Gelsemium elegans (G. elegans) is an extremely poisonous plant that is widely distributed in southern China and southeastern Asia. G. elegans poisoning events occur frequently in southern China, and are therefore an urgent public health problem requiring multidisciplinary action. However, the toxic components and toxicological mechanisms remain unclear. Here, we describe a systematic investigation on the toxic components of G. elegans, resulting in the isolation and identification of 120 alkaloids. Based on acute toxicity screening, the structure-toxicity relationship of Gelsemium alkaloids was proposed for the first time. Moreover, gelsedine- and humantenine-type alkaloids were detected in the clinical blood sample, and were confirmed to be causative in the poisoning. The most toxic compound, gelsenicine (1), had selective inhibitory effects toward ventral respiratory group (VRG) neurons in the medulla, which is the main brain region controlling respiration in the central nervous system. Gelsenicine (1) strongly inhibited the firing of action potentials in VRG neurons through its ability to stimulate GABA_A receptors, the main receptors involved in inhibitory neurotransmission. Application of GABA_A receptor antagonists successively reversed action potential firing in gelsenicine (1)-treated VRG neurons. Importantly, the GABA_A receptor antagonists securinine and flumazenil significantly increased the survival of poisoned animals. Our findings provide insight into the components and mechanisms of G. elegans toxicity, and should assist the development of effective emergency treatments for G. elegans poisoning.

OBJECTIVETo provide prenatal diagnosis for two couples who respectively carried heterozygous CD41-42 (-TCTT) and CD43 (G>T) mutations of the beta hemoglobin gene.

METHODSThe mutations were simultaneously detected with reverse dot blot (two diagnostic kits), multi-color melting curve analysis and sequencing analysis.

RESULTSThe fetus of family 1 was shown to be heterozygous for CD43 (G>T) by the three methods, while the fetus of family 2 was shown to be double heterozygous for CD41-42 (-TCTT) and CD43 (G>T) by multi-color melting curve analysis and sequencing analysis. The two diagnostic kits yielded different results by reverse dot blot, one as double heterozygous for CD41-42 (-TCTT) and CD43 (G>T), and another as homozygous for CD41-42 (-TCTT).

CONCLUSIONFor prenatal diagnosis of couples carrying mutations of beta hemoglobin gene such as CD41-42 (-TCTT) and CD43 (G>T), other methods such as Sanger sequencing should be used in order to avoid misdiagnosis.

Diagnostic Errors ; Female ; Heterozygote ; Humans ; Male ; Mutation ; Pregnancy ; Prenatal Diagnosis ; Reagent Kits, Diagnostic ; beta-Globins ; genetics ; beta-Thalassemia ; diagnosis ; genetics

Objective To establish a method of multicolor melting curve analysis for the prenatal diagnosis ofβthalassemia.Methods Methodology establishment.A total of 95 cases, including 9 fetal villi samples(10-13 weeks)and 86 amniotic fluid samples(18-24 weeks)were collected by Center for Prenatal Diagnosis of Shenzhen Maternity and Child Healthcare Hospital between January 2014 and December 2014.A double-blind test was done to detect the mutations of beta globin gene by means of reverse dot ( RDB) blot and multicolor melting curve analysis ( MMCA).The consistency of the two methods is compared.Results The results of 93 cases detected by MMCA and RDB are completely consistent.The results of the 2 cases detected by MMCA after correction are the same as the results detected by RDB.Finally, the coincidence rate of the result was 100%.Conclusion MMCA can be applied to the prenatal diagnosis ofβthalassemia as an effective supplement to RDB.

OBJECTIVE To assess the application value of multiplex ligation-dependent probe amplification (MLPA) for the detection of gene deletion and prenatal diagnosis of α-thalassemia. METHODS MLPA was applied for 2 cases with α-thalassemia phenotype by whole blood cell counting and hemoglobin component detection but were ruled out by regular molecular diagnosis. Potential gene deletions and point mutations of α-thalassemia gene were detected with regular Gap-polymerase chain reaction (Gap-PCR) and reverse dot blotting (RDB) in 89 cases where one or both partners were carriers of α-thalassemia mutations. Meanwhile, MLPA was used for detecting α-globin gene deletion among the 89 samples. RESULTS For the 2 cases with α-thalassemia phenotype, no α globin gene deletion was detected by MLPA, but were subsequently confirmed as iron-deficiency anemia. The results of MLPA and Gap-PCR detection for the 88 cases were consistent, except for 1 fetal sample (chorionic villi) which could not be diagnosed by Gap-PCR and was confirmed to be - SEA/αα by MLPA. CONCLUSION MLPA can be applied to prenatal diagnosis of α-thalassemia as an effective supplement to Gap-PCR to reduce both misdiagnosis and missed diagnosis and improve the accuracy of prenatal diagnosis.
Adult ; Female ; Humans ; Nucleic Acid Amplification Techniques ; methods ; Pregnancy ; Prenatal Diagnosis ; methods ; alpha-Thalassemia ; diagnosis ; genetics