Lumateperone-mediated effects on prefrontal glutamatergic receptor-mediated neurotransmission: A dopamine D1 receptor dependent mechanism

Lumateperone is a novel drug approved for the treatment of schizophrenia in adults and depressive episodes associated with bipolar depression in adults, as monotherapy and as adjunctive therapy with lithium or valproate treatment in the United States. Lumateperone simultaneously modulates key neurotransmitters, such as serotonin, dopamine, and glutamate, implicated in serious mental illness. In patients with schizophrenia, lumateperone was shown to improve positive symptoms along with negative and depressive symptoms, while also enhancing prosocial behavior. Moreover, in patients with bipolar I or II disorder, lumateperone improved depressive symptoms as well. To further understand the mechanisms related to lumateperone's clinical response, the aim of this study was to investigate the effect of lumateperone on dopaminergic- and glutamatergic signaling in the rat medial prefrontal cortex (mPFC). We used the conditioned avoidance response (CAR) test to determine the antipsychotic-like effect of lumateperone, electrophysiology in vitro to study lumateperone's effects on NMDA- and AMPA-induced currents in the mPFC, and the neurochemical techniques microdialysis and amperometry to measure dopamine- and glutamate release in the rat mPFC. Our results demonstrate that lumateperone; i) significantly suppressed CAR in rats, indicating an antipsychotic-like effect, ii) facilitated NMDA and AMPA receptor-mediated currents in the mPFC, in a dopamine D₁-dependent manner, and iii) significantly increased dopamine and glutamate release in the rat mPFC. To the extent that these findings can be translated to humans, the ability of lumateperone to activate these pathways may contribute to its demonstrated effectiveness in safely improving symptoms related to neuropsychiatric disorder including mood alterations.

Epstein-Barr virus is not detected in mucosal lichen planus

Background

Lichen planus (LP) is a chronic inflammatory, immunological, mucocutaneous disease can affect skin, genital and oral mucosa. Oral lichen planus (OLP) is the most common noninfectious, chronic inflammatory oral disease affecting 1-2% of the general adult population. World Health Organization (WHO) classifies OLP as a potentially malignant disorder. Epstein Barr virus or human herpesvirus-4, is a member of the herpes virus family and one of the most ubiquitous viruses known to human, infecting approximately 90% of the world’s adult population. The virus often infects B lymphocytes resulting in a wide spectrum of mucocutaneous and systemic diseases, ranging from mild lesions to aggressive malignancies. The aim of this study was to investigate expression of the EBV encoded RNAs EBER1 and EBER2 in oral and genital lichen planus and compare results with normal tissues in situ hybridization which is considered the golden standard for detection of EBER.

Material and Methods

A total of 68 biopsies, 25 oral LP, 26 genital LP, 10 oral controls and finally 7 genital controls were analysed using situ hybridization.

Results

All samples had RNA as shown by the control slide, whereas no case contained neither EBER1 nor EBER2.

Conclusions

Based on results from our study EBV is not involved in aetiology of lichen planus.

Key words:Mucosal lichen planus, Epstein - Barr virus.

Increased expression of p16 in both oral and genital lichen planus

Background

Lichen Planus, LP, is an inflammatory disease of possible autoimmune origin affecting mainly oral and genital mucosa and skin. According to the WHO oral LP is considered a potentially malignant disorders. The p16 tumour suppressor protein can act as an inhibitor of cyclin dependent kinases 4 and 6 and thus down regulate cell cycle progression. Since the discovery of p16 several studies have evaluated its expression in various forms of human cancers. The aim of this study was to evaluate and compare the expression of p16 in oral and genital LP and corresponding healthy mucosa.

Material and Methods

A total of 76 cases of oral LP (OLP), 34 cases of genital LP (GLP), 12 cases of healthy oral and 9 cases of healthy genital mucosa were analysed by the use of immunohistochemistry.

Results

Data showed p16 to be highly expressed in both oral and genital LP, higher than in oral (p=0.000), and genital controls (p=0.002).

Conclusions

Results suggest that the over-expression of p16 seen in LP play a part in the histopathology of the disease.

Key words:p16, inflammation, oral, genital, lichen planus, malignant risk.

Autoantibodies and decreased expression of the transcription factor ELF-3 together with increased chemokine pathways support an autoimmune phenotype and altered differentiation in lichen planus located in oral mucosa

BACKGROUND

The pathogenesis of oral lichen planus (OLP), a chronic inflammatory disease, is not fully understood. It is known that OLP has autoimmune features, and it is suggested to be an autoimmune disease. ELF-3 is involved in differentiation of keratinocytes and deregulated in different tumours and inflammatory diseases. CXCR-3 and its ligands CXCL-10 and CXCL-11 are increased in autoimmune diseases and linked to Th-1 immune response.

OBJECTIVES

To analyse and compare expression of ELF-3, CXCR-3, CXCL-10 and CXCL-11 in OLP lesions and controls in whole and microdissected epithelium.

METHODS

Tissue biopsies from 20 patients clinically and histologically diagnosed with OLP and 20 healthy controls were studied using whole tissues or microdissected epithelium. By the use of qRT-PCR, mRNA levels of ELF-3, CXCR-3, CXCL-10 and CXCL-11 were studied. Western blot was used for analysis of ELF-3 protein expression. Sera from 19 OLP patients and 20 controls were analysed with ELISA in search for autoantibodies. Results  The upregulation of CXCR-3, CXCL-10 and CXCL-11 found in OLP is similar to previous findings showing an autoimmune phenotype in lichen planus (LP) and lichen sclerosus. Decreased expression of the differentiation-related transcription factor ELF-3 was also seen in OLP lesions, and we further demonstrate presence of circulating autoantibodies against the ELF-3 protein in sera from 3 of 19 (16%) LP patients tested.

CONCLUSIONS

On the basis of these findings, we confirm that OLP shows features of an autoimmune disease and suggest deregulated differentiation of keratinocytes to be one of the causes of the disease phenotype.

Increased levels of COX-2 in oral lichen planus supports an autoimmune cause of the disease

BACKGROUND

Oral lichen planus (OLP) is a chronic inflammatory disease for which the pathogenesis is not fully understood. OLP has autoimmune features and auto immunity has been suggested as a potential cause, whereas WHO has classified OLP as a premalignant condition. Association between chronic inflammation and cancer is known and chronic inflammation is one of the characteristics of OLP. A protein connected to inflammation and suggested to be involved in cancer development is cyclooxygenase-2 (COX-2) which can be inhibited by microRNA-26b (miR-26b).

OBJECTIVE

The aim was to map levels of COX-2 and miR-26b in OLP lesions to see if there was any correlation between expression of COX-2 and its regulator miR-26b in OLP.

METHODS

In biopsies from 20 OLP patients and 20 age and gender-matched controls laser- micro dissection of epithelium was performed. Quantitative RT-PCR, immunohistochemistry and Western blot were used in the analysis.

RESULTS

Levels of COX-2 mRNA were significantly higher while levels of miR-26b were significantly lower in OLP lesions compared to controls. Using immunohistochemistry normal oral mucosa samples did not show any expression of COX-2 while OLP samples expressed the protein. No COX-2 protein was detectable with Western blot.

CONCLUSION

Increased expression of COX-2 and decreased expression of miR-26b in OLP suggests both to play a role in OLP. COX-2 has been connected to both malignant development and autoimmunity but as malignant development of OLP is quite rare we suggest that the increased levels of COX-2 seen here support an autoimmune cause of the disease.

Increased expression of Smad proteins, and in particular Smad3, in oral lichen planus compared to normal oral mucosa

BACKGROUND

Oral lichen planus (OLP) is a chronic inflammatory disease of the oral mucosa which the World Health Organisation (WHO) considers a premalignant condition. One step in malignant development is so called epithelial mesenchymal transition (EMT), a process whereby epithelial cells acquire mesenchymal characteristics. EMT occurs during embryogenesis and wound healing but also in some human diseases such as cancer and fibrosis. A factor known to induce EMT is transforming growth factor-β (TGF-β), which uses the Smad proteins as mediators for its signalling. TGF-β is also often over-expressed in squamous cell carcinoma of the head and neck (SCCHN).

METHODS

In the present study we mapped expression of Smad proteins in OLP lesions by immunohistochemistry, and compared to expression in normal and sensitive oral mucosa. The latter group of patients had developed SCCHN after shorter or longer periods of diffuse oral symptoms. The aim was to see if there were any signs of EMT related changes in the OLP lesions, as judged by changes in the TGF-β pathway.

CONCLUSION

Changes in the TGF-β pathway related to EMT are seen in the very earliest stages of oral malignancy and become more severe as lesions progress.

Sex differences in schizophrenia as seen in the Rorschach test

Research has shown the importance of sex differences for various aspects of schizophrenia. This study focused on sex-related differences in thought processing as shown in the Rorschach test. Thirty-six schizophrenic patients (18 men and 18 women) were tested with the Rorschach in accordance with the Comprehensive System. The results showed that the female patients were more active in handling information input but showed more impairment in conceptualization. The male patients showed more perceptual disturbance. It was concluded that the Rorschach might add information in differentiating among subtle thought disturbances. It might even be useful to detect relationships between thought processes and neuroleptic medication.

Effects of prenatal exposure to tributyltin and trihexyltin on behaviour in rats

The effects of prenatal administration of tributyltin (1 and 5 mg/kg) and trihexyltin (5 mg/kg) upon the development and behavioural repertoire of rats were studied. The dose levels were selected so as not to induce maternal toxicity. No consistent delay upon occurrence of various maturation markers of the organotin-treated offspring was seen. As adults the tributyltin-treated offspring showed considerable hyperactivity following the initial habituation whereas the trihexyltin-treated offspring showed hyperactivity to a lesser degree. In the spatial learning tasks applied, the radial arm maze and the circular swim maze, tributyltin-treated rats demonstrated a clearly retarded aquisition of the radial arm maze task whereas trihexyltin-treated rats performed as well as the control rats; no differences were obtained in the swim maze task. The tributyltin-treated offspring showed a drastic potentiation of d-amphetamine-induced hyperactivity, whereas trihexyltin treatment induced only a marginal increase.

Repeated application of EMLA cream 5% for the alleviation of cannulation pain in haemodialysis

The analgesic effect and the occurrence of local reactions after repeated application of a lidocaine/prilocaine cream (EMLA 5%) were investigated in 31 haemodialysis patients. The cream was used for alleviation of cannulation pain prior to the haemodialysis (HD) for a period of 1-1.5 years. In each patient 300 to 312 applications of the cream were made during the period. Local skin reactions were recorded after the cream applications and the analgesic effect was evaluated with double-blind, crossover placebo controls at regular intervals. Seventeen patients completed the study. EMLA gave considerable pain relief and was significantly better than placebo at all effect evaluations but one. The frequency of local reactions was low and not correlated to the number of applications of EMLA. Two patients, however, interrupted their treatment due to local irritation.

Long-acting local anaesthetics in oral surgery. Clinical evaluation of bupivacaine and etidocaine for mandibular nerve block

2 long-acting local anaesthetics, bupivacaine and etidocaine, have been compared to lidocaine with regard to effect during surgical removal of impacted mandibular third molars and effect upon the immediate postoperative pain. It can be concluded from this study that both bupivacaine and etidocaine as well as lidocaine were highly effective and without significant difference with regard to pain blocking during surgery. Both long-acting solutions were significantly superior to lidocaine in providing an extended duration of postoperative pain control. Comparing the 2 long-acting solutions, patients in the bupivacaine group had a significantly longer pain-free period than patients in the etidocaine group.

Long-acting local anesthetics in oral surgery: an experimental evaluation of bupivacaine and etidocaine for oral infiltration anesthesia

The effect of bupivacaine 7.5 mg/ml with epinephrine 5μg/ml, etidocaine 15 mg/ml with epinephrine 5 μg/ml, and lidocaine 20 mg/ml with epinephrine 12.5 μg/ml was studied when used for oral infiltration anesthesia. Twenty healthy volunteers took part in the experimental and double-blind study. One ml of the respective anesthetic solution was deposited supraperiosteally in the apical area of the maxillary right lateral incisor. Onset time, frequency of analgesia, gingival spread, and duration of tooth analgesia were studied and duration of soft-tissue numbness registered. The present investigation showed that lidocaine had a shorter onset time compared with bupivacaine. No difference with regard to frequency was found. Bupivacaine and etidocaine had a longer period of soft-tissue numbness, but a significantly shorter duration of tooth analgesia than lidocaine.

Conduction Block Analgesia in the Mandible: A comparative investigation of the techniques of Fischer and Gow-Gates

An investigation has been made in order to compare two different intraoral methods for mandibular block analgesia. The first method (according to Fischer) anesthetizes the inferior alveolar and lingual nerves just above the level of the mandibular foramen and the other method (according to Gow-Gates) anesthetizes the mandibular nerve just after leaving the ovale foramen. The latter method should, with only one injection, give complete analgesia within the entire distribution zone of the sensory components of the mandibular nerve.The investigation has been performed on 12 test subjects, who each have achieved mandibular block analgesia according to the two methods mentioned above. 1.8 ml lidocaine-adrenaline (20 mg per ml + 12.5 mug per ml) has been used and the analgesic effect has been tested in the pulps and in the vestibular and lingual mucosa at different time intervals. The investigation shows that the onset of analgesia and complete analgesia was more rapid with the first method than with Gow-Gates method.Furthermore Gow-Gates' method shows no superiority in anesthetizing the long buccal nerve without separate injection for this nerve.However, regarding the analgesic effect only, there has been no statistically significant difference between the two methods with this small number of test subjects.