Routine diagnostics for neural antibodies, clinical correlates, treatment and functional outcome

Abstract Objective To determine frequencies, interlaboratory reproducibility, clinical ratings, and prognostic implications of neural antibodies in a routine laboratory setting in patients with suspected neuropsychiatric autoimmune conditions. Methods Earliest available samples from 10,919 patients were tested for a broad panel of neural antibodies. Sera that reacted with leucine-rich glioma-inactivated protein 1 (LGI1), contactin-associated protein-2 (CASPR2), or the voltage-gated potassium channel (VGKC) complex were retested for LGI1 and CASPR2 antibodies by another laboratory. Physicians in charge of patients with positive antibody results retrospectively reported on clinical, treatment, and outcome parameters. Results Positive results were obtained for 576 patients (5.3%). Median disease duration was 6 months (interquartile range 0.6–46 months). In most patients, antibodies were detected both in CSF and serum. However, in 16 (28%) patients with N-methyl-d-aspartate receptor (NMDAR) antibodies, this diagnosis could be made only in cerebrospinal fluid (CSF). The two laboratories agreed largely on LGI1 and CASPR2 antibody diagnoses (κ = 0.95). The clinicians (413 responses, 71.7%) rated two-thirds of the antibody-positive patients as autoimmune. Antibodies against the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR), NMDAR (CSF or high serum titer), γ-aminobutyric acid-B receptor (GABABR), and LGI1 had ≥ 90% positive ratings, whereas antibodies against the glycine receptor, VGKC complex, or otherwise unspecified neuropil had ≤ 40% positive ratings. Of the patients with surface antibodies, 64% improved after ≥ 3 months, mostly with ≥ 1 immunotherapy intervention. Conclusions This novel approach starting from routine diagnostics in a dedicated laboratory provides reliable and useful results with therapeutic implications. Counseling should consider clinical presentation, demographic features, and antibody titers of the individual patient

Heat and water stress induce unique transcriptional signatures of heat-shock proteins and transcription factors in grapevine

Grapevine is an extremely important crop worldwide. In southern Europe, post-flowering phases of the growth cycle can occur under high temperatures, excessive light, and drought conditions at soil and/or atmospheric level. In this study, we subjected greenhouse grown grapevine, variety Aragonez, to two individual abiotic stresses, water deficit stress (WDS), and heat stress (HS). The adaptation of plants to stress is a complex response triggered by cascades of molecular networks involved in stress perception, signal transduction, and the expression of specific stress-related genes and metabolites. Approaches such as array-based transcript profiling allow assessing the expression of thousands of genes in control and stress tissues. Using microarrays, we analyzed the leaf transcriptomic profile of the grapevine plants. Photosynthesis measurements verified that the plants were significantly affected by the stresses applied. Leaf gene expression was obtained using a high-throughput transcriptomic grapevine array, the 23K custom-made Affymetrix Vitis GeneChip. We identified 1,594 genes as differentially expressed between control and treatments and grouped them into ten major functional categories using MapMan software. The transcriptome of Aragonez was more significantly affected by HS when compared with WDS. The number of genes coding for heat-shock proteins and transcription factors expressed solely in response to HS suggesting their expression as unique signatures of HS. However, a cross-talk between the response pathways to both stresses was observed at the level of AP2/ERF transcription factors

Differential responses between mature and young leaves of sunflower plants to oxidative stress caused by water deficit

The effects of water stress and rehydration on leaf gas exchange characteristics along with changes in lipid peroxidation and pirogalol peroxidase (PG-POD) were studied in mature and in young leaves of sunflower (Helianthus annuus L.), which were grown in a greenhouse. Water stress reduced photosynthesis (Pn), stomatal conductance (g s), and transpiration (E) in both young and mature leaves. However, the amplitude of the reduction was dependent on leaf age. The intercellular CO2 concentration (Ci) was increased in mature leaves but it was not altered in young leaves. Instantaneous water use efficiency (WUE) in mature stressed leaves was reduced when compared to control leaves while in young stressed leaves it was maintained to the same level as the control. After 24h of rehydration, most of the parameters related to gas exchange recovered to the same level as the unstressed plants except gs and E in mature leaves. Water stress did not activated PG-POD independently of leaf age. However, after rehydration the enzyme activity was increased in mature leaves and remained to the same as the control in young leaves. Malondialdehyde (MDA) content was increased by water stress in both mature and young leaves. The results suggest that young leaves are more susceptible to water stress in terms of gas exchange characteristics than mature leaves although both went through oxidative estresse.Os efeitos do estresse hídrico e da reidratação nas trocas gasosas juntamente com alterações na lipoperoxidação e atividade da pirogalol peroxidase (PG-POD) foram estudados em folhas adultas e jovens de plantas de girassol (Helianthus annuus L.) cultivadas em casa de vegetação. O estresse hídrico reduziu a fotossíntese (P N), a condutância estomática (g s) e a transpiração (E) nas folhas adultas e jovens. No entanto, a amplitude da redução foi dependente da idade da folha. A concentração intercelular de CO2 (Ci) aumentou nas folhas adultas, mas não apresentou alteração nas folhas jovens sob condições de estresse hídrico. A eficiência instantânea do uso da água (WUE) nas folhas adultas e estressadas foi reduzida em comparação com o controle, enquanto que, nas folhas jovens e estressadas, não foi alterada. Após 24h de reidratação, as folhas apresentaram valores semelhantes aos dos controles em todos os parâmetros relacionados com as trocas gasosas, exceto gs e E nas folhas adultas. O estresse hídrico não ativou a PG-POD, independente da idade da folha, e após a reidratação a atividade da PG-POD foi aumentada apenas nas folhas adultas. O estresse hídrico aumentou o teor de malondialdeído (MDA) nas folhas adultas e jovens. Os resultados sugerem que as folhas jovens são mais susceptívies ao déficit hídrico em termos de trocas gasosas que as folhas adultas, embora ambas tenham sido expostas ao estresse oxidativo

Plant senescence and proteolysis: two processes with one destiny

Abstract Senescence-associated proteolysis in plants is a complex and controlled process, essential for mobilization of nutrients from old or stressed tissues, mainly leaves, to growing or sink organs. Protein breakdown in senescing leaves involves many plastidial and nuclear proteases, regulators, different subcellular locations and dynamic protein traffic to ensure the complete transformation of proteins of high molecular weight into transportable and useful hydrolysed products. Protease activities are strictly regulated by specific inhibitors and through the activation of zymogens to develop their proteolytic activity at the right place and at the proper time. All these events associated with senescence have deep effects on the relocation of nutrients and as a consequence, on grain quality and crop yield. Thus, it can be considered that nutrient recycling is the common destiny of two processes, plant senescence and, proteolysis. This review article covers the most recent findings about leaf senescence features mediated by abiotic and biotic stresses as well as the participants and steps required in this physiological process, paying special attention to C1A cysteine proteases, their specific inhibitors, known as cystatins, and their potential targets, particularly the chloroplastic proteins as source for nitrogen recycling

Polarization splitter/combiner in high index contrast Bragg reflection waveguides

NRC publication: Ye

Passband shaping of grating-based WDM using cylindrical microlenses

NRC publication: Ye