Neoadjuvant radiotherapy in rectal cancer - less is more?

AIM: There is significant international variation in the use of neoadjuvant radiation prior to total mesorectal excision. The MERCURY group advocate selective neoadjuvant chemoradiotherapy (CRT). We have performed a retrospective, single-centre study of patients treated with CRT, where only the circumferential resection margin is threatened, with the aim of identifying whether a more selective approach to CRT provides acceptable local relapse rates (LRRs). METHOD: All consecutive patients who underwent radical surgery for rectal adenocarcinoma over a 5-year period (2007-2012) in the Oxford University Trust were considered. Electronic hospital systems were reviewed to obtain patient and tumour demographics, treatment and follow-up information. All patients were classified into risk categories according to National Institute for Health and Care Excellence guidance. Data were analysed using Microsoft Excel and R. RESULTS: Two hundred and seventy-two patients were identified: 123, 89 and 60 in the high-, intermediate- and low-risk categories, respectively. Seventy-nine per cent of those in the high-risk group, 6% in the intermediate and 5% in the low-risk group underwent CRT. The overall 5-year LRR and distant recurrence rate (DRR) were 5.2% and 17.8%, respectively. The 5-year LRR for those who went straight to surgery was 2.0% and for those who had neoadjuvant CRT it was 7.4%. The DRR for these two groups was 8.5% and 18.9%, respectively. CONCLUSION: Our series demonstrates that the use of CRT only in margin-threatening tumours, results in an exceptionally low LRR for those without margin-threatening disease. In routine clinical care, this strategy can minimize the significant morbidity of multimodal treatment and allow earlier introduction of systemic therapy to minimize distant recurrence.

Targeting radiation-resistant hypoxic tumour cells through ATR inhibition.

BACKGROUND: Most solid tumours contain regions of sub-optimal oxygen concentration (hypoxia). Hypoxic cancer cells are more resistant to radiotherapy and represent the most aggressive fraction of a tumour. It is therefore essential that strategies continue to be developed to target hypoxic cancer cells. Inhibition of the DNA damage response (DDR) might be an effective way of sensitising hypoxic tumour cells to radiotherapy. METHODS: Here, we describe the cellular effects of pharmacological inhibition of the apical DDR kinase ATR (Ataxia Telangiectasia and Rad 3 related) with a highly selective inhibitor, VE-821, in hypoxic conditions and its potential as a radiosensitiser. RESULTS: VE-821 was shown to inhibit ATR-mediated signalling in response to replication arrest induced by severe hypoxia. In these same conditions, VE-821 induced DNA damage and consequently increased Ataxia Telangiectasia Mutated-mediated phosphorylation of H2AX and KAP1. Consistently, ATR inhibition sensitised tumour cell lines to a range of oxygen tensions. Most importantly, VE-821 increased radiation-induced loss of viability in hypoxic conditions. Using this inhibitor we have also demonstrated for the first time a link between ATR and the key regulator of the hypoxic response, HIF-1. HIF-1 stabilisation and transcriptional activity were both decreased in response to ATR inhibition. CONCLUSION: These findings suggest that ATR inhibition represents a novel strategy to target tumour cells in conditions relevant to pathophysiology and enhance the efficacy of radiotherapy.

The adductor minimus muscle revisited.

The adductor minimus muscle has had scant and conflicting reports regarding its anatomy with some authors ignoring its existence altogether. The present study was conducted to more precisely describe the anatomy of this muscle. Forty human cadavers underwent dissection of the posterior thigh for observation of the adductor minimus muscle. When identified, this muscle was measured and relationships to the muscle documented. Additionally, five fetuses were dissected to observe for the presence of the adductor minimus muscle. The adductor minimus muscle was found in roughly one half of our specimens and was seen in all fetal specimens. When absent, the quadratus femoris muscle was always more prominent and extended more inferiorly toward the territory of the adductor minimus muscle. The average maximal length, width and thickness for the adductor minimus muscle was 14.6 cm, 7 cm, and 2.25 mm, respectively. Such data may be of consequence to clinicians who rehabilitate posterior thigh musculature or surgeons who operate this region.

Structural basis for potent inhibition of the Aurora kinases and a T315I multi-drug resistant mutant form of Abl kinase by VX-680.

The small molecule inhibitor of the Aurora-family of protein kinases VX-680 or MK-0457, demonstrates potent anti-cancer activity in multiple in vivo models and has recently entered phase II clinical trials. Although VX-680 shows a high degree of enzyme selectivity against multiple kinases, it unexpectedly inhibits both Flt-3 and Abl kinases at low nanomolar concentrations. Furthermore VX-680 potently inhibits Abl and the Imatinib resistant mutant (T315I) that is commonly expressed in refractory CML and ALL. We describe here the crystal structure of VX-680 bound to Aurora-A and show that this inhibitor exploits a centrally located hydrophobic pocket in the active site that is only present in an inactive or "closed" kinase conformation. A tight association of VX-680 with this hydrophobic pocket explains its high affinity for the Aurora kinases and also provides an explanation for its selectivity profile, including its ability to inhibit Abl and the Imatinib-resistant mutant (T315I).

In vitro and in vivo reversal of P-glycoprotein-mediated multidrug resistance by a novel potent modulator, XR9576.

The overexpression of P-glycoprotein (P-gp) on the surface of tumor cells causes multidrug resistance (MDR). This protein acts as an energy-dependent drug efflux pump reducing the intracellular concentration of structurally unrelated drugs. Modulators of P-gp function can restore the sensitivity of MDR cells to such drugs. XR9576 is a novel anthranilic acid derivative developed as a potent and specific inhibitor of P-gp, and in this study we evaluate the in vitro and in vivo modulatory activity of this compound. The in vitro activity of XR9576 was evaluated using a panel of human (H69/LX4, 2780AD) and murine (EMT6 AR1.0, MC26) MDR cell lines. XR9576 potentiated the cytotoxicity of several drugs including doxorubicin, paclitaxel, etoposide, and vincristine; complete reversal of resistance was achieved in the presence of 25-80 nM XR9576. Direct comparative studies with other modulators indicated that XR9576 was one of the most potent modulators described to date. Accumulation and efflux studies with the P-gp substrates, [3H]daunorubicin and rhodamine 123, demonstrated that XR9576 inhibited P-gp-mediated drug efflux. The inhibition of P-gp function was reversible, but the effects persisted for >22 h after removal of the modulator from the incubation medium. This is in contrast to P-gp substrates such as cyclosporin A and verapamil, which lose their activity within 60 min, suggesting that XR9576 is not transported by P-gp. Also, XR9576 was a potent inhibitor of photoaffinity labeling of P-gp by [3H]azidopine implying a direct interaction with the protein. In mice bearing the intrinsically resistant MC26 colon tumors, coadministration of XR9576 potentiated the antitumor activity of doxorubicin without a significant increase in toxicity; maximum potentiation was observed at 2.5-4.0 mg/kg dosed either i.v. or p.o. In addition, coadministration of XR9576 (6-12 mg/kg p.o.) fully restored the antitumor activity of paclitaxel, etoposide, and vincristine against two highly resistant MDR human tumor xenografts (2780AD, H69/LX4) in nude mice. Importantly all of the efficacious combination schedules appeared to be well tolerated. Furthermore, i.v. coadministration of XR9576 did not alter the plasma pharmacokinetics of paclitaxel. These results demonstrate that XR9576 is an extremely potent, selective, and effective modulator with a long duration of action. It exhibits potent i.v. and p.o. activity without apparently enhancing the plasma pharmacokinetics of paclitaxel or the toxicity of coadministered drugs. Hence, XR9576 holds great promise for the treatment of P-gp-mediated MDR cancers.

A Novel Method for Studying the Pharmacokinetics of [(14) C]Umeclidinium After Application to the Axilla or Palm of Healthy Male Subjects.

Umeclidinium (UMEC), a long-acting muscarinic antagonist approved for chronic obstructive pulmonary disease (COPD), was investigated for primary hyperhidrosis as topical therapy. This study evaluated the pharmacokinetics, safety, and tolerability of a single dose of [(14) C]UMEC applied to either unoccluded axilla (UA), occluded axilla (OA), or occluded palm (OP) of healthy males. After 8 h the formulation was removed. [(14) C]UMEC plasma concentrations (Cp) were quantified by accelerator mass spectrometry. Occlusion increased systemic exposure by 3.8-fold. Due to UMEC absorption-limited pharmacokinetics, Cp data from the OA were combined with intravenous data from a phase I study. The data were described by a two-compartment population model with sequential zero and first-order absorption and linear elimination. Simulated systemic exposure following q.d. doses to axilla was similar to the exposure from the inhaled therapy, suggesting that systemic safety following dermal administration can be bridged to the inhaled program, and offering the potential for a reduced number of studies and/or subjects.

Health Informatics via Machine Learning for the Clinical Management of Patients.

OBJECTIVES: To review how health informatics systems based on machine learning methods have impacted the clinical management of patients, by affecting clinical practice. METHODS: We reviewed literature from 2010-2015 from databases such as Pubmed, IEEE xplore, and INSPEC, in which methods based on machine learning are likely to be reported. We bring together a broad body of literature, aiming to identify those leading examples of health informatics that have advanced the methodology of machine learning. While individual methods may have further examples that might be added, we have chosen some of the most representative, informative exemplars in each case. RESULTS: Our survey highlights that, while much research is taking place in this high-profile field, examples of those that affect the clinical management of patients are seldom found. We show that substantial progress is being made in terms of methodology, often by data scientists working in close collaboration with clinical groups. CONCLUSIONS: Health informatics systems based on machine learning are in their infancy and the translation of such systems into clinical management has yet to be performed at scale.

Clinical protocol. A phase IIb, randomized, multicenter, double-blind study of the efficacy and safety of Trinam (EG004) in stenosis prevention at the graft-vein anastomosis site in dialysis patients.

Hemodialysis access complications remain a major cause of morbidity for patients with end-stage renal disease who are undergoing chronic hemodialysis. Vascular access complications occur in approximately 40% of patients with polytetrafluorethylene (PTFE) grafts within the first 6 months, primarily due to stenosis and thrombosis. Thrombosis at the site of vascular access increases the risk of infection and the need for hospitalization, and may lead to loss of potential new sites for vascular access. To a large extent, the failure of hemodialysis access is due to the rapid development of an intimal hyperplastic lesion in the region of anastomosis between the PTFE graft and the vein. The hospital costs related to hemodialysis access procedures are estimated to be around $1.3 billion per year and the total cost of hemodialysis complications to the US healthcare system is thought to be in excess of $2 billion per year. Ark Therapeutics Ltd. are developing a vascular endothelial growth factor D (VEGF-D) gene in an adenoviral vector which is delivered locally to the adventitial surface of a graft-vein anastomosis by means of a collagen collar device. The proposed indication for this product (Trinam) is the prevention of intimal hyperplasia at the graft-vein anastomosis site in patients who require vascular access to facilitate hemodialysis for end-stage renal disease. The rationale for Trinam to prevent intimal hyperplasia at the graft-vein anastomosis follows the discovery that VEGF has a 'vasculoprotective' action, resulting in inhibition of smooth muscle cell migration and proliferation. The fundamental mechanism for this vasculoprotective effect of VEGF, as distinct from its more widely appreciated 'angiogenic' role, is that VEGF acts on surface receptors on endothelial cells resulting in increased production of nitric oxide and prostacyclin. These entities diffuse into the media of the blood vessel wall and counter the tendency for intimal hyperplasia to develop. In an in vivo rabbit model of intimal thickening in carotid arteries, adventitial delivery of VEGF using a silastic collar as a gene delivery reservoir prevented smooth muscle cell proliferation without evidence of new blood vessel formation, indicating that the mechanism by which VEGF inhibited intimal hyperplasia did not involve angiogenesis. The objective of the proposed study is to assess the efficacy and safety of local delivery of Trinam when applied to the graft-vein anastomosis site in patients with end-stage renal disease who require vascular access for hemodialysis. At the time of surgical placement of a PTFE arm graft, patients will be randomized to either a single administration of Trinam or to 'no treatment' (i.e., control group). It is hypothesised that Trinam administration will result in less stenosis at the graft-vein anastomosis site (as measured by fistulography) compared with controls and therefore will reduce the need for interventions in dialysis patients. Approximately 210 patients will be enrolled from 10-15 centers and patients will be evaluated for efficacy and safety over 6 months. The total dose of Trinam will be 1 x 10(11) viral particles (replication-deficient adenoviral vector). This dose of Trinam was not associated with any significant toxicology findings in a preclinical study of pigs in which a PTFE loop-graft was anastomosed from the carotid artery to the internal jugular vein to mimic hemodialysis vascular access surgery.

Antibodies to PAI-1 alter the invasive and migratory properties of human tumour cells in vitro.

Recent reports suggest that elevated levels of plasminogen activator inhibitor-1 (PAI-1) may contribute to tumour progression. The studies reported here were designed to help elucidate PAI-1's contribution to the invasive and migratory phenotype. Antibodies to PA-1 dose-dependently, and significantly, inhibited the invasive and migratory potential of human HT1080 fibrosarcoma cells, as did an antibody to uPA and the plasmin inhibitor aprotinin. Invasion of the human melanoma cell line, BLM, was also attenuated by the anti-PAI-1 monoclonal antibody MAI-12. The non-invasive human melanoma cell line, IF6, which does not express uPA, provided further confirmation of PAI-1 and uPA's role as, upon transfection with uPA, this cell line attained an invasive phenotype, which was again attenuated by MAI-12. Although antibodies to PAI-1 did not affect the adhesion of HT1080 cells to vitronectin, the antibody to uPA reduced their attachment. Addition of exogenous PAI-1, however, prevented HT1080 cell adhesion (IC50 180 nM) and promoted cell detachment from vitronectin. Furthermore melanoma cells transfected with a uPA variant, which had an impaired interaction with PAI-1, were not invasive and had impaired binding to vitronectin. These data highlight the importance of a balanced proteolysis and suggest an additional role for PAI-1 distinct from its role in proteolysis. These data also suggest that uPA and PAI-1 may co-operate in the migratory process by respectively facilitating the attachment to, and subsequent detachment from, vitronectin in the extracellular matrix. These results support the clinical findings and indicate that modulation of PAI-1 activity may be of therapeutic benefit for the treatment of cancer.

Dicationic bis(9-methylphenazine-1-carboxamides): relationships between biological activity and linker chain structure for a series of potent topoisomerase targeted anticancer drugs.

Bis(9-methylphenazine-1-carboxamides) joined by a variety of dicationic (CH(2))(n)()NR(CH(2))(m)NR(CH(2))(n) linkers of varying length (carboxamide N-N distances from 11.0 to 18.4 A) and rigidity were prepared by reaction of 9-methylphenazine-1-carboxylic acid imidazolide with the appropriate polyamines. The compounds were evaluated for growth inhibitory properties in P388 leukemia, Lewis lung carcinoma, and wild-type (JL(C)) and mutant (JL(A) and JL(D)) forms of human Jurkat leukemia with low levels of topoisomerase II (topo II). The compounds all had IC(50) ratios of <1 in the resistant Jurkat lines, consistent with topo II inhibition not being the primary mechanism of action. Analogues joined by an (CH(2))(2)NR(CH(2))(2)NR(CH(2))(2) linker were extremely potent cytotoxins, with selectivity toward the human cell lines, but absolute potencies declined sharply from R = H through R = Me to R = Pr and Bu. In contrast, (CH(2))(2)NR(CH(2))(3)NR(CH(2))(2) compounds showed reverse effects, with the R = Me analogue being more potent than the R = H one as well as being the most potent in the series [IC(50) in JL(C) cells 0.08 nM; superior to that for the clinical bis(naphthalimide) LU 79553]. Overall, the IC(50)s of analogues with linker chains (CH(2))(n)NH(CH(2))(m)NH(CH(2))(n) were inversely proportional to linker length. Constraining the rigidity of the linker chain by incorporating a piperazine ring did not decrease potency significantly. A representative compound bound tightly to DNA with high selectivity for GC sites, compatible with recent work suggesting that compounds of this type place their side chains in the major groove, making specific contacts with guanine bases. Representative compounds were susceptible to transport mediated resistance, being much less effective in cells that overexpressed P-glycoprotein. Overall the results suggest these compounds have a similar mode of action, mediated primarily by poisoning of topo I (possibly with some involvement of topo II). The bis(9-methylphenazine-1-carboxamides) show very high in vitro growth inhibitory potencies compared to their monomeric analogues. Two compounds showed in vivo activity in murine colon 38 syngeneic and HT29 human colon tumor xenograft models using intraperitoneal dosing.

Evaluation of a low molecular weight modulator of human plasminogen activator inhibitor-1 activity.

A critical component in the regulation of thrombus formation and clearance is the balance between tissue plasminogen activator (tPA) and plasminogen activator inhibitor type-1 (PAI-1). An increase in the plasma concentration of PAI-1 has been proposed as a risk factor in thrombotic disease. Inhibition of PAI-1 activity may have utility in the treatment of thromboembolic disease. We report here the evaluation of three diketopiperazine-based low molecular weight inhibitors of PAI-1 activity (XR334, XR1853 and XR5082). In vitro these compounds reversed the inhibitory effects of PAI-1 against both tPA and urokinase (UK) (IC50: 5 to 80 muM). In contrast, other serpin-serine protease interactions, including alpha 1-antitrypsin-trypsin, alpha 2-antiplasmin- plasmin and antithrombin-thrombin, were not affected, neither did these inhibitors affect global tests of haemostasis. In the light of this promising in vitro profile these compounds were evaluated in a standard radioisotopic assay of clot lysis in whole rat blood following intravenous administration. In this assay these compounds dose-dependently enhanced fibrinolysis ex vivo. After intravenous bolus administration XR334, XR1853 and XR5082 at 5 mg/kg increased clot lysis by 32.0 +/- 5.1% SEM (n = 25, p < 0.01), 36.7 +/- 3.5% SEM (n = 36, p < 0.01) and 60.0 +/- 2.8% SEM (n = 17, p < 0.01) respectively compared to vehicle. Intravenous infusion of these compounds (1 mg/kg/min for 20 min) significantly prolonged (approximately twofold) the time to blood vessel occlusion in the rat electrically-stimulated carotid artery thrombosis model. Thus, these low molecular weight inhibitors of PAI-1 activity enhanced fibrinolysis ex vivo and protected against thrombus formation in the rat.

The molecular interaction of the high affinity reversal agent XR9576 with P-glycoprotein.

1 The kinetics and nature of equilibrium binding were used to characterize the molecular interaction of the anthranilic acid derivative [3H]-XR9576 with the multidrug resistance P-glycoprotein (P-gp). XR9576 displayed specific high-affinity binding to P-gp (Bmax = 275 pmol mg-1, Kd = 5.1 nM). The transport substrates [3H]-vinblastine and [3H]-paclitaxel displayed 4 fold and 20 fold lower affinity respectively for P-gp. The duration of action of XR9576 with P-gp was increased in comparison to that of vinblastine which displayed a slower rate of association and a faster dissociation rate. 2 The relative affinities of several modulators and transport substrates to interact with P-gp were determined from displacement drug equilibrium binding assays. Vinblastine and paclitaxel could only fractionally displace [3H]-XR9576 binding, displaying Ki values significantly different from their measured Kd values. This suggests a non-competitive interaction between XR9576 and the P-gp substrates vinblastine and paclitaxel. 3 XR9576 was shown to be a potent modulator of P-gp mediated [3H]-vinblastine and [3H]-paclitaxel transport as it increased the steady-state accumulation of these cytotoxics in CHrB30 cells to levels observed in non-P-gp-expressing AuxB1 cells (EC50 = 487+/-50 nM). This inhibition of drug transport is not mediated through competition for transport since [3H]-XR9576 accumulation was not influenced by P-gp expression or function. 4 These results demonstrate that the P-gp modulator XR9576 exhibits greater selectivity, duration of inhibition and potency of interaction with this transporter than any other reported modulators. Several lines of evidence suggest that XR9576 inhibits P-gp function by binding at a site which is distinct from the site of interaction of transport substrates. The two sites may be classified as serving modulatory or transport functions.

An investigation into the formation of N- [2-(dimethylamino)ethyl]acridine-4-carboxamide (DACA) and 6-[2-(dimethylamino)ethylamino]- 3-hydroxy-7H-indeno[2, 1-C]quinolin-7-one dihydrochloride (TAS-103) stabilised DNA topoisomerase I and II cleavable complexes in human leukaemia cells.

The antitumour agents DACA (XR5000; N-[2-(dimethylamino)ethyl]acridine-4-carboxamide) and TAS-103 (6-[2-(dimethylamino)ethylamino]-3-hydroxy-7H-indeno[2, 1-c]quinolin-7-one dihydrochloride) have been shown to inhibit two essential nuclear enzymes in vitro, DNA topoisomerase I and DNA topoisomerase (topo) II. To examine whether DACA or TAS-103 stabilise topo I, topo IIalpha, and topo IIbeta cleavable complexes in human leukaemia CCRF-CEM cells, the TARDIS assay (trapped in agarose DNA immunostaining) was used. This assay can reveal drug-stabilised topo-DNA complexes formed in situ in individual cells. The results showed that both DACA and TAS-103 can stabilise topo IIalpha cleavable complexes in these cells. Topo IIbeta cleavable complexes were also formed, but only at high concentrations of DACA and TAS-103. The effect on topo I was less clear, with TAS-103 showing only low levels of cleavable complex formation and DACA having no detectable effect under these assay conditions. This is in contrast to the purified enzyme cleavable complex assay, where both DACA and TAS-103 poisoned topo I. Although both DACA and TAS-103 show a preference for topo IIalpha in whole cells using the TARDIS assay, the formation of low levels of topo I or topo IIbeta cleavable complexes may still play a role in cell death.

Tricho-rhino-phalangeal and branchio-oto syndromes in a family with an inherited rearrangement of chromosome 8q.

Here we report on a family with an inherited rearrangement of chromosome 8q, dir ins(8)(q24.11q13.3q21.13). Individuals with the chromosome abnormality, which does not appear to be associated with deletion of chromosome material, have manifestations of both tricho-rhino-phalangeal syndrome (TRPS) and branchio-oto syndrome (BOS). TRPS has been linked previously to deletions involving 8q24.11----q24.13, but none of the described patients with deletions in this part of 8q have had characteristics of the BOS. The presence of a breakpoint in 8q24.11 without apparent chromosome deletion in the family described suggests that TRPS maps to this band of 8q. Further, it is suggested that BOS maps to either 8q13.3 or 8q21.13.

Acute and chronic effects of renin inhibitor GR70982 in the conscious marmoset.

The effects on plasma renin activity (PRA), mean arterial blood pressure (MABP) and heart rate (HR) of GR70982, a low molecular weight inhibitor of human renin, were studied in conscious marmosets. In vitro, GR70982 is a potent and selective inhibitor of human plasma renin (concentration producing 50% inhibition (IC50): human renin = 6.9 x 10(-9) M; porcine pepsin and bovine cathepin D = greater than 10(-3) M). In normotensive marmosets, i.v. GR70982 (0.001-0.1 mg kg-1) produced a dose-related inhibition of PRA. Larger oral doses (0.2, 1 and 5 mg kg-1) were required to achieve similar effects. In renin-dependent hypertensive marmosets, i.v. GR70982 (0.01 and 0.5 mg kg-1) produced dose-related decreases in MABP (-12 and -18 mm Hg) and PRA (-93 and -100%), with only minimal effects on HR. A 7-day continuous i.v. infusion of GR70982 (0.36 mg kg-1 day-1) in sodium-deplete marmosets produced a gradual decrease in MABP (-17 mm Hg at day 7, cf. control), accompanied by an inhibition of PRA (approximately 75%) and minimal HR effects.

Atrial natriuretic factor in the Langendorff perfused coronary vasculature of the rabbit isolated heart.

Removal of exogenously administered rat ANF (99-126) (rANF) from the rabbit coronary vasculature was investigated. Rabbit hearts were perfused using a modified Langendorff technique and ANF concentrations in the perfusate were measured by a radio-receptor assay. Under these conditions no major degradation of ANF was observed. On perfusion, however, the heart liberated large amounts of ANF. This release peaked 15 minutes after the initiation of perfusion, (685 + 220 pM) and then fell to a sustained basal level (305 + 80 pM) after 45 minutes. Although an increase in the perfusate flow rate reduced the ANF concentration, there was no significant difference in the rate of ANF release between the two flow rates used. After momentary cessation of flow ANF concentration fell to a significantly lower level, however, once again no significant change in rate of release occurred. These results suggest that the heart is not a major site of ANF degradation and that alterations in flow rate through the coronary vascular bed can cause changes in amounts of ANF released.

Inhibition of plasminogen activator inhibitor-1 activity by two diketopiperazines, XR330 and XR334 produced by Streptomyces sp.

Two diketopiperazines, XR334 (1) and the novel compound XR330 (2), were isolated from the lyophilised biomass of an unidentified Streptomyces sp. Their structures were elucidated on the basis of spectroscopic studies and confirmed by chemical synthesis. Both compounds inhibited plasminogen activator inhibitor-1 activity in an amidolytic assay of tissue plasminogen activator mediated plasmin generation. Compound 1 also enhanced fibrinolysis ex vivo and protected against thrombus formation in the rat. These diketopiperazines represent the first low molecular weight inhibitors of plasminogen activator inhibitor-1, a physiological regulator of fibrinolysis.

Novel drimane sesquiterpene esters from Aspergillus ustus var. pseudodeflectus with endothelin receptor binding activity.

A series of novel drimane sesquiterpene esters (1-6) was isolated from fermentations of Aspergillus ustus var. pseudodeflectus and their structures elucidated by spectroscopic methods including the HMQC, HMBC and INADEQUATE NMR experiments. The major component of the fermentation, 1, was (2'E,4'E,6'E)-6-(1'-carboxy-2',4',6'-trien)-9-hydroxydrim-7-ene-11 ,12-olide. Compounds 1, 2, 3 and 5 exhibited endothelin receptor binding inhibitory activity against rabbit endothelin-A and rat endothelin-B receptors with IC50 values in the range 20-150 microM. These compounds had similar levels of activity in assays for binding to human endothelin A and endothelin B receptors. The isolation of 9,11-dihydroxy-6-oxodrim-7-ene, 7, a probable biosynthetic precursor to the drimane esters is also reported.

Ways of coping with psychological distress after trauma.

One hundred and eight survivors of trauma attending a stress clinic were assessed on measures of coping, personality, control expectancies and psychological distress. The psychometric characteristics of these questionnaires are discussed, and the relationships between them investigated using correlational and regression techniques. Although cross-sectional studies can only be indicative, it would appear that most coping strategies, and particularly escape-avoidance, are consistently associated with high psychological distress, with the exception of positive reappraisal and distancing, which are the only strategies associated with better psychological outcome. It may be that deeply distressed survivors cannot find effective ways of obtaining relief, and therefore report many ways of trying to cope.

An open trial of exposure therapy based on deconditioning for post-traumatic stress disorder.

Twenty-three patients who had experienced a major stressful event were given a debriefing session followed by eight weekly sessions of imaginal exposure and in vivo exposure. Patients recounted their traumatic experiences aloud, using the first person and the present tense, and included as much detail as possible. This account was audiotaped and patients were asked to listen to the tape between treatment sessions. There were reductions of 42 percent in the Impact of Events Scale (IES), of 61 percent in the General Health Questionnaire (GHQ), of 38 percent in the Symptom Checklist-90 (SCL-90) questionnaire, and of 35 percent in the Clinician Administered Post-Traumatic Stress scale (CAPS), all of which were statistically significant. The number of patients who satisfied the diagnostic criteria for post-traumatic stress disorder was halved.