Antifungal activity of cinnamic acid derivatives involves inhibition of benzoate 4-hydroxylase (CYP53).

AIMS: CYP53A15, from the sorghum pathogen Cochliobolus lunatus, is involved in detoxification of benzoate, a key intermediate in aromatic compound metabolism in fungi. Because this enzyme is unique to fungi, it is a promising drug target in fungal pathogens of other eukaryotes. METHODS AND RESULTS: In our work, we showed high antifungal activity of seven cinnamic acid derivatives against C. lunatus and two other fungi, Aspergillus niger and Pleurotus ostreatus. To elucidate the mechanism of action of cinnamic acid derivatives with the most potent antifungal properties, we studied the interactions between these compounds and the active site of C. lunatus cytochrome P450, CYP53A15. CONCLUSION: We demonstrated that cinnamic acid and at least four of the 42 tested derivatives inhibit CYP53A15 enzymatic activity. SIGNIFICANCE AND IMPACT OF THE STUDY: By identifying selected derivatives of cinnamic acid as possible antifungal drugs, and CYP53 family enzymes as their targets, we revealed a potential inhibitor-target system for antifungal drug development.

Improved outcome of patients with colorectal cancer: the Ljubljana University Medical Centre experience.

BACKGROUND/AIMS: Analysis of outcome in patients undergoing resection for colorectal carcinoma. METHODS: Between 1/1/1991 and 31/12/2000, 1,478 patients with a colon and rectal carcinoma underwent a potentially curative resection. The results were analyzed for two groups of patients given different treatment regimens during two consecutive 5-year periods. The 5-year survival rate was estimated by the Kaplan-Meier method. RESULTS: Over a period of 10 years, 1,478 patients were treated by resection. The 5-year survival rate for R0 resected patients with stage I and stage III colon cancer in the period 1996-2000 was significantly higher than for patients operated on between 1991 and 1995 (stage I: 86 vs. 70%; stage III: 58 vs. 40%). Similarly, the 5-year survival rate for R0 resected patients with stage III rectal cancer between 1996 and 2000 was significantly better than that for patients operated on during the early period (58 vs. 31%). CONCLUSIONS: Patients who underwent R0 resection for colorectal cancer during the period 1995-2000 showed a significantly improved 5-year survival rate compared to those operated on between 1991 and 1995. Improved survival in these patients is to a great extent attributable to improvements in clinical practice combining surgery and adjuvant therapy.

S100B protein in benzodiazepine overdose.

BACKGROUND: Severe benzodiazepine overdose can result in coma and respiratory depression that might cause brain hypoxia, necrosis and delayed post-anoxic leucoencephalopathy with permanent neurological sequelae. The aim of this study was to assess the possible role of S100B, a structural protein of astroglial cells, as a biochemical marker of brain injury in acute benzodiazepine overdose. METHODS: Serum S100B determination was performed in 38 consecutive patients admitted to the emergency department (ED) in Ljubljana with benzodiazepine overdose. The level of consciousness and respiratory insufficiency on the scene were assessed by responsiveness to a verbal stimulus and pulse oximetry. Blood samples were taken immediately after arrival at the ED and S100B concentrations were measured with a commercial immunoluminometric assay. 20 healthy sex- and age-matched volunteers formed a control group. RESULTS: There were significant differences in S100B levels between the control group and the patients with benzodiazepine overdose according to their responsiveness to a verbal stimulus. Post hoc test results showed that S100B levels in patients with benzodiazepine overdose who were unresponsive to a verbal stimulus were significantly higher than those in patients responsive to a verbal stimulus (median 0.31 vs 0.11 microg/l; p = 0.001). Both groups of patients with benzodiazepine overdose had significantly higher S100B levels than the control group (median 0.07 microg/; both p = 0.001). Arterial oxygen saturation of patients with benzodiazepine overdose unresponsive to a verbal stimulus was significantly lower than in patients responsive to a verbal stimulus (median 83% vs 94%; p = 0.001). There was no significant difference in the systolic blood pressure of patients with benzodiazepine overdose responsive or unresponsive to a verbal stimulus. CONCLUSION: Raised levels of S100B protein are associated with depressed levels of consciousness and respiratory insufficiency in patients with benzodiazepine overdose.

Poisoning with 1-propanol and 2-propanol.

1-Propanol and 2-propanol are isomers of an alcohol with three carbons. They are colorless liquids with a sweet odor. 1-Propanol is metabolized by alcohol dehydrogenase to propionic acid and presents with metabolic acidosis and elevated anion gap, whereas 2-propanol is metabolized by alcohol dehydrogenase to acetone and presents with rapidly developing (within 3-4 h after exposure) ketosis and ketonuria but without metabolic acidosis. We report a patient who simultaneously ingested a lethal dose of 1-propanol and 2-propanol as a hand disinfectant in hospital. The patient lost consciousness and stopped breathing within half an hour after ingestion. He was intubated and artificially ventilated. Initial laboratory results showed mixed acidosis with elevated anion gap, but ketonuria appeared only 12 h after admission and 6 h following the regaining of consciousness. Therefore, laboratory results in simultaneous poisoning with two isomers of alcohol are not just a sum of laboratory results obtained in isolated poisoning with each isomer because they influence each other's metabolism: 1-propanol retards the metabolism of 2-propanol to acetone. In conclusion, 1-propanol and 2-propanol poisoning presents early with mixed acidosis and elevated anion gap and only later with ketonuria.

Butanol ingestion in an airport hangar.

1-Butanol is a colourless organic solvent with a rancid sweet odour. 1-Butanol ingestion may result in vomiting, abdominal pain, headache, drowsiness and unconsciousness. We present a 47-year-old male with no previous medical history, who was found comatose and soiled after having vomited while unconscious. On arrival, he had a Glasgow coma scale of 3, tachycardia, hypotension, shallow tachypnoic breathing, hypotonic muscles, absent myotatic reflexes and aromatic odour. The patient was intubated and treated with oxygen, dopamine and volume replacement therapy. Gastric lavage was performed and activated charcoal was given. His initial laboratory test revealed hypokaliemia, renal failure, acidosis with elevated lactate and hypercapnic respiratory insufficiency. Twelve hours after admission, the patient started to respond to a painful stimulus and 4 h later he was conscious. He was extubated 23 h after admission. All pathological laboratory results gradually returned within normal limits. The subsequent toxicological examination of gastric content and urine sample by gas chromatography revealed 1-butanol. On awakening, he confirmed ingestion of a solvent stored in an airport hangar. In conclusion, we describe a patient who ingested - a posteriori with suicidal intention - an unknown dose of 1-butanol. Symptoms were headache, vomiting, abdominal pain, coma, muscular hypotonus, hypotension, respiratory insufficiency and mixed acidosis. The patient totally recovered after supportive therapy over 30 h. In future cases, intravenous administration of ethanol or even hemodialysis can be considered analogous to the treatment of methanol and ethylene glycol poisoning.

Modulation of visceral function by selective stimulation of the left vagus nerve in dogs.

The superficial regions of the left vagus nerves of a dog were selectively stimulated with 39-electrode spiral cuffs having 13 circumferential groups of three electrodes (GTE) to modulate the function of the innervated internal organs and glands. Under general anaesthesia, the cuffs were chronically implanted around the nerve in the neck in two adult Beagle dogs and remained viable for 16 months. The regions were stimulated with biphasic, rectangular current pulses (2 mA, 200 micros, 20 Hz) delivered to the group of GTE lying close to the region innervating the specific internal organs or glands. The results showed that specific electrode configurations had actions on the heart (GTE 9), lungs (GTE 4) and pressure in the urinary bladder (GTE 1). It was also shown that GTE no. 10 significantly modified the endocrine function of the pancreas. The results of this study clearly demonstrate that internal organs and glands can be selectively stimulated via the selective stimulation of innervating superficial regions of the autonomous peripheral nerve.

Modulation of hormone secretion by functional electrical stimulation of the intact and incompletely dysfunctional dog pancreas.

The purpose of the present study was to modulate the secretion of insulin and glucagon in Beagle dogs by stimulation of nerves innervating the intact and partly dysfunctional pancreas. Three 33-electrode spiral cuffs were implanted on the vagus, splanchnic and pancreatic nerves in each of two animals. Partial dysfunction of the pancreas was induced with alloxan. The nerves were stimulated using rectangular, charge-balanced, biphasic, and constant current pulses (200 micros, 1 mA, 20 Hz, with a 100-micros delay between biphasic phases). Blood samples from the femoral artery were drawn before the experiment, at the beginning of stimulation, after 5 min of stimulation, and 5 min after the end of stimulation. Radioimmunoassay data showed that in the intact pancreas stimulation of the vagal nerve increased insulin (+99.2 microU/ml) and glucagon (+18.7 pg/ml) secretion and decreased C-peptide secretion (-0.15 ng/ml). Splanchnic nerve stimulation increased insulin (+1.7 microU/ml), C-peptide (+0.01 ng/ml), and glucagon (+50 pg/ml) secretion, whereas pancreatic nerve stimulation did not cause a marked change in any of the three hormones. In the partly dysfunctional pancreas, vagus nerve stimulation increased insulin (+15.5 microU/ml), glucagon (+11 pg/ml), and C-peptide (+0.03 ng/ml) secretion. Splanchnic nerve stimulation reduced insulin secretion (-2.5 microU/ml) and increased glucagon (+58.7 pg/ml) and C-peptide (+0.39 ng/ml) secretion, and pancreatic nerve stimulation increased insulin (+0.2 microU/ml), glucagon (+5.2 pg/ml), and C-peptide (+0.08 ng/ml) secretion. It was concluded that vagal nerve stimulation can significantly increase insulin secretion for a prolonged period of time in intact and in partly dysfunctional pancreas.

Modulation of hormone secretion by functional electrical stimulation of the intact and incompletely dysfunctional dog pancreas

The purpose of the present study was to modulate the secretion of insulin and glucagon in Beagle dogs by stimulation of nerves innervating the intact and partly dysfunctional pancreas. Three 33-electrode spiral cuffs were implanted on the vagus, splanchnic and pancreatic nerves in each of two animals. Partial dysfunction of the pancreas was induced with alloxan. The nerves were stimulated using rectangular, charge-balanced, biphasic, and constant current pulses (200 µs, 1 mA, 20 Hz, with a 100-µs delay between biphasic phases). Blood samples from the femoral artery were drawn before the experiment, at the beginning of stimulation, after 5 min of stimulation, and 5 min after the end of stimulation. Radioimmunoassay data showed that in the intact pancreas stimulation of the vagal nerve increased insulin (+99.2 µU/ml) and glucagon (+18.7 pg/ml) secretion and decreased C-peptide secretion (-0.15 ng/ml). Splanchnic nerve stimulation increased insulin (+1.7 µU/ml), C-peptide (+0.01 ng/ml), and glucagon (+50 pg/ml) secretion, whereas pancreatic nerve stimulation did not cause a marked change in any of the three hormones. In the partly dysfunctional pancreas, vagus nerve stimulation increased insulin (+15.5 µU/ml), glucagon (+11 pg/ml), and C-peptide (+0.03 ng/ml) secretion. Splanchnic nerve stimulation reduced insulin secretion (-2.5 µU/ml) and increased glucagon (+58.7 pg/ml) and C-peptide (+0.39 ng/ml) secretion, and pancreatic nerve stimulation increased insulin (+0.2 µU/ml), glucagon (+5.2 pg/ml), and C-peptide (+0.08 ng/ml) secretion. It was concluded that vagal nerve stimulation can significantly increase insulin secretion for a prolonged period of time in intact and in partly dysfunctional pancreas.

Recording of electroneurograms from the nerves innervating the pancreas of a dog.

Electroneurograms (ENGs) from the vagus, splanchnic and pancreatic nerves innervating the pancreas of a dog, were recorded with chronically implanted silicone multi-electrode circular cuffs in an intact pancreas and in a pancreas partly disabled with alloxan. The cuffs contained 33 platinum electrodes (0.6x1.5 mm) arranged in three parallel circular groups integrated into the inner surface of the cuff. Each circular group contained 11 electrodes at a distance of 0.5 mm apart, with 6 mm between the circular groups. The cuffs had an inner diameter of 2.5 mm and the length of 18 mm. In a 2-year study, the cuffs were implanted into two adult Beagle dogs (one female and one male). In the vagus nerve, the cuff was installed on the nerve at the neck, whilst in the splanchnic nerve, the cuff was installed on the nerve before the celiac ganglion, and in the pancreatic nerve, the cuff was installed on the nerve just before it enters the pancreas. In each of the three implanted cuffs, the electrodes of the central circular group were connected to each other and this signal provided one input to a multi-channel ENG amplifying system. The electrodes of each of the two outer spiral groups were connected to each other and then both these groups were short-circuited. This signal then provided another input to the multi-channel ENG amplifying system. The ENG amplifying system was designed to amplify the ENGs 100000 times and to pass frequencies of between 500 and 10 kHz. In our study, three recordings in each animal were conducted. Recordings in the intact pancreas were conducted 2 and 6 months after the implantation, while the recording in the partly disabled pancreas, was conducted 10 months after the implantation and 10 days after the disablement. Due to the fact that the results obtained in both animals were actually quite similar, we present the results of the recordings obtained in one animal. In both animals the cuffs were left implanted for more than 1 year and were used for pancreatic stimulation, although this is not in this paper. The results show that cuffs implanted chronically on the nerves innervating the pancreas of a dog could reliably record the ENGs. This information could be used effectively in further study of pancreatic innervation and its function. Moreover, the results suggest that cuffs could also be useful in recording the ENGs from other nerves of the autonomic nervous system that innervate various glands and internal organs.

Nicardipine dose dependently reduces the effect of equinatoxin II on coronary flow in isolated rat heart.

Equinatoxin II (EqT II) decreases coronary flow in guinea-pig and rat heart. It increases cytosolic Ca2+ activity and is supposed to form cation selective membrane pores. In the present study we tried to evaluate the influence of the L-type Ca2+ channel antagonist nicardipine upon the vasoconstrictory effect of EqT II on coronary vessels in isolated heart of the rat. Coronary flow was measured during the experiment. Ten min after bolus injection of EqT II the coronary flow decreased to 17.2 +/- 4.3% in experiments without nicardipine, and to 39.4 +/- 4.5% in the group with 0.1 microM nicardipine (p < 0.05). Our results indicate the possibility that L-type Ca2+ channels could be involved in the effects of EqT II on coronary flow in the rat heart.

Conversion of atrial fibrillation into a sinus rhythm by coronary angioplasty in a patient with acute myocardial infarction.

Atrial tachyarrhythmias are important complications occurring in more than 8% of acute myocardial infarctions (AMI). Atrial fibrillation (AFi) during the early phase of AMI is caused by atrial ischaemia, atrial distension due to the left ventricular failure or significant diastolic left ventricular dysfunction. AFi in patients with inferior and posterior AMI indicates at least two vessel coronary diseases, a circumflex coronary artery (CX) occlusion before taking off of the left atrial branches as well as significant stenosis or occlusion of the right coronary artery (RCA). In this article the case of a 67-year-old woman with an acute infero-posterior AMI is described. AMI was complicated with a left heart failure, acute AFi with tachyarrhythmia, transient arterial hypotension and ischaemic mitral regurgitation. Emergency coronary angiography disclosed occlusion of the CX, myocardial infarct related artery, and significant stenoses of the RCA. After opening the occluded CX during the PTCA, AFi with a tachyarrhythmia of 160 beats per minute (bpm) immediately converted into a sinus rhythm with 80 bpm, followed by a normalization of blood pressure and cardiac recompensation. Our case report supports the opinion that AFi in patients with inferior and posterior AMI indicates at least a two-vessel coronary disease. Reopening of the occluded atrial coronary branches during urgent medical treatment was casual and effective treatment of both ischaemic heart disease and consequent AFi.

Cardiovascular effects of equinatoxin III from the sea anemone Actinia equina (L.).

Equinatoxin III is the most hemolytic, and the least lethal of the three basic proteins isolated from the sea anemone Actinia equina (L.). Its LD50 in mice is 83 microg/kg. Preliminary results on Wistar rats have suggested cardiorespiratory arrest as a putative cause of death, but the mechanism of its action has not yet been studied. So far only equinatoxin II has been investigated more thoroughly. As equinatoxin II is less lythic, but more toxic, than equinatoxin III (its LD50 in mice=35 microg/kg), it may be assumed that haemolysis with a consequent rise in plasma potassium level is not the major factor in the lethality of equinatoxins. To assess the relative contribution of hyperkalemia in the lethality of the toxin in rat, the effects of equinatoxin III were compared to the effects of hyperkalemia caused by the injection of KCl giving the same final concentration of K+ in the plasma as that observed after an i.v. injection of 3LD50 of equinatoxin III. As coronary vasoconstriction may be an important mechanism of the cardiotoxic action of equinatoxins, the effect of EqT III on isolated porcine coronary arteries was studied by measurements of smooth muscle tension in the presence of 1-100 nM equinatoxin III. The results revealed that animals survive the elevated K+ plasma concentration caused by an i.v. application of KCl. This suggests that equinatoxin III induced haemolysis is not the major mechanism of equinatoxin III lethality. However, equinatoxin III increases the potassium induced contractions of coronary smooth muscle for 289+/-29%, suggesting that coronary vasoconstriction may be an important factor in the cardiotoxic effects of equinatoxin III.

The idiopathic hypereosinophilic syndrome.

Idiopathic hypereosinophilic syndrome (HES) is empirically defined as the presence of prolonged eosinophilia without an identifiable underlying cause, and with evidence of end-organ dysfunction. Virtually any organ system may be involved, most frequently the heart, the central and peripheral nervous system, the lungs and the skin. We report on two clinical cases where the diagnosis of HES, with all the conventional criteria met, was proposed. In the first patient with HES, cardiac and pulmonary involvement was present. Skin changes and lung involvement were observed in the second reported patient with HES. In both patients there was prompt improvement of all clinical signs and symptoms of HES soon after treatment with methylprednisolone was begun. In the first patient long-term methylprednisolone therapy was healed successfully. For 2 years he has shown no clinical signs or symptoms of HES. The second patient is still undergoing long-term therapy with 4 mg of methylprednisolone daily. The histologic findings of the skin biopsy in the second patient were not typical for HES, but skin changes completely healed after corticosteroid therapy. This could mean that that the described skin changes were one of the HES skin manifestations. The other possibility is that the skin changes emerge in coincidence with HES.

Evaluation of the strength of elbow flexors in patients with neuromuscular diseases.

In planning the optimum treatment for patients with neuromuscular diseases (NMD), it is essential to know as much as possible about their functional state. Assessment of the strength of certain muscles is the most direct measure of motor deficiency. In the development of normative data needed for patients with NMD, the use of torque measurements is required. Forty-nine patients (31 men and 18 women),f rom 18 to 54 years (mean age 33 +/- 8.9 years), were included in the study. Five groups of patients, each having one of five different NMDs, were formed. We tested unilaterally the biceps brachii muscle that normally generates the highest torque. For this purpose an eletronic brace enabling isometric measurements of torque during elbow flexion was designed. The patients produced three maximum voluntary elbow flexions that lasted about 3 s and separated by a pause of about 3 s. Force development was rapid with continuous build-up and isometric. About 15 s later the patients produced the last maximum voluntary elbow flexion, keeping it as stable aspossible for a period of 30 s. Patients with mitochondrial myopathy (MM), having the shortest mean half fatigue time (4.3 s), elicited the highest mean torque in both short maximum voluntary elbow flexions (1.34 Nm) as well as in the 30 s-long maximum voluntary elbow flexions. In contrast, patients with facioscapulohumeral muscular dystrophy (MD-FSH), having the longest mean half-fatigue time (15.4 s), elicited the lowest mean torque in both the short maximum voluntary (0.29 Nm) as well as in 30 s-long maximum voluntary elbow flexions. Patients with Becker muscular dystrophy (MD-B), having a mean half-fatigue time (11.1 s) slightly shorter than the patients with MD-FSH, elicited a higher mean torque in both the short (0.82 Nm) and the 30 s-long elbow flexions. Finally, patients with limb-girdle muscular dystrophy (MD-RM) and spinal muscular atrophy type 3 (SMA3), having a similar mean half-fatigue time (6.9 s for patients with MD-RM and 7.4 s for patients with SMA3), also elicited similar torque in both short (0.45 Nm for patients with MD-RM and 0.65 Nm for patient with SMA3) and 30 s-long elbow flexions. The results of the study show that the methodology developed to quantitative measure the torque of elbow flexions in patients with NMD enables the characteristics and natural course of NMD to be more objectively documented. Accordingly, the optimum treatmentforpatients with NMD could be restored.

Measurements of cardiac output of an isolated heart using a specially designed turbine.

Cardiac output is one of the important parameters used in evaluation of heart function. A turbine which works on mechanical principles was designed. It is also suitable for cardiac output measurements on isolated pig hearts in cases where some other equipment is not, like on doppler effect based transducers. The basic principle of measuring liquid flow through a turbine is based on measurement of the time that elapses when the rotor rotates by one degree. For this purpose, the rotor is fitted with transparent foil with a ring of 360 short black lines printed close to its circumference. Two infrared light-emitting diodes are mounted on one side of the foil and two photo-transistors, used as sensors of the transmitted infrared light, are mounted on the other. Voltage-regulated output ranging from 0 to +/- 2048 V at one revolution per second gives 500 mV at the output (changeable by programming), calculating time 2 ms, 1 mV resolution (11 bits), with an external power supply of 5 V. The turbine showed a linear response at a continuous saline flow up to 3000 ml min-1 at pressure loads of between 20 and 220 cm H2O. Pressure drop across the turbine depends on the volume flow and was 1 mm Hg at 100 ml min-1 and 3 mm Hg at 7000 ml min-1. A rotating movement 1.25 x 10(-4) kg m2 s-1 was calculated. The lowest volume change of a bolus of saline solution, detected by the turbine, was 1.6 ml.

Selective recording of electroneurograms from the sciatic nerve of a dog with multi-electrode spiral cuffs.

Electroneurograms (ENGs) from superficial regions of the sciatic nerve of a Beagle dog were recorded selectively with a chronically implanted 33-electrode spiral cuff (cuff). By delivering stimulating pulses to groups of three electrodes (GTEs) within the cuff we could define the relative positions of the particular superficial regions that selectively innervated the tibialis anterior (TA) and gastrocnemius muscles (GM). GTEs with and without contractions of the TA and GM muscles were selected and connected to a 4-channel ENG system designed to amplify ENGs by 100,000 times and to pass frequencies between 500 Hz and 10 kHz. In our study, 12 experiments were conducted on three Beagle dogs with a cuff implanted for up to 2 years. We present the results obtained in four experiments conducted on one animal. With the implanted leg mounted in a special electronic brace we applied extending forces to the ankle, rotating it by up to 37 degrees according to the neutral position, eliciting torque to stretch the TA muscle. Only the ENG from a GTE eliciting maximum contraction of the TA muscle showed activities corresponding to the trajectory of the mechanical load of the muscle. Next, we dissected the calcanean tendon (CT) of the implanted leg and applied repetitive pull forces to the CT. Only the ENG from the GTE eliciting maximum contraction of the GM muscle was activated in correspondence to the trajectory of the mechanical load applied on the CT. The results suggest that the cuff, implanted chronically on the sciatic nerve, is useful to record ENGs of the afferent fibers from TA and GM muscles selectively and that the technique could be extended for human use in the field of rehabilitation for paralysis.

Nicardipine dose-dependently reduces the effect of equinatoxin II on coronary flow in isolated porcine heart.

Death after i.v. administration of equinatoxin II (EqT II) has been attributed to the circulatory failure resulting from cardiotoxic effects. The mechanism of action is unknown. The aim of the present work was to study the effects of the toxin on vascular tone in the isolated porcine coronary artery and on coronary flow in the isolated pig heart. EqT II caused concentration-dependent contractions of rings of the isolated epicardial porcine coronary artery with an EC50 value of 89+/-5 nM (n=5-6) and maximal effect of about 140% of the contraction induced by 20 nM KCl. On Langendorffs porcine heart preparation EqT II caused a dose-dependent decrease of coronary flow. At EqT II doses lower than 0.05 micromol/100 g of heart weight there were no measurable effects of the toxin. At dose 0.5 micromol/100 g the toxin decreased coronary flow to less than 9.8+/-2.5% of the control value. The constrictory effect of the toxin on isolated porcine coronary arteries was diminished by the L-type calcium channel antagonist nicardipine (NC). NC in 1 microM concentration almost completely abolished the effect of EqT II on coronary flow. Our results confirmed involvement of L-type calcium channels in the vasoconstrictory effects of EqT II on epicardial coronary arteries.

The importance of hemolysis in the lethal effects of equnatoxin II, a protein from the sea anemone Actinia equina (L.).

Equinatoxin II (EqT II) is one of the three isotoxins isolated from the sea anemone Actinia equina (L). The cause of death due to i.v. application of Eq T II was attributed to its hemolytic activity and hiperkaliemia, and the direct cardio-respiratory effects of the toxin. The toxin also binds to plasma lipids and forms toxic conglomerates with them. In our study we tried to evaluate the importance of interaction of the toxin with blood components in the toxin lethality. Anaesthetized male Wistar rats were used. The respiratory activity, ECG and animal serum ionic composition were monitored. To simulate isolated effects of the toxin hemolytic activity, hemolysed erythrocytes, KCl and mixture of rat serum with the toxin were injected i.v.. It was shown that neither the lysed erythrocytes nor the mixture of rat serum with the toxin were lethal for the experimental animals. Even KCl, in concentrations detected in serum of rats killed by the toxin, did not cause the death of experimental animals. Our results indicate that either a combination of the tested effects of the toxin on blood components or more probably the direct effects of the toxin on vital organs are responsible for the toxin lethality.

Selective recording of neuroelectric activity from the peripheral nerve.

Electroneurograms (ENGs) from superficial regions of the sciatic nerve of a dog, innervating the tibialis anterior (TA) and gastrocnemius muscles (GM), arising mainly from muscle spindles and Golgi tendon organs were recorded selectively with an implanted 33-electrode spiral cuff (cuff). Relative positions of superficial regions within the cuff were defined by delivering stimulating pulses on groups of three electrodes (GTEs) within the cuff which were in contact with them. It was found that GTEs eliciting maximum contractions of muscles were GTE No. 3 for the TA muscle and GTE No. 8 for the GM muscle. In the first experiment the implanted leg was mounted into a special electronic brace. Extending forces were applied to the ankle rotating it by up to +/-37 degrees according to the neutral position, thus eliciting torques in the TA muscle of up to 1.2 Nm. Channel 1 of the 4-channel preamplifier was connected to GTE No. 8, channel 2 to GTE No. 2, channel 3 to GTE No. 11 and channel 4 to GTE No. 5. Results show that only ENG recorded with GTE No. 8, being close to the region innervating the TA muscle, correspond to the mechanical load. In the second experiment the calcanean tendon (CT) of an implanted leg was dissected. The proximal end of the CT was connected to a force transducer and repetitive pull forces (about 12 N) were applied to the CT. Channel 1 of the preamplifier was connected to GTE No. 5, channel 2 to GTE No. 1, channel 3 to the GTE No. 11 and channel 4 to GTE No. 8. Results show that only ENG recorded with GTE No. 5, being close to the region innervating the GM muscle, correspond to the mechanical load applied on CT.

In vivo effects of head-to-tail 3-alkylpiridinium polymers isolated from the marine sponge Raniera sarai.

Water soluble polymeric 3-alkylpyridinium salts (poly APS; MW 18900 and 5520 Da) were isolated from the marine sponge Raniera sarai. In vitro it strongly inhibited acetyl cholinesterase (AChE) from different species (electric eel, horse serum, human erythrocytes). In our experiments the importance of anti AChE activity in the toxin lethality was evaluated. In vivo experiments were performed on male Wistar rats and ECG, blood pressure and breathing pattern were monitored. After i.v. application of lethal doses of the toxin ECG showed signs of hypo perfusion. Arterial blood pressure fell to mid-circulatory pressure, and breathing stopped after a few breaths At sublethal doses the toxin caused an increase of residual volume, prolongation of expiration, and bradycardia. Patho-anatomical examination revealed that the plugs in lung circulation may cause the death of experimental animals due to cardiorespiratory failure.