The role of arginine vasopressin in alcohol tolerance

Administration of the neuropeptide, arginine vasopressin, to animals that have acquired functional tolerance to ethanol will maintain such tolerance, even in the absence of further ethanol ingestion by the animals. In mice, this action of the peptide is mediated by central nervous system V1 receptors and requires intact brain noradrenergic systems. Autoradiographic studies have shown that some V1 receptors are localized presynaptically on catecholaminergic neuronal terminals in the mouse lateral septum, suggesting that vasopressin may act via modulation of catecholamine release. In addition, vasopressin has been found to increase mRNA levels for the proto-oncogene, c-fos, in septum and hippocampus, possibly by an action at postsynaptic receptors. Expression of c-fos, which has been hypothesized to play a role in central nervous system neuroadaptation, could transform short-term actions of vasopressin into long-term effects on ethanol tolerance. Studies with vasopressin antagonists indicate that the endogenous peptide influences tolerance, and therefore the effect of chronic ethanol ingestion on vasopressin synthesis and release was studied. In mice and rats, hypothalamic vasopressin mRNA is decreased by chronic ethanol exposure, although effects on plasma vasopressin levels differ in the two species. The effect of ethanol on extrahypothalamic vasopressin synthesis in brain is under investigation. The results suggest mechanisms by which vasopressin can produce long-term changes in central nervous system function, and provide evidence for a disturbance of vasopressin regulation during chronic ethanol ingestion.

Cellular immune responses of leprosy contacts to fractionated Mycobacterium leprae antigens

Antigens of armadillo-derived Mycobacterium leprae sonic extract were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and blotted onto a nitrocellulose membrane, and the unstained blot was converted into 20 fractions of antigen-bearing particles. These were tested in cellular proliferation assays, and reproducible results were obtained between batches of fractions. Peripheral blood mononuclear cells from healthy contacts of leprosy patients (presumed to have protective immunity) were tested with the fractions to investigate which antigens they recognized. A small group of tuberculoid leprosy patients were also tested. Both groups showed a wide range of responses. Almost every fraction stimulated proliferation with at least one donor, yet none was clearly immunodominant or inhibitory in either group. Thus, protective immunity did not appear to be associated with proliferation caused by any single fraction.

T-cell recognition of the 18-kilodalton antigen of Mycobacterium leprae

The 18-kilodalton (kDa) antigen of Mycobacterium leprae was expressed as a fusion protein with a 2-kDa leader peptide and used in proliferation assays with peripheral blood cells. Fifty percent of untreated tuberculoid leprosy patients and 93% of long-term leprosy contacts responded to the recombinant protein in lymphocyte transformation tests. Comparison of the stimulation indices in the two groups showed that the contacts responded more strongly than the tuberculoid leprosy patients. Seventy percent of Mycobacterium bovis BCG-vaccinated European donors responded, although with low stimulation indices. The isolation of 18-kDa antigen-responsive T-cell lines from a BCG-vaccinated British donor confirmed that the 18-kDa antigen contains at least one cross-reactive epitope. These results indicate that the 18-kDa protein is an important antigen in the immune response to leprosy.

Chronic tolerance to ethanol in the N:NIH rat

As the basis for selectively breeding rats from the N:NIH stock on the basis of differential development of tolerance to ethanol, chronic tolerance to the motor-disrupting effects of ethanol was examined. Male (n = 50) and female (n = 46) rats were administered 2.5 g/kg ethanol (i.p.) and the blood-ethanol concentration (BEC) at the time of regain of aerial righting reflex (RARR) was measured. The rats were then placed in inhalation chambers for 8 consecutive days and chronically exposed to ethanol. Thirty-two hours following the cessation of chronic ethanol exposure, the rats were again given a 2.5 g/kg dose of ethanol and the BEC at RARR was again measured. The amount of chronic ethanol tolerance developed, as measured by the difference in BEC at RARR prior to and after chronic ethanol administration, was widely and normally distributed for both male and female rats. Control rats, which did not receive chronic ethanol exposure between the two tests of RARR, did not show tolerance on this measure. A negative correlation (r = -0.46) was found between BEC at RARR prior to chronic ethanol treatment and the amount of chronic tolerance developed using the difference in BEC measure. This correlation suggested that the rats who were initially more sensitive to the effects of ethanol were more likely to display the greatest amount of chronic tolerance. However, using the residuals of the regression analysis of post-chronic ethanol BEC at RARR on prechronic BEC at RARR as an index of tolerance, this negative correlation was not found.(ABSTRACT TRUNCATED AT 250 WORDS)

High level expression of genes cloned in phage lambda gt11

Plasmid cloning vectors have been constructed which allow genes originally cloned in lambda gt11 to be expressed at a high level in Escherichia coli. They are based on the pEMBL and pUC vectors, with the genes transcribed from the lac promoter. The EcoRI site in the vector has been altered to be in the same reading frame as the site used for cloning in lambda gt11. Cloned proteins are expressed fused to a 2-kDa leader sequence containing a run of six Aparagine residues which considerably improves the stability of the recombinant proteins, but does not interfere with immunological assays. Using these vectors, the Mycobacterium leprae 18-kDa protein was expressed at 20 mg per litre of culture and constituted 15% of total cell protein.

Reinforcing and discriminative stimulus effects of Ca-acetyl homotaurine in animals

Ca-acetyl homotaurine (Ca-AOTA) has been proposed as an adjunct for ethanol detoxification. The purpose of the present experiment was to determine whether Ca-AOTA would be predicted to have abuse potential. Rhesus monkeys that were experienced in the intravenous self-administration of cocaine (n = 2) or pentobarbital (n = 2) were given the opportunity to self-administer various doses of Ca-AOTA or its vehicle (0.9% saline). Ca-AOTA (1.0-10.0 mg/kg/injection, intravenously) was not self-administered above saline levels. The discriminative stimulus effects of Ca-AOTA were evaluated in a drug discrimination procedure in which animals were trained to make one response after a training drug and a different response after saline. Rhesus monkeys trained to discriminate d-amphetamine (n = 3) or pentobarbital (n = 3) from saline were tested with doses of Ca-AOTA ranging from 10 to 100 mg/kg (PO by nasogastric tube) and at 3 different pretreatment times (1, 2, or 4 hr). Ca-AOTA failed to engender drug-appropriate responding at any dose or pretreatment condition in either group of monkeys. In addition, Ca-AOTA was tested in 4 pigeons trained to discriminate pentobarbital from saline. Ca-AOTA administration did not result in pentobarbital-appropriate responding in doses ranging from 30-300 mg/kg (IM) and pretreatment times ranging from 30 to 240 min. The lack of both reinforcing properties and discriminative stimulus properties similar to d-amphetamine or pentobarbital suggests that Ca-AOTA has little or no abuse potential.

Recognition of mycobacterial antigens by sera from patients with leprosy

Mycobacterium leprae sonic extracts prepared from armadillo-derived bacteria were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting (immunoblotting) procedures and probed with serum or plasma samples from 20 patients with lepromatous leprosy and 14 healthy endemic controls. Five proteins of 33, 25, 18, 15, and 12 kilodaltons (kDa) were frequently recognized; the 33- and 15-kDa proteins were, respectively, recognized with high intensity by 16 and 13 of the 20 samples from patients with leprosy, whereas only one healthy donor had antibodies that recognized the 15-kDa protein. By the use of M. leprae-specific murine monoclonal antibodies it was demonstrated that the 33-, 25-, and 15-kDa antigens were different from those bound by the available murine monoclonal antibodies. The 18- and 12-kDa proteins detected had molecular masses similar to those detected by the corresponding murine monoclonal antibodies. The serum and plasma samples from patients with leprosy were also used to probe Western blots of a soluble extract of M. tuberculosis. They recognized, among others, antigens with molecular weights similar to those detected in the M. leprae antigenic preparations, although with less intensity and at a lower frequency.

Oral ethanol self-administration in free-feeding rhesus monkeys

The ability of a conditioning procedure to establish oral ethanol self-administration in free-feeding rhesus monkeys was assessed. The conditioning procedure required the monkey to drink an ethanol solution in order to have access to a sweet orange-flavored solution. Following an average of 14 sessions under these conditions, the orange solution was no longer delivered and ethanol solution alone was made available in the sessions. During both the conditioning and the ethanol self-administration portions of the experiment each monkey was required to drink an average of 0.5 g/kg ethanol per session in order to continue in the experiment. Of the nine monkeys exposed to these contingencies, five monkeys continued to self-administer ethanol after the presentation of the orange drink was discontinued. However, two of these five monkeys decreased their ethanol solution intake below 0.5 g/kg within 3 weeks after the conditioning sessions had terminated. The three monkeys that sustained high ethanol intake were male and had histories of drug self-administration, suggesting that gender and drug history may influence the initiation of ethanol self-administration. Once ethanol self-administration was established, concentrations of ethanol from 4 to 15% (v/v) were made available. The monkeys consumed intoxicating amounts of ethanol, as indicated by average intakes ranging from 0.5 to 0.9 g/kg and blood ethanol levels over 100 mg/dl. These results demonstrate that ethanol self-administration can be established and maintained through the initial reinforcement of ethanol consumption by the contingent presentation of another reinforcing stimulus. However, the results of this study also indicate that individual differences may be an important determinant of animals initiating ethanol self-administration.

The nature of the scheduled reinforcer and adjunctive drinking in nondeprived rhesus monkeys

Adjunctive drinking was generated in three free-feeding rhesus monkeys by the contingent and intermittent delivery of flavored pellets. The amount of drinking generated was greater when pellet availability was restricted under fixed-interval schedules compared to a massed-reinforcer control condition. The volume of water consumed depended upon the fixed-interval of pellet delivery (FI 180 sec to FI 1800 sec). Peak amounts of water consumed ranged from 532 ml to 650 ml during the 2 hr sessions and the schedule which generated the most drinking was either FI 420 or FI 600 sec, across monkeys. Variables which did not appear to influence the amount of drinking generated within the session were the amount of water consumed outside the session, the rates of responding maintained by pellet delivery and the pattern of responding for pellet delivery. However, when either cocaine or diazepam was the scheduled reinforcer, these same free-feeding monkeys did not engage in adjunctive drinking. The ability of cocaine and diazepam to generate adjunctive drinking was determined first by gradually decreasing the frequency of pellet delivery while keeping drug delivery constant using a second-order schedule of pellet delivery [FR n(FI 300 sec: drug delivery) with n ranging from 1 to 6]. Second, a range of drug doses was tested under a FI 300 sec schedule (cocaine: 0.01-0.3 mg/kg/injection; diazepam: 0.01-0.56 mg/kg/injection). These results suggest that there may be some restriction on the generation of adjunctive drinking depending upon the nature of the scheduled reinforcer.

Discriminative stimulus and subjective effects of smoked marijuana in humans

The discriminative stimulus (DS) effects of smoked marijuana were studied by training marijuana smokers to discriminate between the effects of marijuana containing 2.7% delta 9-THC (M) and marijuana containing 0.0% delta 9-THC (P). In addition to measures of discrimination responding, subjective effects were assessed with standardized mood questionnaires. The post-smoking increase in expired air carbon monoxide (CO) level was used as an index of smoke inhalation. Relative to P cigarettes, M cigarettes increased heart rate and produced changes on eight mood scales. M cigarettes were rated as harsher and more potent than P cigarettes, and produced lower levels of CO than P cigarettes. The P--M discrimination was readily acquired by most subjects. The DS effects of marijuana showed a rapid onset, appearing within 90 s from the beginning of smoking. The DS effects were dose dependent, with 0.9% delta 9-THC marijuana producing primarily placebo-appropriate discrimination responding, and 1.4% delta 9-THC marijuana producing 100% drug-appropriate responding. This experimental paradigm could be used to determine whether the DS effects of smoked marijuana would generalize to those of other psychoactive drugs.

Diazepam self-administration and resistance to extinction

Self-administration behavior was maintained by a unit dose of 0.03 mg/kg diazepam in 4 of 5 monkeys trained to respond on a lever by successive approximation using diazepam or saline. A dose-response function was determined using diazepam doses ranging between 0.01 and 0.3 mg/kg/infusion. Peak rates of responding occurred at doses of 0.01 or 0.03 mg/kg/infusion and drug intake was directly related to dose. When saline was substituted for diazepam either before or again after the dose-response function was determined, levels of responding remained unexpectedly high, even after as many as 16 consecutive sessions. The rates of responding maintained under extinction conditions appeared to be directly related to the amount of diazepam previously self-administered. For instance, monkeys which did not initially have high rates of responding for saline showed increases in responding after additional exposure to diazepam. Furthermore, the one monkey with low diazepam self-administration rates also had low rates of responding for saline. However, following a period of cocaine self-administration, responding declined in all monkeys when saline was substituted for cocaine. The data suggest that diazepam self-administration affects responding under extinction conditions, an effect which makes the interpretation of diazepam's reinforcing properties difficult.

The induction of oral ethanol self-administration by contingent ethanol delivery

The necessity of delivering a highly reinforcing stimulus (20% sucrose) contingent upon ethanol consumption in order to induce ethanol self-administration in free-feeding rats was investigated. Rats water deprived for 12-16 h were placed in an environment in which ethanol drinking resulted in the presentation of ethanol. This procedure was successful in inducing and maintaining ethanol self-administration over concentrations of 5-20% (v/v). Compared to a group of rats initially reinforced for drinking ethanol with sucrose presentation, contingent ethanol delivery resulted in greater ethanol self-administration behavior. When 20% ethanol was available the group trained with ethanol had average intake of 0.91 g/kg, whereas the group trained with sucrose had a mean intake of 0.69 g/kg in a 30-min session. The results suggest that ethanol's reinforcing properties are sufficient to establish ethanol self-administration within the context of the inducing environment.

Chlordiazepoxide effects on ethanol self-administration: dependence on concurrent conditions

Experiments examined the effects of acute doses of chlordiazepoxide upon ethanol self-administration in the rat. A concurrent-schedule procedure was used that employed choice between ethanol (5%) and a second fluid (either water or a 1% sucrose solution). When ethanol and water were the available fluids, chlordiazepoxide at doses of 15 and 20 mg/kg reduced ethanol-reinforced responding and intake, with a greater reduction occurring at the 20 mg/kg dose. However, when ethanol and sucrose were concurrently available, in many rats only the 20 mg/kg dose of chlordiazepoxide reduced ethanol-reinforced responding. The differences in dose response function occurred in most animals without large changes in the baseline ethanol-reinforced responding across the two concurrent conditions. Thus the dose-effect curve relating chlordiazepoxide and ethanol self-administration can be altered, dependent upon the nature of the concurrently available reinforcers.

Oral self administration of ethanol in free feeding rats

The use of animal models to study factors involved in excessive alcohol intake has prompted a number of investigators to propose criteria for an optimal model. One of these criterion, oral ingestion of intoxicating amounts of ethanol without concomitant weight loss and/or food restriction, has proven difficult to fulfill, especially when using rats. The following study reports a conditioning paradigm which was used to establish oral ethanol self administration in free feeding rats. Through initial reinforcement of 5% (v/v) ethanol consumption with 20% (w/v) sucrose solution, rats were trained to work for and consume concentrations of ethanol up to and including 40%. Blood ethanol levels above 100 mg ethanol/dl blood were frequently found. A control group, induced to drink quinine with the same procedures, indicated the relative importance of ethanol's pharmacological effect in maintaining high levels of self administration. The results show ethanol can maintain oral self administration of intoxicating quantities of high ethanol concentrations in free feeding rats, when its initial consumption is paired with an additional reinforcer.

Induction and maintenance of ethanol self-administration without food deprivation in the rat

Rats were trained to lick at a drinking tube containing 5% ethanol to obtain access to a 0.1-ml dipper containing 20% sucrose. Following 20 of these drinking sessions, a lever press response was shaped and maintained with ethanol presentation in the dipper. This induction procedure resulted in rats responding on a FR 8 schedule of reinforcement to receive 40% (v/v) ethanol. Ethanol intakes over 0.5 g/kg in 30 min were obtained when ethanol concentrations over 10% were available. These intakes frequently resulted in blood ethanol levels over 100 mg ethanol/dl blood. This contingent sucrose induction procedure did not use food deprivation at any time. It is suggested that this procedure can be used to investigate the processes involved with the initiation of ethanol as a reinforcer independent of food restriction procedures.

The radiolucent line beneath the tibial components of the Oxford meniscal knee

Radiolucent lines at the bone-cement interface beneath the tibial components were assessed in 91 consecutive Oxford meniscal knee replacements in 78 patients. Of 80 knees in which radio-opaque cement was used, a radiolucent line was observed in 77, with a radiodense line in the bone immediately adjoining. Radiolucent lines developed in the majority of patients within one year after operation. In 11 knees fixed with radiolucent cement (which precluded assessment of the radiolucent line) a radiodense line was observed beneath the lucent cement in all cases. Histological examination of the interface obtained from secure tibial components showed the lucent zone to be composed of fibrocartilaginous connective tissue and the radiodense line to be a thick lamella of bone. It is suggested that the living bone under a rigid prosthesis requires a layer of relatively compliant fibrocartilaginous material at its interface to accommodate load-bearing. Attention is drawn to the importance of the radiodense line: its presence may constitute positive evidence that healing at the level of bone section is complete and that equilibrium is established; its absence at a mature interface may indicate disequilibrium and impending failure.

n-Propanol induced microcephaly in the neonatal rat

Neonatal rats were reared using an artificial feeding technique from postnatal day 5 through 18. On days 5, 6, 7 and 8 some animals received n-propanol in their milk formula with the remaining animals serving as controls. The propanol was given in doses similar to that of ethanol which is known to result in microcephaly using this procedure. Following the 4 day alcohol exposure, all animals received the plain milk formula until day 18, when they were decapitated and various organ weights measured. Brain weights and brain/body weight ratios were significantly decreased in the alcohol exposed group. Biochemical analysis showed the alcohol exposed group had a decreased amount of DNA in all brain areas examined. Cholesterol levels were decreased in the forebrain and cerebellar samples of the alcohol group, while protein levels were decreased only in the forebrain samples. The results suggest that exposure to n-propanol during a portion of the brain growth spurt of the neonatal rat inhibits brain development. The biochemical measures of brain growth imply n-propanol interferes with the development of the brain in a manner similar to ethanol.

Ethanol-induced microcephaly in neonatal rats: relation to dose

Neonatal rats were exposed to several different doses of ethanol during the first part of the brain growth spurt (postnatal days 5, 6, 7 and 8) and examined for decreased brain weights at 18 days of age. The occurrence of reduced brain weight was found to require a dose of at least 6.0 g ethanol/kg body weight/day. Above this dose, the extent of brain weight reduction was related to increased dose, provided death from overdose did not occur. Measured blood ethanol levels suggested that blood levels below 100 mg/100 ml failed to result in significant brain weight reductions. The possibility that blood ethanol levels below this point may impair brain growth in more subtle ways remains to be determined.

Neonatal ethanol exposure: effects on adult behavior and brain growth parameters

Neonatal rats were reared using an artificial feeding technique from postnatal day 4 through 18. On postnatal day 4 through 7, some animals were given ethanol in their milk formula with the remaining animals serving as controls. The ethanol was given in amounts that have been shown to induce microcephaly when animals are examined at 18 days after birth. In this study, on postnatal day 18, all animals were weaned and allowed ad lib food and water until they were sacrificed at 60 days of age. When the animals were 30 days old, they were tested on a battery of behavioral tasks (nose poke, passive avoidance, and open field). No differences were found between the ethanol exposed animals and their controls on passive avoidance or nose poke activity. Ethanol-exposed female animals showed increased activity compared to their controls in the open field. There were no differences in open field activity between the ethanol exposed males and their controls. An examination of brain growth parameters (wet weights, DNA, cholesterol and protein content) showed no difference between the brains of ethanol-exposed males compared to controls at 60 days of age, regardless of brain parameter or brain area studied (forebrain, cerebellum or brainstem). The brains of ethanol-exposed females, however, had considerably less catch-up growth, with the ethanol effect on the cerebellum being very similar to that observed at 18 days of age. The results imply that sex and the time of ethanol exposure may interact to determine the ability of the brain to develop following a neonatal alcohol insult.

Hypogammaglobulinaemia during pregnancy in identical twin sisters

The clinical histories and reaction to pregnancy is described in identical twin sisters with acquired hypogammaglobulinemia. Additional evidence for the genetic basis of this disorder is advanced. A possible association with myasthenia gravis is noted and the occurrence of fetal growth retardation is described. Replacement therapy should be given when the diagnosis is made, and high doses might be useful during pregnancy especially if fetal growth retardation seems to be present.

Ethanol and tertiary butanol induced microcephaly in the neonatal rat: comparison of brain growth parameters

Neonatal rats were reared using an artificial feeding technique from postnatal day 4 through 18. On Postnatal Days 4 through 7, corresponding to the onset of the brain growth spurt, some animals were administered either ethanol or tertiary butanol in the milk formula, with the remaining animals serving as controls. The alcohol dosages were equated to each other by membrane to buffer partition coefficients. Following the 4 day alcohol exposure, all animals were given the plain milk formula until Day 18, when they were decapitated and various organ weights measured. The only significant weight differences between alcohol-exposed animals and controls were absolute brain weights and brain weight/body weight ratios, which were decreased in both alcohol groups. Biochemical analysis of the brains showed similar DNA levels for the ethanol, tertiary butanol, and control group forebrain samples. Both alcohol groups had significantly lower DNA levels than the control group for the hindbrain samples. Cholesterol levels and cholesterol/DNA ratios indicated that ethanol, but not tertiary butanol, impaired myelination and/or arborization. Total protein and protein/DNA ratios suggested that ethanol interfered with protein production and/or incorporation. The tertiary butanol animals did not show this deficit. The results imply that while exposure to either alcohol during the brain growth spurt can lead to microcephaly, the ethanol-induced alteration of myelin formation and protein production in neonatal brain tissue may be due to additional properties of ethanol.

Ethanol induced microcephaly in the neonatal rat: occurrence without withdrawal

Neonatal rats exposed to ethanol with an artificial rearing technique on postnatal days 4--8 have been found to have up to 20% decrease in brain weight when examined on postnatal day 18. Following the four day ethanol exposure these animals went through a moderate to severe abstinence syndrome. Since the appearance of any detectable brain growth differences were not found until after the withdrawal period, it was possible that the microcephaly was a result of withdrawal and not ethanol exposure. To test this hypothesis, neonatal rats were exposed to ethanol for either the four day exposure period used in the previous work, or until determination of brain growth impairment at day 11. This last group of animals were administered a daily dose of ethanol such that they did not have an observable abstinence syndrome. Examination of brain weights on day 11 revealed no differences in the extent of the observed microcephaly between the ethanol exposure conditions, suggesting that withdrawal per se was not responsible for the production of the brain growth retardation.