Neural correlates of interactions between cannabidiol and Δ(9) -tetrahydrocannabinol in mice: implications for medical cannabis.

BACKGROUND AND PURPOSE: It has been proposed that medicinal strains of cannabis and therapeutic preparations would be safer with a more balanced concentration ratio of Δ(9) -tetrahydrocannabinol (THC) to cannabidiol (CBD), as CBD reduces the adverse psychotropic effects of THC. However, our understanding of CBD and THC interactions is limited and the brain circuitry mediating interactions between CBD and THC are unknown. The aim of this study was to investigate whether CBD modulated the functional effects and c-Fos expression induced by THC, using a 1:1 dose ratio that approximates therapeutic strains of cannabis and nabiximols. EXPERIMENTAL APPROACH: Male C57BL/6 mice were treated with vehicle, CBD, THC or a combination of CBD and THC (10 mg·kg(-1) i.p. for both cannabinoids) to examine effects on locomotor activity, anxiety-related behaviour, body temperature and brain c-Fos expression (a marker of neuronal activation). KEY RESULTS: CBD potentiated THC-induced locomotor suppression but reduced the hypothermic and anxiogenic effects of THC. CBD alone had no effect on these measures. THC increased brain activation as measured by c-Fos expression in 11 of the 35 brain regions studied. CBD co-administration suppressed THC-induced c-Fos expression in six of these brain regions. This effect was most pronounced in the medial preoptic nucleus and lateral periaqueductal gray. Treatment with CBD alone diminished c-Fos expression only in the central nucleus of the amygdala compared with vehicle. CONCLUSIONS AND IMPLICATIONS: These data confirm that CBD modulated the pharmacological actions of THC and provide new information regarding brain regions involved in the interaction between CBD and THC.

PD-L1 expression is increased in monocyte derived dendritic cells in response to porcine circovirus type 2 and porcine reproductive and respiratory syndrome virus infections.

Host immune system suppression is thought to be crucial in the development of porcine circovirus associated diseases (PCVAD). Many immune suppressive mechanisms have been studied in cases of PCVAD, however, the role of programmed death ligand-1 (PD-L1) during porcine circovirus type 2 (PCV2) infection and PCVAD development has yet to be determined. PD-L1 has become an important research target because of its ability to interfere with effective T-cell activity and proliferation during the course of an immune response. In this study, porcine monocyte derived dendritic cells (MoDC) were infected with different combinations of PCV2 and porcine reproductive and respiratory syndrome virus (PRRSV) and evaluated for expression levels of PD-L1, as well as the expression levels of swine major histocompatibility complexes 1 and 2 (SLA-1 and SLA-2) as a measure of MoDC stimulatory capacity. PD-L1 expression levels were also tested in MoDCs after treatment with interferon alpha (IFN-α) and beta (IFN-ß). The results showed that the expression levels of PD-L1 were increased in PCV2-infected MoDCs, as well as in PCV2 and PRRSV co-infected MoDCs. The MoDCs infected with PRRSV only also showed a strain-dependent increase in PD-L1 expression. Both IFN-α and IFN-ß treatment also increased the expression levels of PD-L1 in MoDCs. SLA-1 and 2 expression levels were increased by PCV2 infection, and altered in the PRRSV, and PCV2+PRRSV co-infected MoDCs in a strain-dependent manner. These results indicate a potential immuno-suppressive role for dendritic cells during PCV2 infection and the development of PCVAD and will be helpful in more fully elucidating the underlying mechanisms leading to clinical PCVAD.

The PD-L1/CD86 ratio is increased in dendritic cells co-infected with porcine circovirus type 2 and porcine reproductive and respiratory syndrome virus, and the PD-L1/PD-1 axis is associated with anergy, apoptosis, and the induction of regulatory T-cells in porcine lymphocytes.

Porcine circovirus type 2 (PCV2) and porcine reproductive and respiratory syndrome virus (PRRSV) continue to have a negative economic impact on global swine production operations. Host immune modulations that potentiate disease during PCV2 and/or PRRSV infections are important areas of ongoing research. In this study, we evaluated the expression levels of PD-L1, CD86, and IL-10 in order to phenotype dendritic cells following viral infection with PCV2b and/or PRRSV. The results showed that the inhibitory marker PD-L1 was significantly increased in monocyte derived dendritic cells (MoDC) in both singular PCV2 infection and PCV2/PRRSV co-infections. MoDC expression of stimulatory marker CD86 was significantly increased during singular PCV2 infections, while it was significantly decreased in the treatment groups co-infected with both PCV2 and PRRSV. IL-10 production was highest among MoDCs that were co-infected with PCV2 and PRRSV. These results indicate that dendritic cells develop a regulatory phenotype following PCV2/PRRSV co-infections. We further investigated the role of the PD-L1/PD-1 axis in lymphocyte anergy, apoptosis, and the induction of regulatory T-cells in porcine mononuclear cell populations. Lymphocyte populations with normal PD-1 expression had higher percentages of anergic, apoptotic lymphocytes and CD4(+)CD25(HIGH)FoxP3(+) regulatory T-cells when compared to a PD-1 deficient lymphocyte population. These results implicate the PD-L1/PD-1 axis in negative regulation of lymphocyte responses in pigs.

Co-infection of porcine dendritic cells with porcine circovirus type 2a (PCV2a) and genotype II porcine reproductive and respiratory syndrome virus (PRRSV) induces CD4(+)CD25(+)FoxP3(+) T cells in vitro.

Porcine circovirus associated disease (PCVAD) is currently one of the most economically important diseases in the global swine industry. Porcine circovirus type 2 (PCV2) is the primary causative agent, however co-infection with other swine pathogens such as porcine reproductive and respiratory syndrome virus (PRRSV) is often required to induce the full spectrum of clinical PCVAD. While the specific mechanisms of viral co-infection that lead to clinical disease are not fully understood, immune modulation by the co-infecting viruses likely plays a critical role. We evaluated the ability of dendritic cells (DC) infected with PRRSV, PCV2, or both to induce regulatory T cells (T(regs)) in vitro. DCs infected with PCV2 significantly increased CD4(+)CD25(+)FoxP3(+) T(regs) (p<0.05) and DCs co-infected with PRRSV and PCV2 induced significantly higher numbers of T(regs) than with PCV2 alone (p<0.05). Cytokine analysis indicated that the induction of T(regs) by co-infected DCs may be dependent on TGF-ß and not IL-10. Our data support the immunomodulatory role of PCV2/PRRSV co-infection in the pathogenesis of PCVAD, specifically via T(reg)-mediated immunosuppression.

A modified live PRRSV vaccine and the pathogenic parent strain induce regulatory T cells in pigs naturally infected with Mycoplasma hyopneumoniae.

The lack of heterologous protection by porcine reproductive and respiratory syndrome virus (PRRSV) vaccines is currently a major problem in the field. Heterologous protection by PRRS vaccines depends on the ability of the vaccine to induce an interferon gamma (IFN-γ) response. One mechanism by which the virus evades the immune system is by activating regulatory T cells (T(regs)), resulting in induction of interleukin 10 rather than IFN-γ. Our hypothesis that current PRRS vaccines do not differ from pathogenic strains in the ability to induce T(regs) was tested by inoculating three groups of pigs with two pathogenic viruses and an attenuated vaccine strain and evaluating the number of T(regs) in peripheral blood mononuclear cells. Before inoculation, the pigs, although vaccinated became infected naturally with Mycoplasma hyopneumoniae before shipment to our research facility. Our results show that the PRRSV vaccine strain and parent strain are equally able to induce T(regs) in pigs naturally infected with M. hyopneumoniae. Pigs in the vaccine and PRRSV groups had higher lung lesion scores than pigs in the control groups. The results suggest that the exacerbation M. hyopneumoniae respiratory disease may be due to the ability of PRRSV vaccination and viral infection to induce regulatory T cells.

Tissue and life-stage distribution of a defensin gene in the Lone Star tick, Amblyomma americanum.

The transcript sequence of the Amblyomma americanum Linnaeus (Acari: Ixodidae) defensin, termed amercin (amn), was ascertained and a 219-bp amn coding region identified. The gene encodes a 72-amino acid prepropeptide with a putative 37-amino acid mature peptide. This gene shows little similarity to either of the defensins from Amblyomma hebraeum Koch, the only other Amblyomma species for which a defensin has been described. Sequence comparisons with other tick defensins reveal amn to be shorter (6 bp or 2 amino acids) than the Ixodes scapularis Linnaeus (Acari: Ixodidae) and Dermacentor variabilis (Say) (Acari: Ixodidae) defensin sequences. The amercin prepropeptide has 60.8% and 59.5% similarity with the I. scapularis and D. variabilis prepropeptides, respectively, whereas the mature amercin peptide has 73.7% and 71.1% similarity with the mature peptides of these ticks. Similarity with other tick defensins ranges from 42% to 71%. In A. americanum, defensin transcript was found in the midgut, fat body and salivary gland tissues, as well as in the haemocytes. Defensin transcript was also present in early-stage eggs (less than 48 h old), late-stage eggs (approximately 2 weeks old), larvae and nymphs of A. americanum and I. scapularis, both of which are vector-competent for Borrelia spirochetes.

A defensin-like gene expressed in the black-legged tick, Ixodes scapularis.

The black-legged tick Ixodes scapularis Linnaeus (Acari: Ixodidae) is an important vector of microbial pathogens. Knowledge of the tick's innate immune response, particularly defensin and other antimicrobial peptides, is important for understanding how microbes survive in this tick. A defensin gene (slnA) from I. scapularis was obtained by reverse transcription-polymerase chain reaction (RT-PCR) using mRNA extracted from tissues of female ticks. RT-PCR indicated the gene was expressed in the midgut, haemocytes, and fat-body, although no evidence of a peptide was found. Sequencing a cloned cDNA fragment revealed a 225 bp open reading frame encoding a 74 amino acid pre-prodefensin, including the putative 38 amino acid mature peptide. Similarity between the defensin amino acid sequences of I. scapularis and Dermacentor variabilis (Say) (Acari: Ixodidae) was 62.2% for the pre-prodefensin region; for the mature defensins from these two species the similarity was 78.9%, with the six cysteine residues being located in the same relative position. PCR amplification and sequencing of chromosomal DNA suggests that slnA, along with vsnA, the defensin gene from D. variabilis, does not contain any introns. This is in contrast to the defensins described for the soft tick, Ornithodoros moubata (sensu Walton) (Acari: Argasidae). The role of defensin in the innate immune response of I. scapularis following microbial invasions is discussed.

Correlation between molecular structure and helicity of induced chiral nematics in terms of short-range and electrostatic-induction interactions. The case of chiral biphenyls.

The helical structure of the chiral nematic phases induced by chiral dopants in nematic solvents provides a macroscopic image of the molecular chirality of the dopant promoted by the orientational order. Chiral biphenyls are challenging systems because their twisting ability shows a strong dependence on the molecular structure, which does not conform to empirical correlation rules. This points out the need for adequate interpretative tools, able to establish a link between molecular properties and macroscopic response. In this paper the twisting ability of chiral biphenyls is reviewed, by reporting examples taken from the literature together with some new experimental results. The microscopic origin of the observed behavior is explained in terms of chirality and anisotropy of short-range and electrostatic-induction interactions. These are described, respectively, by a shape model and a reaction field method, having the common characteristics of a realistic representation of the structure and properties of the chiral dopants in terms of molecular surface, atom charges, and distributed polarizabilities.

Magnetic resonance imaging in the management of suspected spinal canal disease in patients with known malignancy.

AIM: The aim of this study was to examine the spectrum of spinal canal disease in patients with known malignancy using magnetic resonance imaging (MRI). MATERIALS AND METHODS: One hundred and fifty-five patients underwent a total of 159 spinal MRI examinations over a three-year period. Patients were examined using a 1.0T magnet and a phased array surface spine coil. Sagittal T1 weighted spin echo and STIR sequences were routinely employed. Axial T1 and T2 weighted spin echo images were obtained at sites of identified pathology. Contrast enhanced sagittal and axial T1 weighted spin echo images were acquired when the unenhanced appearances did not correlate with the clinical findings or when the images suggested intradural or intramedullary disease. RESULTS: Malignant disease affecting the spinal cord or cauda equina was noted in 104/159 (65%) patients (extradural n= 78, intradural n= 20, intramedullary n= 7); one patient had evidence of both intradural and intramedullary deposits. Multiple levels of extradural cord/cauda equina compression were present in 18/78 patients (23%). The thoracic spine was the most frequently affected (74%). Bone elements were the major component of extradural compression in 11/78 patients (14%). Intradural metastases were multiple in 15/20 patients (75%). Four of the six solitary intramedullary metastases were situated in the conus medullaris. CONCLUSION: Magnetic resonance imaging of the entire spine is the investigation of choice in patients with known malignancy and suspected spinal canal disease. Contrast-enhanced images should be acquired when the unenhanced appearances do not correlate with the clinical findings or when they suggest intradural or intramedullary disease.Loughrey, G. J. (2000). Clinical Radiology55, 849-855.

Tumour oxygenation levels correlate with dynamic contrast-enhanced magnetic resonance imaging parameters in carcinoma of the cervix.

BACKGROUND AND PURPOSE: The Eppendorf pO(2) histograph is the 'gold standard' method for measuring tumour oxygenation. The method is not suitable for widespread application because its use is limited to accessible tumours. A non-invasive imaging technique would be an attractive alternative. Therefore, the relationships between tumour oxygenation and dynamic contrast-enhanced magnetic resonance imaging (MRI) parameters were investigated. MATERIALS AND METHODS: The study comprised 30 patients with carcinoma of the cervix. Tumour oxygenation was measured pre-treatment as median pO(2) and the proportion of values less than 5 mmHg (HP5) using a pO(2) histograph. Repeat measurements were obtained for nine patients following 40-45 Gy external beam radiotherapy giving a total of 39 measurements. Dynamic contrast-enhanced MRI using gadolinium was performed prior to obtaining the oxygenation data. Time/signal intensity curves were generated to obtain two standard parameters: maximum enhancement over baseline (SI-I) and the rate of enhancement (SI-I/s). RESULTS: Using the 39 measurements, there was a significant correlation between SI-I and both median pO(2) (r=0.59; P<0.001) and HP5 (r=-0. 49; P=0.002). There was a weak, borderline significant correlation between SI-I/s and both median pO(2) (r=0.29; P=0.071) and HP5 (r=-0. 34; P=0.037). There was a significant relationship between tumour size and SI-I (r=0.54; P<0.001), but not SI-I/s. In 29 tumours, where data were available, there was no relationship between histological assessment of tumour angiogenesis (intra-tumour microvessel density; IMD) and either MRI parameter. CONCLUSIONS: Tumour oxygenation levels measured using a pO(2) histograph correlate with dynamic contrast-enhanced MRI parameters. Therefore, non-invasive dynamic MRI may be a method for measuring hypoxia in human tumours.