Un-biodegradable and biodegradable plastic sheets modify the soil properties after six months since their applications.

Nowadays, microplastics represent emergent pollutants in terrestrial ecosystems that exert impacts on soil properties, affecting key soil ecological functions. In agroecosystems, plastic mulching is one of the main sources of plastic residues in soils. The present research aimed to evaluate the effects of two types of plastic sheets (un-biodegradable and biodegradable) on soil abiotic (pH, water content, concentrations of organic and total carbon, and total nitrogen) and biotic (respiration, and activities of hydrolase, dehydrogenase, ß-glucosidase and urease) properties, and on phytotoxicity (germination index of Sorghum saccharatum L. and Lepidium sativum L.). Results revealed that soil properties were mostly affected by exposure time to plastics rather than the kind (un-biodegradable and biodegradable) of plastics. After six months since mesocosm setting up, the presence of un-biodegradable plastic sheets significantly decreased soil pH, respiration and dehydrogenase activity and increased total and organic carbon concentrations, and toxicity highlighted by S. saccharatum L. Instead, the presence of biodegradable plastic sheets significantly decreased dehydrogenase activity and increased organic carbon concentrations. An overall temporal improvement of the investigated properties in soils covered by biodegradable plastic sheets occurred.

Ants modulate stridulatory signals depending on the behavioural context.

Insect societies require an effective communication system to coordinate members' activities. Although eusocial species primarily use chemical communication to convey information to conspecifics, there is increasing evidence suggesting that vibroacoustic communication plays a significant role in the behavioural contexts of colony life. In this study, we sought to determine whether stridulation can convey information in ant societies. We tested three main hypotheses using the Mediterranean ant Crematogaster scutellaris: (i) stridulation informs about the emitter'caste; (ii) workers can modulate stridulation based on specific needs, such as communicating the profitability of a food resource, or (iii) behavioural contexts. We recorded the stridulations of individuals from the three castes, restrained on a substrate, and the signals emitted by foragers workers feeding on honey drops of various sizes. Signals emitted by workers and sexuates were quantitatively and qualitatively distinct as was stridulation emitted by workers on different honey drops. Comparing across the experimental setups, we demonstrated that signals emitted in different contexts (restraining vs feeding) differed in emission patterns as well as certain parameters (dominant frequency, amplitude, duration of chirp). Our findings suggest that vibrational signaling represents a flexible communication channel paralleling the well-known chemical communication system.

The morphology and activity of the extrafloral nectaries in Reynoutria × bohemica (Polygonaceae).

Reynoutria × bohemica is an invasive species causing significant damage to native ecosystems in North America and Europe. In this work, we performed an in-depth micromorphological characterisation of the extrafloral nectaries (EFN), during their secretory and post-secretory phases, in combination with field monitoring of nectary activity over time and the qualitative pool of insect visitors. EFN consist of secretory trichomes and vascularised parenchyma. Polysaccharides, lipids and proteins were histochemically detected in all trichome cells; phenolic substances were detected in parenchyma cells. Our data indicate that all nectary regions are involved in nectar production and release, constituting a functional unit. Moreover, the main compound classes of nectar and their transfer change over time: first, granulocrine secretion for sugars prevails, then eccrine secretion of the lipophilic fraction takes place. Active nectaries are mainly located in the apical portion of the stem during the growth phase (April-May), when we detected the highest number of individuals visited by ants; from mid-August onwards, during flowering, the number of active nectaries declined then ceased production (September), with a concomitant decrease in visits by the ants. The spectrum of nectar-foraging ants mainly included representatives of the genera Formica, Lasius and Camponotus. Reynoutria × bohemica produces an attractive secretion able to recruit local ants that may potentially act as 'bodyguards' for protecting young shoots, reducing secretions during the blooming stage. This defence mechanism against herbivores is the same as that displayed by the parental species in its native areas.

miRNA purification with an optimized PDMS microdevice: Toward the direct purification of low abundant circulating biomarkers.

A reliable clinical assay based on circulating microRNAs (miRNAs) as biomarkers is highly required. Microdevices offer an attractive solution as a fast and inexpensive way of concentrating these biomarkers from a low sample volume. A previously developed polydimethylsiloxane (PDMS) microdevice able to purify and detect circulating miRNAs was here optimized. The optimization of the morphological and chemical surface properties by nanopatterning and functionalization is presented. Surfaces were firstly characterized by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), fluorescamine assay and s-SDTB (sulphosuccinimidyl-4-o-(4,4-dimethoxytrityl) butyrate) assay and subsequently tested for their capacity to adsorb a fluorescent miRNA. From our analysis, modification of surface charge with 0.1% APTMS ((3-Aminopropyl)trimethoxysilane) and 0.9% PEG-s (2-[Methoxy-(polyethyleneoxy)propyl]trimethoxysilane) performed at 60°C for 10min was identified as the best purification condition. Our optimized microdevice integrated with real-time PCR detection, was demonstrated to selectively purify both synthetic and natural circulating miRNAs with a sensitivity of 0.01pM.

Effects of vitamin E supplementation on F(2)-isoprostane and thromboxane biosynthesis in healthy cigarette smokers.

BACKGROUND: Increased formation of 8-iso-prostaglandin (PG) F(2alpha) and thromboxane (TX) A(2), potent agonists of platelet and vascular thromboxane (TH)/PGH(2) receptors, has been detected in cigarette smokers. We performed a randomized, double-blind, placebo-controlled study of the effects of vitamin E (300, 600, and 1200 mg/d, each dose for 3 consecutive weeks) on 8-iso-PGF(2alpha) and TXA(2) biosynthesis in 46 moderate cigarette smokers. METHODS AND RESULTS: Urinary immunoreactive 8-iso-PGF(2alpha) and 11-dehydro-TXB(2), plasma vitamin E, and serum TXB(2) were measured by previously validated techniques. Baseline urinary 8-iso-PGF(2alpha) and 11-dehydro-TXB(2) excretion averaged 241+/-78 and 430+/-293 pg/mg creatinine, respectively. Urinary 8-iso-PGF(2alpha) was significantly correlated with 11-dehydro-TXB(2) (r=0.360, n=138, P<0.0001). Baseline plasma vitamin E levels averaged 20.6+/-4.9 micromol/L and were inversely correlated with urinary 11-dehydro-TXB(2) (r=-0.304, P=0.039) but not with 8-iso-PGF(2alpha) (r=-0.227, P=0.129). Vitamin E supplementation caused a dose-dependent increase in its plasma levels that reached a plateau at 600 mg (42.3+/-11.2 micromol/L, P<0. 001). This was not associated with any statistically significant change in urinary 8-iso-PGF(2alpha) or 11-dehydro-TXB(2) excretion. CONCLUSIONS: Supplementation with pharmacological doses of vitamin E has no detectable effects on lipid peroxidation and thromboxane biosynthesis in vivo in healthy subjects with a mild degree of oxidant stress. These findings are consistent with the hypothesis that the basal rate of lipid peroxidation is a major determinant of the response to vitamin E supplementation and have implications for the use of vitamin E in healthy subjects as well as for the design and interpretation of clinical trials of antioxidant intervention.

High-dose therapy and autologous bone marrow transplantation for adult patients with lymphoblastic lymphoma: results of the European Group for Bone Marrow Transplantation.

PURPOSE: To investigate the results of treatment and factors that affect prognosis in adult patients undergoing high-dose therapy and autologous bone marrow transplantation (ABMT) for lymphoblastic lymphoma (LBL). PATIENTS AND METHODS: The study was a retrospective analysis of 214 patients reported to the Lymphoma Registry of the European Group for Bone Marrow Transplantation (EBMT) between January 1981 and December 1992, including 105 patients undergoing marrow transplantation in first complete remission (CR). Data on all patients were reviewed, and analysis of prognostic factors conducted. RESULTS: The actuarial overall survival rate at 6 years for the entire group is 42%. Disease status at ABMT was the major determinant of outcome: 6-year actuarial overall survival was 63% for patients transplanted in first CR, compared with 15% for those with resistant disease at the time of transplantation. Transplantation in second CR resulted in a 31% rate of actuarial overall survival at 6 years. For patients transplanted in first CR, univariate analysis failed to identify any factors at presentation that predicted for outcome after transplantation. CONCLUSION: These results suggest that ABMT is effective therapy for adults with LBL, even in patients with disease that is resistant to conventional-dose therapy. Results for patients transplanted in second CR are superior to those reported for conventional-dose salvage regimens. The results in first CR require verification in a prospective randomized clinical study.

High-dose therapy and autologous stem-cell transplantation versus conventional-dose consolidation/maintenance therapy as postremission therapy for adult patients with lymphoblastic lymphoma: results of a randomized trial of the European Group for Blood and Marrow Transplantation and the United Kingdom Lymphoma Group.

PURPOSE: To determine whether a combination of high-dose therapy and autologous stem-cell transplantation (ASCT) is superior to conventional-dose consolidation and maintenance chemotherapy as postremission therapy in adults with lymphoblastic lymphoma. PATIENTS AND METHODS: One hundred nineteen patients were entered onto this prospective randomized trial from 37 centers. Patients received standard remission induction therapy, and responding patients were randomized either to continue with a conventional consolidation/maintenance protocol (CC) or to receive high-dose therapy and ASCT. In some centers, patients with HLA-identical sibling donors were registered on the trial but proceeded to allogeneic bone marrow transplantation (BMT) without randomization. RESULTS: Of the 119 patients entered, 111 were assessable for response to induction therapy. The overall response rate was 82% (56% complete response, 26% partial response). Of the 98 patients eligible for randomization, 65 were randomized, 31 to ASCT and 34 to CC. Reasons for failure to randomize included patient refusal (12 patients), early progression or death on induction therapy (eight patients), excessive toxicity of induction regimen (six patients), and elective allogeneic BMT (12 patients). With a median follow-up of 37 months, the actuarial 3-year relapse-free survival rate is 24% for the CC arm and 55% for the ASCT arm (hazards ratio = 0.55 in favor of the ASCT arm; 95% confidence interval [CI], 0.29 to 1.04; P =.065). The corresponding figures for overall survival are 45% and 56%, respectively (hazards ratio = 0.87 in favor of the ASCT arm; 95% CI, 0.42 to 1.81; P =.71). CONCLUSION: The use of ASCT in adults with lymphoblastic lymphoma in first remission produced a trend for improved relapse-free survival but did not improve overall survival compared with conventional-dose therapy in this small randomized trial.

MACOP-B versus ProMACE-MOPP in the treatment of advanced diffuse non-Hodgkin's lymphoma: results of a prospective randomized trial by the non-Hodgkin's Lymphoma Cooperative Study Group.

PURPOSE: The aim of our study was to compare in a multicentric randomized trial two regimens widely used in the treatment of advanced-stage intermediate- to high-grade non-Hodgkin's lymphoma and to assess whether a third-generation regimen (methotrexate with leucovorin, doxorubicin, cyclophosphamide, vincristine, prednisone, and bleomycin [MACOP-B]) was superior to a second-generation regimen (procarbazine, methotrexate with leucovorin, doxorubicin, cyclophosphamide, and etoposide [ProMACE-MOPP]). PATIENTS AND METHODS: Between January 1987 and August 1991, 221 patients with diffuse intermediate- to high-grade non-Hodgkin's lymphoma (Working Formulation groups F, G, H, and K), stage II bulky (> 10 cm), III, or IV, were randomized by the Non-Hodgkin's Lymphoma Cooperative Study Group (NHLCSG) to receive ProMACE-MOPP for six cycles or MACOP-B for 12 weeks. Survival, progression-free survival, and disease-free survival were determined, and multivariate analysis of prognostic factors was performed. RESULTS: In the two groups of patients, there was no significant difference in terms of complete remission (CR) rate (49.1% with ProMACE-MOPP and 52.3% with MACOP-B), 3-year overall survival rate (45.2% with PROMACE-MOPP and 52.3% with MACOP-B), and 3-year progression-free survival rate (36.4% with ProMACE-MOPP and 36.1% with MACOP-B). In terms of toxicity, no significantly greater toxicity occurred in either arm. Overall toxicity was acceptable. The most frequent side effects were grade II through IV leukopenia, infection, mucositis, and anemia. Treatment-related deaths were equally distributed. CONCLUSION: No significant differences in terms of efficacy and/or toxicity between ProMACE-MOPP and MACOP-B are evident. These results are consistent with recent randomized trials showing that the new-generation aggressive regimens are no better than previous ones.

Purging of bone marrow in autologous bone marrow transplantation for non-Hodgkin's lymphoma: a case-matched comparison with unpurged cases by the European Blood and Marrow Transplant Lymphoma Registry.

PURPOSE: The use of in vitro purging of bone marrow in autologous bone marrow transplantation (ABMT) for non-Hodgkin's lymphoma (NHL) has been a controversial issue; its benefit is as yet unproven. Its effect on the clinical outcome of ABMT in these patients is still unclear. We look at this issue using data from the European Blood and Marrow Transplant (EBMT) Lymphoma Registry. PATIENTS AND METHODS: Seventeen hundred twenty-six patients with NHL have been reported to the EBMT registry, of whom 270 had bone marrow purged at transplant. Two hundred twenty-four of these patients were compared with a case-matched group of 224 unpurged patients who had undergone the same procedure. The case matching was made following selection of the main prognostic factors for progression-free survival (PFS) by multivariate analysis. Response, complications, and outcome in ABMT were analyzed. RESULTS: Time to hematologic engraftment, response to ABMT, and number of procedure-related deaths were similar in purged and unpurged patients. The overall survival (OS) rate was 54% at 5 years in purged patients and 48.3% in unpurged patients (P = .1813). The PFS rate was 44.3% and 44.6%, respectively (P = .1961). Patterns of relapse, including bone marrow relapse, were similar in both groups. Patients with low-grade lymphoma did not have a significantly improved PFS if the bone marrow was purged (P = .1757); however, they did have a significantly improved OS (P = .00184). This increased OS was found to be associated with non-totalbody irradiation (TBI) conditioning and also with the purged patients undergoing transplantation at large transplant centers (P = .0016). CONCLUSION: Purging of bone marrow in ABMT for NHL does not affect the rate of hematologic engraftment or risk of procedure-related death (PRD). There is no significant difference in PFS for patients whose bone marrow is purged as compared with unpurged.

VACOP-B versus VACOP-B plus autologous bone marrow transplantation for advanced diffuse non-Hodgkin's lymphoma: results of a prospective randomized trial by the non-Hodgkin's Lymphoma Cooperative Study Group.

PURPOSE: The aim of this multicenter randomized study was to compare conventional therapy with conventional plus high-dose therapy (HDT) and autologous bone marrow transplantation (ABMT) as front-line treatment for poor-prognosis non-Hodgkin's lymphoma (NHL). PATIENTS AND METHODS: Between October 1991 and June 1995, 124 patients, aged 15 to 60 years, with diffuse intermediate- to high-grade NHL (Working Formulation criteria), stages II bulky (> or = 10 cm), III, or IV were enrolled. Sixty-one patients were randomized to receive etoposide, doxorubicin, cyclophosphamide, vincristine, prednisone, and bleomycin (VACOP-B) for 12 weeks and cisplatin, cytarabine, and dexamethasone (DHAP) as a salvage regimen (arm A), and 63 to receive VACOP-B for 12 weeks plus HDT and ABMT (Arm B). RESULTS: There was no significant difference in terms of complete remissions (CRS) in the two groups: 75% in arm A, and 73% in arm B. The median follow-up observation time was 42 months. The 6-year survival probability was 65% in both arms. There was no difference in disease-free survival (DFS) or progression-free survival (PFS) between the two groups. DFS was 60% and 80% (P = .1) and PFS was 48% and 60% (P = .4) for arms A and B, respectively. Procedure feasibility was the major problem. In arm B, 29% of enrolled patients did not undergo HDT and ABMT. A statistical improvement in terms of DFS (P = .008) and a favorable trend in terms of PFS (P = .08) for intermediate-/high- plus high-risk group patients assigned to HDT and ABMT was observed. CONCLUSION: In this study, conventional chemotherapy followed by HDT and ABMT as front-line therapy seems no more successful than conventional treatment in terms of overall results. However, our results suggest that controlled studies of HDT plus ABMT should be proposed for higher risk patients.

Lack of spontaneous sister chromatid exchanges in somatic cells of Drosophila melanogaster.

Neural ganglia of wild type third-instar larvae of Drosophila melanogaster were incubated for 13 hours at various concentrations of BUdR (1, 3, 9, 27 micrograms/ml). Metaphases were collected with colchicine, stained with Hoechst 33258, and scored under a fluorescence microscope. Metaphases in which the sister chromatids were clearly differentiated were scored for the presence of sister-chromatid exchanges (SCEs). At the lowest concentration of BUdR (1 microgram/ml), no SCEs were observed in either male or female neuroblasts. The SCEs were found at the higher concentrations of BUdR (3, 9, And 27 micrograms/ml) and with a greater frequency in females than in males. Therefore SCEs are not a spontaneous phenomenon in D. melanogaster, but are induced by BUdR incorporated in the DNA. A striking nonrandomness was found in the distribution of SCEs along the chromosomes. More than a third of the SCEs were clustered in the junctions between euchromatin and heterochromatin. The remaining SCEs were preferentially localized within the heterochromatic regions of the X chromosome and the autosomes and primarily on the entirely heterochromatic Y chromosome.--In order to find an alternative way of measuring the frequency of SCEs in the Drosophila neuroblasts, the occurrence of double dicentric rings was studied in two stocks carrying monocentric ring-X chromosomes. One ring chromosome, C(1)TR94--2, shows a rate of dicentric ring formation corresponding to the frequency of SCEs observed in the BUdR-labelled rod chromosomes. The other ring studied, R(1)2, exhibits a frequency of SCEs higher than that observed with both C(1) TR94--2 and rod chromosomes.

Mutagen specificity in the induction of chromosomal aberrations in somatic cells of Drosophila melanogaster.

The distribution of chromosomal aberrations between and within chromosomes of male D, melanogaster somatic cells after treatment with UV has been analyzed. -- Distribution of the breaks between chromosomes was largely nonrandom since we found a higher aberration frequency than that expected on the Y chromosome. Moreover, within the chromosomes the aberrations are clustered in the pericentromeric heterochromatic regions. The above distribution is compared with that of the breaks induced by X rays and methyl-methane-sulphonate (MMS) which were distributed in a different pattern.

ProMACE-MOPP vs MACOP-B in high grade non-Hodgkin's lymphomas: a randomised study in a multicenter cooperative study group (NHLCSG).

From January '85 to April '87, 81 patients (pts) with diffuse intermediate and high-grade non-Hodgkin's lymphomas were treated with the ProMace/MOPP protocol in a large Italian Cooperative Study Group (NHLCSG). Criteria for entry into the study included: no prior therapy, stage III-IV or stage II with bulky disease and/or B-symptoms, age below 65. 79 pts were evaluable for response. Almost all pts received six courses of chemotherapy, plus radiotherapy on bulky disease. 53 pts (67%) achieved complete remission (CR), 7 (9%) partial remission (PR), 4 (5%) were considered stable disease (SD) and 15 (19%) progression disease (PD) with 5 of them died early during treatment. The actuarial overall survival (OS) and disease free survival (DFS) are respectively 54% at 61 mos and 62% at 41 mos. The median follow-up from the end of therapy is 56 mos (range 40-68). Until now 20 pts (38%) relapsed on a median time of 8 mos (range 2-21) from CR. These data allowed to us to consider this regimen as effective as the third generation protocols also taking into account the multicenter basis of this study. With the aim to evaluate the impact of the third generation regimen on the outcome of these pts, a randomized study has been performed comparing ProMACE-MOPP with the third generation regimens MACOP-B. Therefore, from 1988 up to now, 206 pts with similar clinical and histological characteristics, have been enrolled in the two arms. No differences in terms of CR and DFS have been registered between the two treatments, with roughly the same toxicity. An analysis of prognostic factors in the larger series of pts treated with ProMACE-MOPP in the first and in the second study (167 pts) was performed. On these basis it seems reasonable that our next step would be to candidate these poor prognosis pts to a new therapeutic strategy which included the use of ABMT and/or PBSC transplantation as first line.

Autologous bone marrow transplantation for adult advanced stage lymphoblastic lymphoma in first CR. A study of the NHLCSG.

Fourty successive adult patients with lymphoblastic lymphoma entered a study of sequential chemotherapy consisting of an intensive LSA-L2-type protocol to induce first complete remission. Twenty-one patients in first CR (median age 24 years, range 15-43), after receiving a conditioning regimen consisting of cyclophosphamide and total body irradiation, underwent autologous bone marrow transplantation. At this time fourteen patients are alive and well 5-72 months post-transplant (median follow-up 58 months) with an actuarial disease free survival of 66%. These early results suggest that high-dose chemoradiotherapy followed by autologous bone marrow transplantation may improve long-term disease free survival in advanced stage adult lymphoblastic lymphoma.

Mobilization/transplantation of peripheral blood progenitor cells for aggressive non-Hodgkin's lymphoma with marrow involvement.

Thirty-five aggressive non-Hodgkin's lymphomas (NHL) with marrow involvement received high-dose cyclophosphamide (7 g/m2) and G-CSF in order to collect peripheral blood progenitor cells (PBPC). Fourteen patients were in partial remission, 16 patients were in relapse ('sensitive', 12; 'resistant', 4) and five patients were refractory to conventional treatment. A good yield of PBPC was obtained in 30 patients, while a low number of CD34+ cells and of CFU-GM was seen in two cases. Two patients entered progression and one patient died. Thirty patients underwent PBPC autografting. Twenty-nine out of 35 (83%) patients entered complete remission (CR). Two patients died in CR of infection following marrow aplasia 3 and 6 months after autografting. At 3 years the probability of survival and disease-free survival (DFS) are 62 and 51%, respectively.

Treatment of severe aplastic anemia with sequential immunosuppression.

Forty-two patients with severe aplastic anemia (SAA) were treated with immunosuppressive therapy (IS) consisting of one or more courses of the following regimens: a) high dose bolus 6 methylprednisolone (BMPr); b) horse antilymphocytic globulin (HALG); c) rabbit ALG (RALG); d) ALG followed by the infusion of haploidentical marrow (ALG +/- BM); e) BMPr in combination with HALG; f) ALG in combination with androgens. All patients received one initial course of IS: 16 (38%) showed hematologic reconstitution and required no further transfusions, of 26 refractory patients 4 died, and 22 received a second course of IS 60 days after the first course. Of these 22, 6 (27%) responded, and of the 16 refractory patients, 9 died, and 7 received a third course of IS 60 days after the second course. Two of these responded (28%), 3 died and 2 are alive but pancytopenic. The overall response rate is 24/42 patients (57%): all of these patients are transfusion independent 6-60 months post-treatment, and 17 are off maintenance therapy with low dose steroids. The actuarial 5 year survival is currently 60%; 13/26 surviving patients have been followed for more than 3 years. The present study confirms that over 50% of patients with SAA can recover from their aplasia following IS treatment, and this is of relevance for patients who can not be offered a bone marrow transplant.

Acetyl-carnitine deficiency in AIDS patients with neurotoxicity on treatment with antiretroviral nucleoside analogues.

OBJECTIVE: A severe dose limiting axonal peripheral neuropathy may develop in subjects on treatment with the nucleoside analogues didanosine (ddl), zalcitabine (ddC), and stavudine (d4T). The impairment of mitrochondrial DNA synthesis is crucial to the pathogenesis of this disorder although other mechanisms have not been ruled out. The depletion of acetyl-carnitine, which regulates the metabolism and function of peripheral nerves could contribute to the neurotoxicity of these compounds. DESIGN: Non-randomized, cross-sectional study of selected patients. METHODS: We measured the serum levels of acetyl- and total carnitine in 12 subjects with axonal peripheral neuropathy developed on treatment with different regimens of neurotoxic nucleoside analogues (ddl, ddC, d4T). Subjects who did not develop peripheral neuropathy while staying on treatment with ddl (n = 10) or zidovudine (n = 11) served as the control groups. HIV-negative subjects with axonal on demyelinating autoimmune neuropathies (n = 10) and healthy individuals (n = 13) were additional control groups. RESULTS: Subjects experiencing axonal peripheral neuropathy on treatment with ddl, ddC and d4T had significantly reduced levels of acetyl-carnitine in comparison to the control groups. No difference was observed in the levels of total carnitine between study subjects and the control groups. CONCLUSIONS: Our results demonstrate that subjects who developed peripheral neuropathy while staying on treatment with ddl, ddC and d4T had acetyl-carnitine deficiency. The normal levels of total carnitine in the study group appear to indicate the specificity of the defect and rule out coexisting relevant nutritional problems. The critical role of acetyl-carnitine for the metabolism and function of the peripheral nerves supports the view that the acetyl-carnitine deficiency found in these subjects may contribute to the neurotoxicity of ddl, ddC and d4T, even though the interference with mitochondrial DNA synthesis is regarded as the main cause of their toxicity.

The human pharmacology of monocyte cyclooxygenase 2 inhibition by cortisol and synthetic glucocorticoids.

BACKGROUND: We studied the concentration dependence of the inhibitory effects of cortisol, 6-methylprednisolone, and dexamethasone on cyclooxygenase-2 (COX-2) expression and activity in human monocytes in response to lipopolysaccharide (LPS) in vitro. Moreover, we characterized the time and dose dependence of the inhibitory effects of 6-methylprednisolone, administered to healthy subjects, on LPS-inducible prostaglandin E2 (PGE2) biosynthesis in whole blood ex vivo. METHODS: Heparinized whole-blood samples obtained from healthy subjects and patients with rheumatoid arthritis were incubated with LPS (10 microg/ml) for 24 hours at 37 degrees C, and PGE2 was measured in plasma as an index of monocyte COX-2 activity. Comparative experiments were performed in LPS-stimulated isolated monocytes. The levels of COX-2-like immunoreactivity in monocyte lysates were measured by a specific Western blot technique. PGE2 was evaluated by radioimmunoassay. RESULTS: Nanomolar concentrations of cortisol, 6-methylprednisolone, and dexamethasone suppressed LPS-induced PGE2 biosynthesis both in whole blood and in isolated monocytes in vitro with relative potencies similar to those reported for their anti-inflammatory effects in vivo. The administration of single oral doses (4, 8, or 16 mg) of 6-methylprednisolone caused a dose- and time-dependent inhibition of whole-blood COX-2 activity. Whole-blood samples obtained from patients with rheumatoid arthritis treated with comparable maintenance doses of glucocorticoids produced significantly lower levels of LPS-inducible PGE2 than were found in untreated patients. CONCLUSIONS: Therapeutic plasma levels of synthetic glucocorticoids down-regulate inducible prostanoid biosynthesis in circulating monocytes. This effect may represent a readily measurable surrogate marker of their clinical efficacy for dose-finding studies.

Effects of nimesulide on constitutive and inducible prostanoid biosynthesis in human beings.

BACKGROUND: The aim of this study was to test the hypothesis that nimesulide, a nonsteroidal antiinflammatory drug, or its principal metabolite 4-hydroxynimesulide, is a selective inhibitor of prostaglandin H synthase-2 in human beings. METHODS: Heparinized whole blood samples obtained from healthy subjects were incubated with lipopolysaccharide (10 micrograms/ml) for 24 hours at 37 degrees C and prostaglandin E2 was measured in plasma as an index of monocyte prostaglandin H synthase-2 activity. The production of thromboxane B2 in whole blood allowed to clot at 37 degrees C for 60 minutes was assessed as an index of platelet prostaglandin H synthase-1 activity. We also measured the urinary excretion of 11-dehydrothromboxane B2, prostaglandin E2, 6-ketoprostaglandin F1 alpha, and thromboxane B2 as in vivo indexes of cyclooxygenase activity. All prostanoids were measured by previously validated radioimmunoassay techniques. RESULTS: In the whole blood assays in vitro, nimesulide was twentyfold more potent than 4-hydroxynimesulide toward the two isozymes and both compounds displayed a twentyfold preference for prostaglandin H synthase-2 versus prostaglandin H synthase-1. The administration of a single oral dose of 100 mg nimesulide to six healthy subjects significantly (p < 0.01) reduced monocyte prostaglandin H synthase-2 and prostaglandin H synthase-1 activity ex vivo by more than 90% and 50%, respectively, up to 6 hours. At 24 hours, prostaglandin H synthase-2 but not prostaglandin H synthase-1 activity was significantly reduced by 49% (p < 0.05). Nimesulide significantly (p < 0.05) reduced the urinary excretion of 11-dehydrothromboxane B2 and 6-ketoprostaglandin F1 alpha by approximately 30% and 25%, respectively, while not affecting that of prostaglandin E2 and thromboxane B2. CONCLUSIONS: Nimesulide is a potent inhibitor of human monocyte prostaglandin H synthase-2. However, despite a twentyfold selectivity ratio, therapeutic plasma levels of nimesulide are sufficiently high to cause detectable inhibition of platelet prostaglandin H synthase-1.

Serum levels of intercellular adhesion molecule 1 in patients with HIV-related Kaposi's sarcoma.

Infection with the human immunodeficiency virus type 1 (HIV-1) in man is associated with an increase in the incidence of Kaposi's sarcoma (KS). The biological and clinical characteristics of these patients differ from those of subjects with other HIV-associated diseases. Here we report that levels of serum-soluble intercellular adhesion molecule 1 (sICAM 1) are increased in HIV-1-positive patients with KS, but not in patients belonging to other CDC classification groups. KS patients with elevated levels of serum sICAM 1 had a significant lowering of CD4 cell counts during the follow-up period compared with those KS subjects whose sICAM 1 levels were only moderately higher. We suggest that increased sICAM 1 levels may have a pathogenetic role in the development of HIV-associated immunodeficiency in KS patients and may also be considered an important prognostic factor.