Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Pan variation”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,009 records · Page 56Linked to original sources
PubMed2002

[Prevalence survey and molecular characterization of alpha and beta thalassemia in Liuzhou city of Guangxi].

OBJECTIVE: To investigate the gene frequencies and mutation patterns of alpha thalassemia (alpha-thal) and beta thalassemia (beta-thal) in Liuzhou city of Guangxi Zhuang Autonomous Region. METHODS: Cluster sampling was used. A total of 1 028 of umbilical blood samples were collected for a prevalence study of alpha-thal and a total of 1 312 healthy young people when receiving pre-marriage consultation were recruited for a beta-thal prevalence survey. Individuals live in city or town area of Liuzhou. A complete blood count as well as hemoglobin electrophoresis analysis were done in all of samples for phenotyping of alpha and beta-thals. Those with Hb Bart's for alpha-thal indicator and those with both microcytosis (MCV < 85 fl) and elevated levels of Hb A(2) (>/=4.0%) for beta-thal were further studied by DNA analysis. PCR-based methodologies were used to characterize the mutation contributions of alpha and beta-thals. All the subjects were tested for the state of carrying beta-thala alleles for evaluating the situation of the compound heterozygotes of alpha-thal with beta-thal. RESULTS: Of 1 028 random samples of umbilical blood screened, 112 of subjects were defined to be the gene carriers of alpha-thal. The alpha-thal carrier rate was as high as 11.19% including 3 compound heterozygotes. Five well-known types of alpha-thal alleles were detected with gene contributions of 37.4% (--(SEA) deletion), 31.3% (-alpha(3.7) deletion), 17.4% (-alpha(4.2) deletion), 12.1% (alpha(CS)alpha mutation), and 0.9% (alpha(QS)alpha mutation), successively. Of the 1 312 adult specimens studied, 89 with beta-thal including 14 of the compound higher Hb F subjects were detected. All of the 89 phenotypic beta-thal carriers had the mutations in the beta-globin gene, making the overall prevalence 6.78%. The commonly seen three mutations, beta CD41 - 42 (-CTTT) frameshift, beta CD17 (T-A) nonsense mutation and beta-28 (A-G) promoter variation were accounted for 90% of the beta-thal alleles in Liuzhou. Of these beta-thal subjects, 16 (accounting for 18%) were found to be the compound heterozygosity for a beta-thal and an alpha-thal with 9 different types of gene defects with a detection rate 1.22%. CONCLUSION: Data from ecidation of alpha and beta-thal gene frequencies and mutation spectrum in Liuzhou city was useful for genetic counselling and prenatal diagnosis of this disease.

Adult↗
PubMed2005

[Validity of high negative pressure drainage for chylous fistula after neck dissection: a report of eight cases].

BACKGROUND & OBJECTIVE: Chylous fistula, a severe complication after operation on neck, has close correlation with definite anatomical position and variation. Its treatment remains controversial. This study was to evaluate the validity of high negative pressure drainage for chylous fistula after neck dissection. METHODS: A treatment of high negative pressure (-30 to -50 kPa) drainage, fasting, and reasonable venous nutrition was applied to 8 patients with postoperative chylous fistula. RESULTS: Of the 8 patients, 7 recovered smoothly without severe complication, and pectoralis major muscle flap was adopted to cure the failed one. CONCLUSION: A treatment of high negative pressure drainage and reasonable diet is effective and safe for chylous fistula at early stage.

Chyle↗
PubMed2005

[Forensic applications of the sequencing of mitochondrial DNA cytochrome oxidase subunit I and II gene for idenfication of Sarcosaphagous flies (diptera)].

OBJECTIVE: This study was based on a 278 and 635 bp region of the gene for cytochrome oxidase subunit I and I (CO I and CO II ) encoding region of mtDNA; the aim was to solve the problems in identifying Sarcosaphagous flies, particularly in the flies' larvae and eggs which could not be identified only by use of their morphologyical features. METHODS: Samples of sarcosaphagous flies and larvae were collected from those on the corps of rabbits on the grassland in the Huhhot district and of a pig on the sandy ground in the Dunhuang district. The mtDNA of flies and their larvae and eggs was extracted using the Chelex technique. Polymerase chain reactions were conducted on a Perkin-Elmer 9600 thermal cycler, followed by vertical non-denaturing polyacrylamide gelectrophoresis. PCR products were purified using the Nucleic Acid Purification Kit. Sequences of both strands were obtained by direct sequencing of the double-stranded PCR product using one of the PCR primers and the ABI PRISM Big Dye Terminator Cycle Sequencing Kit. Sequence reactions were electrophoresed on ABI Model 377 DNA Sequencers. A neighbour-joining tree using the Tamura and Nei model of nucleotide substitution was constructed using the MEGA2. 1 package. RESULTS: A 278 and 635 bp region of the gene for CO I and CO II encoding region of mtDNA of Sarcosaphagous flies and their larvae and eggs was noted to show the percentages for the sequence divergence within species (less than 1%) and the sequence divergence between species (above 3%). For species that diverged from all others by a relatively large percentage and had small within-species variation, the least percentages of sequence divergence were given which distinguished any individual within that species from any other species. CONCLUSION: A 278 and 635 bp region of the gene for CO I and CO II encoding region of mtDNA of Sarcosaphagous flies and their larvae and eggs has been effectively used for the molecular phylogeny and the identification of their species group. CO I and CO II, or CO II, is better than CO I.

Animals↗
PubMed2005

[One major QTL mapping and physical map construction for rolled leaf in rice].

A clonally propagated F2 population (F2CP), derived from the rice cross of Qimiaoxiang/91SP068, was used to map rolled leaf QTLs. As the parent Qimiaoxiang is an unrolling leaf variety, while 91SP068 is a medium rolling variety with about 34% rolling index. One major QTL, rl8, which came from 91SP068, was mapped between two flanking SSR markers, RM6954 and RM6841, on chromosome 5, with genetic distance 3.8 cM, and was 1.0 cM away from RM6954. Its additive effect estimated by composite interval mapping (CIM) was 9.61 in 2002 and 6.23 in 2003, and the dominance effect was also different between two years, -1.19 in 2002 and -4.44 in 2003, respectively. It explained about 20% - 33% of the total phenotypic variation between two years. Furthermore, an integrated physical and genetic map encompassing rl8 region was constructed, and the physical distance of the interval was 542 kb, and the ratio of physical to genetic distance was 144 kb/cM. Based on this research, fine mapping of rolled leaf QTLs will not only facilitate the map-based cloning of the gene itself, but also improve the efficiency of marker-assisted selection in plant breeding.

Chromosomes, Plant↗
PubMed1976

Environmental and genetic factors affecting the response of laboratory animals to drugs.

Only some of the diverse factors that can affect drug disposition and response in laboratory animals have been identified at the present time. These numerous factors contribute to large day-to-day variations that have become a major problem impeding investigation of drug disposition and response in laboratory animals. Although these variations render many experiments difficult to interpret and produce large discrepancies in the literature, few published investigations using laboratory animals provide sufficient details to permit replication of the studies under similar conditions with respect to these variables. Thus, the importance of these variables in affecting results is apparently insufficiently recognized at present. Two commonly overlooked variables affecting the activity of hepatic microsomal enzymes (HME) in rodents and hence the rate at which rodents eliminate from their bodies many foreign compounds are the bedding under the wire mesh cage and the relative cleanliness of the environment. Numerous chemicals present in relatively low concentrations in the environment of the animal room can significantly alter HME activity. Representative of these chemicals are aromatic hydrocarbons in cedarwood bedding, eucalyptol from aerosol sprays, and chlorinated hydrocarbon insecticides, each of which induces HME activity, whereas ammonia generated from feces and urine accumulated in unchanged pans under cages may inhibit HME activity. Chloroform, identified as an environmental contaminant of the water and air of certain cities, exhibits sex and strain differences with respect to toxicity (LD50) in mice. After intraperitoneal injection, twice as much chloroform accumulated in the kidneys of males from the sensitive strain (DBA/2J) as from the resistant (C57BL/6J) strain. First generation offspring were midway between parental strains both with respect to LD50 and renal accumulation of chloroform.

Animals↗
PubMed2004

Vitamin E status and its dietary determinants in Taiwanese--results of the Nutrition and Health Survey in Taiwan 1993-1996.

BACKGROUND: A large proportion of Taiwanese are considered to have inadequate vitamin E intake according to Taiwanese RDA. AIM OF THE STUDY: To evaluate the vitamin E status in Taiwan using biochemical indicators, and to examine the influences of dietary factors. METHODS: The Nutrition and Health Survey in Taiwan 1993-1996 was conducted using a multi-stage sampling scheme. Data of 3614 subjects (1728 males, and 1886 females) aged 4 years and above were included in the current analysis. RESULTS: Females had higher levels of serum alpha-tocopherol than males. Serum level of alpha-tocopherol significantly increased with age and blood lipids (p < 0.001). The prevalence rate of deficiency, assessed by the ratio of serum alpha-tocopherol to cholesterol+triglyceride(TG) < 1.59 micromol/mmol, was 1.4 % for Taiwanese aged 4 and above. The prevalence was 1.02 % for adults. This biochemical profile was superior in women compared to men. The age-serum vitamin E status was U-shaped, being poorest in teenagers. Geographical variation in vitamin E/cholesterol+TG ratio was not apparent across regions. An association was observed between serum vitamin E status and frequency of vitamin E supplements, fresh fruits, and 100 % fruit juices. An association was also seen with dietary intakes of vitamin C and vitamin E assessed by 24-hour recall. CONCLUSION: The prevalence rate of vitamin E deficiency in Taiwan was low. An association was observed between serum vitamin E status and dietary vitamins E and C intakes either from foods or supplements.

Adolescent↗
PubMedDate not supplied

Genetic heterogeneity in primary hyperoxaluria type 1: impact on diagnosis.

Primary hyperoxaluria type 1 (PH1) is an autosomal recessive disease characterized by progressive kidney failure due to renal deposition of calcium oxalate. The disease is caused by a deficiency of alanine:glyoxylate aminotransferase (AGT) which catalyzes the conversion of glyoxylate to glycine. When AGT is absent, glyoxylate is converted to oxalate which forms insoluble calcium salts that accumulate in the kidney and other organs. In the most common phenotype there is a unique phenomenon wherein AGT is mis-targeted to the mitochondria instead of the peroxisomes. The diagnosis of PH1 is complicated by heterogeneity of clinical presentation, course of the disease, biochemical markers, AGT enzymatic activity and genotype. More than 50 mutations and polymorphisms have been reported in the AGT gene; three common mutations accounting for almost 50% of PH1 alleles. The mutations are of all types, with missense making up the largest fraction. There are some mutations with apparent ethnic associations and at least one that appears to be pan-ethnic. Although correlations can in some cases be made between biochemical phenotype and genotype, correlation with clinical phenotype is complicated by the involvement of other genetic and non-genetic factors that affect disease severity. A number of polymorphisms have been described in the AGT gene some of which cause missense changes and, in some cases, alter enzyme activity. As DNA testing becomes more commonly used for diagnosis it is important to correlate observed sequence changes with previously documented changes as an aid to assessing their potential significance.

Genetic Heterogeneity↗
PubMed1996

[K-serotype analyses of Vibrio parahaemolyticus isolated in northern Taiwan, 1983 through 1993].

From 1983 through 1993, 786 strains of Vibrio parahaemolyticus were collected from food-borne disease outbreaks and sporadic cases of diarrheal illness in northern Taiwan, involving 42 K-serotypes. Five top leading serotypes were K8 (36.8%), K15 (10.8%), K12 (8.7%), K56 (7.9%) and K63 (4.7%). However, a variation of K-serotypes was found during this study period. From 112 food-borne outbreaks associated with this microorganism, only 54 (48.2%) outbreaks were caused by a single serotype, while 58 (51.8%) were caused by multiple K-serotypes. Numbers of outbreaks caused by two, three and more than three K-serotypes were 29 (26%), 16 (14.2%), and 13 (11.6%), respectively. In a special outbreak, eight K-serotypes was found. Outbreaks caused by party caterers were most frequently associated with multiple K-serotypes.

Disease Outbreaks↗
PubMed1996

Analysis of the probability of multiple taxa in a combined sample of Swartkrans and Kromdraai dental material.

It has been argued (Grine, [1988] Evolutionary History of the "Robust" Australopithecines [New York. Aldine de Gruyter], pp. 223-243) that the australopithecine material from Swartkrans and Kromdraai represents distinct species. In an attempt to test the validity of separate taxa at Swartkrans and Kromdraai, Cope's (Cope [1989] Systematic Variation in Cercopithecus Dental Samples [Austin: University of Texas]) method of analysis was adapted and utilized. This procedure includes an analysis of the coefficients of variation (CVs) of the individual posterior teeth (buccal-lingual breadth) of a combined fossil sample compared with the CVs of several known single taxon reference groups. The Cope and Lacy (Cope and Lacy [1992] Am. J. Phys. Anthropol. 89:359-378) stimulation technique was also employed in the analysis. Based on these analyses, there is no justification for a taxonomic separation between the australopithecine material from Swartkrans and Kromdraai. Therefore, the assertion that the Swartkrans and Kromdraai material represent two distinct species is not indicated by the available dental metric evidence.

Animals↗
PubMed2005

Contamination of rivers in Tianjin, China by polycyclic aromatic hydrocarbons.

Tianjin urban/industrial complex is highly polluted by some persistent organic pollutants. In this study, the levels of 16 priority polycyclic aromatic hydrocarbons (PAHs) were tested in sediment, water, and suspended particulate matter (SPM) samples in 10 rivers in Tianjin. The total concentration of 16 PAHs varied from 0.787 to 1943 microg/g dry weight in sediment, from 45.81 to 1272 ng/L in water, and from 0.938 to 64.2 microg/g dry weight in SPM. The levels of PAHs in these media are high in comparison with values reported from other river and marine systems. Variability of total concentrations of PAHs in sediment, water, and SPM from nine different rivers is consistent with each other. No obvious trends of total PAHs concentration variations were found between upstream and downstream sediment, water, and SPM samples for most rivers, which indicate local inputs and disturbances along these rivers. The spatial distributions of three-phase PAHs are very similar to each other, and they are also similar to those found in topsoil. However, their chemical profiles are significantly different from that of topsoil. The change of profiles is consistent with the different aqueous transport capability of 16 PAHs. Low molecular weight PAHs predomination suggests a relatively recent local source and coal combustion source of PAHs in the study area.

China↗
PubMed1998

Penicillin-resistant Streptococcus pneumoniae in Argentina: frequent occurrence of an internationally spread serotype 14 clone.

Six Latin-American countries participated in an epidemiological surveillance study conducted by the Pan American Health Organization in order to determine the relative prevalence of capsular types and antimicrobial resistance patterns of Streptococcus pneumoniae (SPN) causing invasive infections in children <5 years of age. In Argentina, the incidence of penicillin resistance (PR) was 24.4%, and it was significantly associated with serotype 14 (p < 0.001). The chromosomal DNA of 56 of those SPN isolates, 39 PR and 17 susceptible, was digested with SmaI and resolved by PFGE. Eighty-two percent (32/39) of the PR isolates shared characteristics with the widely spread International Spanish/French clone (clone B). All members of clone B except one expressed serotype 14, with the exception of one isolate that expressed serotype 19F and probably resulted from an in vivo capsular transformation event. Only a single isolate shared features with the 23F International Spanish/USA clone (clone A). The 17 penicillin-susceptible (PS) SPN isolates presented an enormous degree of variation in the chromosomal background, expressing 12 serotypes and 13 PFGE patterns. The data suggest that over 80% of the SPN-PR isolates in Argentina were imported, and this confirms the importance of the geographic spread of SPN clones in South America.

Argentina↗
PubMed1998

Characterization of chimpanzee TCRV gene polymorphism: how old are human TCRV alleles?

The functional relevance of the majority of human T-cell receptor A and B variable region gene polymorphisms is controversial. Studies of human and nonhuman primate major histocompatibility complex (MHC) class I and II polymorphisms show that allelic lineages predate human speciation and indicate that selection favors the long-term maintenance of these advantageous mutations. We investigated at the DNA level whether 15 human TCRA and B polymorphisms exist in contemporary chimpanzee populations. Polymorphisms consisted of variable region replacements, a recombination signal sequence base change, and silent mutations. With one exception, none of these human TCR polymorphisms were observed in contemporary chimpanzees. Investigation of the same polymorphisms in a range of other nonhuman primates showed little evidence of the existence of human polymorphism prespeciation. Chimpanzee TCRAV and BV regions were however polymorphic for variation so far not observed in human groups. Levels of mitochondrial and nuclear DNA sequence variation in contemporary chimpanzees suggest that population bottlenecks have not been a feature of chimpanzee evolution and it is therefore probable that most human TCR polymorphisms have evolved in the estimated five million years since the speciation of human and chimpanzees. Thus, over the evolutionary time period studied, ancient TCRA and B polymorphisms have not been maintained by selection to the same degree as postulated for MHC polymorphisms.

Alleles↗
PubMed2003

Leukocyte 8-hydroxydeoxyguanosine and aromatic DNA adduct in coke-oven workers with polycyclic aromatic hydrocarbon exposure.

OBJECTIVE: To investigate the potential for exposure to polycyclic aromatic hydrocarbons (PAHs) to induce oxidative DNA damage, we conducted a cross-sectional study in coke-oven workers employed at an iron-steel factory. METHODS: The study population contained 119 coke-oven workers from different work areas of the oven and 38 controls. Personal information on age, employment duration, smoking habit and alcohol consumption was obtained at an interview. Leukocyte 8-hydroxydeoxyguanosine (8-OHdG) was measured by high performance liquid chromatography with electrochemical detection. Leukocyte aromatic DNA adducts as effective dose, and urinary 1-hydroxypyren as internal dose, were also measured, and used to analyze the relationship of 8-OHdG with other biomarkers for PAH exposure, tobacco smoke and alcohol consumption. RESULTS: The leukocyte 8-OHdG revealed a wide inter-individual variation. The highest 8-OHdG level was detected in bottom-workers of the coke-oven. There were significant differences among the four different work areas ( P=0.02). We could not find significant correlation between 8-OHdG levels and urinary 1-hydroxypyrene, but a weakly positive correlation was found between 8-OHdG and leukocyte aromatic DNA adducts among all subjects (r=0.19 P=0.03). We could not observe any effect of smoking and alcohol drinking on 8-OHdG production. CONCLUSION: We could not find clear evidence that PAH exposure induces oxidative DNA damage.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1985

Evolution of the primate beta-globin gene region. High rate of variation in CpG dinucleotides and in short repeated sequences between man and chimpanzee.

A 5500 base-pair fragment including the beta-globin gene downstream from codon 122 and about 4000 base-pairs of its 5' flanking sequence was cloned from chimpanzee DNA and thoroughly sequenced before being compared with the corresponding human sequence: 88 point differences (83 substitutions and 5 deletions or insertions of 1 base-pair) were detected as well as seven more important deletion/insertion events. These changes occur preferentially in two kinds of structure. First, 40% of the CpG dinucleotides present in either human or chimpanzee sequences are affected by nucleotide variations. This corresponds to a divergence level considerably higher than that expected. Second, most short repeated sequences found in the 5' extragenic sequence are involved in mutational events (amplification or contraction of the number of basic motifs as well as point substitutions or deletions/insertions of 1 base-pair). Considering the very low level of nucleotide sequence divergence between these two closely related species, our data provide direct evidence for CpG and tandem array instability.

Animals↗
PubMed2006

Neutron scattering and monte carlo determination of the variation of the critical nucleus size with quench depth.

We have used a combination of neutron scattering experiments and Monte Carlo simulations to study the initial stages of first-order phase transitions. We focus on quenches wherein the nascent phase is formed by homogeneous nucleation, and we approach the spinodal, i.e., the quench depth at which the original phase becomes unstable. In this regime, we show how critical nuclei sizes are determined from neutron scattering structure factors. Prevailing thought is that the size of the critical nucleus should increase with increasing quench depth and diverge at the spinodal. To the contrary, our experiments and simulations indicate that the critical nucleus size decreases monotonically as quench depth is increased and is finite at the spinodal.

Journal Article↗
PubMed2001

Variation in serum pepsinogens with severity and topography of Helicobacter pylori-associated chronic gastritis in dyspeptic patients referred for endoscopy.

BACKGROUND: It has long been recognised that specific patterns of gastritis are linked with different gastroduodenal diseases and that serum pepsinogens vary with the histological state of the gastric mucosa. With the discovery of the role of Helicobacter pylori in chronic gastritis and the availability of noninvasive tests for H. pylori infection, individuals with H. pylori gastritis can now be identified without endoscopic biopsy. However, without a knowledge of the pattern and severity of gastritis it is impossible to predict the likelihood of significant associated gastroduodenal pathology. AIMS: The aim of this study was to evaluate the diagnostic potential of serum pepsinogens I and II in predicting the topography and severity of gastritis in H. pylori-infected dyspeptic patients attending for endoscopy. METHODS: Fasting serum was obtained from consecutive dyspeptic patients attending for endoscopy, and pairs of gastric biopsies obtained from the mid-body and antrum. Gastritis was graded according to the Sydney System, and serum pepsinogen levels determined by radio-immunoassay. RESULTS: Sixty-nine dyspeptic patients were studied (mean age: 49.6 years) of whom 34 had H. pylori-associated chronic gastritis (Hp-gastritis) - antral predominant gastritis (APG) in 41.2%, pangastritis (PAN) in 52.9%, and corpus predominant (CPG) in 5.9%. Serum pepsinogen II levels were significantly higher, and the serum pepsinogen I : II ratio significantly lower, in the H. pylori positive group than in other groups. Within the Hp-gastritis group, there was a step-wise decrease in serum pepsinogen I levels with progression from APG through PAN to CPG pattern (a cut-off value of > or = 100 ng/ml would have identified APG with a positive predictive value of 77%, though with low sensitivity). Within the Hp-gastritis group, serum pepsinogen I and II levels were correlated with antral chronic inflammation score and serum pepsinogen II levels also with antral activity score. Serum pepsinogen I and the pepsinogen I : II ratio were lowest in severe gastric corpus atrophy. CONCLUSION: In dyspeptic patients known to be infected with H. pylori, serum pepsinogen values provide an assessment of the overall topography of gastritis, the severity of antral inflammation and the presence of severe corpus atrophy.

Adult↗
PubMed2006

Bim plays a crucial role in synergistic induction of apoptosis by the histone deacetylase inhibitor SBHA and TRAIL in melanoma cells.

The wide variation in sensitivity of cancer cells to TRAIL- or histone deacetylase (HDAC) inhibitor - induced apoptosis precludes successful treatment of cancer with these agents. We report here that TRAIL and SBHA synergistically induce apoptosis of melanoma cells as revealed by quantitative analysis using the normalized isobologram method. This is supported by enhanced activation of caspase-3 and cleavage of its substrates, PARP and ICAD. Co-treatment with SBHA and TRAIL did not enhance formation of the death-inducing signaling complex (DISC) and processing of caspase-8 and Bid, but potentiated activation of Bax and release of Cytochrome C and Smac/DIABLO from mitochondria into the cytosol. SBHA down-regulated Bcl-X(L), Mcl-1 and XIAP, but up-regulated Bax, Bak, and the BH3-only protein Bim(EL). Up-regulation of the latter by SBHA was attenuated by the presence of TRAIL, which was inhibitable by the pan-caspase inhibitor z-VAD-fmk. Inhibition of Bim by siRNA attenuated conformational changes of Bax, mitochondrial apoptotic events, and activation of caspase-3, leading to marked inhibition of the synergy between SBHA and TRAIL. Thus, Bim plays an essential role in synergistic induction of apoptosis by SBHA and TRAIL in melanoma.

Apoptosis↗
PubMed2000

EFNS task force report: a questionnaire-based survey on the service provision and quality assurance for determination of diagnostic autoantibody tests in European neuroimmunology centres. European Federation of Neurological Societies.

Autoantibodies to a wide variety of neural components are frequently sought in the sera of patients with neurological diseases suspected to have an antibody-associated autoimmune basis. Variations in assay methodology and availability are likely to exist throughout European diagnostic immunology centres, and interlaboratory discrepancies in performance for some assays have been reported. The availability of quality assurance is largely unknown. In this questionnaire-based EFNS task force, all 18 national representatives of the Neuroimmunology Panel within the EFNS were invited to estimate the service provision within their country; 12 panel members responded. From these responses, it emerged that a range of assays are being performed throughout European centres, involving over 20 separate antigens, using a broad array of immunodetection techniques. With the exception of the estimation of anti-AChR antibodies for the diagnosis of myasthenia gravis, no systematic quality assurance schemes are available, this being conducted on an ad hoc basis, or not at all. Since quality is a central component of assay sensitivity and specificity, we conclude that there is an urgent need to introduce pan-European quality assurance schemes, based on provision of positive and negative test sera from a central source, and in which all neuroimmunology laboratories should participate.

Autoantibodies↗