Comprehensive flow cytometric reference intervals of leukocyte subsets from six study centers across Europe.

A group of European FOCIS Centers of Excellence adapted panels of the Human Immunophenotyping Consortium (HIPC) for whole blood analysis. Using four core panels [T/regulatory T cell/B/natural killer (T/Treg /B/NK) and myeloid cells] the main leukocyte populations were analyzed in a clinical-diagnostic setting in a harmonized manner across different platforms. As a first step, the consortium presents here the absolute and relative frequencies of the leukocyte subpopulations in the peripheral blood of more than 300 healthy volunteers across six different European centers.

Circulating ß cell-specific CD8+ T cells restricted by high-risk HLA class I molecules show antigen experience in children with and at risk of type 1 diabetes.

In type 1 diabetes (T1D), autoreactive cytotoxic CD8+ T cells are implicated in the destruction of insulin-producing ß cells. The HLA-B*3906 and HLA-A*2402 class I genes confer increased risk and promote early disease onset, suggesting that CD8+ T cells that recognize peptides presented by these class I molecules on pancreatic ß cells play a pivotal role in the autoimmune response. We examined the frequency and phenotype of circulating preproinsulin (PPI)-specific and insulin B (InsB)-specific CD8+ T cells in HLA-B*3906+ children newly diagnosed with T1D and in high-risk HLA-A*2402+ children before the appearance of disease-specific autoantibodies and before diagnosis of T1D. Antigen-specific CD8+ T cells were detected using human leucocyte antigen (HLA) class I tetramers and flow cytometry was used to assess memory status. In HLA-B*3906+ children with T1D, we observed an increase in PPI5-12 -specific transitional memory CD8+ T cells compared to non-diabetic, age- and HLA-matched subjects. Furthermore, PPI5-12 -specific CD8+ T cells in HLA-B*3906+ children with T1D showed a significantly more antigen-experienced phenotype compared to polyclonal CD8+ T cells. In longitudinal samples from high-risk HLA-A*2402+ children, the percentage of terminal effector cells within the InsB15-24 -specific CD8+ T cells was increased before diagnosis relative to samples taken before the appearance of autoantibodies. This is the first study, to our knowledge, to report HLA-B*3906-restricted autoreactive CD8+ T cells in T1D. Collectively, our results provide evidence that ß cell-reactive CD8+ T cells restricted by disease-associated HLA class I molecules display an antigen-experienced phenotype and acquire enhanced effector function during the period leading to clinical diagnosis, implicating these cells in driving disease.

Resonance signatures in the body-frame valence photoionization of CF4.

We present a combined experimental and theoretical investigation of the electron dynamics and body-frame angular dependence of valence photo-single ionization of CF4 and subsequent dissociation into CF3+ and F. Ionization from a valence t2 orbital shows overlapping shape resonances close to threshold that couple to the same total symmetry, leading to striking changes in the photoelectron angular distributions when viewed in the body-frame.

[Treatment of proximal humerus fractures: relative position of different locking plates to the axillary nerve]. / Versorgung von Humeruskopffrakturen: Lagebeziehung proximaler Verriegelungsplatten zum N. axillaris.

OBJECTIVES: Placement of a proximal humerus locking plate through a percutaneous transdeltoid approach bears the advantages of a minimally invasive approach but may compromise the anterior branches of the axillary nerve. This anatomic study aimed to develop a risk profile for 6 types of modern proximal humerus locking plates as to their interference with the axillary nerve. MATERIALS AND METHODS: In this study six different implants (Arthrex®, DePuy®, Königsee®, Smith & Nephew®, Stryker® and Synthes®) were placed on the intact proximal humerus of 33 embalmed cadaveric upper extremities and the relative positioning between the axillary nerve and the screw holes was determined. RESULTS: All locking plates displayed an area of risk which concerned 3 out of 7 (Arthrex®), 4 out of 10 (DePuy®), 2 out of 9 (Königsee®), 3 out of 11 (Smith & Nephew®), 3 out of 11 (Stryker®) and 6 out of 12 (Synthes®) screw holes of the plate. CONCLUSIONS: Using the anterolateral percutaneous deltoid splitting approach the relative position of the axillary nerve to the holes of a specific implant is of relevance for avoidance of iatrogenic lesions to the nerve.

[Pathophysiology, diagnostics and therapy of chronic cough: neuronal reflexes and antitussiva]. / Pathophysiologie, Diagnostik und Therapie von chronischem Husten: Neuronale Reflexe und Antitussiva.

Cough is the number one symptom for patients to visit a physician worldwide. It is an important neuronal reflex which serves to protect the airways from inhaled exogenous microorganisms, thermal and chemical irritants. Moreover, it prevents the airways from mucus retention.The cough reflex is initiated by activation of different cough receptors. These cough receptors can be divided into three groups according to their electrophysiological properties: into the two Aδ-fiber types "rapid-adapting mechanoreceptor" (RAR) and "slow-adapting mechanoreceptor" (SAR), and the C-fiber receptor.The stimulus is detected by cough receptors which conduct the signal to the cerebral cough centre via vagal-sensory neurons. The cough itself is mediated by efferent motoneurons. Hence the cough reflex consists of 5 functionally sequential parts 1: the cough receptors 2, the primary afferent fibres of the N. vagus 345, N. trigeminus and N. glossopharyngeus 1, the cough centre in the medulla oblongata (N. tractus solitarius) 678, the afferent fibres of the N. phrenicus, spinal nerve and N. laryngeus recurrens, as well as the diaphragm and the abdominal, intercostal and laryngeal muscles. The cough receptors are mainly located in the larynx, trachea and main bronchi 2.The event of coughing can be divided into four subsequent parts: After the first phase of fast inspiration with an opened glottis, there is compression with a closed glottis and increasing tracheal pressure, acceleration and ultimately maximum expiration with an opened glottis 9. According to its characteristics, cough can be split into two distinct types, "aspiration cough", which is loud and involuntary, and "urge-to-cough sensation", which describes an irritant, scratchy, and controlled cough of slowly increasing intensity 10.Acute cough mostly develops because of infection of the respiratory system 111213 and ends spontaneously after 4 weeks. In contrast to this, bacterial infection with pathogens like Adenovirus, Bordetella pertussis and Mycoplasms can last up to 8 weeks 121314. In additional to the division of cough according to its cause, it can also be differentiated according to its manner: dry and mucus-producing cough.With this review we want to give an overview of neuronal processes and mechanisms, as well as diagnostics of and therapy for chronic cough. Thereby the focus is also placed on the efficiency of already established and potential future antitussive agents.

Comparative analysis of the use of natural and synthetic antioxidants in chicken meat: an update review.

The search for healthy foods has attracted the industry's attention to developing products that use natural ingredients, including natural antioxidants. Antioxidants act as free radicals or oxygen scavengers, inhibiting lipid oxidation and adversely affecting meat products' sensory and nutritional quality. Several synthetic antioxidants have been used in the meat industry; however, studies point to health risks related to their consumption. Such fact drives research into natural antioxidants extracted from grains, oilseeds, spices, fruits, and vegetables, which may have a health-promoting effect. This manuscript evaluates the effectiveness of several natural antioxidants in improving the quality and shelf life of chicken meat products during processing, storage, and distribution. The potential effects of natural antioxidants widely used in chicken products are also discussed. It can be concluded that these natural antioxidants are possible substitutes for synthetic ones. However, their use can affect the product's characteristics.

[Distraction arthroplasty for treatment of posttraumatic elbow stiffness]. / Distraktionsarthroplastik zur Behandlung der posttraumatischen Ellenbogensteife.

A stiff elbow is usually defined as having less than 30° in extension or less than 130° in flexion. Most activities of daily living are possible if the elbow has a range of motion of 100° (30-130° of flexion, Morrey's arc of motion). Loss of mobility of the elbow is not uncommon after trauma, burns or coma and severely impairs upper limb function. Loss of mobility may be difficult to avoid and is challenging to treat. Detailed analysis of the etiology and diagnostic evaluation is of utmost importance for planning any surgical intervention for elbow stiffness. Current operative techniques, such as closed distraction with external fixation (arthroplasty), are presented and evaluated. Elbow arthrolysis is a technically demanding procedure but if the indications and techniques are used correctly and the surgeon, physiotherapist and even the patient are familiar with the procedure, good long-term results may be achieved. Contraindications are poor compliance, poorly controlled diabetes mellitus, active hepatitis B and C infections, HIV infection and acute articular infections.

[Fixator with motion capacity and distraction arthrodiatasis in post-traumatic elbow stiffness]. / Bewegungsfixateur und Distraktionsarthroplastik zur Behandlung der posttraumatischen Ellenbogensteife.

Elbow stiffness may result from trauma, burns and head injuries. It is defined as a total range of motion of <100° with no relevant loss of forearm rotation. Of particular relevance is the flexion deficit. A detailed analysis regarding the development of the elbow stiffness is required together with an exact diagnosis in order to plan the surgical intervention. Closed distraction of the elbow joint as arthrodiatasis with an external fixator is described and evaluated. Adequate long-term results can be achieved with this technique, which reflects proper selection of patients as well as coordination between surgeon, aftercare and physiotherapist. Contraindications are poor compliance, poorly controlled diabetes mellitus, active hepatitis B and C infection, HIV infection and acute articular infection.

[External fixation with motion capacity in acute dislocations and fracture dislocations of the elbow. Fixation with motion capacity]. / Die Behandlung der akuten Luxation und Luxationsfraktur des Ellenbogens. Bewegungsfixateur.

Dislocations and fracture dislocations with their typical fracture patterns may substantially affect the complex anatomy and integrity of the elbow joint. The more components of the joint are injured, the more technically demanding is the therapy. Standardized diagnostic and therapeutic algorithms help to avoid misinterpretations regarding the severity of the injury and the subsequent complications. In elbow dislocations and fracture dislocations with persistent instability the hinged external fixator is an excellent device to improve joint stability and allows physiotherapeutic assistance at an early stage.

[External fixation with motion capacity and radius fractures. Methods and results]. / Bewegungsfixateur und distale Radiusfraktur. Methodik und Ergebnisse.

Both the radiocarpal and distal radioulnar joints are often affected in"distal radius fractures". The incidence of this injury increases markedly among women over the age of 40. Bearing in mind the wide variety of distal radius fractures, a fixation system should be used which permits trans- and extra-articular application and subsequent reduction by means of distraction, as well as wrist mobilization. It is important that both reduction and position of the carpal bones can be checked. The possibility of extra-articular (radioradial) fixation should always be considered. AO group A2 and A3 fractures with sufficiently large fragments are suitable for this procedure. In other cases, transarticular application is advised. Complementary measures are justified in the case where two or more cortices in AP and lateral X-rays are destroyed. Adequate implants are also used to stabilize the articular surface. Large bone defects should be filled with corticocancellous material.

Rationale and design of the PRevention of cArdiac Dysfunction during Adjuvant breast cancer therapy (PRADA II) trial: a randomized, placebo-controlled, multicenter trial.

BACKGROUND: Recent advances in the treatment algorithms of early breast cancer have markedly improved overall survival. However, anthracycline- and trastuzumab-associated cardiotoxicity may lead to dose-reduction or halt in potentially life-saving adjuvant cancer therapy. Early initiated neurohormonal blockade may prevent or attenuate the cardiotoxicity-induced reduction in cardiac function, but prior studies have been inconclusive. The angiotensin receptor-neprilysin inhibitor sacubitril/valsartan has been shown to be superior to traditional treatment in heart failure with reduced ejection fraction, but its cardioprotective effects in the cardio-oncology setting remains to be tested. OBJECTIVE: To assess if sacubitril/valsartan given concomitantly with early breast cancer treatment regimens including anthracyclines, with or without trastuzumab, may prevent cardiac dysfunction. METHODS: PRADA II is a randomized, placebo-controlled, double blind, multi-center, investigator-initiated clinical trial. Breast cancer patients from four university hospitals in Norway, scheduled to receive (neo-)adjuvant chemotherapy with epirubicin independently of additional trastuzumab/pertuzumab treatment, will be randomized 1:1 to sacubitril/valsartan or placebo. The target dose is 97/103 mg b.i.d. The patients will be examined with cardiovascular magnetic resonance (CMR), echocardiography, circulating cardiovascular biomarkers and functional testing at baseline, at end of anthracycline treatment and following 18 months after enrolment. The primary outcome measure of the PRADA II trial is the change in left ventricular ejection fraction (LVEF) by CMR from baseline to 18 months. Secondary outcomes include change in LV function by global longitudinal strain by CMR and echocardiography and change in circulating cardiac troponin concentrations. RESULTS: The study is ongoing. Results will be published when the study is completed. CONCLUSION: PRADA II is the first randomized, placebo-controlled study of sacubitril/valsartan in a cardioprotective setting during (neo-)adjuvant breast cancer therapy. It may provide new insight in prevention of cardiotoxicity in patients receiving adjuvant or neo-adjuvant therapy containing anthracyclines. Furthermore, it may enable identification of patients at higher risk of developing cardiotoxicity and identification of those most likely to respond to cardioprotective therapy. TRIAL REGISTRATION: The trial is registered in the ClinicalTrials.gov registry (identifier NCT03760588 ). Registered 30 November 2018.

Functional consequences of posttranslational isomerization of Ser46 in a calcium channel toxin.

The venom of the funnel-web spider Agelenopsis aperta contains several peptides that paralyze prey by blocking voltage-sensitive calcium channels. Two peptides, omega-Aga-IVB (IVB) and omega-Aga-IVC (IVC), have identical amino acid sequences, yet have opposite absolute configurations at serine 46. These toxins had similar selectivities for blocking voltage-sensitive calcium channel subtypes but different potencies for blocking P-type voltage-sensitive calcium channels in rat cerebellar Purkinje cells as well as calcium-45 influx into rat brain synaptosomes. An enzyme purified from venom converts IVC to IVB by isomerizing serine 46, which is present in the carboxyl-terminal tail, from the L to the D configuration. Unlike the carboxyl terminus of IVC, that of IVB was resistant to the major venom protease. These results show enzymatic activities in A. aperta venom being used in an unprecedented strategy for coproduction of necessary neurotoxins that possess enhanced stability and potency.

High probability of comorbidities in bronchial asthma in Germany.

Clinical experience has shown that allergic and non-allergic respiratory, metabolic, mental, and cardiovascular disorders sometimes coexist with bronchial asthma. However, no study has been carried out that calculates the chance of manifestation of these disorders with bronchial asthma in Saarland and Rhineland-Palatinate, Germany. Using ICD10 diagnoses from health care institutions, the present study systematically analyzed the co-prevalence and odds ratios of comorbidities in the asthma population in Germany. The odds ratios were adjusted for age and sex for all comorbidities for patients with asthma vs. without asthma. Bronchial asthma was strongly associated with allergic and with a lesser extent to non-allergic comorbidities: OR 7.02 (95%CI:6.83-7.22) for allergic rhinitis; OR 4.98 (95%CI:4.67-5.32) allergic conjunctivitis; OR 2.41 (95%CI:2.33-2.52) atopic dermatitis; OR 2.47 (95%CI:2.16-2.82) food allergy, and OR 1.69 (95%CI:1.61-1.78) drug allergy. Interestingly, increased ORs were found for respiratory diseases: 2.06 (95%CI:1.64-2.58) vocal dysfunction; 1.83 (95%CI:1.74-1.92) pneumonia; 1.78 (95%CI:1.73-1.84) sinusitis; 1.71 (95%CI:1.65-1.78) rhinopharyngitis; 2.55 (95%CI:2.03-3.19) obstructive sleep apnea; 1.42 (95%CI:1.25-1.61) pulmonary embolism, and 3.75 (95%CI:1.64-8.53) bronchopulmonary aspergillosis. Asthmatics also suffer from psychiatric, metabolic, cardiac or other comorbidities. Myocardial infarction (OR 0.86, 95%CI:0.79-0.94) did not coexist with asthma. Based on the calculated chances of manifestation for these comorbidities, especially allergic and respiratory, to a lesser extent also metabolic, cardiovascular, and mental disorders should be taken into consideration in the diagnostic and treatment strategy of bronchial asthma. BRONCHIAL ASTHMA: PREVALENCE OF CO-EXISTING DISEASES IN GERMANY: Patients in Germany with bronchial asthma are highly likely to suffer from co-existing diseases and their treatments should reflect this. Quoc Thai Dinh at Saarland University Hospital in Homburg, Germany, and co-workers conducted a large-scale study of patients presenting with bronchial asthma in the Saarland region between 2009 and 2012. Patients with asthma made up 5.4% of the region's total population, with a higher prevalence occurring in females. They found that bronchial asthma was strongly associated with allergic comorbidities such as rhinitis. Indeed, asthmatic patients had a seven times higher chance to suffer from allergic rhinitis than the rest of the population, and were at higher risk of respiratory diseases like pneumonia and obstructive sleep apnea syndrome. Further associations included cardiovascular, metabolic and mental disorders. Dinh's team call for asthma treatments to take such comorbidities into account.

The branched-chain amino acid transaminase 1 sustains growth of antiestrogen-resistant and ERα-negative breast cancer.

Antiestrogen-resistant and triple-negative breast tumors pose a serious clinical challenge because of limited treatment options. We assessed global gene expression changes in antiestrogen-sensitive compared with antiestrogen-resistant (two tamoxifen resistant and two fulvestrant resistant) MCF-7 breast cancer cell lines. The branched-chain amino acid transaminase 1 (BCAT1), which catalyzes the first step in the breakdown of branched-chain amino acids, was among the most upregulated transcripts in antiestrogen-resistant cells. Elevated BCAT1 expression was confirmed in relapsed tamoxifen-resistant breast tumor specimens. High intratumoral BCAT1 levels were associated with a reduced relapse-free survival in adjuvant tamoxifen-treated patients and overall survival in unselected patients. On a tissue microarray (n=1421), BCAT1 expression was detectable in 58% of unselected primary breast carcinomas and linked to a higher Ki-67 proliferation index, as well as histological grade. Interestingly, BCAT1 was predominantly expressed in estrogen receptor-α-negative/human epidermal growth factor receptor-2-positive (ERα-negative/HER-2-positive) and triple-negative breast cancers in independent patient cohorts. The inverse relationship between BCAT1 and ERα was corroborated in various breast cancer cell lines and pharmacological long-term depletion of ERα induced BCAT1 expression in vitro. Mechanistically, BCAT1 indirectly controlled expression of the cell cycle inhibitor p27Kip1 thereby affecting pRB. Correspondingly, phenotypic analyses using a lentiviral-mediated BCAT1 short hairpin RNA knockdown revealed that BCAT1 sustains proliferation in addition to migration and invasion and that its overexpression enhanced the capacity of antiestrogen-sensitive cells to grow in the presence of antiestrogens. Importantly, silencing of BCAT1 in an orthotopic triple-negative xenograft model resulted in a massive reduction of tumor volume in vivo, supporting our findings that BCAT1 is necessary for the growth of hormone-independent breast tumors.

Transcriptional cross-talk, the second mode of steroid hormone receptor action.

Physiological and therapeutic activities of glucocorticoids and other steroid hormones are mediated by the family of steroid hormone receptors. In addition to the classical mode of receptor action which involves binding as a dimer to regulatory sequences in target gene promoters and subsequent activation of transcription, a second mode of action is based predominantly on protein-protein interactions. As the paradigm of this so-called transcriptional cross-talk, the glucocorticoid receptor (GR) and the AP-1 transcription factor interact on target gene promoters which contain only a binding site for either one of the two transcription factors. Most frequently negative interference of both factors with each other's activity has been observed, for example, when AP-1 is composed of c-Fos and c-Jun; however, synergism is also possible under cell-specific conditions and when AP-1 is a homodimer of c-Jun. Since the detection of the GR/AP-1 cross-talk numerous other examples of transcription factor interactions have been described. Many members of the nuclear hormone receptor superfamily, including class II receptors, have been shown to participate in such cross-talk. Moreover, the transcription factor families of NF-kappaB/Rel as well as Stat, Oct, and C/EBP are engaged in cross-talk with steroid receptors. Despite the identification of a multitude of target genes which appear to be regulated by this type of transcription factor interaction, the exact molecular mechanism of the cross-talk has not yet been elucidated. This review discusses the current models to explain the molecular events of transcription factor cross-talk. Concepts are emphasized which suggest that the classical and the cross-talk mode of steroid receptor action can be triggered separately by the choice of specific ligands. A final section summarizes the partially contradictory data which assign a certain type of receptor action to a biological response particularly in the immune system.

Biosynthesis of D-amino acid-containing peptides: exploring the role of peptide isomerases.

The discovery of D-amino acid residues in a growing number of gene-encoded peptides suggests that such biochemical modifications are more common than initially thought. In fact, the extent to which D-amino acids are incorporated into peptides by multicellular organisms probably has not been fully realized, since routine Edman sequencing does not provide the absolute stereochemistry of amino acid residues. Unless both the D and L isomers of a particular peptide sequence are isolated, D-amino acid-containing peptides are often identified only after synthesis of naturally-occurring peptide fails to yield the desired activity. To date, D-amino acid residues (e.g., alanine, methionine, leucine, isoleucine, phenyl alanine, asparagine, tryptophan and serine) have been identified in peptides from a variety of species, including frogs, snails, clams, lobsters and spiders. While most have a single D-amino acid residue located near their N-termini, an exception is found with omega-Aga IVB. The examples highlighted in this chapter are the result of a unique strategy of multicellular organisms to circumvent stereochemical limitations imposed by the genetic code in an effort to increase molecular diversity. The presence of D-amino acids permits the generation of novel tertiary structure that could not be accessed from L-amino acids alone. Moreover, advantages of increased potency and protease stability are often observed. Our understanding of the biosynthesis of these D-amino acid-containing peptides is still in its infancy. Nevertheless, the discovery of a novel peptide isomerase from the venom of the Agelenopsis aperta spider provides some important clues to explain the incorporation of single D-amino acid residues within a peptide chain. Given its high homology with other serine proteases, the isomerase may represent an opportune mutation in response to evolutionary pressures. Yet, is the isomerase a unique exception or simply the first in a class of enzymes of varying substrate specificity capable of synthesizing D-amino acid-containing peptides? To be sure, much more remains to be explored about the precise timing and mechanism of the isomerization process, in addition to obtaining further structural data on the enzyme itself. Therein lies the continuation of this fascinating story in enzyme biochemistry.

The female sex hormone oestrogen as neuroprotectant: activities at various levels.

The female sex hormone oestradiol (oestrogen) is a steroidal compound that binds to specific intracellular receptors which act as transcription factors. Oestrogen displays many of its effects by the classical mode of action through receptor binding, transactivation and binding to consensus oestrogen response elements on DNA. Although the primary role of oestrogen as an ovarian steroid was thought to be the regulation of sex differentiation and maturation, since oestrogen receptors are expressed in a variety of other tissues besides sex organs, oestrogen is believed to exert multiple activities in several target sites throughout the body, including the nervous system. In the brain oestrogens have multiple activities. Potential neuroprotective functions of oestrogens are being intensively studied and it is becoming increasingly clear that oestrogens are (1) neuroprotective hormones acting via oestrogen receptor-dependent pathways at the genomic level and (2) neuroprotective steroidal structures acting independently of the activation of specific oestrogen receptors. One striking activity of the molecule oestradiol is its intrinsic antioxidant activity which makes it a potential chemical shield for neurons. Nerve cells frequently encounter oxidative challenges during the normal physiology, but also under pathophysiological conditions. Oxidative stress has been implicated in a variety of neurodegenerative disorders including amyotrophic lateral sclerosis, Parkinson's disease and Alzheimer's disease. It is important to stress that the antioxidant neuroprotective activity of oestrogens is independent of oestrogen receptor activation, since oestrogen derivatives and aromatic alcohols that do not bind to oestrogen receptors share the same antioxidant neuroprotective activity. Although this effect of oestrogens can clearly be separated from oestrogen receptor binding, oestrogens may interact with intracellular signalling pathways, such as the mitogen activated protein kinase, cyclic AMP pathways, and with the activity of the redox-sensitive transcription factor NF-kappa B.

The multicomponent reactions and their libraries for natural and preparative chemistry.

It was recently recognized that three different types of multi-component reactions (MCRs) exist. In preparative chemistry, the MCRs of type II form their products particularly efficiently. These reactions correspond to equilibria of educts and intermediate products, whose final products are formed practically irreversibly. In recent years, the four component reaction of the isocyanides (U-4CR) of type II and their unions with various reactions and MCRs have become an important industrial process for preparing products and their libraries. It has been demonstrated that all conceivable collections of U-4CR educts can be converted into the corresponding products. In the usual chemical reactions, only the substituents of the products can be varied, whereas the U-4CR and related reactions can also produce skeletally different types of products with diverse substituents. The preparative advantages of forming products by the one-pot MCRs and the great variety of the possible products are illustrated in this review.

Expression of eight metabotropic glutamate receptor subtypes during neuronal differentiation of P19 embryocarcinoma cells: a study by RT-PCR and in situ hybridization.

Metabotropic glutamate receptors modulate neuronal activity but expression and alternative splicing of their subtypes (mGluR1-mGluR8) during early neuronal differentiation are essentially unknown. In the mouse embryocarcinoma cell line P19, one of the best established systems to study neurogenesis in vitro, it was shown by RT-PCR and in situ hybridization that the neuronal differentiation process, induced by retinoic acid, is characterized by an early increase in the expression of mGluR3, mGluR7 and mGluR8 and a late rise in the mRNA levels of mGluR1 and mGluR5, whereas mGluR2 and mGluR4 seem to be constitutively expressed. In comparison, in primary embryonic neurons all mGluR subtypes were detected at day 3 after plating while primary astrocytes and oligodendrocytes have diverging mGluR pattern. In addition, the splicing pattern of mGluR1 and mGluR5 transcripts differ remarkably between neural cells in vitro and brain tissue. These data, although not comparable to the situation in vivo, might be a hint on so far unknown functions of metabotropic glutamate receptors during neuronal differentiation.