Vinyl and alkynyl pyrimidines as michael acceptors: an approach to a cylindrospermopsin substructure

Vinyl pyrimidine 9 and alkynyl pyrimidine 24 undergo base-mediated intramolecular conjugate addition reactions in which a carbamate and a urea, respectively, behave as nitrogen nucleophiles. The cyclic carbamate derived from 9 was converted to 11 via a metalation-oxidation reaction in which 2-phenylsulfonyl-3-phenyloxaziridine behaves as a hydroxylation reagent. The cyclic urea derived from 24 was converted to cylindrospermopsin substructure 30 using dimethyldioxirane to introduce the C(7) hydroxyl group.

Syphilis in an urban community

Recent reports of changes in the epidemiology of syphilis prompted a review of syphilis in our urban community. All records of positive syphilis serology reported to the City of Scarborough Health Department between 1990-94 were reviewed for key epidemiological variables. While infectious stages of syphilis were reported more often among young adults, incidence for all stages increased among successive age groups, with a male/female ratio of 1.0. One in five cases were identified during immigration screening, with a disproportionate number of cases immigrating from the Caribbean, Africa and Subcontinental India. Overall, the incidence of syphilis decreased during the study. However, a correlation of 0.95 was found between the provincial incidence of syphilis and number of tests ordered. The observed decrease in syphilis, therefore, may represent a decrease in detection owing to lack of testing.

Genetic determinants of morphine activity and thermal responses in 15 inbred mouse strains

Mice from 15 standard inbred strains were tested for sensitivity to two effects of acute morphine administration, open-field activity, and body temperature changes, at doses of 0, 4, 8, 16, and 32 mg/kg, I.P. Large strain differences were consistently observed, indicating a substantial degree of genetic determination of these traits. For morphine-induced activity, some strains were markedly insensitive to all doses (e.g., C3H/He, CE), while others showed increases and some decreases at the same morphine dose. For thermal responses, one strain was insensitive to all doses employed (C3H/He), while others showed marked hypothermia and some hyperthermia at the same dose. Although strains differed in brain morphine concentrations at time of behavioral testing, pharmacokinetic differences were unrelated to both measures of morphine sensitivity. Correlations among strain means (estimates of genetic correlations) were rather high across doses within each measure, indicating that strain differences to a given effect of morphine were rather stable across doses. This suggests substantial commonality in genetically mediated mechanisms across the dose range used for activity, and also for thermal responses. In contrast, genetic correlations between activity and thermal responses were not significant at any dose, indicating that these two traits are largely genetically independent.

Venous sequelae. Part 2: Other influencing factors and techniques for dealing with the problem

In a previous paper, the nature of venous sequelae were described, and the etiologic factors of mechanical and drug injury related to the development of superficial vein thrombosis were addressed. This paper deals with additional factors that may be involved or that have been exposed for reducing or eliminating the problem.

Maxillary nerve block: a case report and review of the intraoral technique

Maxillary nerve blockade is not commonly used by general practitioners due to a lack of experience with the techniques involved and the fear of iatrogenic damage. Nevertheless, it represents an excellent method of producing profound anesthesia in the maxilla, with definite indications in selected instances. The anatomy and techniques associated with the maxillary block, as well as the indications, contraindications and complications are reviewed, and the use of the greater palatine foramen approach to treat a patient with a facial abscess is described.

Effects of dizocilpine in withdrawal seizure-prone (WSP) and withdrawal seizure-resistant (WSR) mice

Mice selectively bred to be Withdrawal Seizure-Prone (WSP) or Seizure-Resistant (WSR) after chronic ethanol administration have been reported to be differentially sensitive to the anticonvulsant and proconvulsant effects on alcohol withdrawal of drugs interacting with glutamate receptors. Several behavioral effects of the noncompetitive glutamate receptor antagonist, dizocilpine, were determined in WSP and WSR mice to see whether their differential sensitivity generalized to effects unrelated to seizures, and to see whether it was only apparent during ethanol withdrawal. Dizocilpine potentiated the loss of righting reflex induced by ethanol, and dose-dependently stimulated habituated and nonhabituated open field activity. WSP and WSR mice were equally sensitive to these effects of dizocilpine. Pretreatment with dizocilpine increased the transcorneal amperage necessary to produce maximal electroshock seizures: WSR mice were more sensitive than WSP to this effect. Ethanol withdrawal (i.e., testing 6 h after a 24-h exposure to ethanol vapor) and dizocilpine had several effects on mice tested in the hole-in-wall apparatus. Several differences between WSP and WSR mice were also found, but in no case did dizocilpine differentially affect ethanol-withdrawing WSP and WSR mice. Across these experiments, differences between WSP and WSR mice in response to dizocilpine were rather specific. For some responses, WSP and WSR mice were equally sensitive, but only in the seizure-related measure assessed were naive WSR mice more sensitive than WSP.(ABSTRACT TRUNCATED AT 250 WORDS)

Successful mandibular anesthesia following numerous unsuccessful attempts: a case report

The management of a very anxious patient who had undergone uneventful dental treatment in the past, but posed a problem when clinicians attempted to secure profound mandibular anesthesia, is discussed. This case report also examines the advantages and disadvantages of the Gow-Gates mandibular block technique, and describes the patient's subsequent management.

Voluntary consumption of ethanol in 15 inbred mouse strains

To determine genetic differences in ethanol consumption, 15 commonly used inbred strains of mice were given ad libitum two-bottle choice between ethanol, 0.2% saccharin, or ethanol plus saccharin in one bottle versus tap water in the other bottle. Three different concentrations of ethanol were used: 3%, 6% and 10% (v/v). Of the 15 strains, the C57BL/6J, C57BR/cdJ and C57L/J strains showed the most consistent higher intake of ethanol either with or without 0.2% saccharin. In marked contrast, the DBA/1J and DBA/2J strains consistently showed the lowest intake. Consumption of 3% ethanol without saccharin was highly genetically correlated with saccharin consumption (r = 0.77), suggesting that low concentrations of ethanol may have a sweet taste that affects voluntary consumption. Most strains showed very different patterns of response to ethanol with or without saccharin. Three patterns of strain responses were identified. Some strains avoided higher concentrations of ethanol whether in water or saccharin; some appeared to be sensitive to the ability of saccharin to mask the odor of ethanol; and some may have reduced consumption only when ethanol concentrations were high enough to produce aversive postingestional effects. Whereas earlier studies generally attempted to explain strain differences in consumption by invoking a single mechanism, our results demonstrate that more than one mechanism is necessary to explain the preferential ethanol intake of all strains studied.

Serotonin and genetic differences in sensitivity and tolerance to ethanol hypothermia

Mice have been selectively bred for genetic sensitivity (COLD) or insensitivity (HOT) to acute ethanol-induced hypothermia. COLD mice readily develop tolerance to the hypothermic effects of ethanol (EtOH) when it is chronically administered, while HOT mice do not. A number of studies have implicated serotonergic systems in both sensitivity and the development of tolerance to the hypothermic and ataxic effects of EtOH. In the experiments reported here, we administered the serotonin (5HT) neurotoxin 5,7-dihydroxytryptamine (5,7-DHT) to HOT and COLD mice before the acute and chronic administration of equipotent doses of EtOH. 5,7-DHT lesions significantly reduced (by about 65%) whole brain levels of 5HT in both selected lines. This treatment reduced sensitivity to acute EtOH hypothermia in COLD, but not in HOT mice, and blocked the development of tolerance only in COLD mice. Metabolites of 5HT, norepinephrine, and dopamine were generally increased in hypothalamic and brain stem tissue after acute EtOH injection, but HOT and COLD mice were not differentially susceptible to these effects. These results suggest that genes affecting 5HT systems may mediate some of the differences in response to the hypothermic effects of EtOH characterizing HOT and COLD mice.

Local anesthetic update

The development of new local anesthetics has not been an area of particularly active research for a number of years. However, as the use of regional anesthesia has expanded, additional anesthetic requirements and techniques have stimulated the search for newer drugs and ways of modifying existing ones. This article reviews some of the more recent developments in this field.

The pharmacology of local anesthetics--a review of the literature

In the nineteenth century, some natives of Peru noticed circumoral numbness, euphoria and analgesia after chewing the leaves of the Erythroxylen coca bush. By 1850, cocaine was isolated from the plant, marking the start of the local anesthetic era in clinical medicine. Over the past 50 years, many synthetic local anesthetics have been developed which have fewer side effects, increased specificity of action and a wider margin of safety than cocaine. Currently, local anesthetics are used topically, for local infiltration; and intravenously, for peripheral nerve blockade, for sympathetic blockade, as well as for epidural and intrathecal use. Although the route of administration may affect pharmacokinetics and pharmacodynamics, it is the purpose of this article to review the general pharmacology of this entire range of clinically useful compounds.

Malignant hyperthermia and the general dentist: current recommendations

Malignant hyperthermia is a potentially fatal disease that may be triggered by the administration of specific drugs or by stress. Although most often associated with general anesthesia, stress can be a significant stimulus and is therefore of concern to the general dentist. The decision as to how and where to treat these patients is complicated by conflicting recommendations from various sources. The aim of this article is to propose a protocol for the dentist to use in the treatment of patients with a history of malignant hyperthermia. The dentist must assess the patient for both their susceptibility to a crisis and the degree of stress of the planned procedure. For non-stressful treatment, it is reasonable to assume that the general dental practitioner can treat these patients in his office. For stressful treatment, advanced preparation is advised.

Lack of differential effect by Ultracaine (articaine) and Citanest (prilocaine) in infiltration anaesthesia

It has been claimed that anaesthesia of mandibular pulpal and lingual soft tissue, as well as maxillary palatal soft tissue, results following buccal infiltration of the local anaesthetic Ultracaine (articaine HC1). However, this has never been scientifically proven and the aim of this investigation was to test these claims by comparing articaine to a standard anaesthetic, Citanest (prilocaine HC1). In order to study this, a double blind, randomized trial was conducted in healthy adult volunteers. In these subjects, the ability to induce maxillary and mandibular anaesthesia following buccal infiltration with articaine (as compared to prilocaine given contralaterally), was determined by measuring sensation to electrical stimulation at the tooth, buccal and lingual soft tissue at each of the four non-carious, non-restored, second molars. Results showed that there were no statistically significant differences between articaine and prilocaine in their ability to induce anaesthesia for any tissue at any of the six sites (p greater than 0.05) as determined by chi-square analysis. Analysis of effect on sensation for 25 minutes post-administration also failed to demonstrate a difference between the two drugs. Therefore, these data are not consistent with superior anaesthesia efficacy by articaine at any site, including the mandibular pulpal, lingual or maxillary palatal tissues, in the second molars studied.

Acute chest pain during dental treatment--a case report

Acute chest pain is one of the most common and potentially serious medical emergencies seen in hospital emergency departments. Because the elderly population is generally living to an older age, is more ambulatory, and is seeking more sophisticated dental care, an acute episode of chest pain in the dental office is a potential possibility. This paper will discuss a typical case report with emphasis not only on prevention, but on a step-by-step method for stabilizing any emergency situation that may occur in the dental environment.

Comparison of articaine and prilocaine anesthesia by infiltration in maxillary and mandibular arches

Claims that labial infiltration of the local anesthetic articaine HCl (Ultracaine DS) results in anesthesia of mandibular pulpal as well as maxillary and mandibular lingual soft tissue have never been scientifically substantiated. The aim of this investigation was to evaluate these claims, by comparing articaine to a standard anesthetic, prilocaine HCl (Citanest Forte). To investigate this, a double blind, randomized study was conducted in healthy adult volunteers. In each volunteer, the ability to induce maxillary and mandibular anesthesia following labial infiltration with articaine was compared to prilocaine given contralaterally. Anesthesia was determined by measuring sensation to electrical stimulation at the tooth, labial and lingual soft tissue for each of the 4 non-carious, non-restored, canines. Results showed that mandibular canine pulpal anesthesia had a success rate of 65% for articaine and 50% for prilocaine. Success rates for palatal and lingual anesthesia averaged 5% for each agent. As determined by chi-square analysis, no statistically significant differences were found between articaine and prilocaine for any tissue at any of the 6 sites (P greater than 0.05). A time-course assessment also failed to demonstrate a difference between the two drugs. Therefore these data are not consistent with superior anesthesia efficacy being produced by articaine at any site, including the mandibular pulpal, lingual or maxillary palatal tissues, in the canine teeth studied.

Scavenging system developed for the Magill anesthetic circuit for use in the dental office

Numerous potential problems have been associated with long term or occupational exposure to both nitrous oxide and halothane. Despite the lack of firmly established cause-and-effect relationships, particularly in humans, it would seem prudent to use techniques that minimize operator exposure. With this in mind, a scavenging system for use in both conscious sedation and general anesthetic techniques was developed which fulfills the requirements of both general dentists as well as those administering general anesthesia. This paper describes this system and its adaptation to the commonly used Magill circuit. It also briefly reviews the factors involved in potential toxicity caused by long term exposure to nitrous oxide and halothane.

Some clinical properties of Octocaine 200 (2 per cent lidocaine with epinephrine 1:200,000)

This study utilizes healthy volunteers to determine, via electronic pulp tester, such basic clinical parameters as time of onset and duration of action for an infiltration and mandibular block utilizing the recently available local anesthetic preparation, 2 per cent lidocaine with 1:200,000 epinephrine (Octocaine 200). This study showed Octocaine 200 to be both safe and efficacious, producing times of onset and duration within the clinically useful range. The rationale for vasoconstrictor use in dentistry is also reviewed.

An allergic reaction following injection of local anesthetic: a case report

The practice of dentistry necessitates the administration of numerous drugs by the oral route or by injection. This paper presents a case report in which a patient experienced an acute allergic reaction following mandibular block with articaine hydrochloride for dental extraction. It also reviews the pathophysiology of allergy and the office protocol required to successfully manage such a potentially life-threatening reaction.

The thyroid gland and the dental practitioner

The thyroid gland has an important function in almost every aspect of human physiology. As well, its location in the neck allows for easy evaluation by the dentist. Part I of this paper reviews the normal functions of the thyroid gland as well as systemic effects caused by abnormal function. This is supplemented by easily-acquired methods of physical examination of the thyroid gland suitable for the dental practitioner. Part II is a case report highlighting the potential adverse effects of dental treatment of a patient who had poorly controlled thyroid function following total thyroidectomy.

The use of pulse oximetry in the immediate recovery phase following dental extractions under general anesthesia in children

Over the past decade, an array of monitoring devices have been developed to continuously assess patient oxygenation. While actual tissue oxygenation is the most desirable measurement, the pulse oximeter offers a non-invasive method of measuring oxygenation of arterial blood. In this study, the arterial oxygen saturation (SaO2) of children presenting for oral surgical procedures under general anesthesia was continuously monitored. We were particularly interested in the saturation during the period from termination of anesthesia until arrival in the recovery room, a potentially critical 2-3 minutes. This study showed that 22.5 per cent of children significantly desaturated (SaO2 less than 90 per cent) during this period - a figure which is in complete agreement with several similar studies done recently. This desaturation preceded not only hemodynamic changes, but frequently changes in tissue and blood colour as well. The authors conclude that children should receive supplemental oxygen in the immediate recovery phase following general anesthesia.

Sensitivity to the anticonvulsant effects of ethanol and pentobarbital in mouse lines genetically selected for ethanol sensitivity

Mouse lines genetically selected for susceptibility [long sleep (LS)] or resistance [short sleep (SS)] to the acute hypnotic effects of ethanol were tested for sensitivity to maximal electroshock seizures. LS mice were slightly more sensitive than SS mice. Ethanol or pentobarbital pretreatment elevated seizure thresholds in both lines. LS and SS mice were approximately equally protected by ethanol, but LS mice were somewhat more protected than SS mice by pentobarbital. These studies do not provide evidence that sensitivity to the anticonvulsant effect of ethanol is mediated by substantially the same genes as those mediating sensitivity to EtOH's hypnotic effects. However, sensitivity to pentobarbital's anticonvulsant effects may be genetically correlated.

The effect of flumazenil on the recovery time of dental patients sedated with diazepam

Flumazenil is an imidazobenzodiazepine that binds specifically to the central benzodiazepine receptor and antagonizes the actions of diazepam and other benzodiazepines. Previous studies in Europe have shown flumazenil at doses of 2 to 30 mg IV to reverse sedation in patients sedated with flunitrazepam, midazolam, and diazepam when evaluated by subjective criteria. The purpose of this study was to determine if flumazenil at 0.015 mg/kg IV was efficacious in shortening the recovery time of young, healthy dental patients sedated with diazepam (0.15 mg/kg IV) and restoring their psychomotor function to presedation levels. A total of 21 patients were randomized to placebo or flumazenil, sedated with diazepam, underwent a restorative dental procedure, and were then administered the test drug. Evaluations of psychomotor function by the Trieger test, Digit-Symbol Substitution test, Romberg test, and nurse questioning were carried out before sedation and at 10-minute intervals after test drug. Observations by the patients and nurses were not significantly different before versus after test drug. The investigator, however, found that flumazenil resulted in more rapid awakening. Patients treated with placebo exhibited significantly greater deficits in the number of dots missed and sum of deviations on the Trieger test than flumazenil-treated patients. Similar time-related deficits were recorded for the Digit-Symbol Substitution test. Flumazenil, at a dose of 0.015 mg/kg, was found to be efficacious in reducing the recovery time after diazepam sedation in dental patients.

Therapeutics and sedation in dentistry

Sedation can help to overcome the fear that prevents many Canadians from accepting dental treatment. This article discusses the indications and contraindications for oral, intramuscular, and inhalation sedation as used by the general dental practitioner for both adult and child patients, with a note on the growing number of specialist dental anesthetists who provide intravenous out-patient sedation. Local anesthesia is discussed with reference to allergic reactions, malignant hyperthermia, and the use of epinephrine as a vasoconstrictor in patients with cardiovascular diseases.

Environmental variables differentially affect ethanol-stimulated activity in selectively bred mouse lines

Low doses of ethanol (EtOH) stimulate activity in an open field in many strains of laboratory mice. We are selectively breeding two lines of mice to exhibit a large (FAST) response on this test, and two other lines to exhibit a small (SLOW) response (Crabbe et al. 1987). The lines initially diverged in response to EtOH, but despite continued selection pressure, the difference between each pair of FAST and SLOW lines has not increased over generations as much as expected. Our practice has been to test animals on the 1st day after saline injection, and repeat the test after EtOH injection 24 h later. Lister (1987) recently demonstrated that the order in which an animal was exposed to EtOH and saline influenced the magnitude of the response to EtOH, with animals tested initially after EtOH having greater stimulation. Middaugh et al. (1987) recently demonstrated that the magnitude of EtOH stimulation was greater under conditions of relatively bright light than under dim light. Using non-selected Swiss mice, the current experiments essentially confirmed Lister's findings. Using FAST and SLOW mice, the predictions of both groups were tested. Both hypotheses were confirmed. Additionally, these experiments demonstrated that the magnitude of the difference between FAST and SLOW mice was greater under bright light than under dim light. The line difference was also greater when tested in the EtOH-Saline order. In experiments with Swiss mice, the possible role of peritoneal irritation in the EtOH effect was eliminated, and the optimal dose and time for demonstrating the effect was determined.(ABSTRACT TRUNCATED AT 250 WORDS)

Mice genetically selected for differences in open-field activity after ethanol

Starting from a population of genetically heterogeneous mice, selective breeding is being used to develop lines differing in sensitivity to ethanol-induced open-field activity. Mice are tested twice for 4 min in an open field. The first test is between min 2-6 after injection of saline. Twenty-four hr later, a similar test is performed after injection of ethanol (1.5 g/kg). Two independent FAST lines are being selected for ethanol-induced increases in activity, and two independent SLOW lines are being selected for ethanol-induced decreases. After four generations of selection, the lines have diverged significantly. These lines should be useful for exploring the neuropharmacological basis for the activating and rewarding properties of ethanol.

Genetic differences in anticonvulsant sensitivity in mouse lines selectively bred for ethanol withdrawal severity

WSP (withdrawal seizure-prone) mice exhibit approximately 10-fold more severe withdrawal convulsions than WSR (withdrawal seizure-resistant) mice after identical chronic ethanol exposure. Although WSP and WSR mice do not differ in threshold for seizures elicited by electroconvulsive shock (ECS), WSR mice are more sensitive to ethanol-induced elevation of ECS seizure thresholds. The current experiments demonstrated that WSR mice showed more ECS-induced seizure threshold elevation than WSP mice when tested after the administration of C1-C5 straight-chain alcohols. Whereas the brain concentrations of the C1 and C2 alcohols did not differ between the lines, WSP mice tended to have higher brain concentrations than WSR mice of the C3-C5 alcohols, even though they exhibited the smaller behavioral response in all cases. Thus, the difference between WSP and WSR mice was one of neurosensitivity and could not be attributed to pharmacokinetic differences. The WSR line was also more sensitive to ethchlorvynol, methyprylon, barbital, phenobarbital, pentobarbital, diazepam, valproic acid and phenytoin in this test. Examining loss of righting reflex (RR), we found that WSP and WSR mice did not differ in ED50, latency to lose RR or duration of loss of RR. Thus, the genetic anticonvulsant sensitivity difference is not simply a genetic difference in sensitivity to central nervous system depression between the lines. In summary, WSR mice were more sensitive to the anticonvulsant effects of a variety of compounds than WSP mice, suggesting that some genes influence both ethanol withdrawal seizures and ethanol's anticonvulsant effects.

Specific ethanol withdrawal seizures in genetically selected mice

We are selectively breeding mice prone (WSP) and resistant (WSR) to ethanol withdrawal seizures assessed by handling induced convulsions (HIC). The possibility that differences between the lines in HIC scores are a result of differences in general CNS excitability not specific to ethanol withdrawal was examined. Using treatments which produce generalized seizures (electroconvulsive shock, strychnine, and flurothyl) and gamma amino-butyric acid (GABA) antagonists (picrotoxin, bicuculline, and pentylentetrazol), the ED50 for seizures was determined in the selected lines. In addition, the sensitivity of WSP and WSR mice to the anticonvulsant actions of ethanol against each treatment was determined. Neither the convulsant amperage 50 (CA50) for ECS nor the ED50 for any drug treatment differed for the selected lines. When ethanol (1.5 g/kg) was administered prior to ECS, there was a dramatic differential suppression of ECS in the lines: the CA50 of WSR mice was elevated 5-fold, whereas the CA50 of WSP mice increased only two fold. Ethanol pretreatment also elevated the ED50 for strychnine and flurothyl in WSR mice significantly more than WSP mice, but the line difference was smaller than for the anticonvulsant effect against ECS. The ED50s for the GABA antagonists were not different between the WSR and WSP lines after ethanol pretreatment. We conclude that genetic selection is producing lines of mice that differ specifically in the degree of seizure severity caused by withdrawal from ethanol physical dependence and not in generalized CNS excitability. An increased sensitivity to the anticonvulsant effects of ethanol against some convulsant treatments has appeared as a correlated response to selection in the WSR line.

Ethanol dependence and the pituitary adrenal axis in mice. II. Temporal analysis of dependence and withdrawal

The effects of ethanol dependence and withdrawal on pituitary hormone content and corticosterone release were investigated in AKR/J male mice in a vapor chamber. Both chronic ethanol inhalation and ethanol withdrawal were associated with increased adenohypophyseal-adrenocortical activity. Operationally, ethanol exposure was a stressor. Both physical dependence and withdrawal led to increased secretion/synthesis ratios of peptide hormones. The temporal pattern of pituitary ACTH-IR content changes was different from that of beta-endorphin-IR and alpha-MSH-IR. Differences in the pattern of ACTH-IR and alpha-MSH-IR most probably represent lobe-specific differences in the response to chronic ethanol exposure and withdrawal.

Genetic selection for ethanol withdrawal severity: differences in replicate mouse lines

We report an ongoing within-family selective breeding project for the severity of handling-induced withdrawal seizures in mice made physically dependent on ethanol by inhalation. Two Withdrawal Seizure Prone (WSP) and two Withdrawal Seizure Resistant (WSR) lines have been subjected to five generations of selection, and two control (WSC) lines are maintained. Each WSP line had more severe and each WSR line had less severe withdrawal convulsions than its respective WSC line. Differences relative to control lines were more pronounced in the WSP lines and were not due to differences in effective dose of ethanol. Heritabilities were higher in the WSP lines than in the WSR lines. These lines will be useful for studying physiological determinants of ethanol dependence and withdrawal.

Polygenic and single-gene determination of responses to ethanol in BXD/Ty recombinant inbred mouse strains

Male mice of parent inbred strains C57BL/6J and DBA/2J, and mice from several of the BXD/Ty Recombinant Inbred (RI) strains derived from the cross of the parent inbred strains were tested for responsiveness to ethanol. Separate groups of mice from these strains were characterized for sensitivity to ethanol's effects to increase activity in an open field and to induce ambulatory ataxia in the grid test. The strain distribution pattern of the RI strains indicated polygenic control of both responses to ethanol. Other mice from this battery were tested for acceptance of an ethanol solution, a measure related to preference drinking. This trait may be substantially influenced by a single gene. Mice were then rendered physically dependent on ethanol through inhalation of ethanol vapor for three days. Severity of handling-induced convulsions was used to index the severity of the ethanol withdrawal syndrome. The distribution of the RI strains indicated possible influence of a major gene on ethanol withdrawal severity.

Genetic correlations with ethanol withdrawal severity

A major goal of pharmacogenetic research on alcoholism remains the identification of some "marker" that could predict the liability of a particular individual for a genetic susceptibility to develop alcoholism. The present paper presents evidence that the severity of withdrawal from physical dependence on ethanol varies widely among inbred strains of mice, and that withdrawal severity is negatively genetically correlated with initial sensitivity and magnitude of tolerance to ethanol hypothermia. These correlations are supported by differences in hypothermic response between replicate lines of mice genetically selected for susceptibility and resistance to ethanol withdrawal seizures. The genetic relationships reported suggest that the effects of ethanol on thermoregulation in mice may offer a predictive marker for susceptibility to ethanol physical dependence.

Tolerance to ethanol hypothermia in inbred mice: genotypic correlations with behavioral responses

Hypothermia was studied 5 min before, and 30 and 60 min after intraperitoneal administration of ethanol (3 g/kg) in 20 inbred strains of mice. Ethanol was given daily for 8 days, and temperatures were taken on Days 1, 3, 5, and 8. Tolerance was indexed by the reduction in hypothermia over days. There were large strain differences in baseline temperature, the hypothermic effect of ethanol, and in development of tolerance to hypothermia. Some strains of mice (DBA/1J, DBA/2N, MA/MyJ, and PL/J) did not develop tolerance to the hypothermic effect of ethanol. Initial sensitivity to the hypothermic effect of ethanol was significantly genetically correlated with tolerance development, indicating control of these responses by common genes. Ethanol-induced changes in activity and ataxia, as well as blood ethanol concentrations, were also assessed. Although there were significant strain differences in activity reduction, ataxia, blood-ethanol concentrations, and changes in these parameters during the course of chronic treatment, none of these variables could explain the genetic differences in hypothermic sensitivity and tolerance.

Biphasic effects of ethanol on open-field activity: sensitivity and tolerance in C57BL/6N and DBA/2N mice

Male C57BL/6N (C57) and DBA/2N (DBA) inbred mice were found to differ in open-field behavior after an acute ip injection of ethanol and in the development of tolerance to repeated injections. DBA mice showed only increased activity for 28 min after ethanol doses up to 2.67% g/kg when compared with saline-injected controls. Under the same conditions, C57 mice showed dose-related increases in activity during the first 4 min, followed by dose-related decreases in activity. The effects endured for at least 60 min after injection in both strains. In a third experiment, mice were injected daily with saline or 2.0 g/kg ethanol and tested on Days 1, 5, 9, and 13 for open-field activity. On the 17th day, all mice were tested after an ethanol injection. Neither strain showed tolerance to the activity-stimulating effect of ethanol. Some evidence for tolerance to the effect of ethanol to reduce activity in C57 mice was found. In a fourth experiment, twice-daily injections of ethanol for 10 days produced marked tolerance to the depressant effect of an injection on the 11th day in C57 mice, compared with those in a control group given ethanol for the first time on the 11th day. No tolerance to the stimulant effect of ethanol was seen in C57s. DBA mice were injected twice daily for 19 days but did not display tolerance when tested on Day 10 or on Day 20, Indeed, DBA mice chronically treated with ethanol exhibited more marked stimulation of activity after ethanol than mice treated chronically with saline. Differences in blood ethanol concentrations between the strains could not account for any of the observed differences. Implications for the genetic control of responses to ethanol are discussed.

Investigations on a Babesia isolated from Scottish sheep

The pathognomic, serologic and morphometric identity of a Babesia sp. recently isolated from sheep in Argyllshire was studied. Initially, problems were encountered due to the occurrence of Eperythrozoon ovis as a contaminant of the isolate and treatment with neoarsphenamine failed to remove it. Finally, a combination of oxytetracycline therapy and rapid passage allowed isolation of the Babesia sp. and its preservation in the form of a glycerolized, infected blood stabilate. Inoculation of the stabilate into splenectomized sheep produced a mile non-pyrogenic disease. Serologically the parasite was seen to have no affinity with either of the two Babesia recognized as parasitizing sheep, but some affinity with the cattle parasite B. divergens. Morphometrically it was seen to have affinity with the deer parasite B. capreoli and with the Babesia sp. isolated from red deer in Scotland, and the low number of budding forms of the parasite seen suggested that the parasite might be reproducing slowly in an alien host. It was concluded that the parasite was likely to be B. capreoli derived from red deer via the tick Ixodes ricinus.

Investigations on Babesia motasi isolated from Wales

A number of observations were carried out on the effect of the newly isolated parasite, Babesia motasi (Wales) on intact and splenectomised sheep and on a splenectomised goat. The parasite was not pathogenic for intact animals but caused fever and anaemia in splenectomised ones. B motasi (Wales) was also studied morphologically, morphometrically and serologically. The common form of the parasite was seen to be a double pyriform, the mean length of one side being 2.23 micrometer. It appeared to be morphometrically and serologically close to the other north European B motasi strains but distinct from B motasi (Turkey). In a limited serological survey, experience of infection with B motasi appeared to be common in sheep grazing in coastal areas of North Wales, but rare in a part of South Wales known to harbour the vector tick Haemaphysalis punctata. Transovarial transmission of B motasi by H punctata took place with facility.

Strain differences in pituitary beta-endorphin and ACTH content in inbred mice

The whole pituitary contents of beta-endorphin and ACTH were found to vary widely among 5 inbred strains of mice. beta-endorphin values were 2.5-fold different and ACTH values 1.5-fold. Strains low in beta-endorphin were also low in ACTH. The existence of genetic differences raises the possibility that there exist, or can be developed, strains with extremely low or high levels of these peptides that would aid research directed at elucidating the physiology of opioid peptides.

Quinuronium sulphate for the treatment of Babesia divergens infections of splenectomised calves

Quinuronium sulphate was inoculated into splenectomised calves at various times in relation to artificial infection of the calves with Babesia divergens. When the drug was given one day before the parasites it had no effect on the course of the infection. However, when it was given at the time of onset of fever or haemoglobinuria, development of the infection was arrested. Two weeks after therapy, recrudescences of parasites invariably occurred. In the case of animals treated at onset of fever these recrudescences were accompanied by increasing anaemia. Treated animals resisted subsequent challenge but remained as carriers of the parasite.