Pharmacological study of anti-inflammatory activity of aqueous extracts of Mikania glomerata (Spreng.) and Mikania laevigata (Sch. Bip. ex Baker).

ETHNOPHARMACOLOGICAL RELEVANCE: Mikania glomerata Spreng. (MG) and Mikania laevigata Sch. Bip. ex Baker (ML), popularly known as guaco, are medicinal plants similar in morphology, chemical composition and medicinal uses. Both species are often used and sold without distinction; however, it is believed that their chemical composition is different. AIM: Thus, the aim of this study is to investigate if the aqueous extract of MG and ML present similar anti-inflammatory activity to the point of being used interchangeably. MATERIAL AND METHODS: Different doses of both extracts and coumarin were given to rats in different experimental models to assess the anti-inflammatory activity between these two species. For this, the animals were submitted to paw edema, pleurisy and degranulation of peritoneal mast cell and the extracts were also characterized by Ultra High Efficiency Liquid Chromatography coupled to Mass Spectrometry (UHPLC-MS). RESULTS: The chromatographic method showed that ML presents ten times more coumarin than MG. Oral administration of MG, ML and coumarin inhibited paw edema induced by carrageenan (400 mg/kg, 55% inhibition; 400 mg/kg, 57% inhibition; 75 mg/kg, 38% inhibition; p < 0.05, respectively). MG, ML and coumarin treatment also inhibited the edema induced by compound 48/80 (400 mg/kg, 56% inhibition; 400 mg/kg, 69% inhibition; 75 mg/kg, 40% inhibition; p < 0.05, respectively). MG, ML and coumarin did not prevent mast cell degranulation and the consequent histamine release in Wistar rat peritoneal mast cells induced by compound 48/80. MG did not inhibit cell infiltration in pleurisy nor the highest dose tested, while ML decreased the leukocyte migration (200 and 400 mg/kg, 23% and 30% inhibition; p < 0.001, respectively) and, to a lesser extent, coumarin also reduced cell infiltration (10, 50 and 75 mg/kg; 15%, 16% and 17% inhibition; p < 0.001, respectively). CONCLUSION: The variation of the results of the anti-inflammatory activity found in M. glomerata and M. laevigata demonstrates that these two species should not be used interchangeably. Coumarin, as already proven, has anti-inflammatory action however, we have suggested that it probably is not the only component responsible for this therapeutic effect in the extracts.

Male secretory breast cancer: case in a 6-year-old boy with a peculiar gene duplication and review of the literature.

PURPOSE: Secretory breast cancer (SBC) is one of the rarest breast cancer (BC), representing the majority of BC in childhood. Nevertheless, it elicits a lot of interest both for the peculiar morphology and the characteristic genetic features. Currently, there is no consensus on optimal treatment strategy. Therefore, it is useful to report every case in order to establish treatment algorithms. METHODS: We describe the case of a 6-year-old boy diagnosed with a SBC, with peculiar genomic and immunohistochemical features. Moreover, we carried out a review of the literature in order to analyze the present state of knowledge about this rare entity. RESULTS: To the best of our knowledge, there are only 120 cases published in literature, only 32 in males and only 2 younger than 6 years. Furthermore, this one had peculiar genomic and immunohistochemical features. Indeed, even if SBC expresses basal-cell markers, our patient had a triple-negative tumor expressing both basal and luminal cell markers. Furthermore, the boy's genomic profile revealed not only positivity for the typical SBC's translocation t(12;15), but also for a 3q28 duplication, found in his father (healthy) and paternal grandfather (with a previous BC). None were positive for BRCA mutation. This locus includes only one gene encoding for a growth factor recently linked to Early Infantile Epileptic Encephalopathy-47 and Idiopathic ventricular tachycardia. Even if the literature does not provide evidence of a pathogenic role it is not possible to exclude a cancer-predisposing activity. CONCLUSIONS: SBC is a rare type of BC, characterized by triple-negative features with an unexpectedly good prognosis. More data are needed to fully understand the behavior of this cancer and genomic profiling could be helpful in improving its diagnosis and management.

Glutamate receptor and transporter modifications in rat organotypic hippocampal slice cultures exposed to oxygen-glucose deprivation: the contribution of cyclooxygenase-2.

Meloxicam is a non-steroidal anti-inflammatory drug which has been reported to lessen the ischemic transcriptional effects in some of the glutamatergic system genes as well as to decrease the infarct volume in in vivo assays. In this study, we show how the presence of meloxicam decreases cell mortality in assays of oxygen-glucose deprivation (OGD) in rat organotypic hippocampal slices culture. Mortality was measured using propidium iodide. Transcript levels of some glutamatergic system genes, including vesicular and membrane glutamate transporters (VGLUT1, VGLUT2, GLAST-1A, GLT-1, and EAAC-1) and some glutamatergic receptor subunits (NMDA receptor, GluN1, GluN2A and GluN2B subunits and AMPA receptor, GluA1 and GluA2 subunits) were measured by real-time PCR (qPCR). The transcription of vesicular glutamate transporters and glutamatergic receptor subunits, but not membrane glutamate transporters, was modified by the presence of meloxicam. The study demonstrates the neuroprotective role of meloxicam in organotypic hippocampal slice cultures and shows how meloxicam is able to selectively increase or decrease the OGD-induced changes in the expression of the different glutamatergic system genes studied here. We suggest that the neuroprotective role of meloxicam could be due to a modification in the balance of the expression of some glutamatergic receptor subunits, leading to a different stoichiometry of receptors such as NMDA or AMPA. Thus, meloxicam would decrease the excitotoxicity induced by OGD.

PARP-1 activation causes neuronal death in the hippocampal CA1 region by increasing the expression of Ca(2+)-permeable AMPA receptors.

An excessive activation of poly(ADP-ribose) polymerases (PARPs) may trigger a form of neuronal death similar to that occurring in neurodegenerative disorders. To investigate this process, we exposed organotypic hippocampal slices to N-methyl-N'-nitro-N'-nitrosoguanidine (MNNG, 100µM for 5min), an alkylating agent widely used to activate PARP-1. MNNG induced a pattern of degeneration of the CA1 pyramidal cells morphologically similar to that observed after a brief period of oxygen and glucose deprivation (OGD). MNNG exposure was also associated with a dramatic increase in PARP-activity and a robust decrease in NAD(+) and ATP content. These effects were prevented by PARP-1 but not PARP-2 inhibitors. In our experimental conditions, cell death was not mediated by AIF translocation (parthanatos) or caspase-dependent apoptotic processes. Furthermore, we found that PARP activation was followed by a significant deterioration of neuronal membrane properties. Using electrophysiological recordings we firstly investigated the suggested ability of ADP-ribose to open TRPM2 channels in MNNG-induced cells death, but the results we obtained showed that TRPM2 channels are not involved. We then studied the involvement of glutamate receptor-ion channel complex and we found that NBQX, a selective AMPA receptor antagonist, was able to effectively prevent CA1 neuronal loss while MK801, a NMDA antagonist, was not active. Moreover, we observed that MNNG treatment increased the ratio of GluA1/GluA2 AMPAR subunit expression, which was associated with an inward rectification of the IV relationship of AMPA sEPSCs in the CA1 but not in the CA3 subfield. Accordingly, 1-naphthyl acetyl spermine (NASPM), a selective blocker of Ca(2+)-permeable GluA2-lacking AMPA receptors, reduced MNNG-induced CA1 pyramidal cell death. In conclusion, our results show that activation of the nuclear enzyme PARP-1 may change the expression of membrane proteins and Ca(2+) permeability of AMPA channels, thus affecting the function and survival of CA1 pyramidal cells.

Inhibition of inducible nitric oxide synthase-derived nitric oxide as a therapeutical target for acute pancreatitis induced by secretory phospholipase A2.

BACKGROUND: Nitric oxide is a key signalling molecule in the pathogenesis of inflammation, but its role in acute pancreatitis and related abdominal pain induced by secretory phospholipase A2 (sPLA2 ) from Crotalus durissus terrificus (Cdt) venom has not been investigated. METHODS: Male Wistar rats were i.v. injected with L-NAME (20 mg/kg), aminoguanidine (AG, 50 mg/kg), 7-nitroindazole (7-NI, 10 mg/kg) or vehicle 10 min before or 60 min after the injection of sPLA2 (300 µg/kg) into the common bile duct. After 4 h of sPLA2 injection, abdominal hyperalgesia and inflammation were assessed in addition to serum amylase, nitrite/nitrate (NOx), pancreas lipoperoxidation and 3-nitrotyrosine (3-NT) contents. RESULTS: sPLA2 -induced acute pancreatitis, related abdominal hyperalgesia, hyperamylasemia and increased concentration of NOx were not correlated with lipoperoxidation or increased 3-NT in the pancreas. Pretreatment with all the nitric oxide synthase (NOS) inhibitors significantly reduced abdominal mechanical hyperalgesia, but only iNOS blockade by AG suppressed pancreas oedema and serum NOx increase. The therapeutic approach with all the NOS inhibitors produced a similar reduction pattern of the abdominal hyperalgesia, but AG treatment also inhibited serum hyperamylasemia and NOx concentrations and pancreatic myeloperoxidase. The nNOS blockade by 7-NI treatment also inhibited myeloperoxidase activity in both pancreas and lung. CONCLUSIONS: Therapeutic blockade of iNOS or nNOS provides benefits in terms of inhibition of the acute pancreatitis-related abdominal hyperalgesia, while iNOS inhibition also ameliorates the inflammatory cell influx to the pancreas and reduces the resultant hyperamylasemia and NOx levels, thus representing alternative pharmacological strategies for treatment of clinical pancreatitis associated with increased PLA2 .

MPP(+) -dependent inhibition of Ih reduces spontaneous activity and enhances EPSP summation in nigral dopamine neurons.

BACKGROUND AND PURPOSE: 1-Methyl-4-phenylpyridinium (MPP(+) ), a potent parkinsonizing agent in primates and rodents, is a blocker of mitochondrial complex I, therefore MPP(+) -induced parkinsonism is believed to depend largely on mitochondrial impairment. However, it has recently been proposed that other mechanisms may participate in MPP(+) -induced toxicity. We tackled this issue by probing the effects of an acute application of MPP(+) on substantia nigra pars compacta (SNc) dopamine (DA) neurons. EXPERIMENTAL APPROACH: The effects of MPP(+) on SNc DA neurons in acute midbrain slices were investigated with electrophysiology techniques. KEY RESULTS: MPP(+) (50 µM) was able to (i) hyperpolarize SNc DA neurons by ∼6 mV; (ii) cause an abrupt and marked (over 50%) reduction of the spontaneous activity; and (iii) inhibit the hyperpolarization-activated inward current (Ih ). MPP(+) shifted Ih activation curve towards negative potentials by ∼11 mV both in Wistar rats and in C57/BL6 mice. Inhibition was voltage- and concentration-dependent (Imax = 47%, IC50 = 7.74 µM). MPP(+) slowed Ih activation kinetics at all potentials. These effects were not dependent on (i) block of mitochondrial complex I/fall of ATP levels; (ii) activation of type 2 DA receptor; and (iii) alteration of cAMP metabolism. Finally, MPP(+) -dependent inhibition of Ih facilitated temporal summation of evoked EPSPs in SNc DA, but not in CA1 hippocampal neurons. CONCLUSION AND IMPLICATIONS: Reduced functionality of Ih in SNc DA neurons, via increased responsiveness towards synaptic excitation, might play a role in MPP(+) -induced parkinsonism and, possibly, in the pathogenesis of human Parkinson's.

Exercise training reduces pulmonary ischaemia-reperfusion-induced inflammatory responses.

Physical exercise reduces the deleterious effects of cardiovascular and inflammatory disorders. The purpose of the present study was to evaluate the beneficial effects of physical training on the inflammatory responses following lung ischaemia-reperfusion (IR) in rats. Male Wistar rats were divided into sham-operated animals and sedentary and trained animals submitted to lung IR. The run training programme consisted of 5 sessions.week(-1), each lasting 60 min.day(-1), at 66% of maximal oxygen consumption for 8 weeks. The left pulmonary artery, bronchus and pulmonary vein were occluded for 90 min and reperfused for 2 h. Lung protein extravasation was measured as (125)I-human albumin accumulation, whereas lung neutrophil infiltration was measured as myeloperoxidase activity. Lung IR in sedentary rats resulted in marked increases in protein extravasation and neutrophil influx, and in significant elevations of serum tumour necrosis factor (TNF)-alpha and interleukin (IL)-1beta levels. Physical preconditioning attenuated the increased IR-induced protein leakage without affecting neutrophil influx. It also reduced serum TNF-alpha (and IL-1beta) levels, but had no effect on IL-10 levels. Plasma superoxide dismutase activity was significantly increased in trained IR rats. The present data show that physical preconditioning protects the rat lung from ischaemia-reperfusion injury by attenuating the pulmonary vascular permeability that may be a consequence of reduced levels of tumour necrosis factor-alpha and interleukin-1beta and elevated superoxide dismutase activity.

Weekly paclitaxel plus capecitabine in advanced breast cancer patients: dose-finding trial of GOIRC and GOL.

BACKGROUND: Paclitaxel and capecitabine have demonstrated a synergic effect and significant antitumor activity in patients with advanced breast cancer. A weekly schedule of paclitaxel obtained a response rate of 50-68% in advanced breast cancer and less serious side-effects. PATIENTS AND METHODS: Thirty-two patients with advanced breast cancer pretreated with chemotherapy were enrolled in a dose-finding trial to determine the maximum tolerated dose (MTD) and the dose-limiting toxicity (DLT) of paclitaxel given on days 1, 8 and 15 of each cycle combined with capecitabine given twice daily from day 1 through day 14, every 21 days. Three patients were recruited at one of six dose levels (paclitaxel 70-100 mg/m2, capecitabine 1650-2500 mg/m2). RESULTS: Thirty-two patients were accrued and 31 were evaluated for toxicity. One DLT has been experienced at level VI as diarrhea grade 3. We determined dose level V as the MTD, but we recommend dose level IV for phase II studies (capecitabine 1250 mg/m2 orally twice daily plus paclitaxel 80 mg/m2 intravenously weekly), owing to cumulative toxicity at level V. The objective response rate was 43%. CONCLUSIONS: Weekly paclitaxel plus capecitabine is a safety and active chemotherapy in previously treated metastatic breast cancer.

Activity of first-line epirubicin and paclitaxel in metastatic breast cancer is independent of type of adjuvant therapy.

To evaluate the impact of prior adjuvant chemotherapy on response rate (RR), progression-free (PFS) and overall survival (OS) of metastatic breast cancer patients treated with epirubicin/paclitaxel (ET) regimens. In all, 291 patients enrolled in five studies in metastatic breast cancer were analysed: 101 (35%) were chemonaive, 109 (37%) had received adjuvant CMF and 81 (28%) adjuvant anthracyclines. Response rate to ET was 66%. Response rate was 63% for cyclophosphamide plus methotrexate plus 5-fluorouracil (CMF), 67% for prior anthracyclines and 68% in chemonaive patients (P=0.5). By multivariate analysis, adjusted odds ratio for response was 0.81 (95% CI: 0.37-1.79) for CMF and 0.92 (95% CI 0.43-2.01) for anthracyclines (P=0.86). The CR rates were 14% for both CMF and anthracyclines and 22% for chemonaive patients (P=0.2). By multivariate analysis, the relative odds of CR for CMF or anthracyclines were 0.40 and 0.39 as compared to chemonaive patients (P=0.036). The median PFS was 11.0 months for prior CMF, 10.2 months for anthracyclines and 12.5 months in chemonaive patients (P=0.33). In multivariate Cox's model, a nonsignificant increase in the risk of progression was seen in patients treated with adjuvant CMF or anthracyclines. The median OS was 23.8 months for CMF, 20.2 months for anthracyclines and 27.5 months in chemonaive patients (P=0.61). The same, nonsignificant, association was seen in multivariate analysis. The ET regimens provide satisfactory results in metastatic breast cancer, regardless of previous adjuvant chemotherapy.

Inflammatory effects of snake venom myotoxic phospholipases A2.

Snake venom phospholipases A2 (PLA2) show a remarkable functional diversity. Among their toxic activities, some display the ability to cause rapid necrosis of skeletal muscle fibers, thus being myotoxic PLA2s. Besides myotoxicity, these enzymes evoke conspicuous inflammatory and nociceptive events in experimental models. Local inflammation and pain are important characteristics of snakebite envenomations inflicted by viperid and crotalid species, whose venoms are rich sources of myotoxic PLA2s. Since the discovery that mammalian PLA2 is a key enzyme in the release of arachidonic acid, the substrate for the synthesis of several lipid inflammatory mediators, much interest has been focused on this enzyme in the context of inflammation. The mechanisms involved in the proinflammatory action of secretory PLA2s are being actively investigated, and part of the knowledge on secretory PLA2 effects has been gained by using snake venom PLA2s as tools, due to their high structural homology with human secretory PLA2s. The inflammatory events evoked by PLA2s are primarily associated with enzymatic activity and to the release of arachidonic acid metabolites. However, catalytically inactive Lys49 PLA2s trigger inflammatory and nociceptive responses comparable to those of their catalytically active counterparts, thereby evidencing that these proteins promote inflammation and pain by mechanisms not related to phospholipid hydrolysis nor to mobilization of arachidonic acid. These studies have provided a boost to the research in this field and various approaches have been used to identify the amino acid residues and the specific sites of interaction of myotoxic PLA2s with cell membranes potentially involved in the PLA2-induced inflammatory and nociceptive effects. This work reviews the proinflammatory and nociceptive effects evoked by myotoxic PLA2s and their mechanisms of action.

Inflammatory effects of snake venom myotoxic phospholipases A2

Snake venom phospholipases A2 (PLA2) show a remarkable functional diversity. Among their toxic activities, some display the ability to cause rapid necrosis of skeletal muscle fibers, thus being myotoxic PLA2s. Besides myotoxicity, these enzymes evoke conspicuous inflammatory and nociceptive events in experimental models. Local inflammation and pain are important characteristics of snakebite envenomations inflicted by viperid and crotalid species, whose venoms are rich sources of myotoxic PLA 2s. Since the discovery that mammalian PLA2is a key enzyme in the release of arachidonic acid, the substrate for the synthesis of several lipid inflammatory mediators, much interest has been focused on this enzyme in the context of inflammation. The mechanisms involved in the proinflammatory action of secretory PLA2s are being actively investigated, and part of the knowledge on secretory PLA2 effects has been gained by using snake venom PLA2s as tools, due to their high structural homology with human secretory PLA2s. The inflammatory events evoked by PLA2s are primarily associated with enzymatic activity and to the release of arachidonic acid metabolites. However, catalytically inactive Lys49 PLA2s trigger inflammatory and nociceptive responses comparable to those of their catalytically active counterparts, thereby evidencing that these proteins promote inflammation and pain by mechanisms not related to phospholipid hydrolysis nor to mobilization of arachidonic acid. These studies have provided a boost to the research in this field and various approaches have been used to identify the amino acid residues and the specific sites of interaction of myotoxic PLA2s with cell membranes potentially involved in the PLA2-induced inflammatory and nociceptive effects. This work reviews the proinflammatory and nociceptive effects evoked by myotoxic PLA2s and their mechanisms of action. © 2004 Published by Elsevier Ltd.

Epirubicin/taxane combinations in breast cancer: experience from several Italian trials.

Doxorubicin/paclitaxel (Taxol) combinations are very active in advanced breast cancer, with objective response rates up to 90%, but have shown a high incidence of cardiotoxicity. A phase I/II trial replacing doxorubicin with epirubicin (Ellence), a less cardiotoxic analog, produced an objective response rate of 84%, but with a low rate of cardiotoxicity. A careful cardiac monitoring in more than 100 patients treated with this combination has demonstrated that the risk of congestive heart failure is below 10% up to a cumulative epirubicin dose of 990 mg/m2. To examine the possibility that the pharmacokinetic and pharmacodynamic interactions that occur when anthracycline and paclitaxel are administered together might result in subadditive antitumor activity, a phase III study is comparing concomitant vs sequential administration of epirubicin and paclitaxel in patients with advanced breast cancer. A phase I/II study of epirubicin plus docetaxel as first-line chemotherapy for advanced breast cancer patients evaluated the maximum tolerated doses and for subsequent studies recommended epirubicin at 75 mg/m2 plus docetaxel at 80 mg/m2. In the adjuvant setting, an ongoing phase III trial is comparing epirubicin plus paclitaxel vs FEC (fluorouracil, epirubicin, and cyclophosphamide [Cytoxan, Neosar]) in node-positive patients. Preliminary data confirm the cardiac safety of these treatments.

New combinations with epirubicin in advanced breast cancer.

Several trials have shown that anthracyclines and taxanes can be combined to achieve response rates ranging from 70% to 90%, with complete responses ranging from 19% to 41%. In an attempt to increase the activity while maintaining tolerability, gemcitabine (Gemzar) was added to the epirubicin (Ellence)/paclitaxel (Taxol) regimen. Among 36 metastatic breast cancer patients treated with this new combination, the overall response rate was 92%, including 31% with a complete response. Another attempt to improve the outcome of metastatic breast cancer patients involves a phase III multicentric randomized trial (MANTA-1) to evaluate if paclitaxel maintenance therapy after anthracycline/taxane combination therapy can improve time to progression and overall survival. Although anthracyclines are more frequently used in the adjuvant setting, it is important for the clinicians to know whether this class of drugs can be used again for those patients who develop metastatic disease. An analysis of 312 patients treated with epirubicin containing regimens as first-line treatment for metastatic disease shows that epirubicin-based regimens are active in patients already exposed to anthracyclines in the adjuvant setting, and that the risk of cardiac toxicity is low up to a cumulative epirubicin dose of 990 mg/m2.

Gemcitabine, epirubicin, and paclitaxel combinations in advanced breast cancer.

Strategies to improve outcome in metastatic breast cancer include the first-line use of combinations of optimal doses of active agents, with the goal being to improve complete response rates and thus long-term survival. Although prior studies of anthracycline/taxane combinations generally have shown improved response rates and progression-free survival in comparison with single-agent regimens or anthracycline/cyclophosphamide-containing combinations, the data have not consistently demonstrated improved overall survival; indeed, they have yielded generally disappointing complete response rates. We evaluated the combination of gemcitabine (Gemzar; Eli Lilly and Company, Indianapolis, IN), epirubicin, and paclitaxel (GET) based on the hypothesis that epirubicin/paclitaxel is best suited for achieving delivery of optimal doses, and the addition of gemcitabine (which exhibits good single-agent activity with a favorable toxicity profile) will increase activity. In a phase II trial of 36 patients, the GET regimen produced reasonable toxicity and was associated with a 92% response rate, including complete responses in 31% of patients. The overall response rate increased to 97%, including complete responses in 41% of patients, with high-dose consolidation chemotherapy in 25 patients. A trial comparing GET with epirubicin/paclitaxel as first-line treatment in more than 600 patients with metastatic breast cancer has been initiated, with survival as the primary end point. Another large-scale trial is being planned to compare the GET regimen with an anthracycline/cyclophosphamide/paclitaxel combination in patients with early stage high-risk breast cancer. Semin Oncol 28 (suppl 7):15-17.

Leucocyte recruitment induced by type II phospholipases A(2) into the rat pleural cavity.

Bothropstoxin-I (BthTX-I) and bothropstoxin-II (BthTX-II) are Lys-49 and Asp-49 phospholipases A(2) (PLA(2)s), respectively, isolated from Bothrops jararacussu venom. Piratoxin-I (PrTX-I) is a Lys-49 PLA(2) isolated from Bothrops pirajai venom. In this study, the ability of BthTX-I, BthTX-II and PrTX-I to recruit leucocytes into the rat pleural cavity and potential mechanisms underlying this effect were investigated. Intrapleural injection of either BthTX-I or PrTX-I (10-100 microg/cavity each) caused a significant leucocyte infiltration at 12 h after injection. The maximal cell migration was observed with the dose of 30 microg/cavity (14.9+/-15.5 and 17.6+/-1. 6x10(6) cells/cavity, respectively). Leucocyte counts consisted mainly of mononuclear cells, but significant amounts of neutrophils and eosinophils were also observed. Intrapleural injection of BthTX-II (10-100 microg/cavity) caused a marked leucocyte infiltration at 6 and 12 h after injection. The maximal response was observed with the dose of 100 microg/cavity (57.3+/-3.4x10(6) cells/cavity, 6 h). The leucocyte counts were mainly composed of neutrophils and mononuclear cells. The treatment of either BthTX-I (30 microg/cavity, 12 h) or BthTX-II (30 microg/cavity, 6 h) with the PLA(2) inhibitor p-bromophenacyl bromide (p-BPB) had no effect on the total and differential leucocyte counts induced by these proteins. The same treatment partially reduced the PrTX-I-induced pleural leucocyte infiltration. In rats depleted of the histamine and 5-hydroxytryptamine (5-HT) stores by chronic treatment with compound 48/80, the total leucocyte counts in response to BthTX-I, BthTX-II and PrTX-I was not significantly affected compared to control animals. In addition, BthTX-I, BthTX-II and PrTX-I (100 microg/ml each) significantly degranulated pleural mast cells in vitro leading to the release of [(14)C]5-hydroxytryptamine ([(14)C]5-HT). p-BPB and heparin (50 IU/ml) significantly reduced the [(14)C]5-HT release induced by these PLA(2)s. Our results demonstrate that BthTX-I, BthTX-II and PrTX-I recruit leucocyte into the pleural cavity of the rat by mechanisms unrelated to enzymatic activity and pleural mast cell degranulation.

Inflammatory oedema induced by the lys-49 phospholipase A(2) homologue piratoxin-i in the rat and rabbit. Effect of polyanions and p-bromophenacyl bromide.

Piratoxin-I (PrTX-I) is a Lys-49 phospholipase (PLA(2)) homologue, isolated from Bothrops pirajai snake venom, that has no phospholipase activity. In this study, we investigated the in vivo oedematogenic activity of PrTX-I in both the rat and the rabbit as well as the ability of PrTX-I to activate rat mast cells in vitro. In the rat paw and skin, PrTX-I (3-100 microg/paw) induced a dose-dependent oedema that was associated with extensive mast cell degranulation. The involvement of mast cells in PrTX-I-mediated oedema formation in the rat was further confirmed by the findings that this protein significantly activated rat peritoneal mast cells in vitro, causing the release of [(14)C]5-hydroxytryptamine ([(14)C]5-HT; 51 +/- 1%). In the rabbit, PrTX-I (10-100 microg/site) also induced dose-dependent skin oedema formation that was not affected by either mepyramine (a histamine H(1) receptor antagonist) or cyproheptadine (1.0 microg/site), indicating that mast cells do not play a role in this animal species. The bradykinin B(2) receptor antagonist Hoe 140 (0.5 microg/site) and the platelet-activating factor (PAF) receptor antagonist WEB 2086 (200 microg/site) also failed to affect the PrTX-I-induced rabbit skin oedema, ruling out the involvement of kinins and PAF. The PLA(2) inhibitor p-bromophenacyl bromide greatly reduced the PrTX-I-induced oedema in both the rat and the rabbit, and also inhibited the rat in vitro mast cell activation induced by this PLA(2) homologue. The polyanions heparin and dermatan sulphate efficiently prevented oedema formation in both species, and heparin inhibited PrTX-I-induced rat mast cell degranulation. Our results are consistent with the suggestion that the cationic charge of PrTX-I plays a major role in the inflammatory responses induced by this PLA(2) homologue.

Effect of crotapotin and heparin on the rat paw oedema induced by different secretory phospholipases A2.

The effects of crotapotin (a non-toxic and non-enzymatic acid polypeptide naturally complexed with phospholipase A2) and heparin on rat paw edema induced by different secretory phospholipases A2 (sPLA2) have been investigated. The ability of crotapotin to affect the enzymatic activity of the sPLA2(s) have also been evaluated. Secretory PLA2(s) obtained from both snake (Naja naja, Naja mocambique mocambique, Crotalus adamanteus and Crotalus durissus terrificus) and bee (Apis mellifera) venoms as well as that from bovine pancreas were used in this study. Rat paw oedema was induced by a single subplantar injection of the sPLA2s (5-30 microg/paw) in absence and presence of either crotapotin (10-100 microg/paw) or heparin (50 U/paw). Paw volume was measured using a hydroplethysmometer. Phospholipase A2 from Naja naja, Naja mocambique mocambique, Apis mellifera venoms and the basic component of Crotalus durissus terrificus venom all induced dose-dependent rat paw oedema whereas those from Crotalus adamanteus venom and bovine pancreas were ineffective. Paw oedema induced by PLA2(s) from both Naja naja and Apis mellifera venoms was significantly (P < 0.05) inhibited by crotapotin (0.1-100 microg/site) whereas the Naja mocambique mocambique venom PLA2-induced oedema was significantly potentiated (P < 0.05) by this polypeptide (40 microg/site). On the other hand, heparin (50 U/paw) had no effect on the paw oedema induced by PLA2 from Naja naja and Apis mellifera venoms but significantly inhibited the Naja mocambique mocambique venom PLA2-induced oedema. The measurement of the in vitro phospholipasic activity revealed that crotapotin inhibited by 60-70% the enzymatic activities of PLA2(s) from Crotalus adamanteus, Naja mocambique mocambique, Apis mellifera venoms and bovine pancreas. Our results suggest that despite the great homology between the various types of sPLA2 they interact with crotapotin on cell surfaces in different ways leading to either inhibition or potentiation of the paw oedema by a mechanism unrelated to their enzymatic activities. Since heparin reduced paw oedema induced by PLA2 from Naja mocambique mocambique venom it is likely that this sPLA2 is similar to the novel heparin-sensitive PLA2 found in mast cells.

Role of 2-[18F]-fluorodeoxyglucose (FDG) positron emission tomography (PET) in the early assessment of response to chemotherapy in metastatic breast cancer patients.

We investigated the role of 2-[18F]-fluorodeoxyglucose (FDG) positron emission tomography (PET) in the early evaluation of response to chemotherapy in metastatic breast cancer patients. Breast cancer patients who received an epirubicin/paclitaxel--containing regimen as first-line treatment for metastatic disease were included in this study. A PET study was performed within 1 week before the start of treatment, at day 8 after the first course, and at the end of the planned program of chemotherapy. Tumor response was determined clinically and radiographically every 2 courses of treatment. Thirteen patients with metastatic breast cancer who were referred for treatment protocols with gemcitabine/epirubicin/paclitaxel or epirubicin/paclitaxel chemotherapy regimens were included in this study. All metastatic sites were easily visualized on the baseline FDG-PET images, obtained 50 to 60 minutes after tracer injection. Nine patients who completed the planned courses of chemotherapy and the FDG-PET studies were available for analysis. In the six patients who achieved a response to treatment, median glucose standard uptake value (SUV) (semiquantitative analysis) was 7.65 (range, 3.4-12.3) at baseline, 5.7 (range, 2.8-7.6) at day 8 after the first course, and 1.2 (range, 0.99-1.3) at the end of the 6 planned courses of chemotherapy. Three patients who obtained a stable disease as best response had no significant decrease in tumor glucose SUV compared to baseline levels. Qualitative visual analysis in the six responding patients showed a decrease in delineation of tumor mass from background activity soon after the first course, while the nonresponding patients had no significant modification from basal levels. Semiquantitative FDG-PET scanning of metastatic breast cancer sites showed a rapid and significant decrease in tumor glucose metabolism soon after the first course of treatment in patients who achieved a response to first-line chemotherapy. On the contrary, no significant decrease was observed in nonresponding patients.

Role of epirubicin in advanced breast cancer.

Anthracyclines were first introduced for the treatment of metastatic breast cancer in the 1970s and are still among the most active single agents for the treatment of this disease. Unfortunately, their clinical value is limited by late-onset ventricular dysfunction. Epirubicin, an anthracycline analogue, does not eliminate the risk of cardiotoxicity but is less cardiotoxic and myelotoxic than doxorubicin at equimolar doses, thereby allowing the safe administration of cumulative doses between 950 and 1000 mg/m2. The inclusion of epirubicin in combination regimens, such as fluorouracil/epirubicin/cyclophosphamide (FEC), has been shown to be safe and active as first-line treatment for metastatic breast cancer. In the past few years, new drugs, including taxanes, have shown a high level of activity as single agents in the treatment of advanced breast cancer. Doxorubicin/paclitaxel combinations have shown high overall response rates (90%) as first-line chemotherapy of advanced breast cancer; however, congestive heart failure has been reported in up to 20% of patients. Epirubicin/paclitaxel combinations have been associated with grade 3 cardiotoxicity (6%) in only one study. We report findings of a trial of combination epirubicin/paclitaxel as first-line treatment of advanced breast cancer, with overall response rates (ORRs) of 84% and a complete response (CR) rate of 19%. Achieving a CR to first-line chemotherapy for advanced breast cancer appears to predict survival, and adding an active drug with a different mechanism of action and nonoverlapping toxicity might increase the percentage of CRs. We therefore tested the feasibility and activity of 6 to 8 courses of first-line treatment with a three-drug combination (gemcitabine 1000 mg/m2 days 1 and 4, epirubicin 90 mg/m2 day 1, and paclitaxel 175 mg/ m2 over 3 hours on day 1) in a phase II study of 36 metastatic breast cancer patients. Treatment was well tolerated, with an ORR of 92% (95% confidence interval: 77.53%-98.25%) and a CR of 31%. In considering retreating patients who progress or relapse after receiving an anthracycline-/taxane-containing regimen with the same active drugs, epirubicin appears ideal in both the adjuvant and metastatic breast cancer settings.

The amino acid sequence of bothropstoxin-II, an Asp-49 myotoxin from Bothrops jararacussu (Jararacucu) venom with low phospholipase A2 activity.

The complete amino acid sequence of bothropstoxin-II (BthTX-II), a myotoxin isolated from Bothrops jararacussu snake venom, is reported. The results show that BthTX-II is an Asp-49 phospholipase A2 (PLA2)-like protein composed of a single polypeptide chain of 120 amino acid residues (Mr = 13,976), containing one methionine and 14 half-cystines. Despite a high degree of homology with other PLA2's and the presence of the strategic residues known to compose the Ca2+-binding loop, namely Tyr-28, Gly-30, Gly-32, and especially Asp-49, besides His-48, Tyr-52, and Asp-99, all of them directly or indirectly involved in catalysis, BthTX-II revealed a very low PLA2 activity when assayed on egg yolk phosphatidylcholine. We attribute this low catalytic activity to the existence of extra mutations, e.g., Trp-5 for Phe-5, which points to the need of considering other strategic positions, since only Lys-49 PLA2's have been considered to be devoid of this enzymatic activity.