Increased apoptosis, changes in intracellular Ca2+, and functional alterations in lymphocytes and macrophages after in vitro exposure to static magnetic field

Electromagnetic-related alteration of cellular functions is well documented for extremely low-frequency low-energy pulsing electromagnetic fields (ELF-EMF). In this study we examined the in vitro effects of static magnetic fields (SMF) on the cellular immune parameters of the C57BI/6 murine macrophages, spleen lymphocytes, and thymic cells. The cells were exposed in vitro for 24 h at 37 degrees C, 5% CO2, to 250-1500 G SMF. Exposure to the SMF resulted in the decreased phagocytic uptake of fluorescent latex microspheres, which was accompanied by an increased intracellular Ca2+ level in macrophages. Exposure to SMF decreased mitogenic responses in lymphocytes, as determined by incorporation of [3H]thymidine into the cells. This was associated with the increased Ca2+ influx in concanavalin A-stimulated lymphocytes. Furthermore, exposure to SMF produced markedly increased apoptosis of thymic cells, as determined by flow cytometry. Overall, in vitro exposure of immunocompetent cells to 250-1500 G SMF altered several functional parameters of C57BI/6 murine macrophages, thymocytes, and spleen lymphocytes.

Kynurenic acid distribution into brain and peripheral tissues of mice

Kynurenic acid (KYN), an antagonist of excitatory amino acid receptors, is a putative antidote against neuroexcitatory amino acid toxicity. We studied various doses (0.05-3.17 mmol/kg, i.p.) and the effects of probenecid coadministration (0.70 mmol/kg, i.p.) on tissue distribution of KYN in male and female Swiss-Webster mice. After injection of [3H]KYN, samples of brain, heart, liver, kidney, skeletal muscle, and gut were collected at selected times and assayed for KYN by liquid scintillation counting. The substance was absorbed rapidly and distributed into all tissues. Its content (nmol/g, mean +/- SE) at 60 min was 0.26 +/- 0.05, 1.80 +/- 0.05, and 40.4 +/- 8.1 in brain (for 0.05, 0.53, and 3.17 mmol/kg), 1.43 +/- 0.11, 14.3 +/- 3.7, and 212 +/- 32 in heart, 1.16 +/- 0.21, 10.6 +/- 2.6, and 254 +/- 21 in liver, and 7.41 +/- 2.65, 180 +/- 63, and 1899 +/- 254 in kidney. Net accumulation of KYN in brain was much lower than in other tissues. Probenecid increased KYN concentration in brain 2.5-fold. Peak brain:blood concentration ratio occurred between 60 and 180 min, was inversely associated with dose, and was not affected by probenecid. Although brain content was similar, female mice had an earlier peak brain:blood ratio (120 min) than males (180 min) for the 0.05 mmol/kg dose. Our results suggest the presence of a restricted transfer process for KYN with delayed egress from brain.

Phosphate energy metabolism during domoic acid-induced seizures

The effect of domoic acid-induced seizure activity on energy metabolism and on brain pH in mice was studied by continuous EEG recording and in vivo 31P nuclear magnetic resonance (NMR) spectroscopy. Mice were divided into ventilated (n = 6) and nonventilated (n = 7) groups. Baseline EEG was 0.1-mV amplitude with frequence of > 30-Hz and of 4-5 Hz. After intraperitoneal (i.p.) administration of domoic acid (6 mg/kg), electrographic spikes appeared at increasing frequency, progressing to high-amplitude (0.1-0.8 mV) continuous seizure activity (status epilepticus). In ventilated mice, the [31P]NMR spectra showed that high-energy phosphate levels and tissue pH did not change after domoic acid administration or during the intervals of spiking or status epilepticus. Nonventilated mice showed periods of EEG suppression accompanied by decreases in the levels of high-energy phosphate metabolites and in pH, corresponding to episodic respiratory suppression during the spiking interval. In all animals, status epilepticus was followed by a marked decrease in EEG amplitude that progressed rapidly to isoelectric silence. [31P]NMR spectra obtained after this were indicative of total energy failure and tissue acidosis. In a separate group of ventilated mice (n = 4), domoic acid-induced status epilepticus was accompanied initially by an increase in mean arterial blood pressure (MAP) that slowly returned to baseline level. Isoelectric silence was accompanied by a decrease in MAP to 75 +/- 8 mm Hg. These experiments suggest that domoic acid-induced seizures are not accompanied by an increase in substrate demand that exceeds supply.

Effects of excitotoxins on free radical indices in mouse brain

Excitotoxins and free radicals individually have been implicated in several neurological disorders including those associated with aging. We observed that systemically administered domoic acid enhanced mouse brain superoxide dismutase activity with either an associated decrease or no change in mouse brain lipid peroxidation. These findings reflect a state of adequately compensated oxidative stress induced by excitotoxins. In homogenates containing disrupted cells from various regions of mouse brain, however, kainic acid produced a 2 to 5-fold increase in lipid peroxidation. This suggests that excitotoxins cause lipid peroxidation possibly by acting at intracellular loci which become more accessible following disruption of cells in vitro and by extrapolation, possibly in vivo due to cellular permeability changes during the edematous stage of ischemic and other related neuropathological conditions.

Pyridine and other coal tar constituents as inhibitors of potato polyphenol oxidase: a non-animal model for neurochemical studies

Potato polyphenol oxidase activity was strongly and noncompetitively inhibited by the "Perov mixture" of coal tar components and by pyridine alone, while phenol competitively inhibited the enzyme. These two inhibitors are structural components of the parkinsonogenic neurotoxin N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). By extension, dopamine and neuromelanin synthesis in the brain may be influenced by the inhibitory effects of such compounds upon the copper-dependent steps of tyrosine metabolism. The non-animal model used in this study may represent an alternative to the use of animal tissues in neurodegenerative disease research.

Parenteral domoic acid impairs spatial learning in mice

The present study is the first to examine the effect of a single intraperitoneal injection of the neuroexcitotoxin domoic acid on learning in mice. Compared to saline controls, animals exposed to domoic acid (2.0 mg/kg) showed significant impairment on the acquisition of the place task in the Morris water maze. Observation of swim paths taken by mice searching for the underwater platform revealed a failure on the part of the domoic acid-exposed mice to select the appropriate problem solving strategies. The results, along with neuroanatomic work done here and elsewhere, suggest that impairment of acquisition and retention of this spatial navigation task by domoic acid, involves a neuropathology that includes not only the hippocampus, but other limbic, and possibly extralimbic brain regions.

Global elevation of brain superoxide dismutase activity following forebrain ischemia in rat

Regional superoxide dismutase (SOD) activity and lipid peroxidation (as reflected by thiobarbituric acid-reactive substances (TBARS)) have been measured at increasing post-ischemic time intervals following a (10 min) forebrain ischemic insult in rat. All brain regions showed significant progressive increases in SOD activity with increasing post-ischemic time intervals. Lipid peroxidation also was significantly increased in frontal and parietal/occipital regions at 1 and 24 h post-ischemia, although this was several orders of magnitude less than the increase in SOD activity. By 7 days post-ischemia lipid peroxidation had returned to control values for all regions. These data are consistent with the hypothesis that cerebral ischemia is accompanied by glial activation with an associated increase in SOD activity. Global increases in SOD activity may protect the brain from free radicals, thereby preventing large increases in lipid peroxidation.

Circumventricular organ origin of domoic acid-induced neuropathology and toxicology

The neuroexcitotoxin, domoic acid, was responsible for an episode of mussel poisoning in Eastern Canada in 1987. Severe neurologic impairment and some deaths occurred. We have characterized the nature of domoate-induced neuropathology in the mouse brain. Domoic acid was administered intraperitoneally at doses of 2, 3 or 7 mg/kg to Swiss-Webster mice. Brains were examined at 0.5, 1, 24, 48 or 72 h postinjection for evidence of damage. Significant pathologic changes occurred only after the largest dose of domoic acid. Damage was confined to circumventricular organs lacking a blood-brain barrier and their environs, including the organon vasculosum of the lamina terminalis, subfornical organ, mediobasal hypothalamus and area postrema. The neural damage induced by domoic acid was evident at as early as 30 min after injection and increased by 60 min postinjection. The loci of domoic acid-induced neuropathological changes accounts for several central and peripheral effects and toxicities observed following systemic domoate treatment, these included gastroduodenal lesions, hypodipsia, analgesia, and blood pressure fluctuations.

The effects of naloxone on the changes in breathing and behaviour induced by morphine in the foetal sheep

In the foetal sheep, administration of morphine induces apnoea followed by hyperpnoea; during hyperpnoea the foetus arouses. We tested the hypothesis that naloxone, an opiate antagonist, would block these responses. In 14 foetal sheep between 123 and 140 days of gestation, we measured electrocortical activity (ECoG), eye movements (EOG), diaphragmatic activity (EMGdi), blood pressure and amniotic pressure. Morphine (1 mg/kg) was injected in the foetal jugular vein during low-voltage ECoG. Saline or naloxone (0.1, 0.5 and 2.0 mg) were given, in randomized order, before the morphine injection, shortly after morphine injection during apnoea, and during maximum hyperpnoea. Saline alone had no effect on breathing or behaviour. When saline and naloxone preceded the morphine injection the length of apnoea was 26.6 +/- 7.7 and 19.5 +/- 7.0 min (SEM, P = 0.25) while the length of sustained hyperpnoea was 104.8 +/- 11.4 and 29.6 +/- 8.4 min respectively (P = 0.001). When administered during the maximum breathing response, naloxone decreased the length of breathing from 92.2 +/- 8.4 (saline) to 8.8 +/- 2.9 min (P = 0.001). Respiratory output (fEMGdi x f) also decreased from 6545 +/- 912 arbitrary units post saline to 3841 +/- 629 arbitrary units after naloxone (P = 0.05). Arousal disappeared with the decrease in breathing response. The negligible effect of naloxone on apnoea and its strong inhibition of hyperpnoea suggest that morphine may act on two distinct central regions or on two subtypes of opioid receptors to produce apnoea, hyperpnoea and arousal.

Sensitive murine model and putative antidotes for behaviorial toxicosis from contaminated mussel extracts

The recent outbreak of "amnesic" mussel poisoning syndrome, attributed to domoic acid contamination of edible mussels claimed several lives and left many victims impaired with a peculiar loss of memory. We administered the whole mussel extract (WMX) and the mussel hepatopancreas extract (MHX, hepatopancreas being the major site for sequestration of domoic acid in mussels) in Swiss-Webster mice. A characteristic syndrome featuring sluggishness, scratching stereotypy, convulsions and death was noticed. Infant mice were some 3- to 4-fold more sensitive to the WMX toxicity. Kynurenic acid (KYN), an endogenous nonselective excitotoxin antagonist offered significant protection against the toxicosis after its onset had been provoked by the mussel extract. This observation emphasizes the feasibility of using KYN or related compounds in the therapy of poisoning from excitotoxins. As a logical extension of this possibility we examined the possibility that endogenous KYN could be exploited for similar protection against domoate toxicosis in our murine model. The time frame during which KYN was protective was increased by probenecid, a blocker of organic acid transport and by tryptophan, a precursor of endogenous KYN. We examined also the classical anticonvulsants phenytoin and ethosuximide, as well as dextromethorphan at its excitotoxin antagonistic dose. The infant mouse model of domoate-toxicity holds promise for being developed into a rapid, sensitive, reliable and inexpensive biological assay for screening commercial batches of mussel for excitotoxin contamination. Kynurenic acid and dextromethorphan should be further examined as antidotes for possible therapeutic use in existing victims and in the treatment of future domoate toxicosis occurring here or elsewhere.

Gastrointestinal effects of contaminated mussels and putative antidotes thereof

A recent outbreak of amnesic shellfish poisoning (ASP) in Atlantic Canada was characterized by severe gastrointestinal and central nervous system pathology. We examined the gastrointestinal effects of an acidic extract of blue mussels contaminated with domoic acid, the suspected toxin responsible for the ASP. We also tested the gastric effects pure domoic acid as well as a putative antagonist of neuroexcitant amino acid receptors, kynurenic acid. Mussel extract produced gastric (antral) ulcers, duodenal ulcers, gastric and duodenal hyperemia and bleeding, as well as peritoneal ascites. Kynurenic acid protected significantly against extract-induced gastropathy, particularly when given 60 or 75 minutes after extract. Pure domoic acid resulted in fatalities in all infant mice tested. These animals exhibited gastric bleeding and hemorrhage, especially at the higher doses employed. In otherwise untreated rats, kynurenic acid exerted significant anti-stress ulcer and anti-gastric secretory effects, but was less effective at blocking ethanol-induced gastric lesions. We suggest that there may be both peripheral as well as central effects of kynurenic acid in modulating normal and pathological gastric function.

Domoic acid-induced neurovisceral toxic syndrome: characterization of an animal model and putative antidotes

A rodent model of neurovisceral toxic syndrome induced by the neuroexcitant amino acid, domoic acid, is described, along with the activity of a putative antidote, the nonselective excitotoxin antagonist, kynurenic acid. Both an extract of contaminated mussels and pure domoic acid induced a characteristic syndrome including: sluggishness, scratching stereotypy, convulsions and death. Autopsy revealed gastric and duodenal lesions and peritoneal ascites. Kynurenic acid significantly obtunded these behavioral and physiological effects, particularly when given 60-75 min after the toxic insult. Probenecid, a blocker of organic acid transport, and tryptophan, a precursor of endogenous brain kynurenic acid, increased the time frame in which kynurenic acid exerted its protective effects. Kynurenic acid alone, in nontoxin-challenged animals significantly blocked cold-stress gastric lesions, significantly reduced basal gastric acid secretion and was protective to a lesser degree against ethanol-induced gastric mucosal injury. The murine model of domoate toxicity represents an inexpensive, reliable and sensitive biological assay for screening commercial shellfish for excitotoxin contamination. We are currently exploring kynurenic acid and other compounds for possible therapeutic use in both current and any future victims of neuroexcitant amino acid toxicosis.

Effects of metkephamid (LY127623), a selective delta opioid receptor agonist, on gastric function

Metkephamid, a delta opioid receptor agonist, blocked cold-restraint stress ulcers, reduced absolute ethanol-induced gastric ulcers and, at the lowest and highest doses examined, reduced basal gastric acid secretion in conscious rats, all to a significant degree. The dose effects on stress ulcer formation parallel those seen against maximal electroshock seizures and suggest that both central as well as peripheral delta opioid receptors mediate gastrointestinal responses to stress.

Kynurenic acid attenuates experimental ulcer formation and basal gastric acid secretion in rats

Kynurenic acid is a broad spectrum antagonist at neuroexcitant amino acid receptors in the mammalian brain. Preliminary data indicated that kynurenic acid attenuates domoic acid-induced central nervous system pathology, lethality and gastrointestinal pathology. We now show that kynurenic acid significantly blocks restraint-cold stress ulcers, ethanol ulcers and basal, non-stimulated gastric acid secretion in normal rats not subjected to neurotoxin challenge. There may be peripheral actions, in addition to the central effects of kynurenic acid, in modulating normal and pathological gastric function.

Biological and methodological implications of prostaglandin involvement in mouse brain lipid peroxidation measurements

Enhanced cyclooxygenase-mediated prostaglandin (PG) turnover occurring during sacrifice and biochemical processing of tissues also generates malondialdehyde (MDA), a product of lipid peroxidation (LPO). Studies reporting on LPO estimated by thiobarbituric acid reactive substances (TBARS) have failed to consider such artefactual increases. This study reports the relative proportion of PG metabolism-derived MDA (PG-MDA) in mouse brain regions during the TBARS assay. The cyclooxygenase inhibitor indomethacin significantly lowered MDA in fronto-parietal cortex and corpus striatum. Indomethacin (50-800 micrograms/ml, in vitro) increased estimated TBARS in whole brain. Such enhancement was absent when indomethacin (20-80 micrograms/sample) was added to the MDA standard curve, reflecting its interaction with TBARS other than MDA. PG-MDA contributes as much as 15% to the total estimated value of MDA in fronto-parietal cortex and corpus striatum and must be corrected for in LPO studies.

Neurotoxicity and lethality of toxic extracts from Atlantic coast shellfish

1. HCl-extract of poisonous shellfish was injected i.p. into Swiss-Webster mice. 2. Behavioral effects (sluggishness, scratching, huddling, clonic convulsions, respiratory distress and mortality) were noted. 3. Infant mice were more sensitive than were the adults to XTRT toxicity. Estimated LD50 values were; adult: 34.8 ml/kg i.p., infant: 9.6 ml/kg i.p. 4. The mouse model of shellfish-toxicity offers the advantages of a degree of similarity with the human clinical situation and a rapid time course for screening antagonists against shellfish poisoning.

Kynurenic acid protects against neurotoxicity and lethality of toxic extracts from contaminated Atlantic coast mussels

1. An aqueous acidic extract from poisonous Atlantic coast mussels was injected i.p. into groups of Swiss-Webster mice at the LD84 value (= 40 ml of extract/kg). Body-scratching, clonic convulsions and death were consistently observed in response to XTRT injection. These results are consistent with the presumed presence of the neuroexcitant amino acid, domoic acid, in the contaminated mussels. 2. Kynurenic acid at 300 and 600 mg/kg i.p. protected powerfully and significantly against extract-induced neurotoxicity. Greatest protection was observed when the antidote was administered between 30 and 90 min after injection of the toxic extract.

Kynurenic acid protects against gastroduodenal ulceration in mice injected with extracts from poisonous Atlantic shellfish

1. Mice were treated with an extract prepared from poisonous Atlantic mussels. 2. Gastric and duodenal ulcers, duodenal hyperemia and peritoneal ascites resulted from administration of the shellfish extract, with an LD84 of 1.0 ml. 3. Kynurenic acid, an antagonist at excitatory amino acid receptors, protected significantly against gastroduodenal ulcers, ascites and hyperemia when given at 60 or 75 min post-extract. 4. It is likely that the gastrointestinal damage evoked by this extract is due to its domoic acid content and that kynurenic acid may prove useful against domoic acid-induced gastropathy.

Pyridine and other coal tar constituents as free radical-generating environmental neurotoxicants

We have tested the hypothesis that chronic exposure to the principal constituents of the aqueous fraction of coal tar extracts can lead to the in vivo formation of substances which may produce neurological damage as the result of free radical generation and lipid peroxidation, these may be involved in the etiology of some neurological disorders. Artificial mixtures of the aqueous fraction of coal tar extracts were given in low concentrations to pigmented mice in their drinking water over a 3-month period. This resulted in significant increases in lipid peroxidation in the striatum, cerebellum and liver of the mice under test, the rank order being striatum greater than cerebellum greater than liver. These results are compatible with the possibility that coal tar emissions (as would be recovered or liberated in the burning, refining or beneficiation of coal) constitute a potential source of neurotoxicants with a predilection for damaging the nigrostriatal neuronal pathway. Our observations may thus have identified an important and hitherto unsuspected environmental source of neurotoxic chemicals, a possibility consistent with the proposed involvement of an environmental chemical factor in Parkinson's disease and perhaps in other neurological disorders.

Climbing behavior permits in vivo assessment of pre- and postsynaptic extrapyramidal dopaminergic function in mice

The natural tendency of mice to climb has been investigated in this study as an index of extrapyramidal dopaminergic function. Depending on dose, apomorphine reduced (low dose range; presynaptic dopamine receptor agonism) or increased (high dose-range; postsynaptic dopamine receptor agonism) climbing activity with respect to spontaneous basal levels of such activity in Swiss-Webster mice. We report also an increase in apomorphine-induced enhancement of vertical climbing activity in mice withdrawing from the acute effects of cesium chloride. Spontaneous climbing activity in mice could reflect dynamic extrapyramidal motor tone, upon which voluntary motor activity is superimposed and which, in humans, is adversely affected in motor disorders like parkinsonism.

Effect of morphine on breathing and behavior in fetal sheep

To define the dose response of apnea and breathing to morphine we studied 12 fetuses at 116-141 days of gestation using our window technique. We instrumented the fetus to record electrocortical activity (ECoG), eye movements (EOG), diaphragmatic activity (integral of EMGdi), heart rate, carotid blood pressure, and amniotic pressure. Saline and morphine in doses of 0.03, 0.1, 0.5, 1, and 3 mg/kg were injected in random order in the jugular vein of the fetus during low-voltage ECoG. Fetuses were videotaped for evaluation of fetal behavior. We found 1) that saline did not elicit a response; 2) apnea, associated with a change from low- to high-voltage ECoG, increased from 2.2 +/- 1.5 (SE) min in two fetuses at a dose of 0.03 mg to 20 +/- 6.3 min in seven fetuses at 3 mg/kg (P less than 0.005); 3) the length of the breathing responses, associated with a change from high- to low-voltage ECoG, were 15 +/- 1.8 and 135.9 +/- 18.1 min (P less than 0.0005); 4) integral of EMGdi X frequency, an index equivalent to minute ventilation, increased from 1,763 +/- 317 arbitrary units to 10,658 +/- 1,843 at 1.0 mg/kg and then decreased to 7,997 +/- 1,335 at 3.0 mg/kg. These changes were related to a steady increase in integral of EMGdi, whereas frequency decreased at 3 mg/kg. There was an increase in breathing response to morphine plasma concentrations or morphine doses.(ABSTRACT TRUNCATED AT 250 WORDS)

Randomized trial of combined modality therapy with and without thymosin fraction V in the treatment of small cell lung cancer

A randomized trial of thymosin fraction V (60 mg/m2 s.c. twice weekly) given during induction chemotherapy and radiation therapy was performed in 91 patients with small cell carcinoma of the lung. Induction chemotherapy consisted of four cycles of an alternating combination of drugs (cyclophosphamide/Adriamycin/vincristine and cisplatin/etoposide). Radiation to the primary complex was given to patients with limited disease. All patients received prophylactic cranial irradiation. There were 35 patients with limited disease (18 randomized to thymosin and 17 to no thymosin) and 56 with extensive disease (28 thymosin and 28 no thymosin). Pretreatment immunological parameters were comparable between the two groups. For limited disease patients the overall response rate was 100%, including 66% (21 of 32) complete responders. The median duration of response was 19 mo (range, 5-57 mo) and survival 21 mo (range, 4 days to 57 mo). The 3-yr survival was 32%. For ED patients the overall response rate was 95% with 29% (13 of 48) complete. The median duration of response was 10 mo and the median duration of survival 12 mo with 13% alive at 2 yr. A comparison of the thymosin-versus no thymosin-treated patients revealed no difference in response rate, response duration, or survival whether analyzed as a whole or by extent of disease. An analysis based on pretreatment immune function and total white blood cell and absolute lymphocyte count revealed no difference in the survival distributions. No differences in the pattern of toxicity were observed between the thymosin- versus no thymosin-treated patients. The addition of thymosin fraction V during induction chemotherapy and consolidation radiotherapy did not alter outcome.

Effects of 4-acetylpyridine on stress ulcer formation in mice

4-Acetylpyridine, earlier reported by us to be an anticonvulsant, offers long-lasting protection after a single administration against hypothermic restraint stress-induced gastric ulceration in mice. Electroshock convulsions, marginally but not significantly protective against such ulcers themselves, when coupled with 4-acetylpyridine administration fully prevented gastric ulcers from occurring in this murine model of experimentally induced stress.

L-deprenyl attenuates stress ulcer formation in rats

Both intraperitoneal and intracerebroventricular (i.c.v.) administration of the monoamine oxidase-B inhibitor L-deprenyl markedly attenuated restraint stress-induced gastric ulcers in rats. L-Deprenyl given i.c.v. attenuated stress ulcers in microgram doses and virtually abolished ulcer formation at a dose of 2.0 micrograms. These data suggest that intact or augmented central dopaminergic function may be an essential component of gastric mucosal protection.

Specific binding and uptake of opioids in brain slices

Studies on slices from whole rat brain indicate that the opioid peptide/receptor, but not the opiate drug/receptor, complex is internalized by metabolically-dependent processes. Opiate drugs displace 3H-etorphine from high affinity binding sites with potencies identical to those in brain homogenates. 3H-metenkephalin (ME) binds to a high affinity (IC50 10 nM) and a low affinity (micromolar) site. Opiate drugs and beta-endorphin compete at the high affinity but not at the low affinity binding site for ME. The biological relevance of the low affinity ME-binding site, which like the high affinity site is internalized, remains to be determined. The slice technique should be useful in the characterization of receptor dynamics that may be altered during opiate tolerance and dependence.

Increased survival with high-dose multifield radiotherapy and intensive chemotherapy in limited small cell carcinoma of the lung

From June 1979 through April 1982, we treated 35 patients with limited small cell carcinoma on an intensive chemo-radio-immunotherapy regimen, consisting of induction with cyclophosphamide, doxorubicin, and vincristine, alternately cycled with VP-16 and cisplatin. Patients were stratified by performance status and randomized to thymosin, fraction V, or no thymosin. Induction was followed by consolidation, consisting of prophylactic whole-brain radiotherapy and multifield radiotherapy to the primary and mediastinum with cyclophosphamide and vincristine. Patients who were complete responders (CRs) postconsolidation resumed maintenance immediately. Patients were followed from 1 to 3.8 years (median, 2.2 years) at the time of analysis. After induction, 35% (12/34) had become CRs; after consolidation radiotherapy, an additional 10/34 became CRs for a total CR rate of 65% (22/34). There were only 9/34 local failures (26%), of which all but one were impatients who had not become CRs. A prolonged median survival (21 months) has been obtained in patients with limited small cell carcinoma of lung treated with an intensive combined modality regimen. At 1 year, survival is 83%; at 2 years, 46%. There is a 33% long-term survival (greater than 3 years). There is no difference in survival or recurrence rate between patients treated with or without thymosin.

Peptidases that terminate the action of enkephalins. Consideration of physiological importance for amino-, carboxy-, endo-, and pseudoenkephalinase

The term "enkephalinase" has been frequently applied to enzyme activity in a variety of tissue preparations. In some cases there has been the implication that cleavage of a specific peptide bond in the enkephalin molecule results from the action of a single enzyme with the major responsibility of inactivating synaptic enkephalin. It is not known to what extent diverse enkephalin-degrading enzymes, with differing peptide bond specificities, may act in concert at any given synapse. There do exist, however, enzymes having known characteristic specificities with respect both to peptide substrates, including enkephalins, and to identifiable peptide bonds. Thus, at any given site of enkephalin release there probably resides a characteristic assembly of peptidases concerned with inactivation of this neuromediator. We propose that the term "enkephalinase" be used to encompass the entire family of enkephalin-degrading enzymes, and that "aminoenkephalinase", "carboxyenkephalinase", "endoenkephalinase" and "pseudoenkephalinase" should designate enzymes of known specificities with respect to both peptide substrates and particular peptide bonds.

Central depressant action of cesium in mice

Cesium chloride (CsCl) at several dose levels (1.25-20.0 mEq/kg IP) was administered acutely to albino mice whose behavior was compared with that in corresponding saline controls. Motor activity decreased and Straub tail occurred in a dose-related manner. Signs of autonomic disturbance, diarrhea, and salivation were seen with toxic doses. Subchronic administration of CsCl (5.0 mEq/kg/day IP for 7 days) exerted a phenothiazine-like effect in mice, reducing amphetamine-induced aggregation toxicity and enhancing pentobarbital-induced hypnosis. The antinociceptive action of morphine was unaltered by identical multiple administrations of CsCl. These results indicate a specific neurosuppressant action of CsCl on mouse CNS and suggest exploration of this alkali earth metal for antipsychotic-like activity.

Pharmacological and toxicological investigations of Cesium

Cesium, a mineral resource abundantly present in Manitoba with important existing and potential industrial applications was investigated to study its effects on biological systems. Several rodent models of pharmacological activities were utilized. The profile that emerged indicated that cesium is only moderately toxic and exerts salubrious effects which could be gainfully investigated for application in the treatment of certain psychological disorders and some tumors. Its conjunction with existing pharmacological agents for these two types of disorders could yield a pharmacologically active yet less toxic therapeutic combination.

Cesium attenuates conditioned avoidance response in rats and mice

The pole-climbing conditioned avoidance response (CAR) was attenuated in rats after four once-daily injections of CsCl intraperitoneally at 3.0 mEq kg-1 and in mice after seven such injections at 5.0 mEq kg-1. Suppression of CAR increased with increasing numbers of injections. Treatment with cesium did not attenuate the unconditioned pole-climbing escape response to mild footshock. The cesium effect on CAR resembles that of antidopaminergic phenothiazine like agents, in concordance with our earlier studies which showed cesium potentiation of pentobarbital sleeping time and antagonism of amphetamine toxicity.

Newer concepts of analgesia and anesthesia

Intracerebroventricular (ICV) administration of the peptidase inhibitors amastatin, trasylol, bacitracin, or phe-D-ala and systemic administration of phenylmethylsulfonyl fluoride resulted in one or more of the following responses: analgesia, reduced withdrawal severity in opiate tolerant rats, alterations in motor activity and behavior, hypo- and hyperthermia and others; some of these effects were antagonized by naloxone, suggesting participation of opioid and other endogenous peptides. In addition, peptidase inhibitors enhanced analgesic and other responses to opioid peptides given ICV. Peptidase inhibition affords another method of inducing selective pharmacological responses such as pain relief in individuals resistant to other forms of therapy. ICV administration of beta-endorphin in the rat induces general anesthesia that is instantly reversed by systemic naloxone. Extensions of this work include identification of specific neural pathways that mediate anesthesia and characterization of opiate receptor subtype(s) at these sensitive loci. This approach offers the potential for the design of systemically effective opioid peptide anesthetics with little or no secondary effects and rapid reversibility.

Phenylmethylsulfonyl fluoride (PMSF) given systemically produces naloxone-reversible analgesia and potentiates effects of beta-endorphin given centrally

Intraperitoneal (IP) injection of the serine proteinase inhibitor phenylmethylsulfonyl fluoride (PMSF) produced dose-dependent analgesia in Sprague-Dawley rats. AD50 was 2.9 +/- 1.4 (S.E.) mg kg-1, the analgesia was antagonized by naloxone but unaffected by atropine. PMSF significantly enhanced the analgesic effect of beta-endorphin (END) given by intracerebroventricular (ICV) infusion in rats, the enhanced END analgesia was naloxone-reversible. In Swiss-Webster mice the 24-hr LD50 value for PMSF was 215 +/- 55 mg kg-1 IP; autonomic and behavioral responses were similar to those seen in rats with ICV END. These results indicate that systemic PMSF can protect central endorphin(s) from enzymatic destruction. The significant analgesia, low toxicity, naloxone reversibility and minimal anticholinesterase effects suggest the use of PMSF as a parenteral analgesic.

Peptidase inhibitors reduce opiate narcotic withdrawal signs, including seizure activity, in the rat

Narcotic withdrawal was precipitated by administration of naloxone in a low dose at 2 h after the final dose of morphine in a 9-day dependency-inducing schedule. Withdrawal was characterized by leaps, increased nocifensor activity and by cerebral cortical epileptiform activity, the latter not generally reported to be prominent in narcotic withdrawal. Single large doses of morphine did not provoke epileptiform activity at 2 h postinjection but did induce an acute opioid dependency wherein a moderately high dose of naloxone, ineffective in non-dependent rats, provoked upward leaping and electrocortical epileptiform activity. Pretreatment of the 9-day dependent rats with peptidase inhibitors, administered intracerebroventricularly, significantly reduced withdrawal severity including the epileptiform activity. We propose that peptidase inhibitors protect certain species of endogenous opioids and/or other neuropeptides that tend to suppress expression of the narcotic withdrawal syndrome. Furthermore, our findings suggest that epileptiform activity is a nascent form of cerebral activity hitherto largely unnoticed in narcotic withdrawal and that neuropeptides may be involved in certain epileptic states.

Hyperactivity versus explosive motor behavior induced by opioids in the rat. Mechanisms elucidated with enkephalin-tyrosine-o-sulfate and morphine congeners

A relatively mild hyperactive state (HAS), characterized by agitation and hypermotility, is induced by opiate drugs and opioid peptides in general and is blocked by naloxone. HAS can be distinguished from the profound hyperresponsiveness of an explosive motor behavior (EMB). Sulfation of the phenolic moiety in morphine or in methionine enkephalin essentially abolishes opiate receptor binding activity. The sulfated peptide lacks detectable pharmacological activity in the rat, whereas sulfated morphine is several hundred-fold more potent than morphine in eliciting (EMB). Thus, EMB is elicited only by congeners of morphine having appropriate hydrophilic substitution at C-6 and which is mediated through a receptor that is insensitive to naloxone.

Antibody responses to mycobacterial antigens in patients immunized with BCG for the treatment of neoplastic disease

Precipitin and agglutination antibody response to antigens of Mycobacterium tuberculosis was measured in 43 patients with neoplastic disease who were treated with weekly BCG or intratumor BCG vaccination. Resuspended freeze-dried Tice vaccine was shown to contain soluble mycobacterial antigens. Fourteen patients receiving weekly BCG vaccination developed intense precipitin and agglutination antibody response over the course of several months. Twenty-nine patients receiving intratumor and oral vaccination developed less intense antibody response. Twenty-one of 28 purified protein derivative (PPD)-negative patients converted their PPD. No correlation between antibody, PPD response and antitumor effect could be identified. The importance of identifying the soluble antigen in BCG and of defining the humoral response to purified antigens is discussed.

beta-Endorphin induces general anaesthesia by an interaction with opiate receptors

beta-endorphin, administered into the cerebral ventricles of rats, provokes a sequence of behavioural and electroencephalographic (EEG) responses similar to those observed with general anaesthetics used clinically. Initial behavioural and EEG excitation, motor incoordination and exaggerated responsiveness to sensory stimuli are followed by a stage of rigid immobility with maintenance of local reflexes (withdrawal, corneal) and EEG arousal in response to stimulation. Finally, there is immobility associated with both EEG and behavioural unresponsiveness to severely noxious stimuli. Such a state of unconsciousness with complete analgesia defines general anaesthesia. This state was completely and rapidly reversed by the specific opiate antagonist, naloxone. The induction of general anaesthesia by a water-soluble neurohormonal peptide acting at specific receptor sites has important implications for traditional theories of anaesthesia.

Primary hepatocellular carcinoma with hepatitis B antigenemia: effects of chemotherapy

Eight patients with primary hepatocellular carcinoma (PHC) whose blood was positive for hepatitis B surface antigen (HBsAg) received treatment with cyclophosphamide, adriamycin, and 5-fluorouracil. In 4 cases, a rise in serum HBsAg titer occurred after chemotherapy. In 2 cases involving drug-related leukopenia, the rise in HBsAg titer was marked and associated with a sharp rise in the serum transaminase level (SGOT), up to 1700 in 1 case. Lower-dosage chemotherapy was safely resumed after SGOT had returned to pretreatment levels. No evidence of immunodeficiency after chemotherapy was revealed by in vitro testing of lymphocyte and granulocyte function, percentage of circulating T-cells, and immunoglobulin and complement levels. All 8 cases were negative for e antigen (eAg) and 4 were anti-positive. In 3 of 4 cases, anti-e became negative after chemotherapy, but all remained eAg negative. The negative eAg tests in these cases of PHC suggest they are not highly infectious, in spite of increased HBsAg titers in blood following chemotherapy.

Effects of morphine and naloxone on the K+-stimulated release of methionine-enkephalin from slices of rat corpus striatum

Methionine-enkephalin (ME) released from superfused slices of rat corpus striatum was estimated by radioimmunoassay (RIA). The basal release of 2.5 +/- 0.2 pmol/g/min (0.15% of content per min) was increased approximately 3-fold upon exposure of tissue to 30 mM K+ for 5 min. This increase in release was not observed in the absence of Ca2+. Both morphine (10(-5) M) and (-)-naloxone (10(-5) and 10(-6) M) significantly depressed the release of ME evoked by 30 mM K+ did not alter basal release. The (+)-isomer of naloxone, which lacks opiate antagonist activity, did not affect basal or evoked release. A consistent depression of release was not observed when 47 mM K+ was used to evoke the release of ME. The issue of whether a feedback mechanism controls the release of ME from the striatum cannot be resolved until it is known whether the effect of morphine and naloxone on ME release are mediated by opiate or non-opiate mechanisms.

Morphine derivatives with diminished opiate receptor potency show enhanced central excitatory activity

Central excitatory potency of morphine administered by cerebroventricular infusion in enhanced in derivatives substituted at the 3-position (phenolic group) and/or 6-position (alcoholic group). Morphine-3-glucuronide is several hundred times more potent than morphine in evoking dose-related hyperactive motor behavior which can progress to lethal convulsions. Excitatory potencies in decreasing order are: (1) 3-glucuronide; (2) 3-SO4; (3) 3-OAc, 6-OAc (heroin); (4) 6-OAc; (5) 3-OAc; (6) 3-OH, 6-OH (morphine); (7) 3-OCH3 (codeine); (8) 3-OCH3, 6-OCH3 (thebaine). Levorphanol, lacking a 6-OH group, is devoid of excitatory actions. In this series of substituted morphines, there is an inverse relationship between opiate receptor binding potency and central excitatory potency, but codeine and thebaine behave anomalously. These findings are compatible with the hypothesis that morphine acts upon a species of receptor which mediates behavioral and EEG excitation and is distinct from the recognized opiate receptor mediating sedation and analgesia.

The effect of morphine on human neuromuscular transmission

By utilizing high frequency nerve stimulation, we observed the effects of morphine sulphate, 0.5 mg.kg-1 on human neuromuscular transmission. Tetanic fade at 50, 100 and 200 hz did not change during the one hour period after infusion of morphine. Post-tetanic depression (PTD) of single twitch response increased progressively with time over the one-hour study period. This was most marked with the 100 and 200 hz tetanic frequencies. In contrast, control subjects displayed either no change, or a slight increase (post-tetanic facilitation; PTF), over a similar one-hour test period. We believe these results are best explained by a presynaptic action of morphine, whereby intraterminal mobilization of acetylcholine is impaired by the opiate narcotic drug.

Opiate-like excitatory effects of steroid sulfates and calcium-complexing agents given cerebroventricularly

Intracerebroventricular administration of 10--20 microgram of steroid-O-sulfates induced hypermotility, agitation, salivation, EEG abnormalities, stereotypies, wet dog shakes and seizures. Equivalent effects resulted from 30--200 microgram morphine sulfate (H2SO4 salt), 50 microgram EGTA or 300--400 microgram of sodium sulfate or phosphate, but not chloride, nitrate or acetate. Non-steroid sulfates, steroid glucuronides and steroid phosphates were inactive. Naloxone, previously found to antagonize the excitatory effects of androsterone sulfate, failed to antagonize those of cortisol sulfate, sodium sulfate or EGTA. These findings suggest a role for extracellular calcium ions and for sulfate derived from circulating steroids in central responses to opiates.

Opiate-like naloxone-reversible effects of androsterone sulfate in rats

Androsterone sulfate (5alpha-androstan-3alpha-ol-17-one, 3-sodium sulfate) administered to freely moving rats via cerebroventricular cannulae induced analgesia, wet-dog shakes, body jerks, rigidity, Straub tail, hypermotility, excessive grooming, hyperreactivity to stimuli, aggression, escape behavior, EEG spiking, and behavioral and EEG seizures. These responses resemble those produced by certain opiate drugs and by beta-endorphin, an endogenous peptide; they appear during the 5-min infusion period, persist in some cases for several hours, and are diminished by pretreatment with the narcotic antagonist naloxone. These findings indicate that steroid hormones can act upon at least some of the same central pathways influenced by recognized opiate compounds.