence of Pv change; S was obtained during similar Pv steps as Pv was decreased from 40 to 2 and then returned to 40 Torr. In both groups, delta S was disproportionately greater for delta Pv at higher Pv's, with S vs. Pv fit by an exponential curve (P less than 0.001). The exponential relationship was independent of lung hydration inasmuch as greater edema on the second limb of Pv change did not alter the curve (P greater than 0.05). At 144% weight gain, interstitial compliance was 55.5 +/- 26.8 ml.100 g-1.Torr-1 (n = 10). Interstitial pressure reportedly remains constant, i.e., fails to increase to further buffer fluid filtration, after transition of the lung interstitium from low to high compliance at approximately 40% lung weight gain. If so, then the exponential S vs. Pv relationship observed in the present study at elevated interstitial compliance does not appear related to tissue pressure-buffering effects.     

Effect of systemic venous pressure elevation on lymph flow and lung edema formation

Pulmonary lymph drains into the thoracic duct and then into the systemic venous circulation. Since systemic venous pressure (SVP) must be overcome before pulmonary lymph can flow, variations in SVP may affect lymph flow rate and therefore the rate of fluid accumulation within the lung. The importance of this issue is evident when one considers the variety of clinical interventions that increase SVP and promote pulmonary edema formation, such as volume infusion, positive-pressure ventilation, and various vasoactive drug therapies. We recorded pulmonary arterial pressure (PAP), left atrial pressure (LAP), and SVP in chronic unanesthetized sheep. Occlusion balloons were placed in the left atrium and superior vena cava to control their respective pressures. The superior vena caval occluder was placed above the azygos vein so that bronchial venous pressure would not be elevated when the balloon was inflated. Three-hour experiments were carried out at various LAP levels with and without SVP being elevated to 20 mmHg. The amount of fluid present in the lung was determined by the wet-to-dry weight ratio method. At control LAP levels, no significant difference in lung fluid accumulation could be shown between animals with control and elevated SVP levels. When LAP was elevated above control a significantly greater amount of pulmonary fluid accumulated in animals with elevated SVP levels compared with those with control SVP levels. We conclude that significant excess pulmonary edema formation will occur when SVP is elevated at pulmonary microvascular pressures not normally associated with rapid fluid accumulation.     

Vascular pressure effects on lung edema formation after glass bead embolism

The canine lung lobe was embolized with 100-micron glass beads before lobectomy and blood anticoagulation. The lobe was isolated, ventilated, and pump-perfused with blood at an arterial pressure (Pa) of about 50 (high pressure, HP, n = 9) or 25 Torr (low pressure, LP, n = 9). Rus/PVR, the ratio of upstream (Rus) to total lobar vascular resistance (PVR), was determined by venous occlusion and the isogravimetric capillary pressure technique. The capillary filtration coefficient (Kf), an index of vascular permeability, was obtained from rate of lobe weight gain during stepwise capillary pressure (Pc) elevation. The embolized lobes became more edematous than nonembolized controls, (C, n = 11), (P less than 0.05), with Kf values of 0.20 +/- 0.04, 0.25 +/- 0.06, and 0.07 +/- 0.01 ml X min-1 X Torr-1 X 100 X g-1 in LP, HP, and C, respectively (P less than 0.05). The greater Rus/PVR in embolized lobes (P less than 0.05) protected the microvessels and, although Pc was greater in HP than in controls (P less than 0.05), Pc did not differ between HP and LP (P greater than 0.05). Although indexes of permeability did not differ between embolized groups (P greater than 0.05), HP became more edematous than LP (P less than 0.05). The greater edema in HP did not appear due to a greater imbalance of Starling forces across the microvessel wall or to vascular recruitment. At constant Pc and venous pressure, elevating Pa from 25 to 50 Torr in embolized lobes resulted in greater edema to suggest fluid filtration from precapillary vessels.     

Regulation of extracellular volume and interstitial fluid pressure in rat bone marrow

The volume and fluid pressure characteristics of the intact bone marrow is incompletely understood. We used microspheres and lipoproteins for measurements of intravascular volume (IVV) and EDTA for interstitial fluid volume (IFV) within the rat bone marrow. Interstitial fluid pressure (IFP) was determined with micropipettes connected to a servo-controlled counter-pressure system. Both the microspheres and the lipoproteins yielded estimates of IVV of approximately 1 ml/100 g. After a brief reactive hyperemia, IVV increased to 2.5 ml/100 g, whereas IFV decreased with approximately 1.5 ml/100 g, so that total extracellular volume did not change. Baseline bone marrow IFP was 9.7 mmHg. The hyperemia led to a transient twofold increase in IFP, whereas a marked blood loss decreased IFP by almost one-half. These novel data suggest that extracellular volume and IFP within the bone marrow can be measured with tracer methods and the micropuncture technique. The responses of IVV, IFV, and IFP during changes in blood flow to the bone marrow suggest a tight regulation and are thus compatible with those for a low-compliant tissue.     

Long-term lowering of tumour interstitial fluid pressure reduces Ki-67 expression

High tumour interstitial fluid pressure (TIFP) is a characteristic of most solid tumours. Recent data give first evidence that mechanical stretch induced by TIFP triggers proliferation in solid tumours. In the present study we compared two protocols of TIFP reduction on the expression of the tumour proliferation marker Ki-67: (a) short-term lowering of TIFP by a singular puncture and (b) long-term lowering of TIFP by catheterization. Utilizing two experimental tumours (A431, A549) it was found that the TIFP broke down rapidly after a singular puncture but recovered within 6h. In case of permanent catheterization no TIFP recovery was observed. After 24h tumours were excised and stained against the proliferation marker Ki-67. While a singular puncture had no effect catheterized tumours showed a significant decrease in Ki-67 expression. Our data suggest that long-term lowering of TIFP is required to reduce tumour proliferation.     

Effects of heat and cold exposure and exercise on the interstitial fluid proteins of the rat

1. Interstitial fluid (obtained from capsules implanted subcutaneously) and plasma were obtained from rats before and after heat and cold exposure and exercise. 2. In the case of plasma, cold and heat exposure and exercise decreased A/G ratios. Albumin concentrations also decreased after heat and cold and protein concentration increased after exercise. 3. Cold decreased interstitial protein and albumin concentrations and A/G ratios. Heat exposure increased protein concentration and decreased the A/G ratio. Exercise decreased decreased protein concentrations. 4. The results are discussed in relation to previous findings.     

Effects of sorafenib on intra-tumoral interstitial fluid pressure and circulating biomarkers in patients with refractory sarcomas (NCI protocol 6948)

Purpose

Sorafenib is a multi-targeted tyrosine kinase inhibitor with therapeutic efficacy in several malignancies. Sorafenib may exert its anti-neoplastic effect in part by altering vascular permeability and reducing intra-tumoral interstitial hypertension. As correlative science with a phase II study in patients with advanced soft-tissue sarcomas (STS), we evaluated the impact of this agent on intra-tumor interstitial fluid pressure (IFP), serum circulating biomarkers, and vascular density.

Patients and Methods

Patients with advanced STS with measurable disease and at least one superficial lesion amenable to biopsy received sorafenib 400 mg twice daily. Intratumoral IFP and plasma and circulating cell biomarkers were measured before and after 1–2 months of sorafenib administration. Results were analyzed in the context of the primary clinical endpoint of time-to-progression (TTP).

Results

In 15 patients accrued, the median TTP was 45 days (range 14–228). Intra-tumoral IFP measurements obtained in 6 patients at baseline showed a direct correlation with tumor size. Two patients with stable disease at two months had post-sorafenib IFP evaluations and demonstrated a decline in IFP and vascular density. Sorafenib significantly increased plasma VEGF, PlGF, and SDF1α and decreased sVEGFR-2 levels. Increased plasma SDF1α and decreased sVEGFR-2 levels on day 28 correlated with disease progression.

Conclusions

Pretreatment intra-tumoral IFP correlated with tumor size and decreased in two evaluable patients with SD on sorafenib. Sorafenib also induced changes in circulating biomarkers consistent with expected VEGF pathway blockade, despite the lack of more striking clinical activity in this small series.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00330421","term_id":"NCT00330421"}}NCT00330421