Lurbinectedin, a selective inhibitor of oncogenic transcription, in patients with pretreated germline BRCA1/2 metastatic breast cancer: results from a phase II basket study.

BACKGROUND: Lurbinectedin, a selective inhibitor of oncogenic transcription, has shown preclinical antitumor activity against homologous recombination repair-deficient models and preliminary clinical activity in BRCA1/2 breast cancer. PATIENTS AND METHODS: This phase II basket multitumor trial (NCT02454972) evaluated lurbinectedin 3.2 mg/m2 1-h intravenous infusion every 3 weeks in a cohort of 21 patients with pretreated germline BRCA1/2 breast cancer. Patients with any hormone receptor and human epidermal growth factor receptor 2 status were enrolled. The primary efficacy endpoint was overall response rate (ORR) according to RECIST v1.1. Secondary endpoints included duration of response (DoR), progression-free survival (PFS), overall survival (OS) and safety. RESULTS: Confirmed partial response (PR) was observed in six patients [ORR = 28.6%; 95% confidence interval (CI) 11.3% to 52.2%] who had received a median of two prior advanced chemotherapy lines. Lurbinectedin was active in both BRCA mutations: four PRs in 11 patients (36.4%) with BRCA2 and two PRs in 10 patients (20.0%) with BRCA1. Median DoR was 8.6 months, median PFS was 4.1 months and median OS was 16.1 months. Stable disease (SD) was observed in 10 patients (47.6%), including 3 with unconfirmed response in a subsequent tumor assessment [ORR unconfirmed = 42.9% (95% CI 21.8% to 66.0%)]. Clinical benefit rate (PR + SD ≥ 4 months) was 76.2% (95% CI 52.8% to 91.8%). No objective response was observed among patients who had received prior poly (ADP-ribose) polymerase inhibitors. The most common treatment-related adverse events (AEs) were nausea (61.9%), fatigue (38.1%) and vomiting (23.8%). These AEs were mostly grade 1/2. The most common grade 3/4 toxicity was neutropenia (42.9%: grade 4, 23.8%: with no febrile neutropenia). CONCLUSIONS: This phase II study met its primary endpoint and showed activity of lurbinectedin in germline BRCA1/2 breast cancer. Lurbinectedin showed a predictable and manageable safety profile. Considering the exploratory aim of this trial as well as previous results in other phase II studies, further development of lurbinectedin in this indication is warranted.

Evaluation of plitidepsin in patients with primary myelofibrosis and post polycythemia vera/essential thrombocythemia myelofibrosis: results of preclinical studies and a phase II clinical trial.

Previous data established that plitidepsin, a cyclic depsipeptide, exerted activity in a mouse model of myelofibrosis (MF). New preclinical experiments reported herein found that low nanomolar plitidepsin concentrations potently inhibited the proliferation of JAK2V617F-mutated cell lines and reduced colony formation by CD34+ cells of individuals with MF, at least in part through modulation of p27 levels. Cells of MF patients had significantly reduced p27 content, that were modestly increased upon plitidepsin exposure. On these premise, an exploratory phase II trial evaluated plitidepsin 5 mg/m(2) 3-h intravenous infusion administered on days 1 and 15 every 4 weeks (q4wk). Response rate (RR) according to the International Working Group for Myelofibrosis Research and Treatment consensus criteria was 9.1% (95% CI, 0.2-41.3%) in 11 evaluable patients during the first trial stage. The single responder achieved a red cell transfusion independence and stable disease was reported in nine additional patients (81.8%). Eight patients underwent a short-lasting improvement of splenomegaly. In conclusion, plitidepsin 5 mg/m(2) 3-h infusion q4wk was well tolerated but had a modest activity in patients with primary, post-polycythaemia vera or post-essential thrombocythaemia MF. Therefore, this trial was prematurely terminated and we concluded that further clinical trials with plitidepsin as single agent in MF are not warranted.

First-in-man phase I trial of two schedules of the novel synthetic tetrahydroisoquinoline alkaloid PM00104 (Zalypsis) in patients with advanced solid tumours.

BACKGROUND: PM00104 binds guanines at DNA minor grooves, impacting DNA replication and transcription. A phase I study was undertaken to investigate safety, dose-limiting toxicities (DLTs), recommended phase II dose (RP2D), pharmacokinetics (PKs) and preliminary antitumour activity of PM00104 as a 1- or 3-h infusion three-weekly. METHODS: Patients with advanced solid tumours received PM00104 in a dose escalation trial, as guided by toxicity and PK data. RESULTS: A total of 47 patients were treated; 27 patients on the 1-h schedule (0.23-3.6 mg m(-2)) and 20 patients on the 3-h schedule (1.8-3.5 mg m(-2)). Dose-limiting toxicities comprised reversible nausea, vomiting, fatigue, elevated transaminases and thrombocytopenia, establishing the 1-h schedule RP2D at 3.0 mg m(-2). With the 3-h schedule, DLTs of reversible hypotension and neutropenia established the RP2D at 2.8 mg m(-2). Common PM00104-related adverse events at the RP2D comprised grade 1-2 nausea, fatigue and myelosuppression. In both schedules, PKs increased linearly, but doses over the 1-h schedule RP2D resulted in higher than proportional increases in exposure. A patient with advanced urothelial carcinoma had RECIST shrinkage by 49%, and three patients had RECIST stable disease ≥6 months. CONCLUSION: PM00104 is well tolerated, with preliminary evidence of antitumour activity observed. The 1-h 3-weekly schedule is being assessed in phase II clinical trials.

Trabectedin plus pegylated liposomal doxorubicin in the treatment of patients with partially platinum-sensitive ovarian cancer: current evidence and future perspectives.

The effectiveness of platinum re-treatment in relapsed ovarian cancer depends on relapse-free/treatment-free intervals. Platinum agents can be effectively readministered to platinum-sensitive patients (relapsing >12 months after platinum), but efficacy is lower in partially platinum-sensitive (PPS) disease (relapsing 6-12 months after platinum). There is no clear standard treatment challenging PPS patients. Survival data in this subset with chemotherapy combinations such as pegylated liposomal doxorubicin (PLD) plus carboplatin or gemcitabine plus PLD are available from phase II trials ranging from 16 to 21 months. Recent results from OVA-301 phase III randomized trial evaluating trabectedin plus PLD showed the longest median overall survival ever reported in PPS patients (23 months). Subsequent chemotherapy (including platinum-based regimens) was administered later and survival in patients receiving third-line platinum was longer in patients treated with trabectedin plus PLD compared with those treated with PLD alone. These results suggest that prolonging platinum-free interval (PFI) with an effective non-platinum regimen improves outcome with subsequent third-line platinum treatment. An ongoing phase III trial (INOVATYON) aims to demonstrate if the results observed with trabectedin plus PLD in PPS patients are due to PFI extension, and if PFI extension with non-platinum combination prolongs response to subsequent platinum and survival in this population.

Simple robust autotuning rules for 2-DoF PI controllers.

This paper addresses the problem of providing simple tuning rules for a Two-Degree-of-Freedom (2-DoF) PI controller (PI(2)) with robustness considerations. The introduction of robustness as a matter of primary concern is by now well established among the control community. Among the different ways of introducing a robustness constraint into the design stage, the purpose of this paper is to use the maximum sensitivity value as the design parameter. In order to deal with the well known performance/robustness tradeoff, an analysis is conducted first that allows the determination of the lowest closed-loop time constant that guarantees a desired robustness. From that point, an analytical design is conducted for the assignment of the load-disturbance dynamics followed by the tuning of the set-point weight factor in order to match, as much as possible, the set-point-to-output dynamics according to a first-order-plus-dead-time dynamics. Simple tuning rules are generated by considering specific values for the maximum sensitivity value. These tuning rules, provide all the controller parameters parameterized in terms of the open-loop normalized dead-time allowing the user to select a high/medium/low robust closed-loop control system. The proposed autotuning expressions are therefore compared with other well known tuning rules also conceived by using the same robustness measure, showing that the proposed approach is able to guarantee the same robustness level and improve the system time performance.

Phase II clinical trial of neoadjuvant trabectedin in patients with advanced localized myxoid liposarcoma.

BACKGROUND: To evaluate neoadjuvant trabectedin (1.5 mg/m(2) 24-h i.v. infusion every 3 weeks; three to six cycles) in patients with locally advanced myoxid liposarcoma (ML) previously untreated with chemotherapy or radiation. PATIENTS AND METHODS: Primary efficacy end point was pathological complete response (pCR) or tumoral regression rate. Objective response according to RECIST (v.1.0) was a secondary end point. RESULTS: Three of 23 assessable patients had pCR [13%; 95% confidence interval (CI), 3% to 34%]. Furthermore, very good and moderate histological responses were observed in another 2 and 10 patients, respectively. Histological decrement in the cellular and vascular tumor component and maturation of tumor cells to lipoblasts were observed in both myoxid and myoxid/round cell variants. Seven patients had partial response according to RECIST (objective response rate of 24%; 95% CI, 10% to 44%). No disease progression was reported. Neoadjuvant trabectedin was usually well tolerated, with a safety profile similar to that described in patients with soft tissue sarcoma or other tumor types. CONCLUSION: Trabectedin 1.5 mg/m(2) given as a 24-h i.v. infusion every 3 weeks is a therapeutic option in the neoadjuvant setting of ML.

Spisulosine (ES-285) given as a weekly three-hour intravenous infusion: results of a phase I dose-escalating study in patients with advanced solid malignancies.

PURPOSE: Spisulosine is a marine compound that showed antitumor activity in preclinical studies. We report results of a phase I trial performed in patients with advanced solid tumors with the marine compound, with the aim to determine the maximum tolerated dose (MTD) of a weekly 3-h intravenous (iv.) infusion, and to evaluate the safety, efficacy, and pharmacokinetics (PK) of the compound. PATIENTS AND METHODS: Two centers contributed 25 patients to the trial, and 7 dose levels were explored. RESULTS: In dose levels ranging from 4 to 128 mg/m²/day, no dose-limiting toxicities (DLT) were observed. One patient had DLT at 200 mg/m², a reversible grade 3 ALT increase. The MTD was not reached due to early termination of the Spisulosine trial program but is considered to be likely in the range of 200 mg/m² for this schedule. Drug-related adverse reactions included mild to moderate nausea, pyrexia, injection site reactions, and vomiting. One case of grade 4 peripheral motor and sensory neuropathy associated with general weakness and pain was observed during treatment cycle 4 and possibly contributed to the death of the patient. Grade 3 laboratory abnormalities included anemia and lymphopenia and increases in liver enzymes (alkaline phosphatase, transaminases, and bilirubin). Objective responses were not observed, and only four patients had short-lasting stable disease (<3 months). The PK data indicated a wide distribution, a long residence time, and dose proportionality of the agent. CONCLUSIONS: Hepato- and neuro-toxicity are schedule independent dose-limiting adverse events for this marine compound, as illustrated by this and other early clinical trials.

Second order inverse response process identification from transient step response.

Simple algorithms for identification of inverse response models from step response are difficult to obtain because analytically the solution of a system of coupled nonlinear equations is required. In this article we propose a simple identification procedure for second order inverse response processes, based on the plant step response. The algorithm provides the model parameters in a sequential way, thus avoiding the solution of a nonlinear equation system. Moreover the algorithm is flexible because it can be suited to user requirements, thus modifying the algorithm performance. Finally error bounds on the identified parameters are provided which are useful if the model is used for control design purposes.

Trabectedin plus pegylated liposomal doxorubicin in relapsed ovarian cancer: outcomes in the partially platinum-sensitive (platinum-free interval 6-12 months) subpopulation of OVA-301 phase III randomized trial.

BACKGROUND: OVA-301 is a large randomized trial that showed superiority of trabectedin plus pegylated liposomal doxorubicin (PLD) over PLD alone in relapsed ovarian cancer. The optimal management of patients with partially platinum-sensitive relapse [6-12 months platinum-free interval (PFI)] is unclear. PATIENTS AND METHODS: within OVA-301, we therefore now report on the outcomes for the 214 cases in this subgroup. RESULTS: Trabectedin/PLD resulted in a 35% risk reduction of disease progression (DP) or death [hazard ratio (HR) = 0.65, 95% confidence interval (CI), 0.45-0.92; P = 0.0152; median progression-free survival (PFS) 7.4 versus 5.5 months], and a significant 41% decrease in the risk of death (HR = 0.59; 95% CI, 0.43-0.82; P = 0.0015; median survival 23.0 versus 17.1 months). The safety of trabectedin/PLD in this subset mimicked that of the overall population. Similar proportions of patients received subsequent therapy in each arm (76% versus 77%), although patients in the trabectedin/PLD arm had a slightly lower proportion of further platinum (49% versus 55%). Importantly, patients in the trabectedin/PLD arm survived significantly longer after subsequent platinum (HR = 0.63; P = 0.0357; median 13.3 versus 9.8 months). CONCLUSION: This hypothesis-generating analysis demonstrates that superior benefits with trabectedin/PLD in terms of PFS and survival in the overall population appear particularly enhanced in patients with partially sensitive disease (PFI 6-12 months).

Mapping the literature: role of trabectedin as a new chemotherapy option in advanced pretreated soft tissue sarcoma.

This bibliographic review evaluated phase II clinical trials aimed at the identification of antitumor activity of single agents in soft tissue sarcoma (STS) after failure of standard- of-care therapy including anthracyclines and ifosfamide. A total of 63 articles (on anthracyclines, ifosfamide, trabectedin and 27 investigational agents) were included (data from 1979 to 2008).Trabectedin is the most extensively studied agent in patients with STS after failure of anthracyclines and ifosfamide (457 patients), followed by ifosfamide (412), cisplatin (144), temozolomide (137), docetaxel (114), gemcitabine (112), etoposide (95) and doxorubicin (59). Dacarbazine and the remaining investigational agents have usually been tested in 50 or fewer patients, with vastly negative results not warranting further investigation. Methodological limitations are identified in the majority of the reviewed phase II studies, including small sample size, single-institution studies, lack of independent review of the antitumor responses and inadequate description of previous therapies/agents. However, all trabectedin studies fulfilled these methodological characteristics relevant for a phase II trial. A phase II randomized trial confirmed the results of 3 prior nonrandomized studies and, therefore, trabectedin is currently considered an important new option to control advanced sarcomas in patients with STS following failure of all conventional treatments.

In vitro fertilization and development of OPU derived goat and sheep oocytes.

The recent upgrade in IVP technology seen in cattle can be adapted to embryo production in small ruminants to overcome limitations exhibited by surgical procedures on preserving the reproductive potential of donors and the efficiency of embryo production. The aim of the present study was to assess the current procedures used in cattle for the production of IVP embryos in goats and sheep based on laparoscopic-aided ovum pick-up (LOPU) supplied oocytes. Sexually matured goat and sheep donors were treated during the breeding season with FSH and subjected to laparoscopic-guided follicular puncture under general anaesthesia. The collected cumulus-oocyte complexes were matured in medium 199 and fertilized by frozen-thawed spermatozoa using Talp medium supplemented with heparin and oestrus-sheep serum. Cleaved ova were either cultured in sheep in vitro fertilization medium plus amino acids or transferred to sheep oviducts. Blastocyst rate, hatching rate and development rate up to term were used as markers of embryo function. The results obtained for goat and sheep involving 30 and 35 donors respectively (10 and 9 LOPU sessions) were 81.2% and 85.2% of oocyte collection rate; 88.3% and 98.6% oocyte incubation rate; 85.6% and 76.0% fertilization rate; 82.4% and 93.4% of cleavage rate; 50.0% and 61.5% IVP blastocyst rate; 42.1% and 45.5% blastocyst rate in oviducts; 73.0% and 66.7% embryo survival up to term, respectively. The results are comparable to those obtained in small ruminants and in bovines suggesting that requirements for embryo production and development are similar.

[Glutamate-related excitotoxicity neuroprotection with memantine, an uncompetitive antagonist of NMDA-glutamate receptor, in Alzheimer's disease and vascular dementia]. / Neuroproteccion con memantina (antagonista no competitivo del receptor NMDA-glutamato) frente a la excitotoxicidad asociada al glutamato en la enfermedad de Alzheimer y en la demencia vascular.

AIM: To review the therapeutic efficacy of memantine, an uncompetitive antagonist of N-methyl-D-aspartate (NMDA)-glutamate receptor. DEVELOPMENT: Alzheimer's disease (AD) is the most common neurodegenerative disorder and cause of dementia with ageing worldwide. The main AD symptoms are a gradual loss of cognitive function and a functional impairment. Glutamatergic excitatory neurotransmission, an important process in learning and memory, is severely disrupted in AD, probably due to the oxidative stress associated with the beta-amyloid peptide (1-42) increase. The glutamate-related excitotoxicity, mainly mediated by NMDA subtype of the glutamate receptors, is a common clue of pathogenesis for neurodegenerative disorders. CONCLUSIONS: Memantine, a moderate-affinity, voltage-dependent, uncompetitive antagonist of NMDA receptor, shows neuroprotective effects in patients with moderate-to-severe AD. Memantine is a drug with neuroprotective and cognition-enhanced properties, which can be combined with other treatments for AD. Thus, memantine does not stop or reverse AD, but its moderating effect in protecting the brain from the toxic levels of calcium, allows normal signaling among brain neurons. The efficacy and safety profile of memantine have been reported in several clinical trials for treatment of AD and vascular dementia.

Neuroprotección con memantina (antagonista no competitivo del receptor NMDA-glutamato) frente a la excitotoxicidad asociada al glutamato en la enfermedad de Alzheimer y en la demencia vascular / Glutamate-related excitoxicity neuroprotection with memantine, an uncompetitive antagonist of nmda-glutamate receptor, in Alzheimer’s disease and vascular dementia

Objetivo. Realizar una revisión de la eficacia terapéuticade memantina, un antagonista no competitivo del receptor de Nmetil-D-aspartato (NMDA)-glutamato. Desarrollo. La enfermedadde Alzheimer (EA) es el trastorno neurodegenerativo y la causa dedemencia asociada al envejecimiento más frecuente en todo elmundo. Los síntomas principales de la EA son una pérdida gradualde la función cognitiva y el deterioro funcional. La neurotransmisiónexcitatoria glutamatérgica, un proceso importante en elaprendizaje y la memoria, se encuentra gravemente alterada en laEA, debido probablemente al estrés oxidativo asociado con el aumentodel péptido amiloide β (1-42). La excitotoxicidad asociadaal glutamato, mediada principalmente por el subtipo NMDA de losreceptores de glutamato, es un indicio frecuente de patogenia entrastornos neurodegenerativos. Conclusiones. La memantina, unantagonista no competitivo, dependiente de voltaje y con una moderadaafinidad por el receptor de NMDA, induce efectos neuroprotectoresen pacientes con EA entre moderada y grave. La memantinaes un fármaco con propiedades neuroprotectoras y potenciadorasde la cognición que se puede combinar con otros tratamientoscontra la EA. Por tanto, la memantina no detiene ni reviertela EA, pero su efecto moderador al proteger el cerebro de losniveles tóxicos de calcio permite una transmisión normal de señalesentre las neuronas cerebrales. Se describen aquí diferentesensayos clínicos que han detallado la eficacia y la seguridad de lamemantina en el tratamiento de la EA y la demencia vascular

Aim. To review the therapeutic efficacy of memantine, an uncompetitive antagonist of N-methyl-D-aspartate (NMDA)-glutamate receptor. Development. Alzheimer’s disease (AD) is the most common neurodegenerative disorder and cause ofdementia with ageing worldwide. The main AD symptoms are a gradual loss of cognitive function and a functional impairment.Glutamatergic excitatory neurotransmission, an important process in learning and memory, is severely disrupted in AD,probably due to the oxidative stress associated with the β-amyloid peptide (1-42) increase. The glutamate-related excitotoxicity,mainly mediated by NMDA subtype of the glutamate receptors, is a common clue of pathogenesis for neurodegenerativedisorders. Conclusions. Memantine, a moderate-affinity, voltage-dependent, uncompetitive antagonist of NMDAreceptor, shows neuroprotective effects in patients with moderate-to-severe AD. Memantine is a drug with neuroprotective andcognition-enhanced properties, which can be combined with other treatments for AD. Thus, memantine does not stop orreverse AD, but its moderating effect in protecting the brain from the toxic levels of calcium, allows normal signaling amongbrain neurons. The efficacy and safety profile of memantine have been reported in several clinical trials for treatment of ADand vascular dementia

Computer-assisted analysis of sperm motion in goats and its relationship with sperm migration in cervical mucus.

In vitro sperm migration in cervical mucus relates to sperm concentration at the utero-tubal junction and to in vivo fertilization performance in goats. The present study aimed to characterize, using Computer-Assisted Sperm Analysis (CASA), motility patterns depicted by buck sperm and their relation to the migration efficiency in homologous (goat) and heterologous (heifer) cervical mucus in vitro. Semen was collected from 23 sexually mature bucks from three breeds by artificial vagina and sperm were assessed for motility parameters with a Hobson Sperm analyzer following extension in Sperm Analysis Medium (SAM). To study the relationship between kinematics parameters and the ability of sperm to migrate in cervical mucus, in a first experiment, motility performance of buck sperm suspended in SAM was compared against seminal plasma. In a second experiment, kinematics parameters of sperm were characterized. In a third experiment, bucks with sperm that differed in specific motion parameters were compared for the ability of their sperm to migrate through goat and bovine cervical mucus collected at estrus. In a fourth experiment, ejaculates that were compared in their migration ability and were assessed simultaneously for their motility parameters. Overall, sperm suspended in SAM medium had better velocity and similar linearity and lateral head displacement than those suspended in seminal plasma; furthermore, caprine sperm swam relatively fast (relative to bovine and ovine sperm), following a very linear trajectory. Under the conditions used, velocity parameters, linearity and lateral head displacement seemed to be related to sperm migration efficiency in homologous mucus but not in bovine cervical mucus.

Specification of laboratory animal use in scientific articles: current low detail in the journals' instructions for authors and some proposals.

The scientific article communicates results of research to other investigators; therefore, it must contain a complete description of the experiment to help other researchers when designing their future investigations. However, poorly detailed data on laboratory animal use is given in published articles. Despite the well-known and important contribution of the International Committee of Medical Journal Editors (ICMJE) to standardize scientific writing and submission of manuscripts to biomedical journals, no specific instructions on the reporting of animal use are given in the ICMJE Uniform Requirements and, therefore, most journals do not detail this to the authors. Individual efforts from groups like the Working Committee for the Biological Characterizations of Laboratory Animals, the Boyd Group, or the Committee on Publication Ethics are commendable. These contributions should be incorporated into the ICMJE Uniform Requirements and, later, into the Instructions for Authors of peer-reviewed journals. This would be the only efficient way to instruct authors on how to report laboratory animal use in their submitted manuscripts. The present article relates some proposals for helping authors when reporting animal use in scientific articles. These proposals are not only based on previous guidelines for animal specifications, but also on Instructions for Authors from journals specialized in Laboratory Animal Science. These proposals are classified into major and minor issues, and they are located in the corresponding parts of the article, as defined by the Introduction, Methods, Results, and Discussion (IMRAD) method.

Role of histamine and platelet-activating factor in allergic rhinitis.

This review is focused on the effects of histamine and platelet-activating factor (PAF) in allergic rhinitis and the plausible implications for therapy. Rhinitis is defined as a heterogeneous disorder resulting from an IgE-mediated reaction associated with nasal inflammation of variable intensity. Two phases of response are triggered by an IgE/allergen cross-linking event: the first is the release of preformed mediators such as histamine or interleukins from mast cells and basophils; the second begins when cells start producing lipid-derived mediators. One of these mediators is PAF. Apart from leukotrienes, PAF is perhaps the most potent inflammatory mediator in allergic rhinitis for inducing vascular leakage, a response that may contribute to the appearance of rhinorrhea and nasal congestion.

Intestinal ischemic preconditioning: less xanthine accumulation relates with less apoptosis.

Ischemic preconditioning has shown to reduce apoptosis in the intestinal mucosa during ischemia/reperfusion. This study evaluated if the decrease of apoptotic events found during preconditioning could be related with a reduction of the substrate (i.e., xanthine/hypoxanthine) available for xanthine oxidase (XO). Animals were randomly assigned to the following study groups: C, control; I/R, ischemia/reperfusion; P+I/R, ischemic preconditioning; P+I/R+H/X, ischemic preconditioning plus hypoxanthine/xanthine, and P+I/R+H/X+Allo, ischemic preconditioning plus hypoxanthine/xanthine plus allopurinol. Caspase-3 activity, DNA fragmentation and TUNEL staining increased in the I/R group compared to control. Ischemic preconditioning (P+I/R group) was able to reverse these apoptotic variables to a level similar to that of control rats. The addition of hypoxanthine/xanthine to rats subjected to ischemic preconditioning (P+I/R+H/X group) showed the highest apoptotic activity; however, further addition of allopurinol (P+I/R+H/X+Allo group) decreased significantly apoptotic activity and events. In conclusion, intestinal ischemic preconditioning is able to reduce apoptosis during the following sustained ischemia/reperfusion event because of a reduced accumulation of xanthine/hypoxanthine nucleotide.

Exogenous adenosine enhances caspase-3 activity in warm renal ischaemia.

Renal injury due to ischaemia/reperfusion (I/R) leads to impaired renal function. One of the essential pathological changes thereby is cell death due to apoptosis. This study investigated the effect of adenosine administration on caspase-3 (C3) activity and expression during warm renal ischaemia in rat kidney and the role of nitric oxide (NO) as a mediator of the adenosine-induced effect. The following experimental groups were studied: control, ischaemia, ischaemia with adenosine administration, ischaemia with adenosine and N-nitro- l-arginine methyl ester (L-NAME) treatment and ischaemia with NO donor administration. C3 activity was measured and its protein expression determined by Western blot analysis. Supplementation of adenosine or NO during ischaemia increased C3 activity and protein expression but the effect of adenosine was reversed in rats treated with L-NAME. We conclude that adenosine increases C3 activity through an NO-dependent mechanism.

Nucleotides modulate renal ischaemia-reperfusion injury by different effects on nitric oxide and superoxide.

1. The present study investigated the effects of kidney ischaemia duration on nitric oxide (NO) and superoxide (O2-) generation at reperfusion and the role of xanthine and adenosine as mediators of NO/O2- generation. 2. The effect of the duration of ischaemia on renal nucleotide levels was studied in two ischaemic groups (10 and 30 min). The role of adenosine and xanthine was studied in ischaemic-reperfused groups (subjected to 10 and 30 min ischaemia and 60 min reperfusion). 3. Tissue levels of adenosine decreased significantly after 30 min ischaemia, whereas xanthine/hypoxanthine levels increased concomitantly with renal dysfunction and histological damage. 4. Nitric oxide production increased significantly after 10 min ischaemia and 60 min reperfusion, whereas lipoperoxidation increased significantly after 30 min ischaemia and 60 min reperfusion. The administration of theophylline (40 mg/kg, i.p.) reversed the early increase in NO production. 5. Xanthine supplementation decreased renal function and increased lipoperoxidation. 6. In conclusion, NO/O2- production and the subsequent renal injury/dysfunction may be modified by changes in the adenosine and xanthine levels of the injured kidney, although the present data show a significant in vivo role only for xanthine.

Extracellular pH affects inflammatory cell production of superoxide and nitric oxide.

Previous research has described how high cellular metabolism creates an acidic environment in inflammatory cells during respiratory burst. The aim of our work was to describe the acid-base dependence of exudate in superoxide (O2.-) and nitric oxide (NO.) generation by inflammatory cells from a carrageenan-granuloma. Although the carrageenan solution was alkaline (pH 7.74 when equilibrated with air) the exudate showed an acidification that stabilised at around 7 units of pH. A notable hypercapnia, but not hypoxia, was found in the exudate at up to 24 h. The effect of extracellular acidosis on O2.- and NO. production by inflammatory cells was also studied. The maximum O2.- production and the lowest levels of NO. were found at pH 7, which was closer to the pH of the granuloma-pouch. These results suggest that experiments with inflammatory cells ex vivo should be carried out at an identical pH to that found in vivo in order to reproduce the physiological mechanisms of free radical generation during inflammatory processes.