[Nursing Team Applied Learning Organization to Patient Group Care].

This article reports on an effort to use the learning organization to change the existing mental model of a nursing team in order to transform from a nursing-oriented group to a patient-oriented group and to build shared vision, self-affirmation, and self-transcendence in order to change perspectives using team-learning spirit. The nursing group built partnerships with the patient group. The nursing group learning process fostered positive thinking logic and, under the inheritance of knowledge and technology, the patient-oriented group was successfully established. This model will be expanded to more patient-oriented groups. Through the experience sharing and joint supervision, this model may change lifestyles by implementing the concept of "My health, I care" and, ultimately, help patients achieve self-healthcare.

Degradation of glycosphingolipids in oyster: ceramide glycanase and ceramidase in the hepatopancreas of oyster, Crassostrea virginica.

The hepatopancreas of oyster, Crassostrea virginica, was found to contain two unique glycosphingolipid (GSL) cleaving enzymes, ceramide glycanase (CGase) and ceramidase. These two enzymes were found to be tightly associated together through the consecutive purification steps including gel filtration, hydrophobic interaction and cation-exchange chromatographies. They were separated only by preparatory SDS-PAGE. The purified CGase was found to have a molecular mass of 52 kDa and pH optimum of 3.2-3.3. This enzyme prefers to hydrolyze the acidic GSLs, II3SO3LacCer and gangliosides over the neutral GSLs. Oyster ceramidase was found to have a molecular mass of 88 kDa and pH optimum of 4-4.5. Since oyster ceramidase greatly prefers ceramides with C6 to C8 fatty acids, C6-ceramide (N-hexanoyl-D-sphingosine) was used as the substrate for its purification and characterization. The oyster acid ceramidase also catalyzed the synthesis of ceramide from a sphingosine and a fatty acid. For the synthesis, C16 and C18 fatty acids were the best precursors. The amino acid sequences of the two cyanogenbromide peptides derived from the purified ceramidase were found to have similarities to those of several neutral and alkaline ceramidases reported. The tight association of CGase and ceramidase may indicate that CGase in oyster hepatopancreas acts as a vehicle to release ceramide from GSLs for subsequent generation of sphingosines and fatty acids by ceramidase to serve as signaling factors and energy source.

Effects of motivational enhancement therapy plus cognitive behaviour therapy on depressive symptoms and health-related quality of life in adults with type II diabetes mellitus: a randomised controlled trial.

OBJECTIVE: This paper evaluates the effectiveness of motivational enhancement therapy plus cognitive behavioural therapy on depressive symptoms, glycosylated haemoglobin, fasting glucose, body mass index (BMI), and health-related quality of life in type II diabetes patients. METHODS: A controlled trial was conducted to compare patients who received the behavioural intervention with untreated controls on measures of health outcomes. A total of 31 intervention group participants and 30 controls were selected from patients that met the inclusion criteria from a hospital-based endocrinology outpatient department. The outcome measures including depressive symptoms, glycosylated haemoglobin, fasting glucose, BMI, and both physical and mental quality of life were collected before (T1), after (T2), and after 90 days (T3) following the intervention. RESULTS: The experimental group showed a significant reduction in glycosylated haemoglobin, fasting glucose, and depressive symptoms and a significant increase in physical quality of life and mental quality of life at T2 and T3, while patients in the control group with usual care showed no changes over time. CONCLUSION: The behavioural intervention facilitated a significant improvement in psychological adjustment and glycemic control, thus strengthening diabetes control skills and leading to healthy outcomes. It is feasible that nurses and psychiatrists can deliver the behavioural intervention for diabetes patients to decrease their depressive symptoms. Sharing discussion and problem-solving experiences is particularly helpful method for self-control, and these will be beneficially influential on further research.

Cloning and expression of 3-deoxy-d-manno-oct-2-ulosonic acid α-ketoside hydrolase from oyster hepatopancreas†.

We have previously reported that oyster hepatopancreas contained three unusual α-ketoside hydrolases: (i) a 3-deoxy-d-manno-oct-2-ulosonic acid α-ketoside hydrolase (α-Kdo-ase), (ii) a 3-deoxy-D-glycero-D-galacto-non-2-ulosonic acid α-ketoside hydrolase and (iii) a bifunctional ketoside hydrolase capable of cleaving both the α-ketosides of Kdn and Neu5Ac (Kdn-sialidase). After completing the purification of Kdn-sialidase, we proceeded to clone the gene encoding this enzyme. Unexpectedly, we found that instead of expressing Kdn-sialidase, our cloned gene expressed α-Kdo-ase activity. The full-length gene, consisting of 1176-bp (392 amino acids, Mr 44,604), expressed an active recombinant α-Kdo-ase (R-α-Kdo-ase) in yeast and CHO-S cells, but not in various Escherichia coli strains. The deduced amino acid sequence contains two Asp boxes (S(277)PDDGKTW and S(328)TDQGKTW) commonly found in sialidases, but is devoid of the signature FRIP-motif of sialidase. The R-α-Kdo-ase effectively hydrolyzed the Kdo in the core-oligosaccharide of the structurally defined lipopolysaccharide (LPS), Re-LPS (Kdo(2)-Lipid A) from Salmonella minnesota R595 and E. coli D31m4. However, Rd-LPS from S. minnesota R7 that contained an extra outer core phosphorylated heptose was only slowly hydrolyzed. The complex type LPS from Neisseria meningitides A1 and M992 that contained extra 5-6 sugar units at the outer core were refractory to R-α-Kdo-ase. This R-α-Kdo-ase should become useful for studying the structure and function of Kdo-containing glycans.

Combined pre-treatment and middle-treatment Epstein-Barr virus DNA load contributes to prognostication and treatment modification in nasopharyngeal carcinoma patients.

Objective: To investigate whether pre-treatment and middle-treatment plasma Epstein-Barr virus (EBV) DNA loads are useful predictors of prognosis and indicators of therapy modification in nasopharyngeal carcinoma (NPC) patients undergoing radical concurrent chemoradiotherapy (CCRT). Methods: Plasma EBV DNA load was measured by quantitative polymerase chain reaction before treatment (pre-DNA) and during the second cycle of DDP (mid-DNA). The primary endpoint was 5-year progression-free survival (PFS). Results: A total of 775 NPC patients treated with CCRT were included. In total, 553 patients with pre-DNA <4000 copies/mL and 222 with ⩾4000 copies/mL. A total of 559 patients had mid-DNA undetectable and 216 had detectable. Multivariate analysis showed that pre- and mid-DNA were independent prognostic predictors of PFS [hazard ratio (HR), 2.035; 95% confidence interval (CI), 1.406-2.944; p < 0.001; HR, 1.597; 95% CI, 1.101-2.316; p = 0.014]. The area under the curve of the combination of pre-DNA and mid-DNA for 5-year PFS was higher than that of pre-DNA, mid-DNA, and tumor node metastasis (TNM) stage (0.679 versus 0.622, 0.608, 0.601). In the low-risk group (pre-DNA <4000 copies/mL and undetectable mid-DNA), patients receiving ⩽200 mg/m2 showed similar efficacy as those receiving >200 mg/m2 cumulative cisplatin dose (CCD) but were associated with fewer all-grade late toxicities. However, in the high-risk group (pre-DNA ⩾4000 copies/mL or detectable mid-DNA), patients receiving >200 mg/m2 CCD showed a higher 5-year PFS (73.1% versus 58.6%, p = 0.027) and locoregional relapse-free survival (88.5% versus 76.1%, p = 0.028) than those receiving ⩽200 mg/m2 CCD. Conclusion: The combination of pre-DNA and mid-DNA could be particularly useful for guiding risk stratification and early treatment modification for NPC treated with CCRT. A total of 200 mg/m2 cisplatin seemed to be the optimal dose for the low-risk patients, while >200 mg/m2 cisplatin may be adequate to achieve satisfactory survival outcomes in the high-risk group.

Ceramide glycosylation by glucosylceramide synthase selectively maintains the properties of breast cancer stem cells.

Cancer stem cells are distinguished from normal adult stem cells by their stemness without tissue homeostasis control. Glycosphingolipids (GSLs), particularly globo-series GSLs, are important markers of undifferentiated embryonic stem cells, but little is known about whether or not ceramide glycosylation, which controls glycosphingolipid synthesis, plays a role in modulating stem cells. Here, we report that ceramide glycosylation catalyzed by glucosylceramide synthase, which is enhanced in breast cancer stem cells (BCSCs) but not in normal mammary epithelial stem cells, maintains tumorous pluripotency of BCSCs. Enhanced ceramide glycosylation and globotriosylceramide (Gb3) correlate well with the numbers of BCSCs in breast cancer cell lines. In BCSCs sorted with CD44(+)/ESA(+)/CD24(-) markers, Gb3 activates c-Src/ß-catenin signaling and up-regulates the expression of FGF-2, CD44, and Oct-4 enriching tumorigenesis. Conversely, silencing glucosylceramide synthase expression disrupts Gb3 synthesis and selectively kills BCSCs through deactivation of c-Src/ß-catenin signaling. These findings highlight the unexploited role of ceramide glycosylation in selectively maintaining the tumorous pluripotency of cancer stem cells. It speculates that disruption of ceramide glycosylation or globo-series GSL is a useful approach to specifically target BCSCs specifically.

Global microRNA profiling of well-differentiated small intestinal neuroendocrine tumors.

Well-differentiated small intestinal neuroendocrine tumors are rare malignancies. They arise from enterochromaffin cells and very little is known about differential microRNA (miRNA) expression. The aim of this study was to identify the miRNA profile of well-differentiated small intestinal neuroendocrine tumors, which may have a critical role in tumor development, progression and potentially develop miRNAs as novel clinical biomarkers. Specimens from two test groups, 24 small intestinal neuroendocrine tumor specimens at different stages of malignancy, are included in this study. Total RNA from the first test group, five primary tumors, five mesentery metastases and five liver metastases was hybridized onto the Affymetrix Genechip miRNA arrays to perform a genome-wide profile. The results were validated by using quantitative real-time PCR (QRT-PCR) and northern blot analyses. We then expanded the investigation to laser capture microdissected small intestinal neuroendocrine tumor cells and immuno-laser capture microdissected normal enterochromaffin cells of the first test group. Furthermore, a second test group, three primary tumors, three mesentery metastases and three liver metastases, was included in the study. Thus, two independent test groups validated the data by QRT-PCR. Moreover, we characterized nine miRNAs, five (miR-96, -182, -183, -196a and -200a), which are upregulated during tumor progression, whereas four (miR-31, -129-5p, -133a and -215) are downregulated. Several online software programs were used to predict potential miRNA target genes to map a number of putative target genes for the aberrantly regulated miRNAs, through an advanced and novel bioinformatics analysis. Our findings provide information about pivotal miRNAs, which may lead to further insights into tumorigenesis, progression mechanisms and novel therapeutic targets recognition.

Application of deep reinforcement learning for spike sorting under multi-class imbalance.

Spike sorting is the basis for analyzing spike firing patterns encoded in high-dimensional information spaces. With the fact that high-density microelectrode arrays record multiple neurons simultaneously, the data collected often suffers from two problems: a few overlapping spikes and different neuronal firing rates, which both belong to the multi-class imbalance problem. Since deep reinforcement learning (DRL) assign targeted attention to categories through reward functions, we propose ImbSorter to implement spike sorting under multi-class imbalance. We describe spike sorting as a Markov sequence decision and construct a dynamic reward function (DRF) to improve the sensitivity of the agent to minor classes based on the inter-class imbalance ratios. The agent is eventually guided by the optimal strategy to classify spikes. We consider the Wave_Clus dataset, which contains overlapping spikes and diverse noise levels, and the macaque dataset, which has a multi-scale imbalance. ImbSorter is compared with classical DRL architectures, traditional machine learning algorithms, and advanced overlapping spike sorting techniques on these two above datasets. ImbSorter obtained improved results on the Macro_F1. The results show ImbSorter has a promising ability to resist overlapping and noise interference. It has high stability and promising performance in processing spikes with different degrees of skewed distribution.

Can the prognosis of individual patients with nasopharyngeal carcinoma be predicted using a routine blood test at admission?

BACKGROUND AND PURPOSE: We sought to determine the prognostic value of a pre-treatment peripheral blood signature and the peripheral blood signature-based nomogram for patients with non-metastatic nasopharyngeal carcinoma (NPC). MATERIALS AND METHODS: We retrospectively collected 21 peripheral blood indicators from patients with NPC between 2004 and 2015. Data were randomly divided into a training and a validation set (ratio: 6:4). The peripheral blood signature was constructed based on candidate biomarkers using the least absolute shrinkage and selection operator Cox regression model. Multivariable logistic regression was applied to identify the independent risk factors of overall survival to build the nomogram. The predictive value of the peripheral blood nomogram was evaluated using time-dependent area under the curve, decision curve analysis, and calibration curve. RESULTS: In total, 6668 patients were enrolled with 4000 and 2668 in the training and validation cohorts, respectively. Four peripheral blood indicators, (white blood cell count, lymphocyte percentage, haemoglobin, and mean platelet volume), were included to construct the peripheral blood signature. Patients were divided into low- and high-risk groups using an optimal cut-off value of - 1.71142. Patients in the high-risk group had significantly lower overall, distant metastasis-free, and progression-free survival than patients in the low-risk group in both cohorts (P < 0.05). We constructed and validated a peripheral blood signature-based nomogram in combination with five vital clinical characteristics, (age, sex, tumour stage, nodal stage, and pre-treatment Epstein-Barr virus DNA), which showed favourable performance. CONCLUSION: Patients with NPC with different outcomes could be distinguished based on their peripheral blood signature score; the proposed peripheral blood signature-based nomogram offers individualised risk estimation.

A new prognostic model for predicting outcomes of patients with recurrent or metastatic nasopharyngeal carcinoma receiving subsequent line (≥2 lines) anti-programmed death-1 monotherapy.

OBJECTIVES: About 17.7-34.0 % of patients with recurrent or metastatic nasopharyngeal carcinoma (RM-NPC) responded well to anti-PD-1 monotherapy. We sought to establish a nomogram to estimate the progression-free survival (PFS) of RM-NPC patients receiving subsequent-line anti-PD-1 monotherapy. MATERIALS AND METHODS: This cohort study investigated consecutive RM-NPC patients undergoing anti-PD-1 monotherapy. A nomogram was developed in the training cohort (n = 161), using a Cox multivariate model with backward stepwise inclusion, and was validated in the validation cohort (n = 69). Its predictive accuracy was assessed using a concordance index (C-index) and calibration curve. The primary endpoint was PFS. Secondary endpoints included the objective response rate (ORR), disease control rate (DCR), and overall survival (OS). RESULTS: Liver metastasis, albumin, lactate dehydrogenase, monocyte-to-lymphocyte ratio, and plasma Epstein-Barr virus DNA were used to develop a nomogram that could separate patients into favourable- and unfavourable-prognosis groups. The C-index in the training and validation cohort were 0.70 and 0.68, respectively, which was confirmed by calibration curves. Median PFS (mPFS) was lower for the unfavourable-prognosis than for the favourable-prognosis group (1.80 vs 4.93; hazard ratio 2.49 [95 % confidence interval: 1.78-3.49]; p < 0.001), across all subgroups. OS exhibited the same pattern. The ORR and DCR were markedly lower in the unfavourable-prognosis than in the favourable-prognosis group. All results were confirmed in the validation cohort. CONCLUSION: Our model is a reliable prognostic indicator of PFS in RM-NPC patients undergoing anti-PD-1 monotherapy, allowing robust estimation of the immunotherapy benefit an individual might derive.

Camrelizumab combined with apatinib in patients with first-line platinum-resistant or PD-1 inhibitor resistant recurrent/metastatic nasopharyngeal carcinoma: a single-arm, phase 2 trial.

Immunotherapy combined with antiangiogenic targeted therapy has improved the treatment of certain solid tumors, but effective regimens remain elusive for refractory recurrent/metastatic nasopharyngeal carcinoma (RM-NPC). We conducted a phase 2 trial to evaluate the safety and activity of camrelizumab plus apatinib in platinum-resistant (cohort 1, NCT04547088) and PD-1 inhibitor resistant NPC (cohort 2, NCT04548271). Here we report on the primary outcome of objective response rate (ORR) and secondary endpoints of safety, duration of response, disease control rate, progression-free survival, and overall survival. The primary endpoint of ORR was met for cohort 1 (65%, 95% CI, 49.6-80.4, n = 40) and cohort 2 (34.3%; 95% CI, 17.0-51.8, n = 32). Grade ≥ 3 treatment-related adverse events (TRAE) were reported in 47 (65.3%) of 72 patients. Results of our predefined exploratory investigation of predictive biomarkers show: B cell markers are the most differentially expressed genes in the tumors of responders versus non-responders in cohort 1 and that tertiary lymphoid structure is associated with higher ORR; Angiogenesis gene expression signatures are strongly associated with ORR in cohort 2. Camrelizumab plus apatinib combination effectiveness is associated with high expression of PD-L1, VEGF Receptor 2 and B-cell-related genes signatures. Camrelizumab plus apatinib shows promising efficacy with a measurable safety profile in RM-NPC patients.

The designer aminoglycoside NB84 significantly reduces glycosaminoglycan accumulation associated with MPS I-H in the Idua-W392X mouse.

Suppression therapy utilizes compounds that suppress translation termination at in-frame premature termination codons (PTCs) to restore full-length, functional protein. This approach may provide a treatment for diseases caused by nonsense mutations such as mucopolysaccharidosis type I-Hurler (MPS I-H). MPS I-H is a lysosomal storage disease caused by severe α-L-iduronidase deficiency and subsequent lysosomal glycosaminoglycan (GAG) accumulation. MPS I-H represents a good target for suppression therapy because the majority of MPS I-H patients carry nonsense mutations, and restoration of even a small amount of functional α-L-iduronidase may attenuate the MPS I-H phenotype. In this study, we investigated the efficiency of suppression therapy agents to suppress the Idua-W392X nonsense mutation in an MPS I-H mouse model. The drugs tested included the conventional aminoglycosides gentamicin, G418, amikacin, and paromomycin. In addition, the designer aminoglycosides NB54 and NB84, two compounds previously designed to mediate efficient PTC suppression with reduced toxicity, were also examined. Overall, NB84 suppressed the Idua-W392X nonsense mutation much more efficiently than any of the other compounds tested. NB84 treatment restored enough functional α-L-iduronidase activity to partially reverse abnormal GAG accumulation and lysosomal abundance in mouse embryonic fibroblasts derived from the Idua-W392X mouse. Finally, in vivo administration of NB84 to Idua-W392X mice significantly reduced urine GAG excretion and tissue GAG storage. Together, these results suggest that NB84-mediated suppression therapy has the potential to attenuate the MPS I-H disease phenotype.

Comparison of tissue distribution of free and protein bound Nɛ-carboxymethyllysine after long-term oral administration to mice.

Nɛ-Carboxymethyl-lysine (CML) is a primary advanced glycation end product that exists in the body and food as free and bound forms with different bioavailability and physiological effects. To compare the uptake, tissue distribution, and fecal excretion of dietary free and bound CML, free or bound CML were administered to healthy mice at 10 mg CML kg-1 body weight per day for 12 weeks. The results demonstrated that free CML was significantly absorbed in serum and accumulated in the colon, ileum, lung, kidneys, heart, spleen, brain, and liver after intake of free and bound CML, whereas no statistical increase was found in the accumulation of bound CML in the serum, lung, spleen, kidneys, and liver. The colon was the main tissue for the accumulation of free and total CML. Moreover, the accumulation of free CML in tissues and organs was significantly correlated with free CML levels in serum. In conclusion, consumption of bound CML caused a higher uptake, accumulation, and fecal excretion of CML in the body than intake of free CML.

Promotion and implementation effectiveness of World Health Organization's Caregiver Skills Training program in Taiwan.

The World Health Organization (WHO) developed the Caregiver Skills Training for Families of Children with Developmental Delays and Disabilities (CST) with support from Autism Speaks to address the resource gaps and worldwide needs for interventions for children with developmental disorders or delays, especially those with autism spectrum disorder (ASD), and their families. Evidence has indicated that parent-mediated interventions benefit both caregivers and children by strengthening caregivers' knowledge and confidence and children's social communication skills and behavioral regulation. The CST-Taiwan team began the prepilot field trial in 2017 and developed the project to serve families in various locations. This study (1) delineated the adaptations and promotion of CST-Taiwan; (2) determined the program's effectiveness in the promotional stage, in terms of caregiver and child outcomes, and (3) examined the maintenance of its effects. The materials, delivery, and facilitator training procedure of the original CST were adapted to Taiwan. The quantitative data indicated that CST-Taiwan is a promising program, it positively affected caregiver knowledge and confidence and reduced the severity of the children's autistic symptoms. The 3-month follow-up results suggested that the effects persisted. Thus, CST-Taiwan, and its promotional strategies are feasible and effective.

Selective extraction and effective separation of galactosylsphingosine (psychosine) and glucosylsphingosine from other glycosphingolipids in pathological tissue samples.

To facilitate the study of the chemical pathology of galactosylsphingosine (psychosine, GalSph) in Krabbe disease and glucosylsphingosine (GlcSph) in Gaucher disease, we have devised a facile method for the effective separation of these two glycosylsphingosines from other glycosphingolipids (GSLs) in Krabbe brain and Gaucher spleen samples. The procedure involves the use of acetone to selectively extract GalSph and GlcSph, respectively, from Krabbe brain and Gaucher spleen samples. Since acetone does not extract other GSLs except modest amounts of galactosylceramide, sulfatide, and glucosylceramide, the positively charged GalSph or GlcSph in the acetone extract can be readily separated from other GSLs by batchwise cation-exchange chromatography using a Waters Accell Plus CM Cartridge. GalSph or GlcSph enriched by this simple procedure can be readily analyzed by thin-layer chromatography or high-performance liquid chromatography.

MiR-486-3p was downregulated at microRNA profiling of adrenals of multiple endocrine neoplasia type 1 mice, and inhibited human adrenocortical carcinoma cell lines.

Adrenocortical carcinoma is a rare aggressive disease commonly recurring regardless of radical surgery. Although data on genomic alterations in malignant tumors are accumulating, knowledge of molecular events of importance for initiation of adrenocortical transformation is scarce. In an attempt to recognize early molecular alterations, we used adrenals from young multiple endocrine neoplasia type 1 conventional knock-out mice (Men1+/-) closely mimicking the human MEN1 trait (i.e. transformation of pituitary, parathyroid, endocrine pancreatic, and adrenocortical cells). MicroRNA array and hierarchical clustering showed a distinct pattern. Twenty miRNAs were significantly upregulated and eleven were downregulated in Men1+/- compared to wild type littermates. The latter included the known suppressor miRNA miR-486-3p, which was chosen for transfection in human adrenocortical carcinoma cell lines H295R and SW13. Cell growth decreased in miR-486-3p overexpressing clones and levels of the predicted target gene fatty acid synthase (FASN) and its downstream product, palmitic acid, were lowered. In conclusion, heterozygous inactivation of Men1 in adrenals results in distinct miRNA profile regulating expression of genes with impact on tumorigenesis, e.g. transcription, nucleic acid and lipid metabolism. Low levels of miR-486-3p in the early stages of transformation may contribute to proliferation by increasing FASN and thus fatty acid production. FASN as a potentially druggable target for treatment of the devastating disease adrenocortical carcinoma warrants further studies.

Generation and characterization of CRISPR/Cas9-mediated MEN1 knockout BON1 cells: a human pancreatic neuroendocrine cell line.

Among patients with the rare diagnosis of pancreatic neuroendocrine tumor (P-NET), a substantial proportion suffer from the inherited cancer syndrome multiple endocrine neoplasia type 1 (MEN1), which is caused by germline mutations of the MEN1 suppressor gene. Somatic mutations and loss of the MEN1 protein (menin) are frequently also found in sporadic P-NETs. Thus, a human neuroendocrine pancreatic cell line with biallelic inactivation of MEN1 might be of value for studying tumorigenesis. We used the polyclonal human P-NET cell line BON1, which expresses menin, serotonin, chromogranin A and neurotensin, to generate a monoclonal stable MEN1 knockout BON1 cell line (MEN1-KO-BON1) by CRISPR/Cas9 editing. Changes in morphology, hormone secretion, and proliferation were analyzed, and proteomics were assessed using nanoLC-MS/MS and Ingenuity Pathway Analysis (IPA). The menin-lacking MEN1-KO-BON1 cells had increased chromogranin A production and were smaller, more homogenous, rounder and grew faster than their control counterparts. Proteomic analysis revealed 457 significantly altered proteins, and IPA identified biological functions related to cancer, e.g., posttranslational modification and cell death/survival. Among 39 proteins with at least a two-fold difference in expression, twelve are relevant in glucose homeostasis and insulin resistance. The stable monoclonal MEN1-KO-BON1 cell line was found to have preserved neuroendocrine differentiation, increased proliferation, and an altered protein profile.

Effect of structural modifications of ganglioside GM2 on intra-molecular carbohydrate-to-carbohydrate interaction and enzymatic susceptibility.

The effect of inter-molecular carbohydrate-to-carbohydrate interaction on basic cell biological processes has been well documented and appreciated. In contrast, very little is known about the intra-molecular carbohydrate-to-carbohydrate interaction. The presence of an interaction between the GalNAc and the Neu5Ac in GM2 detected by NMR spectroscopy represents a well-defined intra-molecular carbohydrate-to-carbohydrate interaction. This intriguing interaction is responsible for the GM2-epitope, GalNAcbeta1-->4(Neu5Acalpha2-->3)Gal-, to exhibit a rigid and compact conformation. We hypothesized that this compact conformation may be the cause for both the GalNAc and the Neu5Ac in GM2 to be refractory to enzymatic hydrolysis and the GM2 activator protein is able to interact with the compact trisaccharide GM2-epitope, rendering the GalNAc and the Neu5Ac accessible to beta-hexosaminidase A and sialidase. We have used a series of structurally modified GM2 to study the effect of modifications of sugar chains on the conformation and enzymatic susceptibility of this ganglioside. Our hypothesis was borne out by the fact that when the GalNAcbeta1-->4Gal linkage in GM2 was converted to the GalNAcbeta1-->6Gal, both the GalNAc and the Neu5Ac became susceptible to beta-hexosaminidase A and sialidase, respectively, without GM2 activator protein. We hope our work will engender interest in identifying other intra-molecular carbohydrate-to-carbohydrate interactions in glycoconjugates.

Preparation of homogenous oligosaccharide chains from glycosphingolipids.

After the discovery of glycosphingolipid (GSL) glycan detaching enzymes, Rhodococcal endoglycoceramidase (EGCase) and leech ceramide glycanase (CGase), the method for enzymatically releasing glycans from GSLs has become the method of choice for preparing intact ceramide-free oligosaccharide chains from GSLs. This paper describes (1) the preparation of the intact oligosaccharides from GM1 (II(3)NeuAcGgOse(4)Cer) and GbOse(4)Cer as examples to show the use of CGase to prepare intact glycan chains from GSLs, and (2) the specificity and detergent requirements of Rhodococcal EGCases for the release of glycan chains from different GSLs.

An exposed carboxyl group on sialic acid is essential for gangliosides to inhibit calcium uptake via the sarco/endoplasmic reticulum Ca2+-ATPase: relevance to gangliosidoses.

We previously observed that gangliosides GM2, GM1, and GM3 inhibit Ca2+-uptake via the sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) in neurons and in brain microsomes. We now systematically examine the effect of various gangliosides and their analogs on Ca2+-uptake via SERCA and demonstrate that an exposed carboxyl group on the ganglioside sialic acid residue is required for inhibition. Thus, asialo-GM2 and asialo-GM1 have no inhibitory effect, and modifications of the carboxyl group of GM1 and GM2 into a hydroxymethyl residue (CH2OH), a methyl ester (COOCH3) or a taurine-conjugated amide (CONHCH2CH2SO3H) drastically diminish their inhibitory activities. We also demonstrate that the saccharides must be attached to a ceramide backbone in order to inhibit SERCA as the ceramide-free ganglioside saccharides only inhibit SERCA to a minimal extent. Finally, we attempted to use the ceramide-free ganglioside saccharides to antagonize the effects of the gangliosides on SERCA; although some reversal was observed, the inhibitory effects of the gangliosides were not completely abolished.