The effects of cannabidiol on impulsivity and memory during abstinence in cigarette dependent smokers.

Acute nicotine abstinence in cigarette smokers results in deficits in performance on specific cognitive processes, including working memory and impulsivity which are important in relapse. Cannabidiol (CBD), the non-intoxicating cannabinoid found in cannabis, has shown pro-cognitive effects and preliminary evidence has indicated it can reduce the number of cigarettes smoked in dependent smokers. However, the effects of CBD on cognition have never been tested during acute nicotine withdrawal. The present study therefore aimed to investigate if CBD can improve memory and reduce impulsivity during acute tobacco abstinence. Thirty, non-treatment seeking, dependent, cigarette smokers attended two laboratory-based sessions after overnight abstinence, in which they received either 800 mg oral CBD or placebo (PBO), in a randomised order. Abstinence was biologically verified. Participants were assessed on go/no-go, delay discounting, prose recall and N-back (0-back, 1-back, 2-back) tasks. The effects of CBD on delay discounting, prose recall and the N-back (correct responses, maintenance or manipulation) were null, confirmed by a Bayesian analysis, which found evidence for the null hypothesis. Contrary to our predictions, CBD increased commission errors on the go/no-go task. In conclusion, a single 800 mg dose of CBD does not improve verbal or spatial working memory, or impulsivity during tobacco abstinence.

Retinoid-specific induction of differentiation and reduction of the DNA synthesis rate and tumor-forming ability of a stem cell line from a rat mammary tumor.

Differentiation of the stem cell line rat mammary (Rama) 25 to alveolar-like cells can be monitored by the increase in production of domes (hemispheric blisters) in the cell monolayer and immunoreactive casein in the tissue culture medium. This step was accelerated not only by the synthetic inducer dimethyl sulfoxide (DMSO) but also by all-trans-retinol, all-trans-retinal, all-trans-retinoic acid (RA), and all-trans-retinyl acetate (concentration range, 0.04-4 microM) in the presence of the hormones prolactin, hydrocortisone (HC), insulin, and 17 beta-estradiol; 9-cis-all-trans-retinal was without effect. A combination of RA and HC was active in producing doming, whereas RA, all four hormones, and serum were required for maximum production of immunoreactive casein. The retinoids in the same concentration range also caused a reduction in the DNA synthetic rate in a similar time period. When Rama 25 cells were treated with RA and the four hormones yielding the droplet and doming cultures, subsequent injection of these cells into young, female inbred nu/nu (nude) mice led to a reduced incidence of tumors compared with injections of untreated cells. Tumorigenic variant cell lines were selected previously from Rama 25 that were either elongated and failed to differentiate at all to doming and casein-secreting cultures (Rama 521) or that did so spontaneously but whose rates were not accelerated by addition of DMSO (Rama 259). Both Rama 521 and Rama 259 failed to respond to the retinoids and hormones in producing domes and immunoreactive casein, in decreasing DNA synthetic rates, and in lowering the incidence of tumors induced by injection of the cell lines into nude mice. Thus the anticancer activity of the retinoids in rat mammary gland carcinogenesis may be due in part to their differentiation-inducing properties.

Immunocytochemical demonstration of hormonally regulable casein in tumors produced by a rat mammary stem cell line.

The rat mammary epithelial stem cell line, Rat Mammary 25, and the dimethyl sulfoxide-resistant variant derived from it, Rama 259, when injected separately into female, virgin, athymic nude mice formed tumors which grew at approximately the same rate. When the mice were mated, the growth rate of the Rama 259 tumors increased 2.5-fold during late pregnancy and lactation, while that of the Rama 25 tumors was unaffected. The tumors in all cases consisted of glandular-like structures and blocks of cuboidal and elongated cells. Antibodies were raised against the three major caseins in rat milk. Examination of histological sections showed that antibodies immunocytochemically stained some of the cells (5 to 20%) in the glandular regions, a few (1 to 5%) of the cuboidal cells, and none of the elongated cells in Rama 25 tumors from lactating mice. Only a relative few (1 to 5%) of the glandular cells stained in Rama 25 tumors from perphenazine-treated mice, while no cells (less than 1%) stained in tumors from virgin mice. The casein antibodies failed to stain any cells (less than 1%) in the Rama 259 tumors even when they stained luminal epithelial cells in the mammary glands taken from the same lactating or perphenazine-treated mice. These results demonstrated that a minor population of cells within the Rama 25 tumors can be hormonally regulated to produce casein in a way similar to that for the majority of the cells in normal mammary glands.

Elevated arousal at time of decision-making is not the arbiter of risk avoidance in chickens.

The somatic marker hypothesis proposes that humans recall previously experienced physiological responses to aid decision-making under uncertainty. However, little is known about the mechanisms used by non-human animals to integrate risk perception with predicted gains and losses. We monitored the behaviour and physiology of chickens when the choice between a high-gain (large food quantity), high-risk (1 in 4 probability of receiving an air-puff) option (HGRAP) or a low-gain (small food quantity), no-risk (of an air-puff) (LGNAP) option. We assessed when arousal increased by considering different stages of the decision-making process (baseline, viewing, anticipation, reward periods) and investigated whether autonomic responses influenced choice outcome both immediately and in the subsequent trial. Chickens were faster to choose and their heart-rate significantly increased between the viewing and anticipation (post-decision, pre-outcome) periods when selecting the HGRAP option. This suggests that they responded physiologically to the impending risk. Additionally, arousal was greater following a HGRAP choice that resulted in an air-puff, but this did not deter chickens from subsequently choosing HGRAP. In contrast to human studies, we did not find evidence that somatic markers were activated during the viewing period, suggesting that arousal is not a good measure of avoidance in non-human animals.

Aerosol route enhances the contamination of intact eggs and muscle of experimentally infected laying hens by Salmonella typhimurium DT104.

Commercial laying hens were infected with Salmonella typhimurium DT104 strain 16 alternatively via the crop (10(7) cfu per bird) or by an aerosol delivered directly to the beaks using a Collison nebuliser and Henderson apparatus (2 x 10(2) or 2 x 10(4) cfu per bird). Infection by both routes caused systemic infection and prolonged contamination of faeces. Contamination rates of eggs and muscle were much higher following the aerosol challenges despite the much lower doses given by this route. The frequency of Salmonella isolation from eggs rose from 1.7% following oral challenge to 14% and 25%, for each of the aerosol challenges respectively, and the frequency of isolation from muscle rose from 0% following the oral challenge to 27% following each of the aerosol challenges.

Behavioural and physiological expression of arousal during decision-making in laying hens.

Human studies suggest that prior emotional responses are stored within the brain as associations called somatic markers and are recalled to inform rapid decision-making. Consequently, behavioural and physiological indicators of arousal are detectable in humans when making decisions, and influence decision outcomes. Here we provide the first evidence of anticipatory arousal around the time of decision-making in non-human animals. Chickens were subjected to five experimental conditions, which varied in the number (one versus two), type (mealworms or empty bowl) and choice (same or different) of T-maze goals. As indicators of arousal, heart-rate and head movements were measured when goals were visible but not accessible; latency to reach the goal indicated motivation. We found a greater increase in heart-rate from baseline to the goal-viewing period, more head movements and shorter latencies in all conditions including mealworms compared to those with empty bowls. More head movements when two mealworm bowls were available compared to just one, and prior to occasions when hens accessed an empty bowl rather than declining to move, showed that arousal preceded and influenced decision-making. Our results provide an important foundation for investigating arousal during animal decision-making and suggest that the somatic-marker hypothesis might not only apply to humans.

A comparison of the phototumorigenic potential of 8-MOP and 5-MOP in hairless albino mice exposed to solar simulated radiation.

Hairless albino mice have been treated with topically applied 8-methoxypsoralen and 5-methoxypsoralen at two concentrations and exposed to solar simulated radiation. Both these compounds significantly increased the incidence of cutaneous tumours when compared with controls irradiated after treatment with vehicle. This effect was related to psoralen concentration and at the two concentrations investigated there was no significant difference between the compounds.

Rat mammary preadipocytes in culture produce a trophic agent for mammary epithelia-prostaglandin E2.

Cell strains and cell lines rat mammary (Rama) 350-353 have been isolated from the slowly adherent stromal fraction of enzymatically digested rat mammary glands. Primary cultures of this fraction yield fat cels on extended culture. Their proportion can be increased with horse serum or growth hormone in the medium, and this increase is associated with a 100-fold or more increase in the release of radioimmunoassayable prostaglandins of the E type (PGE). The stromal cell strains and lines that are capable of yielding fat cells also secrete elevated levels (greater than 100 ng/mg/24 hr) of PGE; the fast-sticking epithelial fraction in primary cultures and the epithelial cell lines derived from it secrete 10-100 times less. Chromatography and radioisotopic labeling of the culture media from Rama 352 cells identify the PG as PGE2. PGE2 with insulin and hydrocortisone maximally stimulates [3H]DNA synthesis of epithelial cell lines and primary cultures from normal and tumorous glands by 2-4-fold at concentrations (10-20 ng/ml) well below those released by the preadipocytic stromal cells (20-100 ng/ml). Medium exposed to most cultured cells stimulates [3H]DNA synthesis of one epithelial cell line, Rama 25, by 2-4-fold. Prevention of the synthesis of PGE2 in Rama 352 cultures with indomethacin or flurbiprofen abolishes the mitogenic activity present in the culture medium, and the PG receptor antagonist polyphloretin phosphate inhibits completely the mitogenic activity for Rama 25 cells. Myoepithelial-like cell lines normally secrete moderate levels of PGE (10-100 ng/mg/24 hr) but the mitogenic activity for Rama 25 cells released from one such line, Rama 29, is not abolished by preventing the synthesis of PG's nor by PG-receptor antagonists.

The use of a low-osmolality contrast medium in hysterosalpingography: comparison with a conventional contrast medium.

Hexabrix 320 has been compared with Conray 280 in a randomised double-blind study of 97 patients undergoing hysterosalpingography. Although the lower osmolality and higher viscosity of Hexabrix should make it an ideal hysterosalpingographic agent, no differences were detected between the two contrast media, either in the incidence of side-effects or in radiographic image quality.

Isolation and properties of rat cell lines morphologically intermediate between cultured mammary epithelial and myoepithelial-like cells.

The cloned cuboidal epithelial cell line Rat Mammary (Rama) 25 converts at low frequency in culture to elongated cells that possess some of the properties of myoepithelial cells; one such clonal cell line is termed Rama 29. Three morphologically intermediate clonal cell lines have been isolated from Rama 25 which form a morphological series in the order: Rama 25 cuboidal cells, Rama 25-Intermediate 2(I2), Rama 25-I1, Rama 25-I4, and Rama 29 elongated cells. This same order is largely maintained for increasing percentages of elongated cells, decreasing percentages of cuboidal cells, decreasing tubular structures on collagen gels, and increasing times of appearance of tumors in nude mice. The fully elongated cells fail to revert to cuboidal cells and to form tumors. Binding of antisera to epithelial-specific milk fat globule membranes and human keratin declines whereas binding of antisera to myoepithelial-associated laminin, vimentin, and Thy-1 increases in the cell lines in the same order. Similarly 7 polypeptides characteristic of elongated cells increase and 4 polypeptides characteristic of cuboidal cells decrease in the cell lines in the same way. Anti-actin serum binds equally to all cell lines grown on plastic, except for Rama 25-I4, where its binding is increased. Rama 25-I1 and Rama 25-I4 cells also give rise to anti-actin, anti-myoglobin, and phosphotungstic acid hematoxylin-staining giant, striated cells on collagen gels and in tumors that also have ultrastructural characteristics of skeletal muscle. Fresh elongated converts of Rama 25 bind appreciably more anti-actin serum than many of the clonal elongated cell lines such as Rama 29. Ultrastructural analysis confirms the gradual loss of epithelial characteristics and the acquisition of immature myoepithelial characteristics in the same sequence of cell lines. It is suggested that such a linear sequence of intermediate morphological states occurs between the Rama 25 cuboidal cells and the elongated myoepithelial-like cells in vitro, and that a similar morphological sequence may exist in terminal ductal structures in vivo.

Corticospinal facilitation studied during voluntary contraction of human abdominal muscles.

Transcranial magnetic stimulation (TMS) of the human motor cortex was used to study facilitation of motor-evoked potentials (MEPs) in the rectus abdominis (RA) muscle, a trunk flexor, during voluntary activation. MEPs could be produced in the relaxed RA muscles of all six normal subjects studied. The MEPs had short latencies (18-22 ms) which are consistent with other studies suggesting a fast corticospinal input to the trunk muscles. Marked facilitation was observed in the MEPs when subjects were asked to produce graded levels of voluntary contractions. The two tasks used to produce voluntary contractions were a forced expiration during a breath-holding task (FEBH) and bilateral trunk flexion (BTF). Maximal voluntary EMG activity during the BTF task produced around 4.2 times more integrated EMG than during the FEBH task. Similarly the MEP amplitude at MVC was 2.3 times greater during BTF than FEBH. The pattern of MEP facilitation with increasing voluntary EMG was not linear and a maximal MEP amplitude was observed at a level of voluntary contraction around 30 % MVC in both tasks. There were some subtle differences in the pattern of facilitation in the two tasks. When TMS was applied to the right cortex only, MEPs were seen in both left and right RA muscles suggesting some ipsilateral corticospinal innervation. The latency of the right (ipsilateral) response was approximately 2 ms longer than the left. Comparison with studies in hand and leg muscles suggests that the facilitation pattern in RA may reflect a substantial degree of corticospinal innervation. Experimental Physiology (2001) 86.1, 131-136.