Ammonium treatment inhibits cell cycle activity and induces nuclei endopolyploidization in Arabidopsis thaliana.

MAIN CONCLUSION: This study determined the effect of ammonium supply on the cell division process and showed that ammonium-dependent elevated reactive oxygen species production could mediate the downregulation of the cell cycle-related gene expression. Plants grown under high-ammonium conditions show stunted growth and other toxicity symptoms, including oxidative stress. However, how ammonium regulates the development of plants remains unknown. Growth is defined as an increase in cell volume or proliferation. In the present study, ammonium-related changes in cell cycle activity were analyzed in seedlings, apical buds, and young leaves of Arabidopsis thaliana plants. In all experimental ammonium treatments, the genes responsible for regulating cell cycle progression, such as cyclin-dependent kinases and cyclins, were downregulated in the studied tissues. Thus, ammonium nutrition could be considered to reduce cell proliferation; however, the cause of this phenomenon may be secondary. Reactive oxygen species (ROS), which are produced in large amounts in response to ammonium nutrition, can act as intermediates in this process. Indeed, high ROS levels resulting from H2O2 treatment or reduced ROS production in rbohc mutants, similar to ammonium-triggered ROS, correlated with altered cell cycle-related gene expression. It can be concluded that the characteristic ammonium growth suppression may be executed by enhanced ROS metabolism to inhibit cell cycle activity. This study provides a base for future research in determining the mechanism behind ammonium-induced dwarfism in plants, and strategies to mitigate such stress.

Good performance of the criteria of American College of Medical Genetics and Genomics/Association for Molecular Pathology in prediction of pathogenicity of genetic variants causing thoracic aortic aneurysms and dissections.

BACKGROUND: The identification of pathogenic variant in patients with thoracic aortic aneurysms and dissections (TAAD) was previously found to be a significant indicator pointing to earlier need for surgical intervention. In order to evaluate available methods for classifying identified genetic variants we have compared the event-free survival in a cohort of TAAD patients classified as genotype-positive versus genotype-negative by the American College of Medical Genetics and Genomics and the Association for Molecular Pathology (ACMG-AMP) criteria or by ClinVar database. METHODS: We analyzed previously unreported cohort of 132 patients tested in the routine clinical setting for genetic variants in a custom panel of 30 genes associated with TAAD or the TruSight Cardio commercial panel of 174 genes associated with cardiac disease. The identified variants were classified using VarSome platform. Kaplan-Meier survival curves were constructed to compare the event-free survival between probands defined as 'genotype-positive' and 'genotype-negative' using different classifications in order to compare their performance. RESULTS: Out of 107 rare variants found, 12 were classified as pathogenic/likely pathogenic by ClinVar, 38 were predicted to be pathogenic/likely pathogenic by ACMG. Variant pathogenicity as assessed by ACMG criteria was a strong predictor of event free survival (event free survival at 50 years 83% vs. 50%, for genotype positive patients vs. reference, respectively, p = 0.00096). The performance of ACMG criteria was similar to that of ClinVar (event free survival at 50 years 87% vs. 50%, for genotype positive patients vs. reference, respectively p = 0.023) but independent from it as shown by analysing variants with no ClinVar record (event free survival at 50 years 80% vs. 50%, p = 0.0039). Variants classified as VUS by ACMG criteria or ClinVar did not affect event-free survival. TAAD specific custom gene panel performed similar to the larger universal cardiac panel. CONCLUSIONS: In our cohort of unrelated TAAD patients ACMG classification tool available at VarSome was useful in assessing pathogenicity of novel genetic variants. Gene panel containing the established genes associated with the highest risk of hereditary TAAD (ACTA1, COL3A1, FBN1, MYH11, SMAD3, TGFB2, TGFBR1, TGFBR2, MYLK) was sufficient to identify prevailing majority of variants most likely to be causative of the disease.

Spatiotemporal auxin distribution in Arabidopsis tissues is regulated by anabolic and catabolic reactions under long-term ammonium stress.

BACKGROUND: The plant hormone auxin is a major coordinator of plant growth and development in response to diverse environmental signals, including nutritional conditions. Sole ammonium (NH4+) nutrition is one of the unique growth-suppressing conditions for plants. Therefore, the quest to understand NH4+-mediated developmental defects led us to analyze auxin metabolism. RESULTS: Indole-3-acetic acid (IAA), the most predominant natural auxin, accumulates in the leaves and roots of mature Arabidopsis thaliana plants grown on NH4+, but not in the root tips. We found changes at the expressional level in reactions leading to IAA biosynthesis and deactivation in different tissues. Finally, NH4+ nutrition would facilitate the formation of inactive oxidized IAA as the final product. CONCLUSIONS: NH4+-mediated accelerated auxin turnover rates implicate transient and local IAA peaks. A noticeable auxin pattern in tissues correlates with the developmental adaptations of the short and highly branched root system of NH4+-grown plants. Therefore, the spatiotemporal distribution of auxin might be a root-shaping signal specific to adjust to NH4+-stress conditions.

A Comprehensive miRNome Analysis of Macrophages Isolated from db/db Mice and Selected miRNAs Involved in Metabolic Syndrome-Associated Cardiac Remodeling.

Cardiac macrophages are known from various activities, therefore we presume that microRNAs (miRNAs) produced or released by macrophages in cardiac tissue have impact on myocardial remodeling in individuals with metabolic syndrome (MetS). We aim to assess the cardiac macrophage miRNA profile by selecting those miRNA molecules that potentially exhibit regulatory functions in MetS-related cardiac remodeling. Cardiac tissue macrophages from control and db/db mice (an animal model of MetS) were counted and sorted with flow cytometry, which yielded two populations: CD45+CD11b+CD64+Ly6Chi and CD45+CD11b+CD64+Ly6Clow. Total RNA was then isolated, and miRNA expression profiles were evaluated with Next Generation Sequencing. We successfully sequenced 1400 miRNAs in both macrophage populations: CD45+CD11b+CD64+Ly6Chi and CD45+CD11b+CD64+Ly6Clow. Among the 1400 miRNAs, about 150 showed different expression levels in control and db/db mice and between these two subpopulations. At least 15 miRNAs are possibly associated with MetS pathology in cardiac tissue due to direct or indirect regulation of the expression of miRNAs for proteins involved in angiogenesis, fibrosis, or inflammation. In this paper, for the first time we describe the miRNA transcription profile in two distinct macrophage populations in MetS-affected cardiac tissue. Although the results are preliminary, the presented data provide a foundation for further studies on intercellular cross-talk/molecular mechanism(s) involved in the regulation of MetS-related cardiac remodeling.

Molecular Analysis of the ABCA4 Gene Mutations in Patients with Stargardt Disease Using Human Hair Follicles.

ABCA4 gene mutations are the cause of a spectrum of ABCA4 retinopathies, and the most common juvenile macular degeneration is called Stargardt disease. ABCA4 has previously been observed almost exclusively in the retina. Therefore, studying the functional consequences of ABCA4 variants has required advanced molecular analysis techniques. The aim of the present study was to evaluate whether human hair follicles may be used for molecular analysis of the ABCA4 gene splice-site variants in patients with ABCA4 retinopathies. We assessed ABCA4 expression in hair follicles and skin at mRNA and protein levels by means of real-time PCR and Western blot analyses, respectively. We performed cDNA sequencing to reveal the presence of full-length ABCA4 transcripts and analyzed ABCA4 transcripts from three patients with Stargardt disease carrying different splice-site ABCA4 variants: c.5312+1G>A, c.5312+2T>G and c.5836-3C>A. cDNA analysis revealed that c.5312+1G>A, c.5312+2T>G variants led to the skipping of exon 37, and the c.5836-3C>A variant resulted in the insertion of 30 nucleotides into the transcript. Our results strongly argue for the use of hair follicles as a model for the molecular analysis of the pathogenicity of ABCA4 variants in patients with ABCA4 retinopathies.

Suppression of External NADPH Dehydrogenase-NDB1 in Arabidopsis thaliana Confers Improved Tolerance to Ammonium Toxicity via Efficient Glutathione/Redox Metabolism.

Environmental stresses, including ammonium (NH4⁺) nourishment, can damage key mitochondrial components through the production of surplus reactive oxygen species (ROS) in the mitochondrial electron transport chain. However, alternative electron pathways are significant for efficient reductant dissipation in mitochondria during ammonium nutrition. The aim of this study was to define the role of external NADPH-dehydrogenase (NDB1) during oxidative metabolism of NH4⁺-fed plants. Most plant species grown with NH4⁺ as the sole nitrogen source experience a condition known as “ammonium toxicity syndrome”. Surprisingly, transgenic Arabidopsis thaliana plants suppressing NDB1 were more resistant to NH4⁺ treatment. The NDB1 knock-down line was characterized by milder oxidative stress symptoms in plant tissues when supplied with NH4⁺. Mitochondrial ROS accumulation, in particular, was attenuated in the NDB1 knock-down plants during NH4⁺ treatment. Enhanced antioxidant defense, primarily concerning the glutathione pool, may prevent ROS accumulation in NH4⁺-grown NDB1-suppressing plants. We found that induction of glutathione peroxidase-like enzymes and peroxiredoxins in the NDB1-surpressing line contributed to lower ammonium-toxicity stress. The major conclusion of this study was that NDB1 suppression in plants confers tolerance to changes in redox homeostasis that occur in response to prolonged ammonium nutrition, causing cross tolerance among plants.

Nitrogen Source Dependent Changes in Central Sugar Metabolism Maintain Cell Wall Assembly in Mitochondrial Complex I-Defective frostbite1 and Secondarily Affect Programmed Cell Death.

For optimal plant growth, carbon and nitrogen availability needs to be tightly coordinated. Mitochondrial perturbations related to a defect in complex I in the Arabidopsis thalianafrostbite1 (fro1) mutant, carrying a point mutation in the 8-kD Fe-S subunit of NDUFS4 protein, alter aspects of fundamental carbon metabolism, which is manifested as stunted growth. During nitrate nutrition, fro1 plants showed a dominant sugar flux toward nitrogen assimilation and energy production, whereas cellulose integration in the cell wall was restricted. However, when cultured on NH4⁺ as the sole nitrogen source, which typically induces developmental disorders in plants (i.e., the ammonium toxicity syndrome), fro1 showed improved growth as compared to NO3- nourishing. Higher energy availability in fro1 plants was correlated with restored cell wall assembly during NH4⁺ growth. To determine the relationship between mitochondrial complex I disassembly and cell wall-related processes, aspects of cell wall integrity and sugar and reactive oxygen species signaling were analyzed in fro1 plants. The responses of fro1 plants to NH4⁺ treatment were consistent with the inhibition of a form of programmed cell death. Resistance of fro1 plants to NH4⁺ toxicity coincided with an absence of necrotic lesion in plant leaves.

Diffusion tensor tractography of pyramidal tracts in patients with brainstem and intramedullary spinal cord tumors: Relationship with motor deficits and intraoperative MEP changes.

PURPOSE: To evaluate whether pyramidal tracts course alterations observed in diffusion tensor tractography (DTT) in cases of brainstem and intramedullary spinal cord tumors reflect patient clinical status and prognosis. MATERIALS AND METHODS: For this purpose, we assessed in 17 patients relationships between pyramidal tracts course alterations observed in DTT (classified into four categories: unaffected; displaced or interspaced; partially disintegrated and completely disintegrated) performed on a 1.5 Tesla scanner and the presence of preoperative motor deficits, changes observed in motor evoked potentials (MEPs) records at the beginning of the operation, deterioration of the MEPs records during the operation, and perioperative deterioration of muscle strength. RESULTS: We found that, if the picture of pyramidal tracts in DTT was worse, motor deficit was more common (P = 0.062). This observation was even more evident (P = 0.027), when cases with at least partially destroyed pyramidal tracts were compared with cases with normal or at most displaced or interspaced by tumor but still preserved pyramidal tracts. Significant relationships were also found between changes in DTT and abnormal MEP records at the beginning of the operation (P = 0.032) and perioperative deterioration of muscle strength (P = 0.0058). CONCLUSION: A close relationship was found between pyramidal tracts course alterations in DTT imaging and preoperative motor status and especially with changes in the MEP records at the beginning of the operation. DTT may be a method that allows the better planning of brainstem and intramedullary spinal cord tumors operations and may help in the risk assessment of postoperative motor deficits. LEVEL OF EVIDENCE: 3 Technical Efficacy: Stage 4 J. MAGN. RESON. IMAGING 2017;46:715-723.

Paraphilic Sexual Offenders Do Not Differ From Control Subjects With Respect to Dopamine- and Serotonin-Related Genetic Polymorphisms.

INTRODUCTION: Rape and pedophilic child molestation are the most commonly convicted sexual offenses in Poland. Recent studies have suggested a possible genetic contribution toward pathologic sexual interests and behaviors. AIM: To analyze and compare functional polymorphisms of genes associated with the activity of the serotonin and dopamine systems in a group of paraphilic sexual offenders and control subjects. METHODS: The study sample (n = 97) consisted of two groups: paraphilic sexual offenders (65 pedophilic child molesters and 32 rapists) and controls (n = 76). Genetic polymorphisms previously associated with behavioral control, addictive behaviors, and sexual functions were chosen for analyses. Specifically, functional polymorphisms in dopamine receptors genes (DRD1, DRD2, DRD4), catechol-O-methyltransferase gene (COMT), dopamine transporter gene (DAT), serotonin transporter gene (SLC6A4), serotonin type 2A receptor gene (5HTR2A), tryptophan hydroxylase 2 gene (TPH2), monoamine oxidase A gene (MAOA), and brain-derived neurotrophic factor gene (BDNF) were analyzed. MAIN OUTCOME MEASURES: An association between a history of sexual offense and the distribution of genotypes and alleles in the analyzed polymorphisms. RESULTS: Our results found no association between a history of sexual offense and the distribution of genotypes or alleles in the analyzed polymorphisms. CONCLUSION: Although these results are limited by the small sample and are exploratory, they highlight a novel approach to sample selection in a population that is difficult to access and study. Future research should include larger samples and other relevant polymorphisms to advance this field of study.

Short-term ammonium supply induces cellular defence to prevent oxidative stress in Arabidopsis leaves.

Plants can assimilate nitrogen from soil pools of both ammonium and nitrate, and the relative levels of these two nitrogen sources are highly variable in soil. Long-term ammonium nutrition is known to cause damage to Arabidopsis that has been linked to mitochondrial oxidative stress. Using hydroponic cultures, we analysed the consequences of rapid shifts between nitrate and ammonium nutrition. This did not induce growth retardation, showing that Arabidopsis can compensate for the changes in redox metabolism associated with the variations in nitrogen redox status. During the first 3 h of ammonium treatment, we observed distinct transient shifts in reactive oxygen species (ROS), low-mass antioxidants, ROS-scavenging enzymes, and mitochondrial alternative electron transport pathways, indicating rapid but temporally separated changes in chloroplastic, mitochondrial and cytosolic ROS metabolism. The fast induction of antioxidant defences significantly lowered intracellular H2 O2 levels, and thus protected Arabidopsis leaves from oxidative stress. On the other hand elevated extracellular ROS production in response to ammonium supply may be involved in signalling. The response pattern displays an intricate plasticity of Arabidopsis redox metabolism to minimise stress in responses to nutrient changes.

An association between genetic variation in the glutamatergic system and suicide attempts in alcohol-dependent individuals.

BACKGROUND AND OBJECTIVES: Pathological alterations of glutamatergic systems were observed in neurodegenerative and psychiatric disorders. There is some evidence that this system may be involved in the genetic vulnerability to suicide. The aim of the present study was to analyze possible relationship between the GRIN2B polymorphism and suicidal behavior. We hypothesized that this genetic factor may be associated with suicide attempts in alcohol-dependent patients and with death by suicide. METHODS: To analyze the relationship between GRIN2B and suicide attempts, the selected rs2268115 polymorphism was genotyped in a sample of 345 alcohol-dependent individuals stratified by the history of suicide attempts. The second part of the study concerning suicide was based on a sample of 510 suicide victims and 450 controls. RESULTS: The frequency of rs2268115 G allele among alcohol-dependent patients with the history of suicide attempts was significantly higher than among non-suicidal alcohol-dependent individuals (OR = 1.45, p = .033). This association was more significant when analyzing alcohol-dependent patients only without co-occurring drug dependence (OR = 1.62, p = .021). The analyzed GRIN2B polymorphism was associated with a twofold increase in odds of a suicide attempt (OR = 2.01, p = .004). No relationships between rs2268115 and death by suicide were identified. DISCUSSION AND CONCLUSIONS: Our results suggest that glutamatergic system influence susceptibility to suicide attempts in alcohol-dependent individuals. Suicidal behavior and alcohol dependence may share a common etiology related to the glutamatergic system. SCIENTIFIC SIGNIFICANCE: The major contribution of the present study is a novel finding of the possible association between GRIN2B rs2268115 polymorphism and suicide attempts in alcohol-dependent individuals. (Am J Addict 2017;26:595-601).

Surgical treatment of intramedullary ependymomas.

OBJECT: The aims of this study were to present the results of surgery for intramedullary ependymomas (IEs), analyze complication and recurrence rates, and analyze factors that might influence outcome. METHODS: The charts of 29 consecutive patients (women - 8, men - 21; mean age - 38 years; range: 18-72) operated for IE were retrospectively analyzed. Mean follow-up was 9 years. Eighteen tumors (62%) were located in the cervical or cervicothoracic spine, and average tumor length was four spinal levels. Twenty patients (69%) presented with neurological deficit. RESULTS: Gross total resections (GTRs) comprised 87% of cases, subtotal resections (STRs) 10%, and partial resections 3%. The neurological outcome on postoperative day 1 was as follows: modified McCormick scale (mMS) grade I - 6%, grade II - 21%, grade III - 21%, grade IV - 31%, and grade V - 21%; at follow-up, outcomes were mMS grade I - 42%, grade II - 34%, grade III - 10%, and grade V - 14% of patients. Compared to the preoperative period, 69% of patients deteriorated postoperatively; however, 62% improved or remained without deficit in follow-up, and deterioration persisted in 24%. The functional results were significantly worse when the intraoperative monitoring potentials dropped below 50% (p=0.005) and if the tumor involved >3 spinal levels (p=0.039). Fourteen postoperative complications in 10 patients (34%) included respiratory failure (14%), pneumonia (7%), urinary infection (10%), bed sores (10%), and CSF leak (7%). Two tumors progressed after STR, with progression-free survival times of 5 and 14 years. No recurrence was observed after GTR. CONCLUSIONS: Total tumor resection is the treatment of choice in cases of IEs: no tumor re-growth occurred after total resection, 86% of patients were independent at follow-up, and the 10-year survival rate was 79%.

Surgical treatment of sporadic and von Hippel-Lindau syndrome-associated intramedullary hemangioblastomas.

OBJECT: Intramedullary hemangioblastomas are rare lesions. They can be related to von Hippel-Lindau syndrome or they may be sporadic. This study describes surgical treatment for this infrequent tumor. METHODS: Twelve consecutive patients received surgery to remove sporadic or von Hippel-Lindau syndrome-associated intramedullary hemangioblastomas. Patients were evaluated at four time points: before treatment, on postoperative day one, on the day of discharge, and at a follow-up examination. RESULTS: The patients showed good preoperative neurological status. The cohort had a slight female predominance. All tumors spanned at least one spinal segment. In all cases, total tumor removal was achieved, and a good outcome was obtained. None of the following factors had a significant effect on outcome: age, sex, tumor size, the presence of a syrinx, or the presence of von Hippel-Lindau syndrome. CONCLUSIONS: The surgical removal of intramedullary hemangioblastomas resulted in satisfactory long-term functional outcomes. The best results were obtained before neurological symptoms occurred. Thus, we suggest that surgery should be considered for managing asymptomatic, surgically accessible, space-occupying lesions in sIH group, and isolated, space-occupying lesions in vHLS-IH group.

Surgery for sporadic vestibular schwannoma. Part IV. Predictive factors influencing facial nerve function after surgery.

OBJECTIVE: To analyze the impact of various clinical, radiological and perioperative factors that could influence the facial nerve intraoperative disruption risk (CNVII-IDR) and its long-term function (CNVII-LTF) after vestibular schwannoma (VS) surgery. MATERIAL AND METHODS: The study included 212 patients operated on for sporadic VS with no history of previous treatment for VS or CNVII palsy. The mean size of the tumor was 30 mm. Gross (210) or near-total (2) resections were carried out using the retrosigmoid (210) or translabyrinthine (2) approach. Correlation studies and multivariate regression analysis (RA) were performed. RESULTS: In correlation studies, the CNVII-IDR was increased by: headaches and cerebellar ataxia if one of them was the first symptom of the tumor (33% and 29%, respectively, p=0.008); preoperative hydrocephalus (40% vs. 9%, p=0.01), tumor size >3 cm (18% vs. 5%, p<0.01), tumor volume >10 cm(3) (19% vs. 4%, p<0.01), right-sided location 15% vs. 6%, p=0.047), lateral "park-bench" position (19% vs. 5% for supine position, p<0.01) and the procedure order (16% for the first 106 procedures vs. 6% for the last 106 procedures, p<0.05). In RA the tumor volume (p=0.012), side of the tumor (p=0.028) and patient's position during surgery (p=0.016) independently affected the CNVII-IDR. The following factors correlated significantly with satisfactory CNVII-LTF (HB grades I-III): tumor stage

In comparison with nitrate nutrition, ammonium nutrition increases growth of the frostbite1†Arabidopsis mutant.

Ammonium nutrition inhibits the growth of many plant species, including Arabidopsis thaliana. The toxicity of ammonium is associated with changes in the cellular redox state. The cellular oxidant/antioxidant balance is controlled by mitochondrial electron transport chain. In this study, we analysed the redox metabolism of frostbite1 (fro1) plants, which lack mitochondrial respiratory chain complex I. Surprisingly, the growth of fro1 plants increased under ammonium nutrition. Ammonium nutrition increased the reduction level of pyridine nucleotides in the leaves of wild-type plants, but not in the leaves of fro1 mutant plants. The observed higher activities of type II NADH dehydrogenases and cytochrome c oxidase in the mitochondrial electron transport chain may improve the energy metabolism of fro1 plants grown on ammonium. Additionally, the observed changes in reactive oxygen species (ROS) metabolism in the apoplast may be important for determining the growth of fro1 under ammonium nutrition. Moreover, bioinformatic analyses showed that the gene expression changes in fro1 plants significantly overlap with the changes previously observed in plants with a modified apoplastic pH. Overall, the results suggest a pronounced connection between the mitochondrial redox system and the apoplastic pH and ROS levels, which may modify cell wall plasticity and influence growth.

Association between FKBP5 Functional Polymorphisms and Completed Suicide.

OBJECTIVES: Dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis leads to impaired stress response. FK506-binding protein 51 (FKBP5), which influences HPA axis activity via glucocorticoid receptors, is supposed to play an important role in the regulation of negative feedback and glucocorticoid resistance. Since ineffective stress response mechanisms are considered as a biological background of suicide behavior, we aimed to analyze a possible association between FKBP5 functional polymorphisms and completed suicide. METHODS: The selected FKBP5 polymorphisms rs1360780 and rs3800373 were genotyped in a sample of 563 suicide victims and 475 controls. RESULTS: A significant association between the high-induction rs3800373 C allele and completed suicide was detected (OR = 1.36, p = 0.007). In this polymorphism, genotype distribution supported a codominant model of inheritance. The analyzed SNPs were in strong linkage disequilibrium (D' = 0.916 and r2 = 0.826) with the rs1360780 (T)-rs3800373 (C) haplotype apparently responsible for the observed association (OR = 1.34, p = 0.010). CONCLUSION: The results of the present study indicate that genetic alterations in FKBP5 may influence vulnerability to suicide.

Surgery for sporadic vestibular schwannoma. Part III: Facial and auditory nerve function.

OBJECTIVE: The aim of this analysis was to assess short-term and long-term outcomes with respect to the preservation of facial and auditory nerve function following surgery for sporadic vestibular schwannomas. MATERIAL AND METHODS: The study included 220 consecutive patients operated on with the retrosigmoid (217) or translabyrinthine (3) approach. The mean extrameatal diameter of the tumor was 30mm. In 217 patients, gross total resection was performed and near-total in 3. Before surgery, the facial nerve (CNVII) weakness was found in 18% of patients and only 20% had serviceable hearing. Intraoperative neurophysiological CNVII monitoring was routinely used (the last 211 procedures). Intraoperative monitoring of the cochlear nerve function was used when the preservation of hearing was attempted (45 procedures). RESULTS: The rate of CNVII continuity loss during surgery was 11%, however, this decreased to 6% in the second half of the series. Facial nerve function deteriorated, in 88% of the patients shortly after surgery. However, it improved in 87% in follow-up. Delayed CNVII palsy was found in 5% of the patients and had a good prognosis in 88%. Final satisfactory CNVII function (CNVII-SF, HB grades I-III) was achieved in 76% of the patients when excluding the anastomosis results, and 87% when including them. In recent years, the rate of CNVII-SF has risen to 94%. Non-serviceable hearing was preserved in 49% of the patients, on whom it was attempted. CONCLUSION: Considering the size of the tumors and extent of the resections, the preservation of CNVII function is currently very high. A close surveillance of CNVII function evolution following surgery is mandatory, as 2/3 of the patients discharged with deep paresis will need different face reanimation procedures. The preservation of useful hearing is still problematic, especially in patients with large tumors.

What helps patients to prepare for and cope during awake craniotomy? A prospective qualitative study.

There is growing interest in awake craniotomies, but some clinicians are concerned that such procedures are poorly tolerated by patients. Therefore, we conducted a study to assess this phenomenon. In this prospective qualitative study, 68 patients who qualified for awake craniotomy were asked to complete the Hospital Anxiety and Depression Scale (HADS)-two days before the surgery and visual analogue scales (VAS) for pain and stress, two days before the surgery and again about two days after. In addition, after their surgery, they took part in a structured interview about what helped them prepare for and cope with the surgery. Most patients tolerated the awake surgery well, scoring low on stress and pain scales. They reported a lower level of stress during the surgery (when questioned afterwards) than before it. Intensity of stress before the surgery correlated negatively with age, positively with HADS anxiety score and positively with stress subsequently experienced during surgery. The level of stress during surgery was associated with stress experienced before the surgery, pain and HADS anxiety and depression scores. Severity of pain during the surgery was positively correlated with stress during surgery and HADS depression and anxiety scores before the surgery. There was no correlation between stress, pain, anxiety and depression and the location of the lesion. Patients have a high tolerance for awake craniotomy. Various factors have an impact on how well patients cope with the operation. Extensive preoperative preparation should be considered a key part of the procedure.

Systemic strategies for cytokinin biosynthesis and catabolism in Arabidopsis roots and leaves under prolonged ammonium nutrition.

Cytokinins are growth-regulating plant hormones that are considered to adjust plant development under environmental stresses. During sole ammonium nutrition, a condition known to induce growth retardation of plants, altered cytokinin content can contribute to the characteristic ammonium toxicity syndrome. To understand the metabolic changes in cytokinin pools, cytokinin biosynthesis and degradation were analyzed in the leaves and roots of mature Arabidopsis plants. We found that in leaves of ammonium-grown plants, despite induction of biosynthesis on the expression level, there was no active cytokinin build-up because they were effectively routed toward their downstream catabolites. In roots, cytokinin conjugation was also induced, together with low expression of major synthetic enzymes, resulting in a decreased content of the trans-zeatin form under ammonium conditions. Based on these results, we hypothesized that in leaves and roots, cytokinin turnover is the major regulator of the cytokinin pool and does not allow active cytokinins to accumulate. A potent negative-regulator of root development is trans-zeatin, therefore its low level in mature root tissues of ammonium-grown plants may be responsible for occurrence of a wide root system. Additionally, specific cytokinin enhancement in apical root tips may evoke a short root phenotype in plants under ammonium conditions. The ability to flexibly regulate cytokinin metabolism and distribution in root and shoot tissues can contribute to adjusting plant development in response to ammonium stress.

Ammonium nutrition modifies cellular calcium distribution influencing ammonium-induced growth inhibition.

Proper plant growth requires balanced nutrient levels. In this study, we analyzed the relationship between ammonium (NH4+) nutrition and calcium (Ca2+) homeostasis in the leaf tissues of wild-type and mutant Arabidopsis specimens provided with different nitrogen sources (NH4+ and nitrate, NO3-). Providing plants with NH4+ as the sole nitrogen source disrupts Ca2+ homeostasis, which is essential for activating signaling pathways and maintaining the cell wall structure. The results revealed that the lower Ca2+ content in Arabidopsis leaves under NH4+ stress might result from reduced transpiration pull, which could impair root-to-shoot Ca2+ transport. Moreover, NH4+ nutrition increased the expression of genes encoding proteins responsible for exporting Ca2+ from the cytosol of leaf cells. Furthermore, overexpression of the Ca2+/H+ antiporter 1 (CAX1) gene alleviates the effects of NH4+ syndrome, including stunted growth. The oeCAX1 plants, characterized by a lower apoplastic Ca2+ level, grew better under NH4+ stress than wild-type plants. Evaluation of the mechanical properties of the leaf blades, including stiffness, strength, toughness, and extensibility, showed that the wild-type and oeCAX1 plants responded differently to the nitrogen source, highlighting the role of cell wall metabolism in inhibiting the growth of NH4+-stressed plants.