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PubMed1987

Role of acetaldehyde in ethanol-induced increase in the activity of phosphatidate phosphatase in rat liver.

The effect of ethanol on the activity of phosphatidate phosphatase was studied in rat liver using membrane-bound phosphatidate and phosphatidate emulsion as substrate. A single large dose of ethanol (5 g/kg body wt) caused an increase in the enzyme activity measured with membrane-bound phosphatidate after an approximate 2-hr lag period in both cytosolic and microsomal fraction and the increase was approximately 2.2- and 1.8-fold that in control rats at 5 hr in cytosol and microsomes, respectively. A similar time-course of the increase was obtained with phosphatidate emulsion as substrate. These ethanol-induced increases in the activity of cytosolic and microsomal phosphatidate phosphatase were blocked by the pretreatment of rats with actinomycin D. The ethanol-induced rise in the activity of cytosolic and microsomal phosphatidate phosphatase measured with membrane-bound phosphatidate was abolished when rats were injected with pyrazole prior to ethanol administration. On the other hand, pretreatment with cyanamide enhanced the increase in cytosolic activity produced by a suboptimal dose of ethanol (1 g/kg), while microsomal activity was not affected by the same treatment, suggesting that acetaldehyde may be selectively involved in the ethanol-induced increase in the activity of cytosolic phosphatidate phosphatase. This hypothesis was supported by a finding that administration of paraldehyde, a cyclic trimer of acetaldehyde, produced an increase (35%) in cytosolic activity, but not in microsomal activity.

Acetaldehyde↗
PubMed1985

The action of intravenous anaesthetic and central depressant drugs on the contractures elicited by tetraethylammonium in the chick biventer cervicis muscle.

A group of intravenous anaesthetic drugs was compared with methohexitone sodium for their ability to potentiate tetraethylammonium induced contractures of the chick biventer cervicis muscle (TEA test). The equipotent concentrations in the TEA test were: methohexitone 8.8 X 10(-5) M, propanidid 1.78 X 10(-4) M, althesin 3.58 X 10(-5) M (in terms of alphaxalone), etomidate 1.6 X 10(-4) M, thiopentone 2.13 X 10(-5) M and valium 4.95 X 10(-5) M. There was no relation between activity in the TEA test and excitatory muscular activity reported clinically. The central depressant drugs ethyl alcohol and urethane also potentiated TEA but they were only active in high concentrations (10(-1) - 10(-2) M). alpha-Chloralose was inactive but paraldehyde (3.8 X 10(-3) M) actually reduced TEA induced contractures. Lipophilicity is only one factor in determining activity in the TEA test, the ability to block Ca2+ reuptake may also be important.

Alfaxalone Alfadolone Mixture↗
PubMed2001

Brain-derived neurotrophic factor superinduction parallels anti-epileptic--neuroprotective treatment in the pilocarpine epilepsy model.

Antiepileptic drugs provide neuroprotection in several animal models of brain damage, including those induced by status epilepticus (SE). The mechanisms involved in this action are unknown, but neurotrophic factors such as brain-derived neurotrophic factor (BDNF) may play a role. In this study we investigated the changes in BDNF levels in rats in which SE had been induced by pilocarpine injection (400 mg/kg i.p.) and continued for several hours (unprotected group). In other animals (protected groups), SE was suppressed after 30 min by intraperitoneal injection of either diazepam (10 mg/kg) + pentobarbital (30 mg/kg) or paraldehyde (0.3 mg/kg). In diazepam + pentobarbital-treated rats the hippocampal damage caused by SE was significantly lower (p < 0.05) than in unprotected animals. In addition, 2 and 24 h after pilocarpine injection, the levels of BDNF mRNA were moderately increased in the unprotected group, but 'superinduced' in protected animals, especially in the neocortex and hippocampus. A time-dependent increase in BDNF immunoreactivity was also found by western blot analysis in rats treated with diazepam + pentobarbital. In contrast, a decrease of BDNF immunoreactivity occurred in the unprotected group. In conclusion, these results show that neuroprotection induced by anti-epileptic drugs in pilocarpine-treated rats is accompanied by strong potentiation of BDNF synthesis in brain regions involved in SE.

Animals↗
PubMed1984

Aldehyde-induced platelet aggregation.

Formaldehyde, acetaldehyde, malondialdehyde, glutaraldehyde and paraldehyde, when added in vitro to platelet-rich plasma, generate a similar distinct platelet aggregation response which is dose dependent when measured with a manual visual microscopic technique and by computerized image analysis, 'computerized platelet aggregation analysis'. Light transmission aggregometry did not measure this aggregation in a reliable manner. The aggregating reaction was specific to the aldehyde group and was not seen when the aldehyde was replaced by an alcohol, ketone, or acetate group in the case of acetaldehyde. The maximal aggregating effect of these aldehydes was directly proportional to the number of aldehyde groups per molecule. Aggregation was found to require the presence of plasma, but not von Willebrand's factor.

Acetaldehyde↗
PubMed1971

Blockade of the reticulospinal inhibitory pathway by anaesthetic agents.

1. Adult cats were decerebrated at the intercollicular level. The effect of the anaesthetic agents, pentobarbitone, paraldehyde, tribromethanol, chloralose and procaine on the reticulospinal inhibitory pathway, which produced inhibition of segmental reflex potentials, was analysed.2. The doses which blocked this inhibitory pathway did not exceed the doses required to produce surgical level anaesthesia with any of the drugs.3. After the reticular inhibition of the reflex potentials was abolished, the reflex potentials were augmented by reticular stimulation with a higher intensity. This was thought to be due to spread of current to the excitatory pathways which were not completely depressed by the anaesthetic agent.4. The resistance of the reticular facilitation of the reflex potentials to inhibition by these drugs after abolition of inhibition corresponded in general to the degree of excitement in intact mice produced by the same drugs.5. These findings seem to indicate that the preferential block of the reticulospinal inhibitory pathway may be an important neural mechanism for the excitement stage of anaesthesia.

Action Potentials↗
PubMed1974

The effects of certain anaesthetic and anti-convulsant drugs on the CSF potassium fluxes of the dog.

1 A technique has been developed for open-ended perfusion of the cerebroventricular system of the unanaesthetized dog.2 Perfusion with an artificial CSF solution containing inulin and (42)K allowed the potassium fluxes out of and into the CSF to be monitored over a period of 2 to 3 hours.3 Sodium thiopentone and sodium pentobarbitone, in doses producing light anaesthesia, caused varying degrees of depression (up to 50%) in the CSF potassium fluxes, influx being consistently more affected than efflux. These effects are attributed to a decrease in the potassium exchange between extracellular and intracellular compartments in the brain.4 Diazepam depressed both potassium fluxes by up to 10% while there was some evidence that diphenylhydantoin depressed only potassium influx.5 Paraldehyde, in contrast to the other drugs, when given at a dose level sufficient to produce light anaesthesia, stimulated CSF potassium fluxes, particularly efflux.

Anesthetics↗
PubMed1992

Classical genetic analyses of responses to sedative-hypnotic drugs in crosses derived from long-sleep and short-sleep mice.

A classical (Mendelian) genetic analysis of responses to eight sedative-hypnotic compounds (ethanol, urethane, trifluoroethanol, chloral hydrate, barbital, paraldehyde, methyprylon, pentobarbital) was conducted in crosses derived from mouse lines that were selectively bred for differential duration of anesthesia following ethanol. The sleep-time responses of these mice, the long-sleep (LS) and short-sleep (SS) mouse lines, as well as the F1, F2 and backcross (F1 x LS, F1 x SS) generations were measured. Generally, differences in responses among the generations were greater for water soluble compounds than were differences for more lipid soluble compounds. Also, the inheritance of responses to water soluble compounds could be explained primarily by additive effects of alleles while the inheritance patterns for more lipid soluble compounds were more complex. Genetic correlation with ethanol response decreased with increasing lipophilicity. These results suggest that the selection of the LS-SS mouse lines was specific for water soluble anesthetic agents. Because several of these agents are known to act at GABA receptors, examination of the interactions of compounds which differ in lipid solubility at GABA receptors from LS and SS mice may prove useful in elucidating the mechanism of the anesthetic actions of ethanol and other drugs.

Alcohol Drinking↗
PubMed1989

EEG in anaesthetized rats.

The constancy of rat EEG during surgical anaesthesia induced by phenobarbital, cholorose, paraldehyde, and inactin was investigated. The results showed that intraindividual variations and spontaneity of EEG were not abolished in the anaestheized animals. However, at the higher of the two doses used, the EEG was less variable. Our findings thus indicate that in the study of drug actions on the EEG of anaesthetized animals, the results obtained not only represent the interaction of the anaesthetic and the drug on the animal EEG but is also a reflection of the dosage of the anaesthetic employed.

Anesthesia, General↗
PubMed1989

Clinical and EEG response to anticonvulsants in neonatal seizures.

During a two year period prospective continuous electroencephalographic (EEG) monitoring of 275 infants identified seizure activity in 55 cases, 31 of whom were treated with anticonvulsant drugs on clinical grounds. EEG and clinical response was complete in only two and equivocal in another six. Clinical response with persistent EEG seizures occurred in 13 and neither clinical nor EEG response in 10. There was no significant improvement in the generally poor neurological outcome compared with that in 24 infants whose seizures were not treated because of limited or absent clinical manifestations. Background EEG abnormality (as an index of associated cerebral dysfunction) was a guide to potential lack of response to anticonvulsant drugs; it was also predictive of subsequent clinical outcome irrespective of treatment. This study shows that commonly used anticonvulsant drugs (phenobarbitone, paraldehyde, phenytoin, and diazepam) have little effect on seizure control or neurological outcome in neonatal seizures associated with haemorrhagic, hypoxic, or ischaemic cerebral lesions. In view of the variable clinical appearance of EEG seizure activity, continuous EEG monitoring should be an essential feature of further study of neonatal anticonvulsant treatment.

Anticonvulsants↗
PubMed1969

Dangers of treatment of status epilepticus with diazepam.

The results of treatment of 25 patients admitted from psychiatric institutions indicate that diazepam is the drug of first choice in the treatment of status epilepticus. The dangers of treatment appeared to result from combined use with other drugs. Respiratory depression occurred in one patient and hypotension in five patients, all of whom had been given intramuscular phenobarbitone in addition to intravenous diazepam. The two serious cases of hypotension had also been given parenteral paraldehyde.

Adolescent↗
PubMed1987

The hypothalamic magnocellular system in the domestic fowl. Study on semithin sections.

Neuronal characteristics and location of the neurosecretory, magnocellular, fuchsin-paraldehyde-positive (FA+) system of the fowl are described at the light-microscopic level on serial semithin sections. Three nuclei make up this system, the nucleus supraopticus, n. magnocellularis interstitialis and n. paraventricularis. These nuclei display magnocellular neurons, not showing a parvocellular component. The neurons of the three nuclei showed a scattered pattern of distribution and a dense surrounding neuropil. Groups formed by magnocellular neurons were found in the three nuclei and groups formed by one magnocellular and a parvocellular neurons were only found in the n. magnocellularis interstitialis and in the n. paraventricularis. The presence of neurons in apposition to blood vessels was frequent in the magnocellular FA+ system of the domestic fowl.

Animals↗
PubMed1978

Drug therapy reviews: drug therapy of status epilepticus.

Drug treatment of status epilepticus is reviewed. Tonic-clonic, focal motor, complex partial and absence status epilepticus are discussed. In managing tonic-clonic status epilepticus one should: (1) maintain vital functions at all times, (2) identify and treat precipitating factors and (3) administer an intravenous loading dose of phenytoin sodium or phenobarbital sodium. Careful use of i.v. diazepam sometimes helps to achieve these objectives. Intravenous phenytoin sodium and phenobarbital sodium provide definitive, long-term control of tonic-clonic seizures but must be administered slowly and require time to reach peak brain concentrations. Intravenous diazepam appears to enter and exit from the brain rapidly and may control seizures while therapeutic brain concentrations of long-acting drugs are being achieved. Phenytoin, phenobarbital and diazepam should not be administered intramuscularly in treating status epilepticus. Treatment of focal motor and complex partial status epilepticus is similar to that of tonic-clonic status epilepticus, but i.v. diazepam is required less frequently and loading doses of phenytoin and phenobarbital sometimes can be given more slowly. Status epilepticus of the absence type is managed with i.v. acetazolamide sodium or diazepam. Paraldehyde, muscle relaxants, general anesthesia and lidocaine may be tried when conventional therapies fail.

Anesthesia, General↗
PubMed1977

[Median eminence of the hypothalamus in hypophysectomized rats: its structure and ultrastructure].

The median eminence of the hypothalamus of intact and hypophysectomized rats has been studied by means of light and electron microscopy. Paraldehyde-fuchsin (PAF)-positive material is revealed in the external zone of the median eminence in 2-5 days after the operation. The PAF-positive material is also accumulated in the neurosecretory fibres localized around subependymal blood vessels. A2 fibres containing granules of 100-150 nm in diameter and B type fibres with granules up to 100 nm in diameter are seen in the external zone of the median eminence in intact rats. Besides, A1 fibres with granules of 120-200 nm in diameter are found near hypophyseal portal vessels in hypophysectomized animals. All type terminals make contact with blood vessels in the subependymal zone of the median eminence of hypophysectomized rats. It is suggested that terminals of the neurosecretory fibres of types A2 and B permanently make contact with the primary portal capillaries in the external zone of the median eminence, while A1 fibres ingrow in the median eminence in the course of postoperative reparation.

Animals↗
PubMed1983

[Neurosecretory activity during regeneration in the oligochaete annelid Tubifex tubifex].

Following amputation of the posterior half of Tubifex, all the nerve cells stainable by paraldehyde fuchsin (NF) immediately discharged. Fifteen minutes later, some stained NFs reappeared. Their number increased, reached a peak far above the normal level, then slowly decreased. This peak occurred 8 hours after amputation in the brain, after 3-4 days in the ventral ganglia. A similar cycle took place during the anterior regeneration of Tubifex whose four anterior segments were previously cut away. Following a double amputation (behind the first or fourth segment and at half length), the stimulation of the neurosecretory activity was even clearer, the number of NFs reaching a higher and earlier peak. Correlatively, the regenerative histogenesis was accelerated in the caudal blastema.

Animals↗
PubMed1978

Management of alcohol withdrawal syndromes.

Withdrawal from alcohol (ethanol, ethyl alcohol) or other general sedatives leads to progressive hyperactivity that progresses from tremulousness, sleep disturbance, and hallucinosis, to the more serious rum fits and delirium tremens (DTs). Withdrawal can be prevented and, in most cases, arrested by prompt replacement of alcohol with paraldehyde, benzodiazepines or other general sedatives. Diazepam is appropriate replacement therapy for most patients. When delirium is manifest, the chance is greater than 15% that the patient will die, and this reaction cannot be aborted. The patient with DTs must be calmed with a general sedative that has a rapid onset of maximal effect to prevent overdosage. Diazepam, 5 mg intravenously every five minutes, permits evaluation of the maximal effect of each dose before the next dose is administered. Although some patients have advance sedative or alcohol withdrawal, great care must be taken to elicit the proper history of alcohol abuse so that sedative replacement therapy will prevent or abort early withdrawal, thus sparing the patient a mortality equivalent to that of acute myocardial infarction or Russian roulette.

Alcohol Drinking↗
PubMed1978

Abnormality in body curvature of Cyprinus carpio after injection of anaesthetics.

Abnormalities in the body curvatures were noticed in Cyprinus carpio after the injection of anaesthetics, viz. paraldehyde, tertiary butyl alcohol and butanol. These abnormalities occurred behind the dorsal fin and progressively developed over a period of four months. The abnormalities affect the locomotion and speed of swimming of the fish and appear to be due to toxic effects of the anaesthetics.

Animals↗
PubMedDate not supplied

Complications following sedation of paediatric oncology patients undergoing radiotherapy.

Sedation is often required to achieve immobilisation of small children during radiotherapy to avoid irradiation of normal tissues during the course of treatment. At the University College Hospital, Ibadan radiotherapists provide sedation for such patients with administration of parenteral and/or oral promethazine, diazepam, chlorpromazine and paraldehyde. This retrospective review of 84 children aged 1 month to 6 years who received sedation for radiotherapy over a period of twenty-one to twenty-eight days showed that 48% had complications. These included injection cellulitis (85.3%), injection abscess (4.87%), paresis of the lower limb (7.3%), aspiration pneumonia (2.4%). Anaesthetists in developing countries should be encouraged to extend their expertise in caring and resuscitation of sedated or unconscious patients to the radiotherapy unit. This will allow for the use of a wider variety of sedative agents and better monitoring as well as minimise or eradicate complications.

Abscess↗
PubMed2003

Ultrastructural aspects of the follicular cells of the pars tuberalis in bats related to the seasonal cycle.

The topography and structure of the follicular cells and the follicular cavity of the hypophyseal pars tuberalis (PT) were studied in adult hibernating bats (Pipistrellus pipistrellus and Rhinolophus ferrumequinum) of both sexes, during the annual seasonal cycle and the reproductive cycle. The follicular cells were found to be organized around a central cavity. They showed a polyhedral shape and apical microvilli protruding into central cavities. During hibernation, the follicular cells showed active cytoplasmic organelles, clusters of glycogen particles, and lipid droplets. In the supranuclear cytoplasm, 9+2 type cilia, some dense bodies, microvesicular vacuoles, and thin actin-like filaments (rather scarce during autumn) were detected. The contents of the follicular cavity showed well-defined ultrastructural seasonal characteristics, with a colloid-like aspect during awakening and a strongly granular aspect during autumn oestrus and mating. Positive staining for PAS and paraldehyde fuchsin, and a marked reaction to lectins PHA-L4, MAM, and RCA 60 suggested the presence of sialo-glycoproteins in the follicular cavities. Both follicular and endocrine PT-specific cells appeared to mark the boundary of follicular cavities. This finding suggests that the follicular cavity contents are comprised of both types of cells, rather than by cell fragmentation or degeneration products.

Animals↗