[Long-term effect of policosanol on the functional recovery of non-cardioembolic ischemic stroke patients: a one year study]

INTRODUCTION

Stroke is a leading cause of mortality and disability. Policosanol has been effective in brain ischemia models. The aim of this study is to investigate whether policosanol, added to aspirin therapy within 30 days of stroke onset, is better than placebo + aspirine for the long-term recovery of non-cardioembolic ischemic stroke subjects.

PATIENTS AND METHODS

Randomized, double-blind, placebo-controlled study. Eighty patients (mean age: 69 years) within 30 days of onset, with a modified Rankin Scale score (mRS) 2 to 4, were included. They were randomized in two groups (policosanol + aspirine or placebo + aspirine) for 12 months.

RESULTS

Policosanol + aspirine decreased significantly mean mRS from the first interim check-up (1.5 months). The treatment even improved after long-term therapy. More policosanol + aspirin (87.5%) than placebo + aspirine (0%) patients achieved mRSs <= 1. Policosanol + aspirine increased significantly Barthel Index, lowered LDL-cholesterol and increased HDL-cholesterol versus placebo + aspirin.

CONCLUSIONS

Long-term (12 months) administration of policosanol + aspirin given after suffering non-cardioembolic ischemic stroke was shown to be better than placebo + aspirin in improving functional outcomes when used among patients with non-cardioembolic ischemic stroke of moderate severity.

D-002 (beeswax alcohols): Concurrent joint health benefits and gastroprotection

Nonsteroidal antiinflammatory drugs include the traditional drugs and more selective COX-2 inhibitors. Traditional nonsteroidal antiinflammatory drug use is hampered by their gastrotoxicity, while COX-2-inhibitors increase the cardiovascular risk. The search of safer substances for managing inflammatory conditions is updated, a challenge wherein dual COX/5-LOX inhibitors have a place. This review summarizes the benefits of D-002, a mixture of higher aliphatic beeswax alcohols, on joint health and gastric mucosa. D-002 elicits gastroprotection through a multiple mechanism that involves the increased secretion and improved quality of the gastric mucus, the reduction of hydroxyl radical, lipid peroxidation, protein oxidation, neutrophil infiltration and the increase of antioxidant enzymes on the gastric mucosa. Consistently, D-002 inhibits NSAIDs, ethanol, pylorus-ligation and acetic acid-induced gastric ulceration in rats, and has reduced gastrointestinal symptoms in clinical studies. Early results found that D-002 was effective in the cotton pellet-induced granuloma and carrageenan-induced pleurisy model in rats, lowering pleural leukotriene B4 levels without causing gastrointestinal ulceration. However, D-002 effects on inflammation received little attention for years. Recent data have shown that D-002 inhibited both COX and 5-LOX activities with a greater affinity for 5-LOX and could act as a dual COX/5-LOX inhibitor. This mechanism might explain efficacy in experimental inflammatory and osteoarthritic models as well as clinical efficacy in osteoarthritic patients while supporting the lack of D-002 gastrotoxicity, but not the gastroprotective effects, which appear to be due to multiple mechanisms. In summary oral D-002 intake could help manage inflammatory conditions that impair joint health, while offering gastroprotection.

Therapeutic Effects of Policosanol and Atorvastatin against Global Brain Ischaemia-Reperfusion Injury in Gerbils

Stroke is the third cause of death and the first of permanent adult disability. Pretreatment with policosanol and atorvastatin has been effective in experimental models of cerebral ischaemia in rodents. The objective was to compare the therapeutic effects of policosanol and atorvastatin in a model of global cerebral ischaemia in gerbils. Gerbils were distributed into seven groups, a negative control and six with ischaemia-reperfusion-induced global cerebral ischemia (one vehicle positive control, two policosanol (100 and 200 mg/kg), two atorvastatin (10 and 20 mg/kg) and one aspirin (60 mg/kg) group). Treatments were given 4 h after ischaemia induction. Effects on ischemia-reperfusion-induced symptoms, hyperlocomotion, damage of pyramidal hipoccampal neurons and increased plasma oxidative markers were investigated. Positive, not negative controls, exhibited clinical symptoms, hyperlocomotion, neuronal damage and increased plasma oxidative markers. Policosanol (100 and 200 mg/kg) reduced significantly ischemia-reperfusion-induced symptoms, the frequency of symptomatic animals, histological scores of neuronal damage and plasma oxidative markers as compared with the positive control group. Atorvastatin (10 and 20 mg/kg) decreased significantly the symptoms and histological scores, but unchanged the frequency of symptomatic gerbils and oxidative variables. Only the highest dose of policosanol (200 mg/kg) and atorvastatin (20 mg/kg) reduced significantly ischemia reperfusion-induced hyperlocomotion, policosanol being the most effective. Aspirin 60 mg/kg lowered significantly symptom score, the rate of symptomatic gerbils and hyperlocomotion versus the positive controls, but failed to modify oxidative parameters. In conclusion, postreperfusion treatment with policosanol and atorvastatin was effective for ameliorating symptoms, hyperlocomotion and neurological damage of hippocampal CA1 neurons in gerbils with ischemia-reperfusion-induced global cerebral ischemia, but only policosanol reduced increased plasma oxidative variables.

Effect of oleic, lauric and myristic acids on phenylephrine-induced contractions of isolated rat vas deferens

D-004, a lipid extract of Roystonea regia fruits that contains oleic, lauric and myristic acids as major components inhibits alpha1-adrenoreceptors-mediated contractile responses in isolated rat vas deferens and prostate trips; no study has demonstrated a similar effect for oleic, lauric or myristic acids individually. Therefore, the effects of D-004 (250 microg/mL), oleic (100 microg/mL), lauric (50 microg/mL) or myristic (25 microg/mL) acids and their combined effects on phenylephrine (PHE: 10(-7)-10(-4) mol/L) induced contractions has been studied. No treatment changed the basal tone of the preparations, but all inhibited PHE-induced contractions. D-004 produced the highest inhibition, followed by lauric acid, which was more effective than myristic and oleic acids against PHE-induced contractions of control group. D-004 and the mixture of the three acids produced similar inhibitions.

One year oral Toxicity of D-004, a lipid extract from Roystonea regia fruits, in Sprague Dawley rats

D-004, a lipid extract of royal palm (Roystonea regia) fruits that contains a reproducible mixture of fatty acids, has been shown to prevent testosterone and phenylephrine-induced prostate hyperplasia in rodents. This study investigated the long-term oral toxicity of D-004 in rats. Rats from both sexes were randomized into four groups (20 rats sex/group): a control and three treated with D-004 (800, 1500 or 2000 mg/kg/day, respectively). At study completion, rats were sacrificed under anaesthesia. Determinations of blood biochemical and haematological parameters and organ weight were done. Also, necropsy and histopathological studies were performed. Four of 160 rats died before study completion. No clinical signs of toxicity were observed throughout the study. Food and water consumption, bodyweight, blood biochemical and haematological parameters, organ weight ratios and histopathological findings were similar in control and treated groups. The histological lesions found in treated animals are commonly present in this specie and strain according to literature and our historical data. In conclusion, long-term (12 months) oral treatment of rats with D-004 (800-2000 mg/kg/day) did not show evidences of D-004-related toxicity under our conditions. The highest dose tested (2000 mg/kg) was a no-observed adverse effect level in this study.

Long-term effects of D-003, a mixture of high molecular weight acids from sugarcane wax, on bones of ovariectomized rats: a one year study

This study was done to determine the long-term effect of D-003 on bones of ovariectomized (ovx) rats distrib-uted in 4 groups: a false-operated and three groups of ovx rats: one treated with the vehicle and two with D-003 (5 and 250 mg/kg). D-003 significantly prevented, in a dose-dependent fashion, the trabecular bone volume (TBV), trabecular number (TbN) and trabecular thickness (TbTh) reduction induced in ovx rats and the increase of trabecular separation (TbSp) osteoclast number (OcN) and osteoclast surface (OcS/BS) increased in the positive controls versus the sham group. It is concluded that D-003 administered for 12 months prevented bone loss and decreased bone resorption in ovx rats, without evidences of impaired bone quality.

Effects of D-003, a mixture of very long chain fatty acids purified from sugar cane wax, at 5 and 10 mg/day on platelet aggregation in healthy volunteers

D-003 is a mixture of high molecular weight aliphatic primary acids purified from sugar cane wax with antiplatelet and cholesterol-lowering effects. Previous studies showed that D-003 (10-20 mg/day) administered for a short time inhibits platelet aggregation, 14 days being the longest duration investigated. This study was conducted to investigate the effects of D-003 (5 and 10 mg/day) for 30 days on platelet aggregation in normocholesterolemic subjects. This report shows the effects of D-003 on platelet aggregation to arachidonic acid (AA) (1.5 mM), collagen (2 microg/ml) and adenosine 5'-diphosphate ADP (2 microM) assessed at baseline and at treatment completion. Fifty-four subjects were randomized to placebo or D-003 (5 or 10 mg/day) for 30 days. Platelet aggregation to AA, collagen and ADP were assessed. D-003 at the lowest dose (5 mg/day) significantly but modestly inhibited (p < 0.01) platelet aggregation to AA (5.0%) and (p < 0.01) to collagen (7.5%). D-003 at 10 mg/day inhibited (p < 0.001) platelet aggregation to AA and collagen (p < 0.01) by 20.3% and 14.7%, respectively. ADP-induced aggregation, however, was unchanged. D-003 at 10 mg/day, but not at 5 mg/day, lowered (p < 0.01) plasma fibrinogen. D-003 (5 and 10 mg/day) reduced low-density lipoprotein cholesterol (LDL-C) by 17.7% and 26.4%, respectively, and total cholesterol (TC) by 14.5% and 18.5%, while at 10 mg/day, but not at 5 mg/day, it increased high-density lipoprotein cholesterol (HDL-C) by 9.6%. Triglycerides, however, were unchanged with D-003. No disturbances in safety indicators were induced with D-003. One subject (D-003 5 mg/day) discontinued the study and four patients (three taking D-003 and one taking placebo) reported adverse effects (AE) (headache in two patients taking D-003 and one patient taking placebo, and polyphagia in one patient taking D-003). In conclusion, D-003 (5-10 mg/day) for 30 days inhibited platelet aggregation to AA and collagen but not to ADP Therefore, the antiplatelet effect was present with the longer treatment, even at a dose of 5 mg/day. The cholesterol-lowering effects of D-003 were consistent with those expected for such a short treatment. In addition, D-003 at 10 mg/day significantly lowered plasma fibrinogen. The treatment was well tolerated.

Comparison of the effects of D-003, a mixture of high-molecular-weight aliphatic acids from sugarcane wax, and pravastatin on bones and osteoclast apoptosis of ovariectomized rats

The mevalonate pathway is relevant in bone cells. Statins inhibit 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, the key enzyme of this route, stimulating osteoblast differentiation and activity. Pravastatin increases bone formation markers in postmenopausal women and bone density in diabetics. D-003 is a mixture of high-molecular-weight acids purified from sugarcane wax which inhibits cholesterol biosynthesis through HMG-CoA reductase regulation, preventing bone loss in osteoporosis induced with ovariectomy and prednisolone in rats. We investigated the effects of D-003 (50 mg/kg) and pravastatin (20 mg/kg) orally administered for 12 weeks to ovariectomized rats. Female rats were randomized in four groups (10 rats/group): two control groups treated with the vehicle, one false-operated (sham) and another ovariectomized (positive control), while two other groups received D-003 or pravastatin. Bone resorption and formation was studied through histomorphometry and apoptosis through immunohistochemistry. D-003 and pravastatin significantly (p < 0.001) prevented the changes of trabecular bone versus ovariectomized rats and (p < 0.001) the increase of the surface and number of osteoclasts versus ovariectomized controls. D-003 and pravastatin, however, did not modify osteoblast surfaces, a bone formation marker D-003 and pravastatin increased osteoclast apoptosis and reduced (p < 0.05) osteoblast and osteocyte apoptosis versus ovariectomized controls; D-003 was more effective (p < 0.05) than pravastatin. In conclusion, D-003 (50 mg/kg) orally administered for 12 weeks prevented bone loss and bone resorption in ovariectomized rats, increasing osteoclast apoptosis. The preventive effects of D-003 on bone loss and resorption in ovariectomized rats are comparable to those of pravastatin. Both drugs inhibited osteoblast apoptosis but failed to change osteoblast surface. The effects of D-003 on bone cell apoptosis were greater than those of pravastatin. Therefore, D-003 could be used to prevent or treat bone loss in postmenopausal women, but further animal studies and clinical trials are required to confirm the clinical relevance of this potential effect.

Effects of Addition of Policosanol to??Omega-3 Fatty Acid Therapy on the??Lipid Profile of Patients with Type??II Hypercholesterolaemia

BACKGROUND

Policosanol is a mixture of higher aliphatic primary alcohols purified from sugar-cane wax. The mixture has cholesterol-lowering efficacy, its specific effects being to reduce serum total (TC) and low-density lipoprotein cholesterol (LDL-C), and to increase high-density lipoprotein cholesterol (HDL-C). The effects of policosanol on triglycerides (TG) are modest and inconsistent. Omega-3 fatty acids (FA) from fish oil protect against coronary disease, mainly through antiarrhythmic and antiplatelet effects. Omega-3 FA also have lipid-modifying effects, mostly relating to TG reduction. Thus, potential benefits could be expected from combined therapy with omega-3 FA and policosanol.

OBJECTIVE

To investigate whether combined therapy with omega-3 FA + policosanol offers benefits compared with omega-3 FA + placebo with respect to the lipid profile of patients with type II hypercholesterolaemia.

METHODS

This randomised, double-blind study was conducted in 90 patients with type II hypercholesterolaemia. After 5 weeks on a cholesterol-lowering diet, patients were randomised to omega-3 FA + placebo, omega-3 FA + policosanol 5 mg/day or omega-3 FA + policosanol 10 mg/day for 8 weeks. Omega-3 FA was supplied as 1g capsules (two per day); placebo and policosanol were provided in tablet form. Physical signs and laboratory markers were assessed at baseline and after 4 and 8 weeks on therapy. Drug compliance and adverse experiences (AEs) were assessed at weeks 4 and 8. The primary efficacy variable was LDL-C reduction; other lipid profile markers were secondary variables.

RESULTS

After 8 weeks, omega-3 FA + policosanol 5 and 10 mg/day, but not omega-3 FA + placebo, significantly reduced LDL-C by 21.1% and 24.4%, respectively (both p < 0.0001). Omega-3 FA + policosanol 5 mg/day also significantly lowered TC (12.7%; p < 0.01) and TG (13.6%; p < 0.05), and significantly increased HDL-C (+14.4%; p < 0.001). Omega-3 FA + policosanol 10 mg/day significantly decreased TC (15.3%; p < 0.001) and TG (14.7%; p < 0.01), and significantly increased HDL-C (+15.5%; p < 0.0001). Omega-3 FA + placebo significantly reduced TG (14.2%; p < 0.05) but had no significant effect on other lipid profile variables. The proportion of randomised patients in the omega-3 FA + policosanol 5 or 10 mg/day groups that achieved LDL-C targets or reductions 15% was significantly greater than in the omega-3 FA + placebo group (p < 0.001). Combined therapy with omega-3 FA + policosanol 5 or 10 mg/day resulted in significantly greater changes in LDL-C, TC and HDL-C than treatment with omega-3 FA + placebo, but did not modify the TG response compared with the omega-3 FA + placebo group. Four patients (two in the omega-3 FA + placebo group and two in the omega-3 FA + policosanol 10 mg/day group) withdrew from the study; none of these withdrawals was due to AEs. Two patients reported mild AEs, namely nausea/headache (one in the omega-3 FA + placebo group) and heartburn (one in the omega-3 FA + policosanol 5 mg/day group).

CONCLUSIONS

Policosanol 5 or 10 mg/day administered concomitantly with omega-3 FA 1 g/day improved LDL-C, TC and HDL-C, maintained the reduction in TG attributable to omega-3 FA monotherapy, and was well tolerated. Treatment with omega-3 FA + policosanol could be useful for regulating lipid profile in patients with type II hypercholesterolaemia, but further studies involving larger sample sizes are needed before definitive conclusions can be drawn.

Oral acute and subchronic toxicity of D-004, a lipid extract from Roystonea regia fruits, in rats

D-004 is a lipid extract obtained from Cuban royal palm (Rosytonea regia) fruits, consisting of a mixture of fatty acids and esters. D-004 has shown protective effects on prostate hyperplasia induced by testosterone in rodents. We report the results of two studies investigating the acute and subchronic oral toxicity of D004 in rats. Oral acute toxicity of D-004 (2,000 mg/kg) was investigated in Sprague Dawley rats according to the acute toxic class method, and the results showed that D-004 oral acute toxicity was practically absent, being defined as unclassified. In the subchronic study, rats were orally treated with D-004 at 500, 1,000 and 2,000 mg/kg for 90 days. No evidence of treatment-related toxicity was detected. Thus, analysis of body weight gain, clinical observations, blood biochemistry, hematology, organ weight ratios and histopathological data did not show significant differences between control and treated groups. We conclude that D-004 orally administered to rats was safe and that no drug-related toxicity was detected even at the highest dose investigated in both acute and subchronic (2,000 mg/kg) studies. Thus, this dose can be considered as a nonobservable-effect dose in rats.

The effect of D-003 (10 mg/day) on biochemical parameters of bone remodelling in postmenopausal women: a randomized, double-blind study

Biphosphonates, which are antiresorptive agents used to treat osteoporosis, inhibit the mevalonate pathway, preventing protein prenylation and inhibiting osteoclast activity. Statins decrease cholesterol biosynthesis by blocking the mevalonate pathway and have been reported to have beneficial effects on bone. D-003 is a mixture of high molecular weight acids purified from sugarcane wax that inhibits cholesterol biosynthesis before mevalonate production. D-003 prevents bone loss and resorption in rats with osteoporosis induced with ovariectomy or corticoids. Biochemical markers of bone turnover are used to monitor the short-term efficacy of antiosteoporotic therapy. This randomized, double-blind, placebo-controlled study was undertaken to investigate the short-term effects of D-003 (10 mg/day) on biochemical markers of bone turnover in postmenopausal women with low bone mineral density (BMD). After 4 weeks on a low-fat diet, 34 women were randomized to D-003 (10 mg/day) or placebo for 6 months. Pre- and post-treatment samples were analyzed for urinary excretion of deoxypyridinoline (DPD)/creatinine (Cr), a marker of bone resorption, and serum bone specific alkaline phosphatase (BSAP), a marker of bone formation. The effects on lipid profile and safety indicators, as well as adverse events (AE), were investigated. D-003 (10 mg/day) lowered urinary excretion of tDPD/Cr versus baseline (20.6%) (p < 0.001) and placebo (33.7%) (p < 0.01), but did not modify serum BSAP. D-003 decreased low-density lipoprotein-cholesterol (LDL-C) (32.8%), total cholesterol (TC) (16.4%) and the TC/high-density lipoprotein-cholesterol (HDL-C) ratio (34.7%), increased HDL-C (30.3%) (p < 0.001) and did not modify triglycerides. The effects on these variables were significant as early as 3 months after treatment initiation. D-003 was well tolerated. Three patients (one in the placebo group and two in the D-003 group) withdrew from the study. Two of these withdrawals were due to AE: abdominal pain (placebo) and heartburn (D-003). Five patients (four in the placebo group [22.2%] and one in the D-003 group [6.3%]) reported mild AE. In conclusion, D-003 (10 mg/day) reduced urinary excretion of tDPD/Cr, a bone resorption marker and did not change serum BSAP, a bone formation marker, while it lowered cholesterol in study patients. These preliminary results suggest that D-003 could be useful in treating postmenopausal women with low BMD. However, the potential value of D-003 in treating or preventing osteoporosis deserves further clinical investigation.

Therapeutic effect of D-004, a lipid extract from Roystonea regia fruits, on prostate hyperplasia induced in rats

Benign prostatic hyperplasia (BPH) is a nonmalignant growth of prostate leading to difficulty in urinating. Drug therapy, phytotherapy included, is frequently used to treat BPH. D-004 is a lipid extract from Roystonea regia fruits, and previous studies have shown that oral treatment with D-004 for 14 days prevented prostate hyperplasia (PH) induced by testosterone in rats. No information is available, however; about the effects of D-004 in reverting already established PH. This study investigated whether D-004 could improve PH after oral dosing with testosterone in rats. Rats were distributed in five groups (10 rats/group). One group was injected with soy oil (negative control) and four groups were injected with testosterone: one was orally treated with the vehicle (positive control), two with D-004 (200 and 400 mg/kg) and the other with Saw palmetto (400 mg/kg). At study completion, the rats were sacrificed and the prostates were removed and weighed. D-004 (200 and 400 mg/kg) significantly and dose-dependently decreased prostate enlargement by 85% and 98%, respectively, versus the positive control. Likewise, Saw palmetto (400 mg/kg) significantly reduced prostate weight by 73% versus the positive control. D-004 (400 mg/kg) was more effective (p < 0.05) than Saw palmetto (400 mg/kg) in lowering prostate enlargement. D-004 and Saw palmetto also decreased the prostate weight to body weight ratio, but did not affect body weight. In conclusion, D-004 (200 and 400 mg/kg) orally administered was effective for reducing PH after testosterone dosing. D-004 (400 mg/kg) was more effective than Saw palmetto (400 mg/kg). Further studies, however, are needed to corroborate the present results.

Concomitant use of policosanol and beta-blockers in older patients

Policosanol is a cholesterol-lowering drug with concomitant antiplatelet effects. It is safe and well tolerated, even in populations with high consumption of concomitant drugs. These data suggest that adverse events (AE) due to drug-to-drug interactions (DDI) with policosanol are not relevant. Experimental data indicate that potential DDI between policosanol and drugs metabolized through the cytochrome P450 hepatic system are not expected, but pharmacodynamic DDI cannot be excluded. Several clinical studies have shown that policosanol decreased arterial pressure compared with placebo, and a pharmacological interaction with beta-blockers was experimentally proven. Therefore, clinical DDI between policosanol and beta-blockers can be expected. This study investigated whether policosanol reinforces the antihypertensive effects of beta-blockers and/or whether this combination impairs some safety indicators or induces specific AE in older patients. After 5 weeks on a diet-only baseline period, 205 older hypercholesterolemic patients taking beta-blockers were randomized to policosanol 5 mg/day or placebo for 3 years. After 1 year on therapy, policosanol significantly reduced (p < 0.00001 versus placebo) low-density lipoprotein-cholesterol (LDL-C) (20.9%), total cholesterol (TC) (19.3%) and triglycerides (TG) (25.7%), whereas it increased (p < 0.01 and p < 0.001 versus placebo) high-density lipoprotein-cholesterol (HDL-C) levels (4.1%). Treatment effects did not to wear off during the 3-year follow-up. At study completion, policosanol lowered (p < 0.00001 versus placebo) LDL-C (34.3%), TC (23.2%) and TG (21.2%) and raised (p < 0.00001 versus placebo) HDL-C (12.3%). Thirty-one patients (15.1%) discontinued the study, 22 in the placebo group (20.6%) and nine in the policosanol group (9.2%). Of these, 20 patients (16 in the placebo group and four in the policosanol group) withdrew from the study due to AE. The frequency of serious adverse events (SAE), mostly vascular, in policosanol patients (3/98, 3.1%) was lower than in the placebo group (15/107, 14.0%). No impairment of safety indicators was observed. Nevertheless, reductions in systolic and diastolic blood pressure were observed in policosanol patients compared with those in the placebo group. The frequency of policosanol patients reporting mild or moderate AE (18/98, 18.4%) was also lower than in the placebo group (30/107, 28.0%). In conclusion, policosanol was well tolerated in elderly patients taking beta-block- ers and did not increase AE. Additional reduction of blood pressure and a lower frequency of SAE were observed in policosanol patients compared with those taking placebo. The cholesterol-lowering efficacy of policosanol was that expected. These results provide support that policosanol therapy added to hypercholesterolemic elderly individuals taking beta-blockers could provide additional benefits in lowering blood pressure; SAE were not more frequent in the policosanol group than in the placebo group and there was no increase in AE.

Effects of d-003, a new substance purified from sugar cane wax, on platelet aggregation and plasma levels of arachidonic acid metabolites in healthy volunteers

D-003 is a mixture of very high molecular weight aliphatic acids purified from sugar cane wax showing cholesterol-lowering and antiplatelet effects proven in experimental and clinical studies. Experimental evidence indicates that inhibition of platelet aggregation induced by D-003 is associated with a reduction of thromboxane B2 (TxB2) and an increase of prostacyclin (Pgl2) serum levels. This double-blinded, randomized, placebo-controlled study was undertaken to investigate whether D-003 (20 mg/day) modifies serum levels of TxB2 and Pgl2 and inhibits platelet aggregation in human healthy volunteers. Thirty-one subjects were randomized to placebo or D-003 at 20 mg/day for 14 days. Serum levels of TxB2 and Pgl2 and platelet aggregation to arachidonic acid (AA) (1.75 mM) and collagen (1 microg/ml) were assessed. D-003 (20 mg/day) significantly reduced (p < 0.001) TxB2by 36.4% and increased Pgl2 serum levels by 31% compared with baseline, and these changes were different from placebo. As expected, D-003 significantly inhibited (p < 0.001) platelet aggregation to AA (81.9-65.6%) and to collagen (75.3-62.3%). No subject withdrew from the study. No drug-related disturbances were observed. We conclude that D-003 at 20 mg/day for 14 days significantly inhibited platelet aggregation to AA and collagen and reduced TxB2 and increased Pgl2 serum levels. These results are consistent with those observed in experimental models, indicating that the antiplatelet effect of D-003 is associated with the observed changes on the levels of AA metabolites. Further studies, however, should explore the mechanism involved in this action in greater depth.

The effect of hyperbaric oxygen treatment on oxidative stress in experimental acute necrotizing pancreatitis

Various protocols may be used for acute pancreatitis treatment. Recently, the benefit of hyperbaric oxygen (HBO) has been demonstrated. To clarify the mechanism of HBO on the process of the acute pancreatitis, we determined the levels of antioxidant enzymes in an acute pancreatitis model. Forty-five Sprague-Dawley rats were randomly divided into three groups: Group I: sham group (n=15), Group II: pancreatitis group (n=15), Group III: pancreatitis group undergoing HBO therapy (n=15). HBO was applied postoperatively for 5 days, two sessions per day at 2.5 fold absolute atmospheric pressure (ATA) for 90 min. Superoxide dismutase (Cu/Zn-SOD), malondialdehyde (MDA), and glutathione peroxidase (GSH Px) activity were measured in pancreatic tissue and erythrocyte lysate. MDA and GSH Px were also determined in plasma. In addition, amylase levels were measured in the serum. While serum amylase levels and MDA values in erythrocyte, plasma and pancreatic tissue were decreased, the levels of GSH Px and SOD were found to be significantly increased in the Group III as compared to those of the Group II. The findings of our study suggest that HBO has beneficial effects on the course of acute pancreatitis and this effect may occur through the antioxidant systems.

Comparison of the efficacy, safety and tolerability of original policosanol versus other mixtures of higher aliphatic primary alcohols in patients with type II hypercholesterolemia

This randomized, double-blind study was undertaken to compare the efficacy and tolerability of policosanol and Octa-60 in patients with type II hypercholesterolemia. After 4 weeks on a diet, 110 patients were randomized to policosanol or Octa-60 5 mg tablets once a day for 5 weeks. The dose was then doubled to 10 mg/day for the next 5 weeks. Policosanol 5 and 10 mg/day significantly lowered low-density lipoprotein-cholesterol (LDL-C) (p<0.0001 and p<0.00001), the main efficacy variable, by 18.6% and 30.2%, while Octa-60 significantly reduced (p<0.05) LDL-C by 10.0% at study completion only. The frequency of policosanol patients reaching reductions of LDL-C > or = 15% after 5 mg/day (37/55; 67.3%) and 10 mg/day (47/55; 88.7%) was greater (p<0.01 and p<0.01) than in the Octa-60 group, which was 5/55 (9.1%) and 20/55 (36.4%). Likewise, the frequency of patients reaching LDL-C values of <3.4 mmol/l at study completion was greater (p<0.001) in the policosanol group (39/55, 70.9%) than in the Octa-60 group (6/55, 10.9%). Policosanol 5 and 10 mg/day significantly lowered (p<0.00001) total cholesterol (TC) (13.4% and 20.4%), LDL-C/high-density lipoprotein-cholesterol (HDL-C) (22.1% and 37.0%) and TC/HDL-C (17.2% and 28.2%). Octa-60 at 10 mg/day lowered (p<0.05) TC (8.7%), LDL-C/HDL-C (12.6%) and TC/HDL-C (9.4%). HDL-C was increased (p<0.001 and 0.0001) by policosanol 5 and 10 mg/day (5.6% and 12.5%) but was unchanged by Octa-60. In both groups, triglycerides remained unchanged. Both treatments were safe and well tolerated. Octa-60, but not policosanol, significantly increased glucose and alanine aminotransferase, but individual values were within the normal range. Four patients (two from each group) discontinued the trial, but only one (in the Octa-60 group) did so because of an adverse event (AE) (skin rash). Overall, three patients (all from the Octa-60 group) reported AEs. In conclusion, original policosanol at 5 and 10 mg/day, but not Octa 60, was effective in patients with type II hypercholesterolemia. Thus, policosanol reached the efficacy criterion for LDL-C reduction in both steps, while Octa-60 failed to reach this goal. In addition, policosanol was better tolerated than Octa-60.

Effect of D-003, a mixture of high molecular weight primary acids from sugar cane wax, on paracetamol-induced liver damage in rats

D-003 is a mixture of very high molecular weight aliphatic primary acids purified from sugar cane (Saccharum officinarum, L) wax, in which the most abundant component is octacosanoic acid. Experimental studies have shown that D-003 not only shows cholesterol-lowering and antiplatelet effects, but also offers strong protection against plasma lipoprotein oxidation. Previous studies demonstrated that D-003 protected against the histological changes characteristic of Cl4C-induced hepatic injury in rats. The aim of the present study was to investigate the effects of D-003 in acute hepatotoxicity induced by paracetamol in rats. Male Sprague Dawley rats were randomly distributed in two experimental series of three experimental groups as follows: group 1--positive control rats (paracetamol-treated); groups 2 and 3--rats with liver damage induced by paracetamol and treated with D-003 at 5 and 25 mg/kg, respectively, and which also received paracetamol to induce liver injury. In experimental series 1, animals received paracetamol orally (600 mg/kg). In series 2, paracetamol was administered through the intraperitoneal route (200 mg/kg). Eighteen hours after paracetamol dosing, rats were anesthetized with ether and livers were removed for histopathological studies. In the two experimental series, D-003 at 5 and 25 mg/kg significantly (p < 0.01) decreased the percentage of turgent cells and hepatocytes with necrosis and increased the percentage of normal hepatocytes with respect to positive controls in a dose-dependent manner. Necrotic areas and inflammatory infiltrates were observed in the liver of nine out of ten (90%) positive controls. In turn, D-003 dramatically reduced both necrotic areas and inflammatory infiltrate and was present in only one out of ten (10%) animals treated in the two experimental series. No histological alterations in liver sections of negative controls were found. D-003 protected against the histological changes characteristic of paracetamol-induced hepatic injury in rats, in which the process of lipid peroxidation plays a major role. The relationship between this protective action of D-003 in this experimental model and its antioxidant effects needs to be further investigated before definitive conclusions are drawn.

Effects of D-003, a mixture of long-chain aliphatic primary acids, fluvastatin and the combined therapy of D-003 plus fluvastatin on the lipid profile of normocholesterolemic rabbits

D-003 is a mixture of long-chain aliphatic primary acids isolated from sugar cane wax with cholesterol-lowering effects proven in animals and healthy human volunteers. D-003 reduced serum total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) in rabbits, while it increased high-density lipoprotein cholesterol (HDL-C) and did not affect triglycerides. D-003 inhibits cholesterol synthesis by regulating, instead of directly inhibiting, hydroxamethylglutaryl-CoA (HMGCoA) reductase activity. Although the ways in which D-003 and statins inhibit cholesterol biosynthesis are not identical, the strong competitive inhibition of cholesterol biosynthesis induced by statins suggests that an enhanced decrease of LDL-C and TC caused by the combined therapy D-003 plus statins is not expected. Nevertheless, taking into account the differential effects of D-003 and statins in HDL-C and triglycerides in rabbits, potential benefits of such combined therapy on other lipid variables cannot been discarded. Fluvastatin is a statin that inhibits competitively HMGCoA reductase, like other members of this class. This study was undertaken to compare the cholesterol-lowering effects of D-003, fluvastatin and the combined therapy of D-003 plus fluvastatin in normocholesterolemic rabbits. Animals were randomly distributed into four groups of eight. One control group received the vehicle, two groups were treated with D-003 or fluvastatin at 5 mg/kg/day each, and the fourth group received the combined therapy of both drugs at 5 mg/kg/day each. Treatments were orally administered for 30 days. Body weight, food consumption and overall animal behavior were recorded to detect any warning sign resulting from combined therapy. After treatment, it was found that both D-003 and fluvastatin had significantly lowered LDL-C - D-003 by 81.5% (p < 0.01) and fluvastatin by 61.4% (p < 0.05). Combined therapy reduced LDL-C values (75.9%). Final values and percent changes reached in all groups were different from the control (p < 0.01). The reductions of TC were consistent with LDL-C decreases, so that D-003, fluvastatin and combined therapy significantly lowered TC by 48.4% (p < 0.01), 39.7% (p < 0.05) and 45.3%, respectively, values being different from those of the control (p < 0.01). The responses of LDL-C and TC to combined therapy were statistically similar, but less pronounced than those reached by D-003 alone. D-003 and combined therapy, but not fluvastatin alone, increased HDL-C (+21.5% and + 19.0%, respectively), these changes being significant versus the control (p < 0.05). In turn, fluvastatin and combined therapy, but not D-003 alone, lowered triglycerides (13.6% and 13.0%, respectively, p < 0.05 versus control). The effects of combined therapy on HDL-C were similar to those of D-003 alone, and the effects of combined therapy on triglycerides were similar to those of fluvastatin alone. The only advantage of combined therapy appears to be that it shows better effects on HDL-C than those of fluvastatin alone and better effects on triglycerides than D-003 alone. No significant changes in lipid profile were observed in the control group. All groups showed similar food consumption and body weight gain, health status being unaffected by the treatments. It is concluded that D-003 and fluvastatin at 5 mg/kg/day administered orally for 30 days to normocholesterolemic rabbits lowered LDL-C and TC, D-003 being more effective in increasing HDL-C and fluvastatin in lowering triglycerides. Combined therapy did not improve the response of LDL-C and TC with respect to monotherapies, but induced better responses of HDL-C and triglycerides than fluvastatin alone had on HDL-C or D-003 alone had on triglycerides.

Electrochemical platinum coatings for improving performance of implantable microelectrode arrays

The formation and properties of electrochemical platinum films grown on platinum contacts contained in implantable flexible microelectrodes were investigated. The resulting platinum deposits were obtained by applying cyclic voltammetry to baths containing concentrations around 70 mM of chloroplatinic acid. A pre-activation step was necessary before the platinum-electroplating step in order to achieve good adhesive properties. The benefits of this process were ascribed to higher corrosion resistance, lower impedance and improved adhesion to the sputtered platinum. These improvements can make the application of this electrochemical technique highly useful for increasing the lifetime of implantable microelectrode arrays, such as cuff structures (IEEE Trans. Biomed. Eng. 40 (1993) 640). These medical devices, obtained by semiconductor technology could be used for selective stimulation of nerve fascicles, although, poor long-term performance has been achieved with them. The dissolution rate for platinum thin-film microelectrodes under fixed corrosion test conditions was 38.8 ng/C. Lower rates were observed for electroplated microelectrodes, obtaining a dissolution rate of 7.8 ng/C under analogous experimental ageing conditions. The corrosion behaviour of the electroplated platinum during stimulation experimental conditions was estimated by electrochemical impedance spectroscopy.

Transfusion-transmitted virus prevalence in subjects at high risk of sexually transmitted infection in Turkey

OBJECTIVE

To assess the possible sexual transmission of virus and to identify the prevalence of TTV viremia in Turkey and its association with other hepatotropic viruses.

METHODS

Serum samples were collected from 81 subjects (74 prostitutes and seven homosexual men) at high risk of sexually transmitted infection and from 81 healthy controls (74 females and seven males). Sera of patients and controls were tested for TTV, hepatitis A virus, hepatitis B virus, hepatitis C virus, and human immunodeficiency virus. Also, serum alanine and aspartate aminotransferases were measured.

RESULTS

The prevalence rates of TTV viremia in the risk group and control group were 86.4% and 82.7%, respectively. There was a statistical difference in mean age between TTV-infected and uninfected subjects (38.6 +/- 9.9 versus 32.2 +/- 6.1 years, respectively, P < 0.001). Prevalence rates of TTV infection in subjects with positive anti-HAV and positive anti-HBc were high when compared with subjects who were negative for these.

CONCLUSION

We suggest that TTV infection has a diverse route of transmission, and its prevalence increases with age; also, the prevalence rate of TTV is high in certain risk groups. The prevalence rates of TTV in the group at risk for sexual transmission (86.4%) and in the control group (82.7%) were among the highest ever reported in the world. Also, we suggest that TTV generally does not cause clinical disease, in spite of this high prevalence.

Efficacy and tolerability of policosanol in hypercholesterolemic postmenopausal women

This randomized, double-blind, multicenter placebo-controlled study was conducted to investigate the efficacy and tolerability of policosanol, a cholesterol-lowering drug purified from sugar cane wax, in women who had experienced menopause and showed elevated serum total cholesterol and low density lipoprotein (LDL)-cholesterol levels despite a 6-week standard lipid-lowering diet. Thus, 56 eligible patients were randomized to receive placebo or policosanol 5 mg/day for 8 weeks and the dose was doubled to 10 mg/day during the next 8 weeks. Policosanol (5 and 10 mg/day) significantly decreased LDL-cholesterol (17.3% and 26.7%, respectively), total cholesterol (12.9% and 19.5%) as well as the ratios of LDL-cholesterol to high-density lipoprotein (HDL)-cholesterol (17.2% and 26.5%) and total cholesterol to HDL-cholesterol (16.3% and 21.0%) compared with baseline and placebo. HDL-cholesterol levels were significantly raised by 7.4% at study completion. No significant changes occurred in the lipid profile of the placebo group. The drug was safe and well tolerated. No drug-related adverse effects were observed. None of the patients administered policosanol but three of those administered placebo withdrew from the trial because of adverse effects: one due to a serious hypertensive status, one because of an allergic reaction (pruritus plus skin rash) and one due to gastrointestinal disturbances (nauseas plus vomiting). Eleven placebo patients reported 24 adverse effects compared with six policosanol patients who reported seven adverse effects (p < 0.05). In addition, five placebo (17.9%) and 13 policosanol patients (46.4%) (p < 0.05) reported improvements in habitual symptoms and health perception during the study. In conclusion, policosanol was effective and well tolerated in hypercholesterolemic postmenopausal women, showing additional benefits in the health perception of the study patients.

Effects of policosanol 20 versus 40 mg/day in the treatment of patients with type II hypercholesterolemia: a 6-month double-blind study

Policosanol is a well defined mixture of higher aliphatic primary alcohols isolated from sugar cane wax with cholesterol-lowering effects proven for a dose range from 5-20 mg/day in patients with type II hypercholesterolemia and dyslipidemia associated with noninsulin dependent diabetes mellitus. This randomized, double-blind study investigated the cholesterol-lowering efficacy and tolerability of policosanol 20 mg/day compared with 40 mg/day. Changes in low-density lipoprotein (LDL)-cholesterol levels were predefined as the primary efficacy endpoint. Patients with type II hypercholesterolemia were enrolled in the study and instructed to continue a step I cholesterol-lowering diet for 6 weeks and those eligible to be included (89) were randomly allocated to receive under double-blind conditions placebo (n = 30), policosanol 20 mg/day (n = 29) or 40 mg/day (n = 30). After 24 weeks, policosanol at 20 and 40 mg/day significantly (p < 0.00001) lowered LDL-cholesterol by 27.4% and 28.1%, total cholesterol (p < 0.00001) by 15.6% and 17.3%, and the LDL-cholesterol/high-density lipoprotein (HDL)-cholesterol ratio by 37.2% and 36.5%, respectively The ratio of total cholesterol/HDL-cholesterol was lowered by 27.1% and 27.5%, while HDL-cholesterol levels increased (p < 0.001) by 17.6% and 17.0%, respectively. Compared with baseline, policosanol 20 mg/day lowered triglycerides (p < 0.05) by 12.7%, while they were lowered (p < 0.01) by 15.6% at a dose of policosanol 40 mg/day All the above-mentioned significant differences were also different from placebo and no significant changes occurred in any lipid profile parameters in the placebo group. Based on the mean values of LDL-cholesterol levels at study completion, the mean percent reductions from baseline were 27.4% and 28.1% for the 20 and 40 mg/day groups, respectively. Thus, the effects of both policosanol doses on the main efficacy variable were practically identical. Consistent with the data obtained for LDL-cholesterol, both doses were similarly effective in changing all the other lipid profile parameters. No unexpected adverse effects were observed and there were no significant between-group differences regarding safety indicator values or reported adverse effects. In conclusion, although the tolerability profile remains excellent, according to the present results policosanol at a dose of 40 mg/day does not offer significant additional cholesterol-lowering efficacy over the 20 mg/day dose.

Acute and oral subchronic toxicity of D-003 in rats

D-003 is a mixture of higher aliphatic primary acids purified from sugar cane wax (Saccharum officinarum) with cholesterol-lowering and antiplatelet effects experimentally proven. The present work reports the results of two studies investigating the acute and subchronic oral toxicity of D-003 in rats. Oral acute toxicity of D-003 (2000 mg/kg) was investigated according to the Acute Toxic Class (ATC) method (an alternative for the classical LD(50) test), which was performed in Wistar rats. The results obtained in this study defined D-003 oral acute toxicity as unclassified. In the subchronic study, rats of both sexes were orally treated with D-003 at 50, 200 and 1250 mg/kg for 90 days. At this time, animals were sacrificed. No evidence of treatment-related toxicity was detected during the study. Thus, data analysis of body weight gain, food consumption, clinical observations, blood biochemical, haematology, organ weight ratios and histopathological findings did not show significant differences between control and treated groups. It is concluded that D-003 orally administered to rats was safe and that no drug-related toxicity was detected even at the highest doses investigated in both acute (2000 mg/kg) and subchronic (1250 mg/kg) studies.

Evaluation of hepatocyte function after extracorporeal shock wave lithotripsy with hepatobiliary scintigraphy

OBJECTIVE

Extra corporeal shock wave lithotripsy is a promising and effective therapy mode in the nonsurgical therapy of gallstones. This prospective study was conducted to investigate the effects of ESWL on hepatocellular function, using quantitative hepatobiliary scintigraphy, serum aminotransferase, alkaline phosphatase (ALP), amylase (AML), and direct and indirect bilirubin levels.

METHODS

The study consisted of 22 patients with ultrasonographically documented gallstones. Hepatobiliary scintigraphy was applied to all patients before ESWL and biochemical tests were performed. Scintigraphy and biochemical tests were repeated in 16 patients 24 h, in seven patients 72 h, and in six patients 1 wk after ESWL. The hepatic extraction fraction (HEF) was calculated using deconvolution analysis of scintigraphic data.

RESULTS

All patients' pre-ESWL biochemical tests and HEF values were within the normal range. The 24- and 72-h post-ESWL aminotransferase, ALP, and AML levels and HEF values were significantly different from pre-ESWL values (p < 0.05). After 1 wk this difference disappeared. Decreased HEF values were observed in 50% of patients 24 h, in 71.7% of patients 72 h, and in 16.6% of patients 1 wk after ESWL. A direct relationship was also observed between the number of shocks applied and the degree of impairment in HEF values.

CONCLUSION

Transient hepatocellular dysfunction, which usually occurs after ESWL, can be demonstrated and monitored using quantitative hepatobiliary scintigraphy.

Effect of D-002 on the pre-ulcerative phase of carrageenan-induced colonic ulceration in the guinea-pig

D-002 is a natural mixture of higher aliphatic primary alcohols, isolated and purified from beeswax which has anti-inflammatory properties, reduces leukotrienes (LTB4) and thromboxane B2 (TXB2) in exudated carrageenan-induced pleurisy, and has anti-ulcer activity in different experimental models. This study was conducted to determine the effect of D-002 on the pre-ulcerative phase of carrageenan-induced colonic ulceration in guinea-pigs. Animals were randomly distributed among a negative control, a positive control group treated with the vehicle Tween 20 in H2O and two experimental groups receiving D-002 at 25 and 50 mg kg(-1). All treated animals received degraded carrageenan for three days for induction of colonic ulceration. Significant reductions in wet weight, wall thickness, counts of infiltrating polymorphonuclear neutrophils and of macrophages, and histological index were observed in colonic mucosa of D-002-treated animals compared with controls. It is concluded that D-002 has a protective effect on the pre-ulcerative phase of carrageenan-induced colonic ulceration in the guinea-pig.

Effect of policosanol on in vitro and in vivo rat liver microsomal lipid peroxidation

Policosanol, a defined mixture of high molecular weight aliphatic alcohol isolated and purified from sugar cane (Saccharum officinarum, L) wax is a new cholesterol-lowering agent effective in experimental models, healthy volunteers, and patients with type II hypercholesterolemia. Also, policosanol prevents the onset of spontaneously- and experimentally-induced atherosclerotic lesions and cerebral ischemia in Mongolian gerbils. Free radicals are linked to many diseases including atherosclerosis and ischemia/ reoxidation cellular injury. Therefore, in this study the authors evaluate the antioxidant activity of policosanol on rat liver microsomes. The extent of lipid peroxidation was measured by thiobarbituric acid reactive substances (TBARS). When policosanol was administered orally (100 and 250 mg/kg) for up to 4 weeks, a partial prevention of rat in vitro microsomal lipid peroxidation was noted. The formation of TBARS in microsomes isolated from treated rats was significantly decreased by about 50%, when peroxidation was initiated by Fe3+/ADP/ NADPH, Fe2+/ascorbate and CCl4/NADPH-generating system. Also, oral administration of policosanol in rats provides a partial inhibition of lipid peroxidation, but the mechanism supporting such effect remains to be elucidated. This beneficial effect of policosanol on membrane lipid peroxidation may be useful in protecting to some extent against free radical-associated diseases.

[Maternity protection legislation: a tool for promoting mother-child health]

OBJECTIVE

To describe the legislation existing in Spain on the protection of women in paid work after giving birth.

SETTING

Spanish legislation was reviewed and the following aspects examined: time off for childbirth, leave to care for children, hours for breast-feeding, reduction in the working day for the care of small children and time off because of children being ill.

MEASUREMENTS AND MAIN RESULTS

Time off for childbirth is 16 weeks, of which 6 must be after the birth. If both parents work, the father can opt for the last 4 weeks. The amount paid is 100% of the regulated basic wage and will be paid directly by the relevant managing body. Both workers under the general regimen and those under special regimens can receive this benefit. Workers in normal employment can have unpaid leave for a period of up to three years. Other measures are the daily period of one hour for breast-feeding a child under 9 months, the reduction in the working day by between a third and a maximum of half its length to care for children under 6 and the possibility of being away from work for two days because of a child's serious illness.

CONCLUSIONS

The existence of specific legislation protecting maternity is an important, though insufficient, step towards guaranteeing equal opportunities for men and women in the labour market. Specially noteworthy is the reconciliation of paid work and family responsibilities.

Effect of policosanol on the hepatic cholesterol biosynthesis of normocholesterolemic rats

We have suggested previously, measuring 14C-acetate incorporation into free cholesterol, that oral administration of policosanol inhibits hepatic cholesterol biosynthesis in rats. Nevertheless, since acetate has limitations to study cholesterol synthesis in vivo, we now investigate rates of incorporation of labeled water into hepatic sterol after policosanol treatment. Absolute rates of incorporation of 3H-water in sterols were depressed by policosanol by about 20%, giving a more accurate degree of cholesterol biosynthesis inhibition in this species. Since policosanol did not inhibit labeled mevalonate incorporation into cholesterol in rat liver, we also studied the effect of policosanol on hydroxy-methylglutaryl-coenzyme A (HMG-CoA) reductase. Reductase activity assayed in microsomes treated with policosanol remained unchanged, suggesting that cholesterol synthesis is not inhibited by a direct action of policosanol on this enzyme.

Effects of Policosanol on platelet aggregation in rats

Policosanol is the trivial name of a mixture of high molecular weight alcohols isolated from sugar cane, wherein octacosanol is the main component. The effects of Policosanol treatment on rat platelet aggregation were studied. Depending on the dose, Policosanol (5-20 mg/kg, perorally) inhibited the decrease in circulating platelet counts and collagen-induced malondialdehyde concentration in plasma. In rat clotted whole blood thromboxane B2 formation was inhibited by Policosanol (25 mg/kg). Policosanol (50-200 mg/kg, single doses) inhibited ADP-induced platelet aggregation in platelet-rich plasma, while lower doses (25 mg/kg) did not change responses to ADP significantly. However, rats treated with this dose (25 mg/kg) for 4 weeks showed a significant inhibition of platelet aggregation in PRP when a submaximal ADP concentrations was administered.

Effects of a high molecular weight toxin from Physalia physalis on glutamate responses

The effects of a high molecular weight toxin from Physalia physalis (P3) were investigated on glutamate evoked potentials in snail (Zachrysia guanesis) neurons and in crayfish (Cambarus clarkii) neuromuscular junction. The glutamate evoked potentials of snail neurons were reversibly blocked by P3 in a dose-dependent manner (2-200 microM). A reversible blocking action was also found for P3 on excitatory junctional potentials and on glutamate potentials of crayfish at a concentration range of 6 nM-60 microM. Experiments carried out with independent stimulation of the excitatory and inhibitory nerves showed that the effect of P3 (60 nM-10 microM) was exerted predominantly on excitatory junctional potentials. However, at higher doses (greater than 10 microM) a slight reduction of the inhibitory potentials was also observed. These results suggest that P3 reversibly blocks glutamate receptors. Thus, it could be a promising tool for further studies on glutamatergic transmission.