Inmunoferon, an immunomodulator of natural origin, does not affect the rat liver cytochrome P-450 and phase II conjugation enzymes

Inmunoferon is a glycoconjugate of natural origin with immunomodulatory properties. It has recently been shown to regulate TNF-alpha expression induced by lipopolysaccharide (LPS) challenge through a hypothalamo-pituitary-adrenal (HPA)-dependent mechanism. Inmunoferon is orally administered to immunocompromised patients as an adjuvant during immune therapy such as vaccination or infectious diseases treatment. Due to its mainly adjuvant nature, it is necessary to determine if coadministration of Inmunoferon affects the activity of other drugs. In this study we analyzed the possible modification of the hepatic drug biotransformation system by using Inmunoferon in a rat model, which may result in changes in the biological activity of other drugs administered simultaneously. Inmunoferon-treated animals showed no differences to control littermates in antipyrine metabolism. No differences were found in either cytochrome P-450 and b5 levels or cytochrome P-450-dependent activities and phase II conjugation enzymes in lysates from Inmunoferon-treated rat hepatic cells. The same treatment reduced levels of serum TNF-alpha in LPS-challenged animals. In summary, Inmunoferon is unable to affect the hepatic bioconjugation system during administration and thus seems unlikely to interact with, or modify the effect of, coadministered drugs.

The effect of propofol on the interaction of platelets with leukocytes and erythrocytes in surgical patients

We tested the antiplatelet effect described for propofol in vitro in surgical patients. Platelet aggregation induced by adenosine diphosphate, collagen, and arachidonic acid was tested in samples of whole blood, platelet-rich plasma (PRP), PRP with red blood cells, and PRP with leukocytes. Also measured were platelet production of thromboxane (Tx)B(2) and leukocyte production of 6-keto-prostaglandin F(1 alpha) (a stable metabolite of prostacyclin) and plasma levels of nitrites + nitrates (indicator of nitric oxide production). Anesthesia was induced with a bolus IV injection of sodium thiopental 4 mg/kg (n = 10), with a bolus dose of 2.5 mg/kg of propofol (n = 20), or with propofol total IV anesthesia (n = 20). Sodium thiopental did not modify any of the analytical values. In patients who received a bolus injection of propofol, platelet aggregation was significantly reduced in whole blood and in PRP + leukocytes. Platelet production of TxB(2) was reduced by 35%; the inhibition of 6-keto-prostaglandin F(1 alpha) was not statistically significant. Plasma levels of nitrites + nitrates increased by 37%; this change correlated significantly with the decrease in systolic and diastolic blood pressure (both P < 0.05). Similar changes, albeit of larger magnitude, were seen in patients who were given total IV anesthesia with propofol. In conclusion, propofol inhibited platelet aggregation in surgical patients mainly as a result of the inhibition of Tx synthesis and the increase in nitric oxide production. These effects are thought to be related to the hypotensive effect of this anesthetic.

IMPLICATIONS

In vitro experiments have shown that propofol inhibits platelet aggregation and increases nitric oxide production. This study shows that doses habitually used to induce or maintain anesthesia also have these effects. These findings have potential applications for patients at increased risk for bleeding and may partly explain the hypotensive effect of propofol.

Role of aluminous component of fly ash on the durability of Portland cement-fly ash pastes in marine environment

The durability, of mixtures of two kinds of Spanish fly ashes from coal combustion (ASTM class F) with 0, 15 and 35% replacement of Portland cement by fly ash, in a simulated marine environment (Na(2)SO(4)+NaCl solution of equivalent concentration to that of sea water: 0.03 and 0.45 M for sulphate and chloride, respectively), has been studied for a period of 90 days. The resistance of the different mixtures to the attack was evaluated by means of the Koch-Steinegger test. The results showed that all the mixtures were resistant, in spite of the great amount of Al(2)O(3) content of the fly ash. The diffusion of SO(4)(2-), Na+ and Cl- ions through the pore solution activated the pozzolanic reactivity of the fly ashes causing the corresponding microstructure changes, which were characterized by X-ray diffraction (XRD), mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM). As a result, the flexural strength of the mixtures increased, principally for the fly ash of a lower particle size and 35% of addition.

[Peritoneal equilibrium test using icodextrin and glucose at different concentrations]

The aim of this study was to compare, under standard conditions (Peritoneal Equilibrium Test, "PET"), the peritoneal permeability to water and several solutes using icodextrin and glucose (3.86% and 1.36%) dialysates. The study includes 14 patients (3 women and 11 men), mean age 64 +/- 13 years, average time on peritoneal dialysis 23.5 +/- 17 months. PETs with icodextrin were performed in all of them (n = 14); PETs with 3.86% glucose were carried out in 7, and PETs with all the three solutions were performed in 5 patients. Samples were taken at 0, 30, 60, 120, 240 minutes, and after the rinsing procedure using 1.36% glucose in order to calculate the residual volume.

RESULTS

Sodium concentration in the effluent and D/P sodium did not change significantly from minute 0 to 240 with icodextrin and 1.36% glucose; but with 3.86% glucose both sodium and D/P sodium decreased at thirty minutes, remained at the same levels till the 120 minutes and then had a tendency to increase. Glucose concentration and osmolarity in the effluent did not vary throughout the time with icodextrin, but progressively decreased during the 4-hour period with 3.86% and 1.36% glucose solutions. The drainage after the 4-hour period was higher for the 3.86% glucose (2,608 +/- 388 ml, p = 0.03) than for the 1.36% glucose (2,070 +/- 120 ml) or the icodextrin (2,212 +/- 213 ml). Low molecular weight permeability: D/P creatinine after the 4-hour dwell was significantly lower for the icodextrin (0.66 +/- 0.1, p = 0.05) than for the 3.86% glucose (0.71 +/- 0.1) or the 1.36% glucose (0.72 +/- 0.1). The creatinine clearance for 3.86% glucose (7.4 +/- 0.4 ml/min p = 0.007) was higher than for icodextrin (5.6 +/- 0.5 ml/min) or for 1.36% glucose (5.8 +/- 0.6 ml/min). The clearances for total protein, albumin and beta 2-microglobulin did not show significant differences between the solutions.

CONCLUSIONS

Our study confirms that the icodextrin solution remains iso-osmolar with plasma during the 4-hour dwell. The sodium profile suggests that the ultrafiltration induced by icodextrin and 1.36% glucose depends on small pore-mediated sodium and water transport; on the other hand, 3.86% glucose also induces transport of water without solutes throughout the ultra-small aquaporin-mediated, pores, producing sodium dilution in the effluent. Ultrafiltration and solute clearances for icodextrin are lower than for 3.86 glucose during a 4-hour dwell.

Effects of the selective inhibition of platelet thromboxane synthesis on the platelet-subendothelium interaction

1. Drugs that inhibit TxA(2) synthesis are used to reduce platelet aggregation. The aim of this study was to compare the effects of a cyclo-oxygenase (COX) inhibitor (acetylsalicylic acid, ASA), a thromboxane synthetase (TxS) inhibitor (dazoxiben) and a dual TxS inhibitor and TxA(2) receptor blocker (DT-TX 30) on platelet aggregation and the platelet-subendothelium interaction in flow conditions. 2. The techniques used in this in vitro study were platelet aggregometry in whole blood, and measurement of platelet thromboxane B(2) and prostaglandin E(2) production and leucocyte production of 6-keto-PGF(1alpha). The platelet-subendothelium interaction was evaluated in rabbit aorta subendothelium preparations exposed to flowing blood at a shear stress of 800 s(-1). Morphometric methods were used to calculate the percentage of subendothelium occupied by platelets. 3. The 50% inhibitory concentration (IC(50)) of DT-TX 30 in whole blood was in the range of 10(-7) micro M (induced with collagen or arachidonic acid) to 10(-5) micro M (induced with thrombin) or 10(-4) (induced with ADP). IC(50) values under all experimental conditions were lower with DT-TX 30 than with ASA. For thromboxane B(2) the IC(50) were: ASA 0.84+/-0.05 micro M, dazoxiben 765+/-54 micro M, DT-TX 30 8.54+/-0.60 micro M. Prostaglandin E(2) was inhibited only by ASA (IC(50) 1.21+/-0.08 micro M). Leucocyte 6-keto-PGF(1alpha) was inhibited by ASA (IC(50) 6.58+/-0.76 micro M) and increased by dazoxiben and DT-TX 30. The greatest reduction in percentage subendothelial surface occupied by platelets after blood perfusion was seen after treatment with DT-TX 30 in the range of concentrations that inhibited collagen-induced platelet aggregation (control group: 31.20+/-3.8%, DT-TX 30 at 0.1 micro M: 10.71+/-0.55%, at 1.0 micro M: 6.53+/-0.44%, at 5.0 micro M; 1.48+/-0.07%). All three drugs reduced thrombus formation, although ASA (unlike dazoxiben or DT-TX 30) increased the percentage surface occupied by adhesions. 4. In conclusion, the effect of specific blockage of TxS together with blockage of membrane receptors for TxA(2) can surpass the effect of ASA in inhibiting the platelet-subendothelium interaction in flow conditions.

The conus arteriosus of the adult gilthead seabream (Sparus auratus)

This paper reports on the presence of the conus arteriosus in the heart of the adult gilthead seabream, Sparus auratus (Perciformes, Teleostei). The junctional region between the single ventricle and the bulbus arteriosus has been studied by conventional light microscopy, and by scanning and transmission electron microscopy. In addition, fluorescent phalloidin and antibodies against the muscle myosin heavy chains, laminin and collagen type IV have been used. The conus arteriosus is a distinct muscular segment interposed between the ventricle and the bulbus arteriosus. It is clearly different from the bulbus arteriosus due to its myocardial nature. It can also be distinguished from the ventricular myocardium because: (1) it has a conus shape; (2) it is formed by compact, well-vascularized myocardium; (3) it is surrounded on its inner and outer faces by fibrous layers rich in collagen and elastin; (4) it constitutes the anatomical support of the so-termed conus valves; (5) it shows intense staining for laminin and type-IV collagen; and (6) the myocardial cells located close to the inner fibrous layer are helicoidally arranged. By contrast, the ventricular myocardium is highly trabecular, lacks a compacta, shows no vessels, and presents barely detectable amounts of laminin and collagen type IV. The presence of a distinct conus arteriosus in the heart of an evolutionary advanced teleost species indicates that the conus is not a vestigial segment from the evolutionary or embryological points of view. The characteristic spatial arrangement of the conus myocytes strongly suggests that the conus is implicated in the mechanical performance of the conus valves.

Identification and characterization of the peptidic component of the immunomodulatory glycoconjugate Immunoferon

Inmunoferon is a glycoconjugate of natural origin, formed by the noncovalent association of a protein from Ricinus communis and a polysacharidic moiety, and endowed with immunomodulatory as well as pharmacological activities. This study investigated the nature of polypeptidic component of Inmunoferon. Through biochemical procedures and comparison with protein databases, the isolated protein was identified as the processed form of the seed of Ricinus communis 2S storage polypeptide, which has been termed RicC3. Further analysis of the isolated protein has revealed that it is composed of two different subunits, alpha and beta, which form an heterodimer of high stability and resistance to denaturation, acidic pH and proteolytic cleavage. These findings confirm the excellent properties of the product after oral administration and provide additional support for the pharmacological activities of Inmunoferon.

Comparative studies of female sex pheromone components and male response of the corn stalk borer Sesamia nonagrioides in three different populations

Studies to determine possible differences in the pheromone communication system of three different populations of the corn stalk borer Sesamia nonagrioides (Lef.) in France. Spain. and Greece were carried out. The two main pheromone components (Z)-11-hexadecenyl acetate (Z11-16:Ac) and (Z)-11-hexadecenol (Z11-16:OH), were detected in all analyses with very small differences in the three populations. Among the minor components, analyzed by GC-MS on concentrated gland extracts from French and Greek origin females, (Z)-l1-hexadecenal (Z11-16:Ald) was detected in minor amounts. Wind-tunnel and field studies revealed similar a male response in the three populations to pheromone glands extracts and synthetic pheromone regardless of the female/male origin. The results do not support the assumption of the existence of different pheromone types of the corn stalk borer S. nonagrioides due to geographic isolation.

Inmunoferon, a glycoconjugate of natural origin, regulates the liver response to inflammation and inhibits TNF-alpha production by an HPA axis-dependent mechanism

In this report, we have examined the mechanism of action of Inmunoferon, a patented glycoconjugate (GC) of natural origin with immunomodulatory properties, in the regulation of TNF-alpha expression induced by LPS challenge in a rodent model. GC was found to be dependent on a normal HPA response to exert its regulatory effect on TNF-alpha expression. Adrenalectomized mice were unresponsive to the drug in terms of TNF-alpha levels after LPS challenge, whereas control mice showed lower serum TNF-alpha levels when treated with GC than vehicle-treated animals. GC treatment also induced the expression of acute phase proteins but it did not alter the normal metabolism or viability of hepatic cells. These data suggested the employment of GC as a novel adjuvant during antibacterial treatment without disadvantages such as side effects in the metabolism of the liver, thus, acting as an enhancer of the host response against infection.

[Clinical experience with icodextrin. Multicenter study]

The aim of this study was to analyse our experience with icodextrin in Andalusia, Spain. The study includes 51 patients (30 women and 21 men) on peritoneal dialysis (21 on CAPD and 30 on Automated Peritoneal Dialysis) treated with icodextrin for 10.3 +/- 7 months (0-41 months). Their mean age was 57 +/- 18 years (18-86 years). We have recorded the appearance of side effects, and the evolution of several biochemical parameters at baseline and after 6, 12 ans 18 months from initiation of icodextrin. We also studied drainage fluid from 12 patients after an icodextrin exchange.

RESULTS

There were side effects (all cutaneous) in 4 out of 51 patients (7.8%). Two of the affected suffered from cutaneous hypersensitivity reactions, and icodextrin had to be suspended; the other two had exfoliative dermatitis affecting hands and feet that disappeared without have to withdraws icodextrin. Biochemical parameters: Serum sodium levels decreased from baseline to six months (138 +/- 6 mEq/l vs 136 +/- 3 mEq/l; p = 0.006), and then persisted at the same levels throughout the rest of the study period. There was a slight but significant decreased of serum HDL-cholesterol at six months vs baseline (55 +/- 26 mg/dl vs 51 +/- 20 mg/dl, p = 0.04), and a further decrease at twelve months vs six months (42 +/- 15 mg/dl vs 51 +/- 13 mg/dl, p = 0.054). There were no significant variations of glucose, osmolality, cholesterol, LDL-cholesterol (tendency to increase), triglycerides, beta 2 m and weight (tendency to increase; p = 0.08). In relation with the icodextrin exchange: average ultrafiltration 296 +/- 119 ml (ranging from 104 to 480 ml), creatinine clearance 1.9 +/- 0.5 litres (20.5% of daily creatinine clearance), urea clearance 2.08 +/- 0.5 litres (18.7% of daily urea clearance), total protein losses 3.2 +/- 0.9 g, albumin losses 1.4 +/- 0.5 g; urea and creatinine clearances were negatively correlated with ratios D/P4 of urea and creatinine of PET and positively correlated with ratio G4/G0. In conclusion, side effects are scarce with the use of icodextrin. As described in other studies, there is a trend to a slight decrease in serum sodium. The long-term use of icodextrin does not-prevent weight gain or deterioration of patients on peritoneal dialysis, despite the diminution of glucose load.

Influence of nitric oxide on the in vitro antiaggregant effect of ticlopidine

The aim of this study was to evaluate the influence of leukocyte nitric oxide (NO) production on the antiplatelet aggregant effect of aspirin and ticlopidine. This in vitro study was done with platelets (platelet-rich plasma, PRP) and polymorphonuclear leukocytes (PMNLs) separated from samples of human blood. Collagen-induced platelet aggregation and calcium-dependent NO production by PMNL were quantified. The inhibition of NO production in PRP significantly reduced the antiaggregant affect of aspirin (IC50 2.64-fold greater), whereas it had no significant effect on the effect of ticlopidine (IC50 1.03-fold greater). Incubating PMNL in PRP increased the antiaggregant effect of both aspirin (IC50 5.09-fold lower) and ticlopidine (IC50 10.16-fold lower). The inhibition of NO production in PMNL significantly reduced the antiaggregant effect of both aspirin (IC50 2.21-fold greater) and ticlopidine (IC50 3.26-fold greater). Both drugs increased leukocyte NO production. The concentration of aspirin that raised NO production by 50% was greater than 1000 microM, whereas the concentration of ticlopidine that led to this effect was 9.14 +/- 0.87 microM. We conclude that the effect of ticlopidine on leukocyte NO production may constitute an addition mechanism to the IIb/IIIa glycoprotein complex inactivation in the inhibition of platelet activation.

Effect of aspirin on prostanoids and nitric oxide production in streptozotocin-diabetic rats with ischemic retinopathy

The importance in experimental diabetic retinopathy of prostacyclin and nitric oxide (NO), as well as the possible effect of acetylsalicylic acid (ASA), are well known. To investigate the effect of two doses of aspirin in the prevention of retinal ischemia in streptozotocin-diabetic rats, we compared nondiabetic rats and diabetic rats after 1, 2 and 3 months of diabetes, and diabetic rats treated with 2 mg or 10 mg ASA/kg per day p.o. from the first day of diabetes. The parameters determined after 1, 2 and 3 months of development were platelet aggregation, thromboxane B(2) (TxB(2)) production, 6-keto-prostaglandin F(1)(alpha) (stable metabolite of prostacyclin), NO, plasma nitrites/nitrates, and percentage retinal surface occupied by horseradish peroxidase (HRP)-permeable vessels. In diabetic rats platelet aggregation and thromboxane concentration were increased, and prostacyclin, NO and area occupied by HRP-permeable vessels were decreased. Acetylsalicylic acid reduced platelet aggregation, and lowered thromboxane production by 82%-99%. Prostacyclin production was inhibited by 92%-95% with 10 mg ASA/kg per day, and by 8%-20% with 2 mg ASA/kg per day. In diabetic rats NO production increased after 2 and 3 months of treatment to levels seen in nondiabetic rats. The reduction in HRP-permeable retinal surface decreased from a maximum of 87% in DR to 51% after treatment with 2 mg ASA/kg per day, and to 62% after 10 mg ASA/kg per day. We conclude that ASA (2 mg/kg per day and 10 mg/kg per day) increased NO production in streptozotocin-diabetic rats and reduced the degree of retinal ischemia.

Effects of S-adenosyl-L-methionine on lipid peroxidation and glutathione levels in rat brain slices exposed to reoxygenation after oxygen-glucose deprivation

We analyzed the effects of S-adenosyl-L-methionine (AdoMet) on tissue oxidative stress in rat brain slices exposed to reoxygenation after oxygen-glucose deprivation. The thiobarbituric acid reactive substances (TBARS), total and oxidized glutathione, and lactate-dehydrogenase efflux (LDH) from tissue to the incubation medium, were measured. Brain slices were incubated without glucose and with N2, then glucose was added and O2 was perfused. After the anoxic-reoxygenation period, increase in TBARS, oxidized glutathione and LDH efflux, and decrease in total glutathione levels, were observed. The incubation with AdoMet before the anoxic period reduced TBARS (31-1000 micromol/l), glutathione production was increased (31-1000 micromol/l), LDH efflux decreased 6.41% with 15 micromol/l and 61.5% with 500 micromol/l). In the ex vivo experiments, we administered 50 mg/kg per day p.o., AdoMet for 3 days, then brain slices were collected and the anoxia-reoxygenation experiment was carried out. AdoMet led to the inhibition of brain lipid peroxidation and increased total glutathione production, after 3 h-reoxygenation. The increase of LDH efflux in non-treated rats was reduced by 77%. We conclude that AdoMet exerts citoprotective effects in an experimental model of brain slices reoxygenation after oxygen-glucose deprivation.

Antiangiogenic effect of betamethasone on the chick cam stimulated by TA3 tumor supernatant

Tumor growth is the result of combined cell proliferation overwhelming cell death and neoangiogenesis. This report shows CAM angiogenesis promoted by TA3 tumor supernatant with or without low dosis of betamethasone (Minimal antiangiogenic concentration: beta-MAAC). Methylcellulose discs instilled with 10 microliters of beta-MAAC (0.08 microgram/ml), 10 microliters of tumor supernatant (TA3ts), 5 microliters beta-MAAC + 5 microliters TA3ts, and 10 microliters of PBS as control were implanted in host chick eggs. On day 12, the grafts were removed, photographed and fixed. Sections were stained in parallel, one and three with hematoxylin-eosin, and section two by the Tunel method. The number of vessels was evaluated in a microscopic field of the CAM (2250 micron 2). The results show that beta-MAAC produced a significant inhibition of neovascularization in comparison to that observed in controls (P < 0.0025; Student t-Test). Discs instilled with TA3ts produced an intense stimulation of angiogenesis in contrast, when discs were instilled with 5 microliters of beta-MAAC + 5 microliters of TA3ts the angiogenesis was significantly inhibited (P < 0.001). The results show that effective antiangiogenic doses of betamethasone are in the range of 10(-7) M, (probably a genomic mediated action) and that this effect of low concentration may have clinical applications.

Efficiency of a blast furnace slag cement for immobilizing simulated borate radioactive liquid waste

The efficiency of a blast furnace slag cement (Spanish CEM III/B) for immobilizing simulated radioactive borate liquid waste [containing H3BO3, NaCl, Na2SO4 and Na(OH)] has been evaluated by means of a leaching attack in de-mineralized water at the temperature of 40 degrees C over 180 days. The leaching was carried out according to the ANSI/ANS-16.1-1986 test. Moreover, changes of the matrix microstructure were characterized through porosity and pore-size distribution analysis carried out by mercury intrusion porosimetry (MIP), X-ray diffraction (XRD) and thermal analysis (TG). The results were compared with those obtained from a calcium aluminate cement matrix, previously published.

Nitric oxide-cGMP and prostacyclin-cAMP pathways in patients with type II diabetes and different types of retinopathy

The aim of this study was to investigate two factors of endothelial dysfunction and their platelet second messengers in patients with type II diabetes and different types of retinopathy. We compared 20 healthy volunteers and 117 patients with type II diabetes (34 with no signs of diabetic retinopathy, 26 with background diabetic retinopathy, 29 with ischemic-proliferative diabetic retinopathy and 28 with edematous diabetic retinopathy). The following parameters were recorded: platelet aggregometry, nitrites, 6-keto-prostaglandin-F(1alpha) and intraplatelet cAMP and cGMP. Platelet aggregation was greater in patients with diabetic retinopathy. The concentration of ADP that produced 50% maximum intensity of aggregation was 1.81 microM in patients without diabetic retinopathy, 0.92 microM in patients with background diabetic retinopathy, 0.85 microM in patients with ischemic-proliferative diabetic retinopathy and 0.44 microM in patients with edematous diabetic retinopathy. The platelets in these patients were more resistant to inhibition by SIN-1 (concentrations of SIN-1 that produced 50% inhibition of maximum intensity of collagen-induced aggregation in the four patient groups: 18.1, 13.6, 16.2 and 33.2 microM, respectively). Nitrite concentration in patients with ischemic-proliferative diabetic retinopathy was one sixth of the value in healthy controls, but there was no significant difference between the control group and patients with edematous diabetic retinopathy. In the latter group, neutrophils increased nitrite production by 68.7 +/- 3%, whereas in patients with ischemic-proliferative diabetic retinopathy, this increase was 18.7 +/- 2.0%. We conclude that nitric oxide production is higher in patients with type II diabetes and edematous retinopathy than in those with ischemic-proliferative retinopathy. This finding, together with the possibly greater production of free radicals, may explain the greater impairment of platelet function in the former patients.

Effects of two preparations of 75-mg extended-release aspirin on platelet aggregation, prostanoids and nitric oxide production in humans

OBJECTIVE

The lowest dose of aspirin shown to be effective in the secondary prevention of thrombotic accidents is 75 mg/day. Presystemic acetylation of cyclooxygenase and the formation of salicylic acid in the liver are fundamental to ensure optimum antithrombotic effects of aspirin. This study was designed to compare the effects of two forms of extended-release aspirin (at 75 mg/day) on prostanoid and nitric oxide synthesis in healthy volunteers.

METHODS

The participants in this single-blind cross-over study (n = 6) were randomly assigned to receive one of three different formulations: plain-formulated aspirin (PF), extended-release aspirin that released acetylsalicylic acid steadily over 5 h (EX5) or an extended-release formulation that released 49% of the drug during the first 2 h after intake (EX2) and the rest of the dose during the subsequent 5 h. Laboratory analyses were done for platelet aggregation and thromboxane B2 (in whole blood), 6-keto-prostaglandin F1alpha (in leucocytes), neutrophil nitric oxide production and plasma nitrite/ nitrate levels.

RESULTS

The PF and EX2 formulations inhibited platelet aggregation by 97% with no significant difference in effect between the two. In contrast, maximum inhibition of aggregation by the EX5 formulation was only 30%. Similar effects were found for platelet thromboxane production: PF and EX2 led to 99% inhibition, whereas EX5 led to 76% inhibition (P < 0.05). The inhibition of prostacyclin production differed in all three treatments (63% for PF, 40% for EX2 and 24% for EX5). The increase in leucocyte nitric oxide production also differed in all three treatments (1.01-fold the basal value with PF, 1.4-fold with EX5 and 3.6-fold with EX2). Both extended-release formulations maintained high levels of nitric oxide production 24 h after the last dose, whereas in the PF period nitric oxide concentration had returned to basal values after this time. The changes in plasma nitrite concentrations in each period of treatment were similar to those seen for leucocyte nitric oxide.

CONCLUSION

The pharmacodynamic profile of the extended-release formulations was better than that of plain-formulated aspirin in terms of thromboxane/prostacyclin balance and nitric oxide production. However, the EX2 formulation inhibited platelet function more effectively than did the EX5 formulation.

Removal of bacterial and viral faecal indicator organisms in a waste stabilization pond system in Choconta, Cundinamarca (Colombia)

A major objective for domestic wastewater treatment using waste stabilization pond systems is the removal of pathogenic microorganisms. Traditional evaluation parameters for faecal contamination are the total and faecal coliforms. However, epidemiological studies, environmental resistance and the behaviour in the treatment systems, show that viruses are an important disease agent and even more resistant to disinfection than bacteria. Therefore, it is important to introduce viruses as a faecal indicator and to compare them with the traditional bacterial indicators. A waste stabilization pond system was evaluated in the municipality of Chocontá, Cundinamarca (Colombia), for the removal of faecal indicators (such as Escherichia coli, Streptococcus faecalis, Clostridium perfringens) and viruses like F+, somatic and Bacteroides fragilis phages. The system includes two facultative ponds in series with a flow of 1555 m3/day. Samples were collected at the entrance of the system, in the two ponds and from the final effluent. Results show a decrease between 0.3 and 4.7 logarithmic units in the bacterial indicators and between 1 and 4.6 logarithmic units with viral indicators.

Olfactory responses of Plutella xylostella natural enemies to host pheromone, larval frass, and green leaf cabbage volatiles

The parasitoids Trichogramma chilonis (Hymenoptera: Trichogrammatidae) and Cotesia plutellae (Hymenoptera: Braconidae), and the predator Chrysoperla carnea (Neuroptera: Chrysopidae), are potential biological control agents for the diamondback moth, Plutella xylostella (Lepidoptera: Yponomeutidae). We present studies on the interactions between these bioagents and various host-associated volatiles using a Y olfactometer. T chilonis was attracted to a synthetic pheromone blend (Z11-16:Ald, Z11-16:Ac, and Z11-16:OH in a 1:1:0.01 ratio), to Z11-16:Ac alone, and to a 1:1 blend of Z11-16:Ac and Z11-16:Ald. C. plutellae responded to the blend and to Z11-16:Ac and Z11-16:Ald. Male and female C. carnea responded to the blend and to a 1:1 blend of the major components of the pheromone, although no response was elicited by single compounds. Among the four host larval frass volatiles tested (dipropyl disulfide, dimethyl disulfide, allyl isothiocyanate, and dimethyl trisulfide), only allyl isothiocyanate elicited significant responses in the parasitoids and predator, but C. plutellae and both sexes of C. carnea did respond to all four volatiles. Among the green leaf volatiles of cabbage (Brassica oleracea subsp. capitata), only Z3-6:Ac elicited significant responses from T. chilonis, C. plutellae, and C. carnea, but C. plutellae also responded to E2-6:Ald and Z3-6:OH. When these volatiles were blended with the pheromone, the responses were similar to those elicited by the pheromone alone, except for C. carnea males, which had an increased response. The effect of temperature on the response of the biological agents to a mixture of the pheromone blend and Z3-6:Ac was also studied. T. chilonis was attracted at temperatures of 25-35 degrees C, while C. plutellae and C. carnea responded optimally at 30-35 degrees C and 20-25 degrees C, respectively. These results indicate that the sex pheromone and larval frass volatiles from the diamondback moth, as well as volatile compounds from cabbage, may be used by these natural enemies to locate their diamondback moth host.

[Cytomegalovirus sensitivity to anti-retroviral agents in patients infected with the human immunodeficiency virus with chorioretinitis in Spain]

OBJECTIVES

To determine the prevalence of the in vitro resistance rate of cytomegalovirus (CMV) to gancyclovir (GCV) and foscarnet (FOS) among patients with AIDS and chorioretinitis. Furthermore, in vitro sensitivity results were compared with the clinical response to therapy.

PATIENTS AND METHODS

Thirty-six patients with the diagnosis of CMV retinitis and AIDS were included in the study. Antiviral sensitivity testing was performed to 51 clinical CMV strains from these patients. The in vitro sensitivity was compared with the clinical response to therapy. The resistance criteria were the inhibitory dose50 (ID50) GCV > 5 M and ID50 FOS > 400 M.

RESULTS

None of the CMV tested strains was resistant to GCV or FOS; however, six patients who had relapses of chorioretinitis while on maintenance therapy and isolation during the condition had mean ID50 of strains (n=8) of 1,95 M for GCV (standard deviation [SD] of 0.71) and 115.2 for FOS (SD, 34.7). These patients responded well when drugs were used at induction doses.

CONCLUSION

The in vitro sensitivity testing is not a good predictor of infection control when the drug is used at maintenance doses. This suggests that these strains should be classified in the intermediate resistant category.