[The influencing factors of functional somatic discomfort in clinical nurses].

Objective: To investigate the functional somatic discomfort status, and to analyze the effect of job stress, hostile attribution bias and ego depletion on functional somatic discomfort in clinical nurses. Methods: In May 2019, 10 cities in Henan Province and Fujian Province were randomly selected as sampling cities. Using the stratified cluster sampling method, nurses of clinical nursing posts in 22 third class hospitals and 23 second class hospitals were selected as the research objects. The general information, job stress, hostile attribution bias, ego depletion and functional somatic discomfort of clinical nurses were investigated by self-designed general information questionnaire, Perceived Stress Scale, Social Information Processing-attribution Bias Questionnaire, Self-regulatory Fatigue Scale, Patient Health Questionnaire-15. 1200 clinical nurses included, and a total of 1159 valid questionnaires were collected, the effective rate of questionnaire collection was 96.6%. The t test was used to compare the difference of the functional somatic discomfort scores of clinical nurses with different demographic characteristicst. The influence of job stress, hostile attribution bias and ego depletion on functional somatic discomfort of clinical nurses were analyzed with Bootstrap. Results: The functional somatic discomfort score of clinical nurses was (8.95±4.38), of which 859 (74.12%) had functional somatic discomfort symptom. The functional somatic discomfort score of clinical nurses aged 36-50 years old was higher than that of 19-35 years old, the functional somatic discomfort score of clinical nurses with service age ≥5 years was higher than that of <5 years, the functional somatic discomfort score of non-permanent clinical nurses was higher than that of permanent clinical nurses, the functional somatic discomfort score of clinical nurses in tertiary hospitals was higher than that of secondary hospitals, the functional somatic discomfort score of clinical nurses in surgical departments were higher than those in non-surgical departments, and the differences were statistically significant (P<0.05). Job stress affected functional somatic discomfort through the single mediating role of hostile attribution bias, the single mediating role of ego depletion, and the chain mediating role of hostile attribution bias and ego depletion (ß=0.17, 95%CI: 0.10-0.20; ß=0.16, 95%CI: 0.10-0.20; ß=0.07, 95%CI: 0.03-0.10; P<0.05) . Conclusion: The functional somatic discomfort symptoms of clinical nurses are significant and varied among different age, working age, employment form, hospital grade and department groups. They are affected by work stress directly and through the separate mediating effect of hostile attribution bias and ego depletion, and the chain mediating effect of hostile attribution bias and ego depletion.

Propofol ameliorates acute postoperative fatigue and promotes glucagon-regulated hepatic gluconeogenesis by activating CREB/PGC-1α and accelerating fatty acids beta-oxidation.

Postoperative fatigue (POF) is the most common and long-lasting complication after surgery, which brings heavy burden to individuals and society. Recently, hastening postoperative recovery receives increasing attention, but unfortunately, the mechanisms underlying POF remain unclear. Propofol is a wildly used general anesthetic in clinic, and inspired by the rapid antidepressant effects induced by ketamine at non-anesthetic dose, the present study was undertaken to investigate the anti-fatigue effects and underlying mechanisms of propofol at a non-anesthetic dose in 70% hepatectomy induced POF model in rats. We first showed here that single administration of propofol at 0.1 mg/kg ameliorated acute POF in hepatectomy induced POF rats. Based on metabonomics analysis, we hypothesized that propofol exerted anti-fatigue activity in POF rats by facilitating free fatty acid (FFA) oxidation and gluconeogenesis. We further confirmed that propofol restored the deficit in FFA oxidation and gluconeogenesis in POF rats, as evidenced by the elevated FFA utilization, acetyl coenzyme A content, pyruvic acid content, phosphoenolpyruvic acid content, hepatic glucose output and glycogen storage. Moreover, propofol stimulated glucagon secretion and up-regulated expression of cAMP-response element binding protein (CREB), phosphorylated CREB, peroxlsome prolifeator-activated receptor-γ coactivator-1α (PGC-1α), phosphoenolpyruvate carboxykinade1 and carnitine palmitoltransferase 1A. In summary, our study suggests for the first time that propofol ameliorates acute POF by promoting glucagon-regulated gluconeogenesis via CREB/PGC-1α signaling and accelerating FFA beta-oxidation.

[The influence of workplace violence on burnout sense in clinical nurses].

Objective: To explore the influence mechanism of intrusive thoughts and ego depletion between effects of workplace violence on burnout sense in clinical nurses. Methods: In May 2019, 10 cities in Henan Province and Fujian Province were selected as sampling cities by the method of grabbing random balls. Using the stratified cluster sampling method, nurses in clinical nursing posts in 22 third class hospitals and 23 second class hospitals were selected as the research objects for a cross-sectional epidemiological survey, including 1200 nurses. A total of 1159 valid questionnaires were collected, and the effective rate was 96.6%. 1159 clinical nurses were investigated by workplace violence scale, event impact scale, self-regulation fatigue scale and job burnout scale. The items contained in the questionnaire were analyzed by exploratory factor analysis with Harman single factor test, and the demographic characteristics of nurses' workplace violence, invasive thinking, self loss and job burnout were compared and analyzed with s-n-k. Results: Those with less than 3 years of service, those with more than 3 years of aggressive thinking and self loss score, and those with less than 3 years of job burnout score; The score of job burnout of unmarried was lower than that of married; The scores of invasive thinking and self loss of non editors were higher than those of current editors; The scores of workplace violence, aggressive thinking, self loss and job burnout of clinical nurses in tertiary hospitals were higher than those in secondary hospitals; The score of job burnout of undergraduate and above is higher than that of junior college and below; The scores of workplace violence, aggressive thinking and self loss of clinical nurses in surgical departments were higher than those in non-surgical departments; The job burnout score of those aged 36 and above was higher than that of those aged <36, The difference was statistically significant (P< 0.05) . Aggressive thinking and self attrition played a mediating role between workplace violence and job burnout. Workplace violence affected job burnout through the single mediating role of aggressive thinking, the single mediating role of self attrition, and the chain mediating role of aggressive thinking self attrition (ß=0.16、0.08、0.03, 95%CI: 0.251~0.190、0.121~0.028、0.050~0.012, P<0.05) . Conclusion: Workplace violence affects burnout sense through the independent mediating role of intrusive thoughts and ego depletion and the chain mediating role of intrusive thoughts and ego depletion in clinical nurses.

Effects of three different first-aid training methods on knowledge retention of caregivers and teachers: a randomized and longitudinal cohort study in China.

OBJECTIVES: The purpose of this study was to assess the effects of pediatric first-aid training methods on caregivers' and teachers' knowledge retention. STUDY DESIGN: This was a randomized longitudinal cohort study. METHODS: A stratified random sampling method was used to select 1282 caregivers and teachers with the help of local education authorities in 18 districts and 1 county of Shanghai, China. The selected caregivers and teachers were randomly allocated into groups that were exposed to 3 models of training, including an interactive training model (group A), lecture-based training model (group B), and video instruction training model (group C), for pediatric first-aid training for caregivers and teachers (PedFACTs). Before and after the training, a descriptive questionnaire composed of demographic information and 37 simple-choice questions about first aid was administered. During the follow-up, 120 caregivers and teachers from each of the three methods were randomized and retested 9 months after their training and 120 caregivers and teachers were randomly reselected in each of the three methods and retested 4 years after their training. RESULTS: Immediately after training, there was a significant difference in the postassessment results between groups A and B (P = 0.002) as well as between groups A and C (P < 0.001). The average interactive training model score was the highest, followed by the instruction training model and video instruction training model. There was no significant difference among the three groups in the reassessment scores at 9 months and 4 years after training (P = 0.744, P = 0.595). The difference in passing the assessment among the three groups at 9 months or 4 years after training was not maintained at a significant level. CONCLUSION: The three training methods did not affect knowledge retention of the caregivers and teachers at nine months or four years after training completion. Video instruction may be an effective, convenient, and feasible method to train caregivers and teachers.

Low regional cerebral blood flow in burning mouth syndrome patients with depression.

OBJECTIVES: The main aims of this study were to (i) investigate the emotional disorder status of patients with burning mouth syndrome (BMS) and (ii) detect regional cerebral blood flow in BMS patients with the application of combined single-photon emission computed tomography and computed tomography (SPECT/CT). SUBJECTS AND METHODS: The degree of pain was measured using the visual analysis scale, and emotional disorder with the self-rating anxiety scale, self-rating depression scale, and Hamilton depression rating scale in 29 patients with BMS and 10 healthy controls. SPECT/CT was performed in 29 patients with BMS and 10 healthy controls, and statistical parametric mapping method was used for between-group analyses. RESULTS: The incidence rate of depression in patients with BMS was 31.0%. Compared to the control group, patients with BMS displayed significantly different depression and anxiety scales (P < 0.05). Significantly lower regional cerebral blood flow in the left parietal and left temporal lobes was recorded for BMS patients with depression (P < 0.05). CONCLUSIONS: Patients with BMS experience more depression and anxious emotion. Moreover, depression in patients with BMS may be associated with lower regional cerebral blood flow in the left temporal and left parietal lobes.

Associations between parent-reported sleep duration and adiposity in Chinese early adolescents.

BACKGROUND: Short sleep duration has recently been found to be associated with obesity in children, but findings involving adolescents have been less consistent, and some have mentioned gender differences. OBJECTIVES: To investigate the association between parent-reported sleep duration and adiposity in early adolescence (10-12 years old) and to explore gender differences within this population. METHODS: Participants were 1309 fifth-grade students (685 boys) from 10 primary schools in Shanghai, China. Body mass index (BMI), waist-height ratio (WHeR) and body fat percentage (BF%) were assessed. Sleep and other potential contributors were recorded by parents or self-reported. RESULTS: Compared with adolescents in the longest sleep group (greater than or equal to +1 SD, ≥10.05 h), those in the shortest sleep group (less than -1 SD, <8.89 h) had significantly higher BMI, WHeR and BF%. Sleep was found to be closely related to increased adiposity in girls who were in the shortest and shorter sleep group (

blaKPC and rmtB on a single plasmid in Enterobacter amnigenus and Klebsiella pneumoniae isolates from the same patient.

Enterobacter amnigenus (EA76) and Klebsiella pneumoniae (KP76) isolates with multidrug-resistant (MDR) patterns were identified from the same patient in the neurosurgery department of our hospital. An outbreak of MDR K. pneumoniae had also occurred in this department. To characterize the resistance mechanism and molecular epidemiology of these isolates, sequential experiments including antimicrobial susceptibility testing, polymerase chain reaction (PCR), plasmid analysis, pulsed field gel electrophoresis (PFGE), and multilocus sequence typing (MLST) were performed. EA76 and KP76 were resistant to all of the antibiotics tested, except colistin and tigecycline. blaKPC-2, blaTEM-1, blaSHV-12, blaCTX-M-3, blaCTX-M-14, and rmtB genes were identified in both isolates, with blaKPC-2, blaTEM-1, blaCTX-M-14, and rmtB being co-carried on one plasmid in each isolate. Further analysis showed different restriction patterns between the two KPC-carrying plasmids. Of the 11 carbapenem-resistant isolates found in the outbreak, all were resistant to all of the ß-lactams tested, with 63.64% (7/11) also exhibiting resistance to aminoglycosides and 72.73% (8/11) exhibiting resistance to quinolones. PCR analysis and molecular typing of the 11 K. pneumoniae strains revealed that the seven aminoglycoside-resistant isolates shared the same antibiotic-resistant gene pattern and identical or one-band-difference PFGE profiles relative to KP76. In addition, all of the eight aminoglycoside-resistant isolates, including KP76, belonged to the national epidemic clone ST11. The overall results indicate the emergence of E. amnigenus and outbreak of ST11 K. pneumoniae, with both co-harboring blaKPC and rmtB genes on a single plasmid in our neurosurgery wards.

Altered microRNA expression profile with miR-27b down-regulation correlated with disease activity of oral lichen planus.

BACKGROUND: Increasing evidence indicates that microRNAs (miRNAs) play a vital role in the pathogenesis of inflammatory and autoimmune diseases. The objective of this study was to investigate the altered miRNA expression profile in patients with oral lichen planus (OLP) and determine the miR-27b expression. METHODS: We compared miRNA expression patterns in oral biopsy specimens from patients with OLP (n=3) with those from normal controls (n=3) using microarray technology. We further assessed the miR-27b expression in specimens from patients with OLP (n=53) against controls (n=34) using real-time quantitative PCR (RT-QPCR), and miR-27b expression in specimens from patients with OLP (n=15) against controls (n=12) using in situ hybridization (ISH). RESULTS: Using microarray analysis, a total of 46 differentially expressed miRNAs with more than 2-fold change were identified, including 8 up-regulated and 38 down-regulated miRNAs. Both RT-QPCR and ISH analyses revealed that miR-27b was significantly down-regulated in OLP tissue, and miR-27b expression was even more suppressed in atrophic-erosive OLP than in reticular OLP. In addition, miR-27b was found to be expressed in the epithelial keratinocyte layer of both normal and OLP tissues. CONCLUSION: These data indicate that miRNAs may be the novel candidate biomarkers for the implication of miRNAs in the pathogenesis of OLP.

LINC00887 aggravates the malignant progression of glioma via upregulating CCND1.

OBJECTIVE: This study aims to explore the impact of LINC00887 on the malignant progression of glioma via upregulating CCND1. PATIENTS AND METHODS: LINC00887 and CCND1 levels in glioma patients in different tumor grades or metastasis statuses were detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). Kaplan-Meier curves were depicted for analyzing the prognostic potential of LINC00887 in glioma patients. Meanwhile, Pearson correlation test was conducted to assess the expression correlation between LINC00887 and CCND1 in glioma tissues. After knockdown of LINC00887 in LN229 and U251 cells, proliferative abilities were examined by cell counting kit-8 (CCK-8) and 5-Ethynyl-2'- deoxyuridine (EdU) assays. Subcellular distribution of LINC00887 was determined. Thereafter, RNA Binding Protein Immunoprecipitation (RIP) was performed to uncover the interaction between LINC00887 and CCND1. After α-amanitin induction in glioma cells overexpressing LINC00887, RNA degradation of CCND1 was examined at 0, 6, 12 and 24 h, respectively. Finally, the synergistic regulation of both LINC00887 and CCND1 on glioma proliferation was explored by CCK-8 assay. RESULTS: It was found that LINC00887 was upregulated in glioma tissues, especially in stage III+IV or metastatic glioma cases. Overall survival was remarkably worse in glioma patients expressing a high level of LINC00887 than those with a low level. CCND1 was upregulated in glioma tissues as well, showing a positive correlation to LINC00887. In addition, LINC00887 was mainly distributed in the cytoplasm and interacted with CCND1, and it shortened the half-life of CCND1. Moreover, the knockdown of LINC00887 inhibited glioma cell proliferation, and this inhibitory effect was abolished by overexpression of CCND1. CONCLUSIONS: LINC00887 is upregulated in glioma tissues, and it aggravates the malignant progression of glioma by upregulating CCND1.

[Effect of imatinib on the height of children with chronic myeloid leukemia in the chronic phase].

Objective: To evaluate the effect of imatinib on growth impairment in children with chronic myeloid leukemia (CML-CP) in the chronic phase. Methods: From July 2018 to July 2019, questionnaires were distributed to CML children aged <18 years at the time of diagnosis who were receiving imatinib for at least 3 months or to their parents in China. The height-for-age standard deviation score (HtSDS) and the difference of standard deviation integral (△HtSDS) were used to explore the change in height with imatinib therapy. Results: The data of 238 respondents were included; 138 (58.0% ) respondents were men. The median age at the first diagnosis of CML was 11.0 years (range, 1.4-17.9 years) , and 93 (39.0% ) respondents were at the prepuberty stage. At the time of completing the questionnaires, the median age was 15.0 years (range, 2.0-34.0 years) . The median duration of imatinib therapy was 28 months (range, 3-213 months) . Among all the respondents, the mean HtSDS when completing the questionnaires (-0.063±1.361) was significantly lower than that at the time of starting imatinib treatment (0.391±1.244) (P<0.001) . Total 71.0% respondents showed growth impairment that was more common in those starting imatinib therapy at prepubertal age than in those starting at pubertal age. Multivariate analysis showed that younger at the start of imatinib therapy (P<0.001) and longer duration of imatinib therapy (P<0.001) were significantly associated with severe growth impairment on imatinib therapy. Conclusions: Imatinib induced growth impairment in children with CML-CP. Younger the age of initiation and longer the duration of imatinib therapy, more obvious the effect of imatinib on growth impairment.

Mode switching kinetics produced by a naturally occurring mutation in the cytoplasmic loop of the human acetylcholine receptor epsilon subunit.

We describe the genetic and kinetic defects in a congenital myasthenic syndrome caused by heteroallelic mutations of the acetylcholine receptor (AChR) epsilon subunit gene. The mutations are an in-frame duplication of six residues in the long cytoplasmic loop (epsilon1254ins18) and a cysteine-loop null mutation (epsilonC128S). The epsilon1254 ins18 mutation causes mode switching in the kinetics of receptor activation in which three modes activate slowly and inactivate rapidly. The epsilon1245ins18-AChR at the endplate shows abnormally brief activation episodes during steady state agonist application and appears electrically silent during the synaptic response to acetylcholine. The phenotypic consequences are endplate AChR deficiency, simplification of the postsynaptic region, and compensatory expression of fetal AChR that restores electrical activity at the endplate and rescues the phenotype.

Acetylcholine receptor M3 domain: stereochemical and volume contributions to channel gating.

By defining the functional defect in a congenital myasthenic syndrome (CMS), we show that the third transmembrane domain (M3) of the muscle acetylcholine receptor governs the speed and efficiency of gating of its channel. The clinical phenotype of this CMS results from the mutation V285I in M3 of the alpha subunit, which attenuates endplate currents, accelerates their decay and causes abnormally brief acetylcholine-induced single-channel currents. Kinetic analysis of engineered alpha V285I receptors demonstrated a predominant effect on channel gating, with abnormally slow opening and rapid closing rates. Analysis of site-directed mutations revealed stereochemical and volume-dependent contributions of alpha V285 to channel gating. Thus, we demonstrate a functional role for the M3 domain as a key component of the nicotinic acetylcholine receptor channel-gating mechanism.

[Impact of allergic airway diseases on risk of attention deficit hyperactivity disorder in school-age children].

Objective: To investigate the impact of allergic airway diseases on the risk of attention deficit hyperactivity disorder (ADHD) in school-age children. Method: Used stratified cluster sampling method, school-age children in first to sixth grade in primary schools in 9 randomly selected cities including Shanghai, Guangzhou, Xi'an, and Wuhan were enrolled in the study. Interview of parents with questionnaires, which included school-age individual and family social environment questionnaire (including history of diagnosed ADHD, allergic rhinitis, and bronchial asthma) and Children's Sleep Habits Questionnaire (CSHQ), were finished and collected during November to December in 2005.Diagnosed allergic rhinitis and asthma by specialist were independent variables and divided into following three categories as no allergic diseases (neither allergic rhinitis nor asthma), single allergic disease (allergic rhinitis or asthma), and combined allergic diseases (allergic rhinitis and asthma). Diagnosed ADHD as dependent variable, binary logistic regress model was used to analyze the risks of ADHD in school-age children. Result: Totally 23 791 questionnaires were handed out, while 22 018 were collected. The children had an average age of (8.8±1.8) years, within which 10 869 were male, and 11 021 were female. The risk ratios of ADHD were 2.197 (95%CI: 1.823-2.648) and 3.150 (95%CI: 2.082-4.760) in children with single allergic disease and combined allergic diseases separately. There was no significant difference after adjusting for the factor of sleep habits, as the risk ratios were 2.055 (95%CI: 1.683-2.508) and 3.140 (95%CI: 2.061-4.784) in children with single and combined allergic airway disease separately. Conclusion: Allergic rhinitis and bronchial asthma increased the risk of ADHD, not depending on sleep habits. Hence, allergic airway diseases could be independent risk factors of ADHD.

Spectrum of splicing errors caused by CHRNE mutations affecting introns and intron/exon boundaries.

BACKGROUND: Mutations in CHRNE, the gene encoding the muscle nicotinic acetylcholine receptor epsilon subunit, cause congenital myasthenic syndromes. Only three of the eight intronic splice site mutations of CHRNE reported to date have had their splicing consequences characterised. METHODS: We analysed four previously reported and five novel splicing mutations in CHRNE by introducing the entire normal and mutant genomic CHRNEs into COS cells. RESULTS AND CONCLUSIONS: We found that short introns (82-109 nucleotides) favour intron retention, whereas medium to long introns (306-1210 nucleotides) flanking either or both sides of an exon favour exon skipping. Two mutations are of particular interest. Firstly, a G-->T substitution at the 3' end of exon 8 predicts an R286M missense mutation, but instead results in skipping of exon 8. In human genes, a mismatch of the last exonic nucleotide to U1 snRNP is frequently compensated by a matching nucleotide at intron position +6. CHRNE intron 8 has a mismatch at position +6, and accordingly fails to compensate for the exonic mutation at position -1. Secondly, a 16 bp duplication, giving rise to two 3' splice sites (g.IVS10-9_c.1167dup16), results in silencing of the downstream 3' splice site. This conforms to the scanning model of recognition of the 3' splice site, which predicts that the first "ag" occurring after the branch point is selected for splicing.

Myopathy, myasthenic syndrome, and epidermolysis bullosa simplex due to plectin deficiency.

Plectin, an intermediate filament linking protein, is normally associated with the sarcolemma, nuclear membrane, and intermyofibrillar network in muscle, and with hemisdesmosomes in skin. A 20-year-old female with epidermolysis bullosa simplex since birth had progressive ocular, facial, limb, and trunkal weakness and fatigability since age 9, fivefold CK elevation, a 25% decrement with myopathic motor unit potentials and increased electrical irritability on electromyography, and no anti-acetylcholine receptor (AChR) antibodies. Plectin expression was absent in muscle and severe plectin deficiency was noted in skin. Morphologic studies revealed necrotic and regenerating fibers and a wide spectrum of ultrastructural abnormalities: large accumulations of heterochromatic and lobulated nuclei, rare apoptotic nuclei, numerous cytoplasmic and few intranuclear nemaline rods, disarrayed myofibrils, thick-filament loss, vacuolar change, and pathologic alterations in membranous organelles. Many endplates (EPs) had an abnormal configuration with chains of small regions over the fiber surface and a few displayed focal degeneration of the junctional folds. The EP AChR content was normal. In vitro electrophysiologic studies showed normal quantal release by nerve impulse, small miniature EP potentials, and fetal as well as adult AChR channels at the EP. Our findings support the notion that plectin is essential for the structural integrity of muscle and skin, and for normal neuromuscular transmission.

Three novel COLQ mutations and variation of phenotypic expressivity due to G240X.

OBJECTIVE: To determine the molecular basis and consequences of endplate (EP) acetylcholinesterase (AChE) deficiency. BACKGROUND: The EP species AChE is an asymmetric enzyme consisting of a tail subunit composed of three collagenic strands (ColQ), each attached to a tetramer of catalytic subunits. The tail subunit is essential for insertion of AChE into the synaptic basal lamina. Human EP AChE deficiency is caused by mutations in COLQ. The authors report three novel COLQ mutations in eight kinships. METHODS: Immunocytochemistry, electron microscopy, microelectrode recordings, mutation analysis, and expression studies in COS cells were employed. RESULTS: Two mutations (275insC and Q211X) were heterozygous in one patient. EP studies in this patient revealed no EP AChE, small nerve terminals, reduced presynaptic membrane length, as well as abnormally low-evoked quantal release. The third mutation (G240X) was homozygous in six Palestinian Arab families of the same tribe and in an Iraqi Jewish patient. Expression studies of the three mutations in COS cells indicate that each abrogates formation of insertion competent asymmetric AChE. Although the three mutations have identical predicted consequences at the EP, their phenotypic expressivity varies as regards age at onset, rate of progression, and severity of symptoms. CONCLUSIONS: 1) After mutations in the AChR epsilon subunit, mutations in COLQ are emerging as second most common cause of congenital myasthenic syndromes. 2) A founder effect is likely for G240X in the Palestinian Arab families. 3) That mutations predicting total absence of AChE from the EP have variable phenotypic expressivity suggests that modifying genes or environmental factors can partially compensate for EP AChE deficiency.

Congenital myasthenic syndrome caused by low-expressor fast-channel AChR delta subunit mutation.

OBJECTIVE: To determine the molecular basis of a disabling congenital myasthenic syndrome (CMS) observed in two related and one unrelated Arab kinship. BACKGROUND: CMS can arise from defects in presynaptic, synaptic basal lamina-associated, or postsynaptic proteins. Most CMS are postsynaptic, and most reside in the AChR epsilon subunit; only two mutations have been reported in the AChR delta subunit to date. METHODS: Cytochemistry, electron microscopy, alpha-bungarotoxin binding studies, microelectrode and patch-clamp recordings, mutation analysis, mutagenesis, and expression studies in human embryonic kidney cells were employed. RESULTS: Endplate studies showed AChR deficiency, fast decaying, low-amplitude endplate currents, and abnormally brief channel opening events. Mutation analysis revealed a novel homozygous missense mutation (deltaP250Q) of the penultimate proline in the first transmembrane domain (TMD1) of the AChR delta subunit. Expression studies indicate that deltaP250Q (1) hinders delta/alpha subunit association during early AChR assembly; (2) hinders opening of the doubly occupied closed receptor (A(2)R); and (3) speeds the dissociation of acetylcholine from A(2)R. Mutagenesis studies indicate that deltaP250L also has fast-channel effects, whereas epsilon P245L and epsilon P245Q, identical mutations of the corresponding proline in the epsilon subunit, have mild slow-channel effects. CONCLUSIONS: deltaP250Q represents the third mutation observed in the AChR delta subunit. The severe phenotype caused by deltaP250Q is attributed to endplate AChR deficiency, fast decay of the synaptic response, and lack of compensatory factors. That the penultimate prolines in TMD1 of the delta and epsilon subunits exert a reciprocal regulatory effect on the length of the channel opening bursts reveals an unexpected functional asymmetry between the two subunits.

Congenital myasthenic syndrome associated with episodic apnea and sudden infant death.

The sudden infant death syndrome has multiple etiologies. Some congenital myasthenic syndromes can cause sudden infant death syndrome by apnea, but the frequency of this etiology is unknown. We report here a young patient with sudden respiratory crises culminating in apnea followed by recovery, against a background of no or variable myasthenic symptoms without dyspnea. One sib without myasthenic symptoms and one sib who only had mild ptosis died previously during febrile episodes. Studies reported by us elsewhere traced the proband's illness to mutations in choline acetyltransferase. Here, we describe in detail the morphologic investigations and electrophysiologic findings, which point to a presynaptic defect in acetylcholine resynthesis or vesicular filling, in the proband. Analysis of DNA from a sib who previously died of sudden infant death syndrome revealed the same choline acetyltransferase mutation. Thus, mutations in choline acetyltransferase may be a cause of sudden infant death syndrome as, theoretically, could other presynaptic myasthenic disorders.

Oxidation chemistry of (-)-norepinephrine in the presence of L-cysteine.

The noradrenergic neurotransmitter (-)-norepinephrine (1) is very easily oxidized at physiological pH to an o-quinone (2) that normally cyclizes and subsequently oxidatively polymerizes to black melanin. In this investigation it is demonstrated that L-cysteine (CySH) can divert the melanin pathway by efficiently scavenging o-quinone 2 to give, initially, 5-S-cysteinylnorepinephrine (6) and 2-S-cysteinylnorepinephrine (7). These cysteinyl conjugates are appreciably more easily oxidized than 1 to o-quinones that, in part, are further attacked by CySH to give 2,5-bi-S-cysteinylnorepinephrine (8), an even more easily oxidized compound. The o-quinone intermediates formed upon oxidation of 6-8 can also undergo facile intramolecular cyclizations to bicyclic o-quinone imines that oxidize the cysteinyl conjugates from which they are derived in a reaction sequence that leads initially to a number of dihydrobenzothiazines. At least two of these compounds, 7-(1-hydroxy-2-aminoethyl)-3,4-dihydro-5- hydroxy-2H-1,4-benzothiazine-3-carboxylic acid (9) and 8-(1-hydroxy-2-aminoethyl)-3,4-dihydro-5-hydroxy-2H-1, 4-benzothiazine-3-carboxylic acid (10) are lethal when administered into the brains of mice. The in vitro chemical pathways elucidated in this investigation might be of relevance to the depigmentation and degeneration of neuromelanin-pigmented noradrenergic cell bodies in the locus ceruleus in Parkinson's Disease and to the degeneration of noradrenergic nerve terminals in Alzheimer's Disease and following transient cerebral ischemia (stroke).

Effect of positioning on pulmonary function of newborns: comparison of supine and prone position.

The effect of positioning on pulmonary function has been previously evaluated, and the prone position has been reported to be preferable for neonates with various respiratory diseases. Studies in healthy neonates have yielded conflicting results. Using a crying pulmonary function test, we examined the effect of positioning on pulmonary function in healthy full-term neonates. Thirty-nine infants with a mean birthweight (+/- SD) of 3,140 +/- 379 g and a mean gestational age (+/- SD) of 39.8 +/- 1.6 weeks were investigated during the first 6 hours of life. Measurements were obtained in both supine and prone positions using a computerized volume-flow system. There were statistically significant decreases in crying vital capacity (CVC) and peak expiratory flow rate (PEF) in the prone compared with the supine position. However, there were no significant differences in forced expiratory flow rate at 75% (V(75)), 50% (V(55)), and 25% (V(25)) of vital capacity between the two positions. These results suggest that prone positioning decreases lung volume and increases resistance of upper airways. We conclude that healthy neonates should be in the supine posture for optimal ventilation.