Multiple Shape Coexistence in ^{110,112}Cd

From detailed spectroscopy of ^{110}Cd and ^{112}Cd following the β^{+}/electron-capture decay of ^{110,112}In and the β^{-} decay of ^{112}Ag, very weak decay branches from nonyrast states are observed. The transition rates determined from the measured branching ratios and level lifetimes obtained with the Doppler-shift attenuation method following inelastic neutron scattering reveal collective enhancements that are suggestive of a series of rotational bands. In ^{110}Cd, a γ band built on the shape-coexisting intruder configuration is suggested. For ^{112}Cd, the 2^{+} and 3^{+} intruder γ-band members are suggested, the 0_{3}^{+} band is extended to spin 4^{+}, and the 0_{4}^{+} band is identified. The results are interpreted using beyond-mean-field calculations employing the symmetry conserving configuration mixing method with the Gogny D1S energy density functional and with the suggestion that the Cd isotopes exhibit multiple shape coexistence.

High-precision half-life measurement for the superallowed β+ emitter ²⁶Al(m)

A high-precision half-life measurement for the superallowed β+ emitter 26Al(m) was performed at the TRIUMF-ISAC radioactive ion beam facility yielding T 1/2 6346.54 ± 0.46(stat) ± 0.60 (syst) ms, consistent with, but 2.5 times more precise than, the previous world average. The 26Al(m) half-life and ft value, 3037.53(61) s, are now the most precisely determined for any superallowed β decay. Combined with recent theoretical corrections for isospin-symmetry-breaking and radiative effects, the corrected Ft value for (26)Al(m), 3073.0(12) s, sets a new benchmark for the high-precision superallowed Fermi β-decay studies used to test the conserved vector current hypothesis and determine the V(ud) element of the Cabibbo-Kobayashi-Maskawa quark mixing matrix.

Functionalized chitosan/NIPAM (HEMA) hybrid polymer networks as inserts for ocular drug delivery: synthesis, in vitro assessment, and in vivo evaluation

A series of hybrid polymeric hydrogels, prepared by the reaction of acrylic acid-functionalized chitosan with either N-isopropylacrylamide or 2-hydroxyethyl methacrylate monomers, were synthesized, pressed into minitablets, and investigated for their ability to act as controlled release vehicles for ophthalmic drug delivery. For comparison, interpolymeric complex analogues synthesized using the same monomers and pure, unfunctionalized chitosan were examined by means of an identical characterization protocol. The effects of network structure and composition upon the swelling properties, adhesion behavior, and drug release characteristics were investigated. Comparative in vitro studies employing chloramphenicol, atropine, norfloxacin, or pilocarpine informed the selection of drug-specific carrier compositions for the controlled delivery of these compounds. In addition, in vivo (rabbit model) experiments involving the delivery of pilocarpine indicated that chitosan-based hybrid polymer networks containing 2-hydroxyethyl methacrylate are useful carriers for the delivery of this therapeutic agent.

Functionalized chitosan/NIPAM (HEMA) hybrid polymer networks as inserts for ocular drug delivery: Synthesis,in vitro assessment, andin vivo evaluation

A series of hybrid polymeric hydrogels, prepared by the reaction of acrylic acid-functionalized chitosan with either N-isopropylacrylamide or 2-hydroxyethyl methacrylate monomers, were synthesized, pressed into minitablets, and investigated for their ability to act as controlled release vehicles for ophthalmic drug delivery. For comparison, interpolymeric complex analogues synthesized using the same monomers and pure, unfunctionalized chitosan were examined by means of an identical characterization protocol. The effects of network structure and composition upon the swelling properties, adhesion behavior, and drug release characteristics were investigated. Comparative in vitro studies employing chloramphenicol, atropine, norfloxacin, or pilocarpine informed the selection of drug-specific carrier compositions for the controlled delivery of these compounds. In addition, in vivo (rabbit model) experiments involving the delivery of pilocarpine indicated that chitosan-based hybrid polymer networks containing 2-hydroxyethyl methacrylate are useful carriers for the delivery of this therapeutic agent.

Vinylpyrrolidone-co-(meth)acrylic acid inserts for ocular drug delivery: Synthesis and evaluation

Copolymeric hydrogels constituting of vinylpyrrolidone and methacrylic or acrylic acid repeat units have been prepared and investigated for their ability to act as controlled release vehicles in ophthalmic drug delivery. The materials were synthesized by radical-induced polymerization in the presence of N,N'-methylenebisacrylamide crosslinker, and the influences of network composition and drug solubility upon the swelling properties, adhesion behavior, and drug release characteristics were studied. In vitro release experiments showed that some of these materials could be useful vehicles for the delivery of drugs such as pilocarpine or chloramphenicol, while in vivo studies, using the rabbit model, confirmed their high potential for the controlled ocular delivery of pilocarpine hydrochloride.

A quantitative evaluation of radiolabelled lectin retention on oral mucosa in vitro and in vivo

Previous work has identified lectins that bind to the cells present on the oral mucosa for their potential use as a means of retaining a drug delivery system on the mucosal surfaces of the mouth. In this study, a radiolabelling technique was developed to allow the quantification of lectin binding to human buccal cells in vitro, and the retention of the lectins in the oral cavity of a rat model in vivo. Lectins were labelled with 99mTc using a cyclic diethylene triamine pentaacetic acid conjugation technique. In the in vitro study, human buccal cells were obtained by scraping the inner surface of the cheek. The suspended cells were exposed to the labelled lectin solution for 30 min and after washing with buffer the activity associated with the cells determined. In the in vivo study, male Wistar rats were briefly anaesthetized during which 10 microl of a solution containing labelled lectin was applied into the buccal pouch. At set times the rats were killed and the lower buccal cavity mucosal tissue and tongue dissected out and monitored for bound lectin. The in vitro study indicated that the lectins from Arachis Hypogaea, Canavalia ensiformis and Triticum vulgaris bound to oral mucosal cells. The T. vulgaris lectin showed the greatest binding, calculated to be 6.77 x 10(9) molecules per cell. The in vivo retention of C. ensiformis and T. vulgaris lectins on rat oral mucosal tissue was also evident. The T. vulgaris lectin showed significantly higher levels of retained lectin after 30 min (29.54 +/- 4.20 microg SD) on the oral mucosal tissue and 28.37 microg (+/-2.13 SD) on the tongue and was still detected at similar levels after 2 h. These studies indicate that significant lectin binding to human buccal cells occurs in vitro and retention in an animal model occurs for over 2 h in vivo. The T. vulgaris lectin showed most promise for further work.

The gastrointestinal transit profile of 14C-labelled poly(acrylic acids): an in vivo study

The gastrointestinal distribution profiles for three 14C-labelled poly(acrylic acid)s of different average molecular weights and degrees of cross-linking have been established using the rat model. Despite initial differences in transit times and retention characteristics, these structural features were found to be of little influence to the overall gastrointestinal transit of the materials under consideration. No evidence for the systemic absorption of any of the polymers could be identified.

Participatory action research: lessons learned with Aboriginal grandmothers

Participatory action research is evolving as both a research methodology and an intervention for health promotion. Here we describe its use in conducting a health assessment as part of a larger project for older Aboriginal women (hereafter known as the grandmothers). The overall purpose of the project was to study the women's health needs and respond through health promotion programming. The experience of using participatory action research revealed a number of lessons, including challenges and points of tension, and determinants and indicators of success. The research team identified some implications for consideration by others interested in participatory action research.

Health risks and opportunities for harm reduction among injection-drug-using clients of Saskatoon's needle exchange program

Information about injection drug users' lifestyles is necessary to develop effective harm reduction strategies. One way to gather this information is through needle exchange programs. In 1998, a convenience sample of 100 clients of Saskatoon's needle exchange service was interviewed about their injection and sexual practices. Ritalin and morphine were the most commonly injected drugs. Over half the participants (53%) reported having shared needles, usually with friends, relatives, and partners. Slightly more (62%) had shared injection equipment. Most participants had multiple sexual partners, especially the women, half of whom were sex trade workers. Condom use was higher with casual partners than with regular partners. While awareness about HIV transmission was high, most participants considered their risk of infection to be below average. These findings are discussed in light of the insights they provide regarding both health risks and opportunities for harm reduction in the study population.

The effects of benzamide analogues on cocaine self-administration in rhesus monkeys

RATIONALE

Based on the differential distribution of dopamine (DA) D(3) receptors in mesolimbic regions relative to nigrostriatal regions, the hypothesis was that D(3)-selective antagonists (i.e., higher affinity at D(3)- than D(2)-receptors) would be more potent than D(2)-selective antagonists at decreasing total cocaine intake relative to disrupting rates of responding.

OBJECTIVE

To evaluate the effects of acute administration of seven DA antagonists with varying affinities for D(2) and D(3) receptors in monkeys self-administering cocaine.

METHODS

Rhesus monkeys were trained to self-administer intravenous cocaine (0.01-0.3 mg/kg per injection) under a fixed-interval (FI) 5-min schedule during daily 4-h sessions. The use of a FI schedule allowed for independent assessment of rate effects and changes in reinforcement frequency as a consequence of drug pretreatments. The compounds examined, in order of D(3) binding affinity, were: 2,3-dimethoxy-N-(9-p-fluorobenzyl)-azabicyclo[3.3. 1]nonan-3beta-yl benzamide (MABN) = eticlopride = 5-bromo- 2, 3-dimethoxy-N-[1-(4-fluorobenzyl)piperidin-4-yl]benz-amide (BBP) > spiperone > fluoroclebopride (FCP) > 2, 3-dimethoxy-N-(p-fluorobenzyl)piperdin-4-yl benzamide (MBP) > haloperidol.

RESULTS

In the absence of any pretreatments, cocaine-maintained responding varied as a function of dose and was characterized as an inverted U-shaped function, while cocaine intake increased in a dose-related fashion. When the dose of cocaine that maintained peak rates was available, all DA antagonists decreased response rates and cocaine intake in a dose- dependent manner. Increases in cocaine dose attenuated the effects of the DA antagonists, resulting in rightward shifts of the cocaine dose-response curves. Based on the ratio of behavioral potency at decreasing response rates relative to intake (ED(50) rate/ED(50) intake) when the highest cocaine dose was available, the order of potency and ED(50) ratio values were: MABN (2.5) > eticlopride (1. 63) > BBP = spiperone (1.5) > FCP (1.35) > MBP = haloperidol (0.89). This order parallels each compound's affinity at D(3) receptors (r(2)=0.84) to a greater degree than D(2) receptor affinity (r(2)=0. 34).

CONCLUSIONS

These results, using a FI schedule of cocaine self-administration, suggest that D(3) receptor antagonists are more likely to selectively decrease intake relative to response rates than D(2) receptor antagonists.

The influence of menstrual cycle phase on sensitivity to ethanol-like discriminative stimulus effects of GABA(A)-positive modulators

Previous studies showed that sensitivity to the ethanol-like discriminative stimulus effects of allopregnanolone and ethanol are enhanced during the luteal phase of the menstrual cycle when progesterone levels peak in monkeys trained to discriminate 1.0 g/kg ethanol. The present study further explored the influence of the menstrual cycle phase on the discriminative stimulus effects of ethanol, allopregnanolone, and midazolam. Female adult cynomolgus monkeys (Macaca fascicularis) were trained to discriminate 1.0 g/kg ethanol (n = 3) or 2.0 g/kg ethanol (n = 4) (20% w/v; i.g.) from water (i.g.). A cumulative dosing procedure was used to test discriminative stimulus effects of ethanol (0.5-2.5 g/kg; i.g.) and the ethanol-like discriminative stimulus effects of allopregnanolone (0.1-1.0 mg/kg; i.v.) or midazolam (1.0-17 mg/kg; i.g.) during the follicular vs. luteal phase of the menstrual cycle. In the 2.0-g/kg group, sensitivity to the ethanol-like effects of allopregnanolone was increased during the luteal vs. follicular phase in two of three monkeys. In contrast, average sensitivity to ethanol was not different in the luteal compared to the follicular phase in the 2.0-g/kg group. Finally, there was no difference in sensitivity to midazolam between the follicular and luteal phases in monkeys trained with either 2.0 g/kg or 1.0 g/kg ethanol. Overall, the ethanol-like discriminative stimulus effects of midazolam are not sensitive to the menstrual cycle phase. In addition, there was less influence of the menstrual cycle phase on allopregnanolone and ethanol sensitivity in a 2.0-g/kg compared to a 1.0-g/kg ethanol training dose.

Lectins in drug delivery: a study of the acute local irritancy of the lectins from Solanum tuberosum and Helix pomatia

Lectins are proteins or glycoproteins of non-immune origin capable of binding to one or more specific sugar residues. The potential for using lectins as a means of 'anchoring' a drug delivery system to the mucosal surfaces of the eye has been investigated in previous work, with the lectins from Solanum tuberosum and Helix pomatia showing particular promise. In this study the acute local dermal irritancy of these lectins, in terms of their potential to cause inflammation and tissue necrosis, was investigated. After an initial study in terminally anaesthetised animals (to ensure no gross toxicity was evident), five male New Zealand white rabbits from the same litter were briefly anaesthetised and Evans blue injected intravenously as a marker of inflammation. Sterile lectin solutions in normal saline at a range of concentrations from 50 to 500 microg ml(-1) were prepared and 50-microl volumes injected intradermally at 18 sites across a shaved area of each rabbit's back. The rabbits were then allowed to regain consciousness. There was no evidence of tissue necrosis, oedema or Evans blue infiltration with any of the lectin solutions administered. The rabbits did not display any signs of discomfort such as scratching or continued grooming throughout the experiment. Histological examination of the injection sites revealed little sign of any inflammation, such as heterophil migration, oedema or tissue damage. It was concluded that these lectins demonstrate minimal acute irritancy, and will, therefore, be taken forward for formulation and in vivo studies.

Preventing bacterial adhesion onto surfaces: the low-surface-energy approach

Good-quality coatings prepared from poly(methylpropenoxyfluoroalkylsiloxane)s or poly(perfluoroacrylate)s are capable of inhibiting the bacterial colonisation of surfaces.

Effects of L-type voltage-sensitive calcium channel modulators on the discriminative stimulus effects of ethanol in rats

The purpose of the present investigation was to determine whether administration of dihydropyridine-sensitive calcium channels plays a role in modulating the discriminative stimulus effects of ethanol. A food-reinforced operant methodology was used to train adult male Long-Evans rats to discriminate either 1.0 g/kg of ethanol from water or 2.0 g/kg of ethanol from water. After training, two sets of experiments were conducted. First, a time course procedure was implemented whereby a single intraperitoneal dose of either nimodipine (3, 10, 30 mg/kg), nifedipine (3, 10, 30 mg/kg), or isradipine (1, 3, 10, 17 mg/kg) was administered, and test sessions were conducted 10, 20, 30, 60, and 90 min postinjection. Complete substitution (80% or greater ethanol-appropriate responding) for ethanol by these dihydropyridine compounds varied among subjects with dose and pretreatment time. Overall, isradipine substituted for the discriminative stimulus effects of ethanol in the greatest percentage of animals in both training groups. However, substitution varied with dose. Nifedipine dose dependently substituted for ethanol in half of the animals trained with 1.0 g/kg of ethanol but was less effective in animals trained with 2.0 g/kg of ethanol. For the second set of experiments, a single dose of nimodipine, nifedipine, isradipine, or (-)-BAY k 8644 was administered before determination of the cumulative ethanol dose response. Nifedipine produced a significant leftward shift and (-)-BAY k 8644 produced a significant rightward shift in the ethanol dose-response curve in animals trained to discriminate 2.0 g/kg of ethanol from water. These results indicate that the administration of VGCC modulators plays an indirect role in the discriminative stimulus effects of ethanol.

Comparison of ethanol metabolism in male and female cynomolgus macaques (Macaca fascicularis)

The physiological consequences of drinking ethanol differ among men and women; however, the biological basis of this gender difference is unknown. Our study characterized sex-related blood ethanol concentration (BEC) 60 min postethanol administration and ethanol elimination rates in male and female monkeys and across the phases of the menstrual cycle. Subjects were male (n = 4) and female (n = 4) cynomolgus monkeys (Macaca fascicularis) with a history of ethanol exposure and maintained at a lean body weight by food restriction. On three separate occasions, each monkey was administered 1.0 g/kg ethanol intragastrically and blood samples (20 microl) were collected every 60 min over a 5-hr period. For females, three phases of the menstrual cycle were determined by the presence of menses and plasma progesterone levels. There was no effect of menstrual cycle on mean 60 min BECs or mean rates of elimination. Mean BECs 60 min after 1.0 g/kg ethanol were: males = 86 mg/dl (+/- 2; n = 4) and females = 82 mg/dl (+/- 5; n = 4). There was no effect of sex on the highest BEC measured, which occurred at the 60 min time point in all subjects. Female monkeys did have faster average rates of ethanol elimination [34 +/- 2 (mg/dl)/hr] compared with males [23 +/- 1 (mg/dl)/hr]. The sex differences in metabolism of ethanol found with the macaque monkey model correlates well with human subject studies and suggests this is an appropriate model to further explore gender differences in response to ethanol.

Evidence for overshadowing by components of the heterogeneous discriminative stimulus effects of ethanol

The present study used a drug discrimination paradigm to characterize the contribution of separate receptor systems to the stimulus effects of different training doses of ethanol. In a two-lever drug discrimination paradigm two groups of adult male Long-Evans rats (n = 8 per group) were trained to discriminate either 1.0 g/kg ethanol from water or 2.0 g/kg ethanol from water, administered intragastrically (i.g.), 30 min prior to the start of daily sessions in which responding was maintained under a fixed ratio 20 schedule of food presentation. Following training, cumulative dosing substitution tests were conducted with the GABAA positive modulator pentobarbital (1-17 mg/kg, i.p.), the uncompetitive NMDA antagonist dizocilpine (0.01-0.3 mg/kg, i.p.) and the 5-HT1B/2C agonist m-trifluoromethylphenylpiperazine (TFMPP 0.17-1.7 mg/kg, i.p.). Next, the rats initially trained at 1.0 g/kg ethanol were retrained to discriminate 2.0 g/kg ethanol from water, and the rats initially trained at 1.0 g/kg were retrained to discriminate 2.0 g/kg ethanol from water. Both groups were then re-tested with the same ligands. Regardless of training history, animals currently discriminating 1.0 g/kg were more sensitive to the ethanol-like effects of TFMPP and pentobarbital compared to rats discriminating 2.0 g/kg ethanol. However, no difference in sensitivity to the ethanol-like effects of dizocilpine based on ethanol training dose was detected. These results support the view that ethanol is a heterogeneous discriminative stimulus comprised of GABAA, NMDA and 5-HT1B/2C receptor-mediated activity. Furthermore, changes in sensitivity to GABAA and 5-HT ligands as a function of training dose could be indicative of overshadowing by other components of ethanol's heterogeneous cue. Finally, it appears that the current profile of ethanol's heterogeneous stimulus effects, rather than an interaction with ethanol training history, determines the substitution pattern of specific receptor ligands.

Weight dissatisfaction and weight loss attempts among Canadian adults. Canadian Heart Health Surveys Research Group

OBJECTIVE

To describe the pattern of weight dissatisfaction and weight loss attempts among Canadian adults and the reasons for and methods of weight loss among those trying to lose weight.

DESIGN

Population-based, cross-sectional surveys.

SETTING

Ten Canadian provinces between 1986 and 1992.

PARTICIPANTS

A probability sample of 29,855 men and women aged 18 to 74 years was selected using provincial health insurance registration files; this paper describes the subsample of 19,841 (66%) participants from whom anthropometric data were collected.

OUTCOME MEASURES

Discrepancy between actual and desired body mass index (BMI); attempts to lose weight; reasons for losing weight; methods of weight loss used.

RESULTS

Whether their weight was in the acceptable range (BMI 20-24 kg/m2) or at a level of increasing risk (BMI > or = 27 kg/m2), women were more likely than men to wish they weighed less and to be trying to lose weight; almost two-thirds of women but less than half the men with BMI > or = 27 kg/m2 were trying to lose weight. Even among those with BMI 20-24 kg/m2, 32% of women (v. 10% of men) were trying to reduce their weight. Weight dissatisfaction and current and past weight loss attempts were all negatively associated with age among women, but were unrelated to age among men. People with higher ratios of waist to hip circumference (WHR), controlling for BMI, were no more likely to be trying to lose weight than those with lower WHR; in fact, for women with BMI 27-29 kg/m2, WHR was negatively associated with prevalence of weight loss attempts. The presence of diabetes, hypertension and hypercholesterolemia was also unrelated to weight loss attempts; regular smokers and sedentary people were less likely to report trying to lose weight, controlling for BMI. Among those currently trying to lose weight, the most commonly mentioned reason was to improve general health, followed by increasing attractiveness. Overall, the most frequently mentioned method of weight loss was dieting, followed by exercise.

CONCLUSIONS

Substantial numbers of men whose BMI places them at increased health risk appear to be content with their weight and are not attempting to reduce it. Conversely, women, especially the young and middle-aged, are likely to consider themselves above their desired weight and to be trying to lose weight, even when their weight is within acceptable limits. This reinforces the need to consider differences between men and women in efforts to promote and support healthy weights among Canadians.

The nitric oxide synthase inhibitor L-NAME (N omega-nitro-L-arginine methyl ester) does not produce discriminative stimulus effects similar to ethanol

N-methyl-D-aspartate (NMDA) antagonists substitute for the discriminative stimulus effects of ethanol, indicating that a component of ethanol's behavioral activity is produced via blockade of NMDA receptor/channel function. Recently, it has been reported that ethanol inhibits NMDA-stimulated nitric oxide synthase (NOS) activity in cortical neurons, thereby decreasing the formation of nitric oxide (NO) in the brain. These findings suggest that some of the behavioral effects of ethanol may be mediated by inactivation of NOS. The present study examined the role of NO formation in mediating the discriminative stimulus effects of ethanol. To address this hypothesis, an NOS inhibitor, N omega-nitro-L-arginine methyl ester (L-NAME) and an NMDA competitive antagonist, (D)-4-(3-phosphonoprop-2-enyl) piperazine-2-carboxylic acid (CPPene), were administered to two groups of rats trained to discriminate 1.5 g/kg of ethanol (n = 6) or 2.0 g/kg (n = 7) of ethanol from water. After training, dose ranges of CPPene (3 to 17 mg/kg, ip) and L-NAME (100 to 780 mg/kg, ip) were tested for ethanol-like effects. L-NAME was also tested under a range of pretreatment times (20, 60, 90, and 120 min). An additional group of rats trained to discriminate 2.0 g/kg (n = 7) of ethanol from water was also tested with CPPene (10 mg/kg, ip) and L-NAME (100 and 300 mg/kg, ip) to verify data gathered from the original 2.0 g/kg of ethanol group tested with L-NAME after a 20-minute pretreatment. Although overall, 17 of 20 animals trained to discriminate ethanol from water exhibited complete substitution of CPPene for ethanol, L-NAME, without affecting response rates, did not consistently substitute for either 1.5 g/kg or 2.0 g/kg of ethanol. These results indicate that inhibition of NO formation is less effective than direct NMDA receptor antagonism in producing ethanol-like discriminative stimulus effects.

A health promotion perspective on the House of Commons' report "Foetal Alcohol Syndrome: a Preventable Tragedy"

The Ottawa Charter for Health Promotion is used as a conceptual framework to examine the recommendations concerning prevention in the House of Commons' Report "Foetal Alcohol Syndrome: A Preventable Tragedy." Fetal alcohol syndrome cannot be separated from the complex social, physical and economic environments affecting alcohol consumption. For substantial progress to be made in preventing this significant cause of mental handicap, it will be necessary to consider a wide range of preventive actions, beyond public education and mandatory warning labels on alcoholic beverages. A health promotion framework offers a comprehensive, intersectoral approach to this problem.

Evaluation of the Heart Smart Restaurant Program in Saskatoon and Regina, Saskatchewan

The consumer-driven Heart Smart Restaurant Program was developed by the Heart and Stroke Foundation of Saskatchewan and the Saskatoon Community Health Unit, with the aim of improving the nutritional quality of food consumed in table-service restaurants. To participate, restaurateurs must agree to provide smoke-free seating and specific more healthful food choices upon request of the customer. The program was evaluated through telephone interviews with 999 individuals in randomly selected households in Saskatoon and Regina. While public awareness of the program was satisfactory, over half of those who knew of the program misunderstood its function, believing that more healthful choices are indicated on the menu. When choosing a restaurant, individuals are not greatly influenced by whether it is Heart Smart, but in Saskatoon, they are more likely to request a more healthful alternative in a Heart Smart restaurant than in others. Implications of these and other findings for future program development and research are discussed.

Treatment of antigen-induced arthritis in rabbits by the intra-articular injection of methylprednisolone, 90Y or chlorambucil

Rabbits with a bilateral antigen-induced arthritis were injected intra-articularly (i.a.) in one joint with methylprednisolone (1 mg), 90Y (18.5 MBq) or chlorambucil (1 mg) as a single dose. The severity of arthritis was determined by measuring joint swelling and skin surface temperature, macroscopic and histological changes in the joint being assessed 8 weeks after induction of arthritis when the rabbits were killed. Methylprednisolone injected at the time of antigen challenge or 3 weeks later caused a reduction in joint swelling and temperature (P < 0.05) for 1 to 6 weeks after injection. 90Y had an initial proinflammatory effect lasting several days, but later caused a modest reduction in joint swelling for up to 4 weeks (P < 0.05). Eight weeks after induction of arthritis, neither methylprednisolone nor 90Y-treated joints showed any significant reduction in erosion or histopathology compared with control arthritic joints. Chlorambucil injected 1 week after antigen challenge caused a rapid reduction in joint swelling which was maintained for the duration of the study. Joint surface temperature was reduced to a lesser extent. Eight weeks after induction of arthritis, chlorambucil-treated joints showed a decrease (P < 0.05) in all of the parameters of disease pathology assessed. Treatment with chlorambucil intra-articularly was clearly more effective than with methylprednisolone or 90Y at the doses employed and deserves further study as a potential treatment for chronic synovitis.

Treatment of antigen-induced arthritis in rabbits with liposome-entrapped methotrexate injected intra-articularly

Rabbits with a bilateral antigen-induced arthritis were injected intra-articularly in one joint with methotrexate as the free drug or entrapped in liposomes. Free methotrexate (1 mg) injected as a single dose at the time of antigen challenge, suppressed the development of joint swelling and the rise in skin surface temperature of treated joints by 20-30% compared with contralateral control arthritic joints. The beneficial effect of methotrexate occurred within 24 h of injection and was maintained for at least 56 days. However, methotrexate was ineffective in suppressing arthritis when injected 7 days after antigen challenge. Liposomal methotrexate suppressed the development of arthritis at a dose one-tenth that of the free drug and it was also effective in suppressing arthritis of 7 days duration, although significant beneficial effects of liposomal methotrexate were delayed for 10 to 14 days after injection. Neither free nor liposomal methotrexate was effective in suppressing an established arthritis, having no significant effect on joint swelling or skin surface temperature when injected 21 and 35 days after antigen challenge. At the end of the study, 8 or 9 weeks after induction of arthritis, the joints were examined morphologically and histologically. Free methotrexate generally had no significant effect on joint pathology. However, liposomal methotrexate suppressed the development of synovial hyperplasia, cellular infiltration and the erosion of cartilage and bone when injected at the time of antigen challenge or 7 days later, but affected none of these parameters in an established arthritis of 3 weeks duration.

Effects of selective D1 and D2 dopamine agonists on cockroach salivary gland acinar cells in vitro

1. The ability of the selective dopamine receptor agonists, fenoldopam and SKF38393 (D1) and quinpirole and LY163502 (D2), to mimic the effect of dopamine on cockroach salivary gland acinar cells has been investigated. 2. Intracellular recordings of the membrane potential established that all the agonists mimicked dopamine (i.e. they induced a hyperpolarization which was occasionally followed by a depolarization), whether applied by addition to the superfusate or locally by pressure ejection. 3. The rank order of potency of the agonists to induce a hyperpolarization was (equipotent molar ratio relative to dopamine in parentheses): dopamine (1) much much greater than fenoldopam (1000) greater than SKF38393 (3500) greater than LY163502 (13750) greater than quinpirole (35000). 4. The agonists also elicited secretion from the salivary gland when superfused onto the preparation. SKF38393 and quinpirole did not induce the same maximum rate of secretion as dopamine. The rank order of potency of the agonists was (minimum effective concentration in parentheses): dopamine (0.03 microM) much much greater than fenoldopam (4.8 microM) greater than SKF38393 (40.8 microM) greater than quinpirole (132 microM). 5. Both the hyperpolarizing and secretory responses to all the agonists were antagonized by the selective D1 antagonist, (+)-SCH23390, but not the selective D2 antagonist, (+/-)-sulpiride. 6. These results support the idea that the same receptors mediate both the hyperpolarizing and secretory responses, and that they are similar to the mammalian D1 receptor.

The effect of domperidone on the electrical response of cockroach salivary gland acinar cells

The effects of domperidone on the electrical response of the cockroach salivary gland to applied dopamine and to nerve stimulation have been investigated. Dopamine and nerve stimulation induced a hyperpolarization of the salivary gland acinar cells, which was occasionally followed by a depolarization. At 1 and 10 microM domperidone had no effect on the responses; however, at higher concentrations domperidone (50 and 100 microM) potentiated the hyperpolarization induced by both dopamine and nerve stimulation. Domperidone (50 microM) also potentiated the hyperpolarization induced by 5-HT. Thus the potentiation probably results from a post synaptic action independent of either the dopamine or 5-hydroxytryptamine receptor. In addition, domperidone (50 and 100 microM) had two delayed effects; one, presynaptic, led to a reduction in the response to nerve stimulation; the other, postsynaptic, led to the abolition of the depolarizing phase of the response.

The effects of psychosocial work organization on patterns of cigarette smoking among male chemical plant employees

We tested the hypothesis that job strain (the combination of high psychological job demands and low work control) is positively associated with smoking prevalence and intensity in a study group of 389 males employed in a chemical plant, using a self-administered questionnaire. In a logistic regression analysis which controlled for a number of sociodemographic factors, job strain was not found to be associated with smoking cessation. However, among smokers, those in higher-strain jobs smoked more heavily than those in lower-strain positions (OR 1.70, 95% CI = 1.10, 2.61) and were more likely to have increased the amount they smoke (OR 3.72, 95% CI = 1.92, 7.17).

Characterization of the dopamine receptor mediating the hyperpolarization of cockroach salivary gland acinar cells in vitro

1. Intracellular recordings have been made of the hyperpolarization of cockroach salivary gland cells induced by nerve stimulation and dopamine. 2. The relative potency of a number of dopamine antagonists in inhibiting the dopamine- and nerve-mediated hyperpolarization was studied. SCH23390 (10-50 microM), chlorpromazine (0.1-5 microM), haloperidol (10-100 microM) and metoclopramide (1 mM) inhibited the hyperpolarization. 3. In contrast, domperidone and (+/-)-sulpiride potentiated the hyperpolarization induced by both nerve stimulation and dopamine. 4. Apparent dissociation constants (KDapp) were obtained for the blockade of the dopamine-induced hyperpolarization. The rank order of potency (KDapp in parentheses) was as follows: chlorpromazine (0.2 microM); haloperidol (3.3 microM); SCH23390 (4.1 microM); metoclopramide (265 microM); domperidone and (+/-)-sulpiride (inactive). 5. It is concluded that the receptor subserving the dopamine-induced hyperpolarization of the salivary gland acinar cells is the same as that mediating the secretory response to dopamine. In addition these data support our findings, which suggested that this receptor is similar to the D1 dopamine receptor, but distinct from the D2 receptor found in mammalian systems.

The action of dopamine receptor antagonists on the secretory response of the cockroach salivary gland in vitro

1. A study has been made of the potency of a number of dopamine antagonists to inhibit dopamine-induced secretion from the cockroach salivary gland in vitro. 2. Chlorpromazine (0.5-5 microM), SCH23390 (10-100 microM), haloperidol (10-100 microM) and metoclopramide (2 mM) competitively inhibited the secretory response to dopamine. In contrast (+/-)sulpiride (1-100 microM) and domperidone (1-100 microM) had no effect on either basal or dopamine-induced secretion. 3. Apparent dissociation constants (KDapp) were obtained using a 'three point assay'. The rank order of potency (KDapp in parentheses) was as follows: chlorpromazine (0.2 microM) greater than SCH23390 (2.2 microM) greater than haloperidol (17.5 microM) much greater than metoclopramide (1.2 mM). 4. It is concluded that the receptor mediating dopamine-induced secretion in the cockroach salivary gland is similar to the D1/DA1 dopamine receptor and distinct from the D2/DA2 receptor found in mammalian systems.

Effects of a new neuromuscular blocking agent (Org 9426) in anaesthetized cats and pigs and in isolated nerve-muscle preparations

The effects of Org 9426 (the 2-morpholino, 3-hydroxy, 16N-allyl pyrrolidino analogue of vecuronium) were studied in anaesthetized cats and pigs and in isolated nerve--muscle preparations using tension and intracellular recording techniques. In isolated preparations, the effects of Org 9426 were antagonized by neostigmine. No contracture of the chick muscle preparation occurred. Org 9426 reduced the amplitude of endplate currents (EPC) in rat and snake muscle, but had no major effects on EPC decay characteristics, indicating a lack of endplate channel blocking action. In anaesthetized animals, no fasciculations were observed and the neuromuscular block was associated with tetanic and train-of-four fade and was antagonized by neostigmine. In anaesthetized cats and pigs, Org 9426 was approximately 20% as potent as vecuronium, its onset of action was twice as rapid as that of vecuronium in the cat and its duration of action was similar to that of vecuronium in both cats and pigs. It blocked the bradycardia produced by vagal stimulation only in doses greater than those necessary to produce neuromuscular block (ratios 7.2 in the cat and 4.4 in the pig--10-14% of the corresponding ratios for vecuronium). Ganglion block was seen only at doses several times those producing vagal block. In general the effects of Org 9426 on the cardiovascular system were slight, a small depressor effect occurring at high doses in the cat. The 17-hydroxy analogue, the potential metabolite of Org 9426, was approximately 20 times less potent than Org 9426 and is thus unlikely to contribute to the neuromuscular block produced by the parent compound.

Issues of control and responsibility in workers' health

The issues of responsibility for health and control of factors influencing health are discussed with regard to workplace health programs. The role of each of the parties involved - workers, unions, management, and the government - can best be understood in relation to the interests they hold in workers' health. A matrix is presented which divides influences on workers' health according to the degree to which they are controlled by employers and workers. This matrix is used to suggest that workplace health promotion and employee assistance programs may represent employer involvement in areas over which they lack legitimate control. These programs are also criticized for their emphasis on behavior and their neglect of work-related causes of ill health and unhealthy behavior. They should be considered supplemental to a work environment which is conducive to both physical and psychosocial health; they will be most effective and appropriate with a high degree of worker involvement and control. Evidence regarding the effects of occupation and class on health and health-related behavior is presented to support the need for a comprehensive, ecological approach to workers' health. Such an approach should take into account the full range of influences and recognize the limits of legitimate control.

Retention and distribution of liposome-entrapped [3H]methotrexate injected into normal or arthritic rabbit joints

Normal or arthritic rabbits were injected intra-articularly (i.a.) with free [3H]methotrexate ([3H]MTX) or liposomes containing [3H]MTX with [14C]cholesteryl oleate as a lipid marker. The distribution of 3H and 14C in the injected joint and other tissues was determined. Free [3H]MTX was rapidly cleared from the joint, 79% being excreted in the urine within 24 h of injection. Liposome-entrapment retarded [3H]MTX clearance from the joint (P less than 0.001), 45.5% being recovered from the joint 24 h after injection. Uptake of liposomes by the inflamed synovium was lower than expected, 4% liposomal [3H]MTX injected being associated with the synovium after 24 h. Nevertheless, this was 40-fold greater than when free [3H]MTX was injected. Liposome entrapment should improve the efficacy and reduce the side effects of drugs injected directly into the joint cavity.

A further study of the neuromuscular effects of vesamicol (AH5183) and of its enantiomer specificity

1. The effects of vesamicol (2-(4-phenylpiperidino) cyclohexanol), an inhibitor of acetylcholine storage, and its two optical isomers have been studied on neuromuscular transmission in rat and frog muscle, and on nerve conduction in frog nerve. 2. Racemic vesamicol produced a pre-block augmentation of twitch tension that also occurred in directly-stimulated muscle. This effect is thus at least partially due to an increase in muscle contractility. 3. (-)-Vesamicol was approximately 20 times more potent than (+)-vesamicol in blocking twitches elicited at 1 Hz. This degree of stereoselectivity is similar to that measured for inhibition of acetylcholine uptake by isolated synaptic vesicles. Both enantiomers were equally weak in reducing nerve action potential amplitude in frog nerve. 4. Further studies with the active isomer, (-)-vesamicol, showed that, like that produced by racemic vesamicol, the neuromuscular block was highly frequency-dependent. The block was not reversed by choline or neostigmine, but was partially reversed by 4- or 3,4-aminopyridine. 5. Preliminary electrophysiological studies showed that vesamicol reduced miniature endplate potential amplitude in rapidly-stimulated frog nerve-muscle preparations. Addition of lanthanum ions increased the frequency of miniature endplate potentials and led to the appearance of apparently normal-sized potentials amongst those of reduced amplitude. 6. The results show the close agreement between pharmacological and biochemical observations indicating the suitability of the rat diaphragm as a test model for substances of this nature. The degree of reversibility of the vesamicol-induced neuromuscular block by aminopyridines was unexpected, and it is suggested that in the presence of a drug which greatly increases release, a pool of acetylcholine is capable of being released which is not normally releasable after block of storage by vesamicol. It is also considered possible that the results from the intracellular recording studies may be explained in these terms.

Association of liposome-entrapped [3H]methotrexate with thioglycollate-elicited macrophages in-vitro

The association of free or liposome-entrapped [3H]methotrexate [( 3H]MTX) with thioglycollate-elicited macrophages was investigated in-vitro. [14C]Cholesteryl oleate was incorporated into the liposomes as a lipid marker. [3H]MTX association with the macrophages was 5 to 9-fold higher with liposome-entrapped [3H]MTX than with the free drug. Macrophage-liposome association was biphasic, temperature-dependent and saturable at high liposomal lipid concentration. A high liposome cholesterol (CH) content or the presence of 2,4-dinitrophenol or colchicine also reduced macrophage-liposome association.

Kinetic therapy for spinal cord injury

Kinetic therapy, also referred to as kinetic nursing, is the process of mobilizing severely disabled individuals by placing them on a special rotating bed. This therapy has the unique capability of anatomically immobilizing acutely ill patients while simultaneously creating a state of relative physiological mobility. A series of 162 patients suffering acute spinal cord injuries were treated with kinetic therapy during a 60-month period. A retrospective review of this patient population was performed with regard to the effectiveness of kinetic therapy in reducing commonly occurring sequelae in major organ systems. Results of the study provide preliminary evidence for the efficacy of kinetic therapy, yet point to the need to assess benefits relative to those achieved with standard therapy within a prospective randomized trial.

Kinetic Nursing for acute spinal cord injury patients

This paper is a review of 105 acute spinal cord injured patients treated on the Roto-Rest Mark I hospital bed during a 42-month period at the South Florida Regional Spinal Cord System at the Jackson Memorial Hospital in Miami and the Miami Veterans Administration Hospital Spinal Cord Injury Center. The authors observed that Kinetic Nursing was effective in reducing commonly occurring complicatings in pulmonary, cardiovascular, skin, musculo-skeletal, nervous, gastro-intestinal, and genito-urinary systems. Of special interest in the patient group was the unique ability to maintain spinal stability while mobilising these acutely injured patients in the Roto-Rest bed.

Quantitative studies on the accumulation of serum albumin and erythrocytes in mouse paw oedema induced by bradykinin or thermal injury

The accumulation of 125I-labelled serum albumin and 51Cr-labelled erythrocytes was measured in mouse paw oedema induced by bradykinin or by heating the paw at 46.5 degrees. The extravasating fluid in bradykinin oedema consistently contained 50% of the albumin concentration of plasma, whereas the extravasating fluid induced by thermal injury initially had a low albumin content, but it progressively increased over a period of 30-40 min to equal albumin levels in plasma. Thermal injury also caused the extravascular accumulation of erythrocytes. Errors involved in attempting to measure the albumin content of the additional extravascular fluid in inflammation are discussed. Adrenaline suppressed bradykinin oedema, but potentiated thermal injury. These results do not support the view that bradykinin is the inflammatory mediator in thermally-induced oedema.

Role of endogenous catecholamines in the anti-inflammatory activity of alpha-adrenoceptor blocking agents

1 Drugs which release or modify the response to catecholamines were examined for their effect on the permeability of the mouse peritoneal vascular bed to circulating plasma albumin, labelled with Evans blue.2 Phenoxybenzamine, phentolamine, piperoxane, yohimbine or cocaine reduced the extravasation of Evans blue into the peritoneum, an effect which was antagonized by beta-adrenoceptor blocking drugs. The inhibitory effect of desipramine on the extravasation of Evans blue was less completely antagonized by beta-adrenoceptor blockade.3 Inhibition of catecholamine biosynthesis, ganglion blockade or adrenergic neurone blockade antagonized the reduction in dye extravasation by alpha-adrenoceptor blocking agents and cocaine, but had no significant effect on the response to desipramine. The inhibitory effects of alpha-adrenoceptor blocking agents on dye extravasation were not prevented by bilateral adrenalectomy.4 Mice subjected to the procedure for estimation of vascular permeability excreted increased amounts of adrenaline and noradrenaline. Pretreatment with phenoxybenzamine, piperoxane or cocaine further increased catecholamine excretion, but desipramine caused only a small increase in catecholamine excretion which did not correlate with its effect on dye extravasation.5 It is suggested that phenoxybenzamine, phentolamine, piperoxane and cocaine reduce vascular permeability in the mouse peritoneum by releasing and/or potentiating the effects of endogenous catecholamines on beta-adrenoceptors. Endogenous catecholamines do not appear to be involved in the anti-inflammatory activity of desipramine.

Mechanism of the pro-inflammatory activity of sympathomimetic amines in thermic oedema of the rat paw

1 Thermic oedema induced by heating rat paws at 46.5 degrees C was potentiated by local injection of adrenaline, noradrenaline or high doses of isoprenaline. The pro-inflammatory effect of sympathomimetic amines was antagonized by phenoxybenzamine or phentolamine but not by propranolol.2 The subcutaneous space of heated rat paws was perfused with Tyrode solution and the perfusate collected and assayed for bradykinin, bradykininogen, kinin-forming activity and kininase activity. When adrenaline (0.5 mug/ml) was included in the perfusion fluid, kininase activity of the perfusate was increased by 76% and free bradykinin reduced by 46%.3 Increased vascular permeability induced by injection of bradykinin or kallikrein was reduced by adrenaline or noradrenaline, but isoprenaline had no significant effect.4 Pretreatment with soya bean trypsin inhibitor (SBTI) or heparin did not antagonize the pro-inflammatory effect of adrenaline or thermic oedema per se.5 Potentiation of thermic oedema similar to that induced by sympathomimetic amines was obtained by injecting paws with vasopressin prior to heating, or by applying a ligature to stop blood flow to the paw for the first 15 min of heating.6 Thermistor probes inserted beneath the paw skin showed that sympathomimetic amines increased the internal temperature of heated paws. This was significant, as small changes in temperature had a marked effect on the development of thermic oedema.7 It is suggested that sympathomimetic amines potentiate thermic oedema of rat paws heated at 46.5 degrees C by reducing blood flow to the paw, thereby causing a greater rise in paw temperature and consequently greater injury.

The anti-inflammatory effect of catecholamines in the peritoneal cavity and hind paw of the mouse

1. Carrageenin or 5-hydroxytryptamine-induced oedema of the mouse hind paw was antagonized by catecholamines acting on both alpha- and beta-adrenoceptors.2. Increased permeability of the mouse peritoneum induced by the local injection of acetic acid or pro-inflammatory mediators was antagonized by catecholamines acting predominantly on beta-adrenoceptors.3. The anti-inflammatory effect of catecholamines was due neither to hyperglycaemia nor to the release of adrenal cortical hormones.