The genus Pistacia L. belongs to the Anacardiaceae family and includes at least eleven species. Cytogenetic studies addressing the genus Pistacia are rather few. Chromosome numbers of the different Pistacia species, r...The genus Pistacia L. belongs to the Anacardiaceae family and includes at least eleven species. Cytogenetic studies addressing the genus Pistacia are rather few. Chromosome numbers of the different Pistacia species, revealed by these studies, are questionable due to the fact that poor chromosome counting protocols were used, and these protocols are hampered by the extremely small-sized chromosomes of Pistacia species. The aim of this study was to develop a more effective method to resolve the chromosome numbers in Pistacia species using a fluorescent microscope. The method described here is modified from the Sigma Plant Protoplast Digest/Wash Solution protocol. The method used here is highly effective for karyotyping analysis and studying population genetics of Pistacia species. Moreover, it is easy and can be reproduced for other species that have smaller chromosomes. This method can be used for plant herbarium specimens or field plants. This study provides valuable chromosomal data for cytogeneticists and plant breeders who are working on this genus. It provides additional insight into understanding the taxonomic and phylogenetic relationships among Pistacia species. The chromosomes described here are also suitable for gene and genome mapping.展开更多
适当降低株高可以提高植物的养分利用效率和抗倒伏性,对高粱的高产和稳产具有重要意义。为揭示高粱株高遗传机制,本研究以242份中国高粱为研究对象,利用2,015,850个单核苷酸多态性(SNP)标记,在7个不同环境条件下对株高、节间数及节间长...适当降低株高可以提高植物的养分利用效率和抗倒伏性,对高粱的高产和稳产具有重要意义。为揭示高粱株高遗传机制,本研究以242份中国高粱为研究对象,利用2,015,850个单核苷酸多态性(SNP)标记,在7个不同环境条件下对株高、节间数及节间长度进行全基因组关联分析(Genome-wide association study,GWAS)。表型调查表明,株高、节间数和节间长度的表型变异系数在13.47%~30.06%之间,在所有环境下的偏度和峰度的绝对值均小于1。利用2种不同的关联模型(Blink和FarmCPU)对株高、节间数及节间长度进行GWAS分析,在10条染色体上共鉴定出118个与这3个性状显著相关的数量性状核苷酸(QTN)。其中,与株高、节间数及节间长度显著相关的QTN分别为60个、37个和32个,株高与节间数、节间长度共定位QTN分别有8个和3个。通过对候选基因的序列分析和功能注释,在12个QTN置信区间或附近鉴定出14个候选基因,它们与水稻和玉米中参与糖代谢、激素合成与信号传递以及细胞分裂的基因同源。选择性消除分析揭示,位于1号染色体的候选基因Sobic.001G510400在中国南北高粱群体中受到强烈选择,形成了以北方矮秆高粱为主的单倍型Hap1和以南方高秆高粱为主的单倍型Hap2。携有Hap1的北方种质871255和携有Hap2的南方种质红缨子之间,该基因表达存在显著差异。本研究结果为中国高粱品种株高遗传改良提供了理论依据。展开更多
[Objective] This study aimed to clarify the correlation between changes of Apis mel ifera and the nectar secretion characteristics of nectariferous plants. [Method] Considering the nectar secretion characteristics of ...[Objective] This study aimed to clarify the correlation between changes of Apis mel ifera and the nectar secretion characteristics of nectariferous plants. [Method] Considering the nectar secretion characteristics of major and auxiliary nec-tariferous plants, six Apis mel ifera colonies were selected for measure the number of eggs, larvae, pupae and adult bees from Jan. to Dec. in 2012; based on that, their annual change curves were also plotted. [Result] The results showed that there were three peaks of the total number of A. mel ifera workers throughout the year：the first occurred on May 15th, with bees developed into an ideal population for col-lecting pomegranate nectar, and the second and third peaks occurred on July 15th and Oct. 15th, respectively, with bees developed into an ideal population for col ect-ing E. ciliate （Thuab） Hyland. [Conclusion] Prevention of Varroa jacobsoni should be carried out with two or more types of acaricides at the late nectar flow stages of the two nectariferous plants（pomegranate and E. ciliate （Thuab） Hyland） when there was a nectar deficiency. Prevention of Tropilaelaps clareae should be timely per-formed with sublimed sulfur in conjunction with acaricides. This study provides a theoretical basis for the high-quality and high-yielding production of honey, as wel as for the product safety.展开更多
Plant phenomics has the potential to accelerate progress in understanding gene functions and environmental responses. Progress has been made in automating high-throughput plant phenotyping. However, few studies have i...Plant phenomics has the potential to accelerate progress in understanding gene functions and environmental responses. Progress has been made in automating high-throughput plant phenotyping. However, few studies have investigated automated rice panicle counting. This paper describes a novel method for automatically and nonintrusively determining rice panicle numbers during the full heading stage by analyzing color images of rice plants taken from multiple angles. Pot-grown rice plants were transferred via an industrial conveyer to an imaging chamber. Color images from different angles were automatically acquired as a turntable rotated the plant. The images were then analyzed and the panicle number of each plant was determined. The image analysis pipeline consisted of extracting the i2 plane from the original color image, segmenting the image, discriminating the panicles from the rest of the plant using an artificial neural network, and calculating the panicle number in the current image. The panicle number of the plant was taken as the maximum of the panicle numbers extracted from all 12 multi-angle images. A total of 105 rice plants during the full heading stage were examined to test the performance of the method. The mean absolute error of the manual and automatic count was 0.5, with 95.3% of the plants yielding absolute errors within ± 1. The method will be useful for evaluating rice panicles and will serve as an important supplementary method for high-throughput rice phenotyping.展开更多
A chromosome segment substitution line (CSSL) is a powerful tool for combining quantitative trait locus (QTL) mapping with the pyramiding of desirable alleles. The rice CSSL Z1364 with increased kernel number was iden...A chromosome segment substitution line (CSSL) is a powerful tool for combining quantitative trait locus (QTL) mapping with the pyramiding of desirable alleles. The rice CSSL Z1364 with increased kernel number was identified in a BC3F8 population derived from a cross of Nipponbare as the recipient with Xihui 18 as the donor parent. Z1364 carried three substitution segments distributed on chromosomes 1, 6, and 8. The mean substitution length was 1.19 Mb. Of 17 QTL identified on the substitution segments, qSP1 for spikelets per panicle, qSSD1 for seed-set density, and qNSB1 for number of secondary branches explained respectively 57.34%, 87.7%, and 49.44% of the corresponding phenotypic variance and were all linked to RM6777. Chi-square analysis showed that the increased kernel number in Z1364 was inherited recessively by a single gene. By fine mapping, qSP1 was delimited to a 50-kb region on the short arm of chromosome 1. Based on DNA sequence, a previously uncharacterized rice homolog of Arabidopsis thaliana AT4G32551 was identified as a candidate gene for qSP1 in which mutation increases the number of spikelets and kernels in Z1364. qSP1 was expressed in all tissues, but particularly in 1-cm panicles. The expression levels of OsMADS22, GN1A, and DST were upregulated and those of LAX2, GNP1, and GHD7 were downregulated in Nipponbare. These results provide a foundation for functional research on qSP1.展开更多
Soybean is one of the most important food crops worldwide.Like other legumes,soybean can form symbiotic relationships with Rhizobium species.Nitrogen fixation of soybean via its symbiosis with Rhizobium is pivotal for...Soybean is one of the most important food crops worldwide.Like other legumes,soybean can form symbiotic relationships with Rhizobium species.Nitrogen fixation of soybean via its symbiosis with Rhizobium is pivotal for sustainable agriculture.Type Ⅲ effectors(T3Es)are essential regulators of the establishment of the symbiosis,and nodule number is a feature of nitrogen-affected nodulation.However,genes encoding T3Es at quantitative trait loci(QTLs)related to nodulation have rarely been identified.Chromosome segment substitution lines(CSSLs)have a common genetic background but only a few loci with heterogeneous genetic information;thus,they are suitable materials for identifying candidate genes at a target locus.In this study,a CSSL population was used to identify the QTLs related to nodule number in soybean.Single nucleotide polymorphism(SNP)markers and candidate genes within the QTLs interval were detected,and it was determined which genes showed differential expression between isolines.Four candidate genes(GmCDPK28,GmNAC1,GmbHLH,and GmERF5)linked to the SNPs were identified as being related to nodule traits and pivotal processes and pathways involved in symbiosis establishment.A candidate gene(GmERF5)encoding a transcription factor that may interact directly with the T3E NopAA was identified.The confirmed CSSLs with important segments and candidate genes identified in this study are valuable resources for further studies on the genetic network and T3Es involved in the signaling pathway that is essential for symbiosis establishment.展开更多
The somaclone, C39, derived by tissue culture from the obligate apomict Paspalum dilatatum cv Raki (2n=50), had 50 chromosomes and a karyotype apparently identical to Raki.SC2 seedlings of C39 showed a high degree of ...The somaclone, C39, derived by tissue culture from the obligate apomict Paspalum dilatatum cv Raki (2n=50), had 50 chromosomes and a karyotype apparently identical to Raki.SC2 seedlings of C39 showed a high degree of phenotypic variation which was of ten associated with increased chromosome numbers, but some of the variant seedlings were karyotypically indistinguishable from Raki or C39. Plants with increased chromosome numbers exhibited a high degree of intraplant chromosome variation (aneusomaty). In one of the SC2seedlings, the chromosome number of root tip cells varied from 58 to 82 and in several other seedlings the range was more than 10. The results suggested that the ability to form seed apomictically was much reduced in C39 and that this plant showed some capacity for sexual reproduction and the resulting seedlings, with a chromosome number of about 70, were genetically unstable. Of 11 SC2 seedlings examined cytolog ically, 6 did not produce any viable seed. Seedlings grown from seed of the remaining 5 plants showed that aneusomaty persisted in the SC3 generation. SC3 seedlings which were phenotypically similar to their maternal parent showed a similar range of chromosome numbers to that parent. Some of the SC3 seedlings exhibited an even wider range of chromosome numbers (e.g.56-136), and these plants were all dwarfs.展开更多
This article proves the existence of a hyper-precise global numerical meta-architecture unifying, structuring, binding and controlling the billion triplet codons constituting the sequence of single-stranded DNA of the...This article proves the existence of a hyper-precise global numerical meta-architecture unifying, structuring, binding and controlling the billion triplet codons constituting the sequence of single-stranded DNA of the entire human genome. Beyond the evolution and erratic mutations like transposons within the genome, it’s as if the memory of a fossil genome with multiple symmetries persists. This recalls the “intermingling” of information characterizing the fractal universe of chaos theory. The result leads to a balanced and perfect tuning between the masses of the two strands of the huge DNA molecule that constitute our genome. We show here how codon populations forming the single-stranded DNA sequences can constitute a critical approach to the understanding of junk DNA function. Then, we suggest revisiting certain methods published in our 2009 book “Codex Biogenesis”. In fact, we demonstrate here how the universal genetic code table is a powerful analytical filter to characterize single-stranded DNA sequences constituting chromosomes and genomes. We can then show that any genomic DNA sequence is featured by three numbers, which characterize it and its 64 codon populations with correlations greater than 99%. The number “1” is common to all sequences, expressing the second law of Chargaff. The other 2 numbers are related to each specific DNA sequence case characterizing life species. For example, the entire human genome is characterized by three remarkable numbers 1, 2, and Phi = 1.618 the golden ratio. Associated with each of these three numbers, we can match three axes of symmetry, then “imagine” a kind of hyperspace formed by these codon populations. Then we revisit the value (3-Phi)/2 which is probably universal and common to both the scale of quarks and atomic levels, balancing and tuning the whole human genome codon population. Finally, we demonstrate a new kind of duality between “form and substance” overlapping the whole human genome: we will show that—simultaneously with the duality between genes and junk DNA—there is a second layer of embedded hidden structure overlapping all the DNA of the whole human genome, dividing it into a second type of duality information/redundancy involving golden ratio proportions.展开更多
Objectives： An open-label prospective, combined basic and clinical controlled study was done to investigate the effects of biological therapy using rituximab, and cytotoxic drug treatment with methotrexate on morphol...Objectives： An open-label prospective, combined basic and clinical controlled study was done to investigate the effects of biological therapy using rituximab, and cytotoxic drug treatment with methotrexate on morphology and quantifitiation of chromosomes in rheumatoid arthritis patients. Methods： This study is follow-up of a prior publication, with new observations in comparison with control subjects. A total of 16 subjects were divided into two groups. Group I comprised 8 seropositive rheumatoid arthritis patients who were analysed for the primary end point of possible cytotoxic effects of rituximab and methotrexate. Group II included 8 healthy individuals who served as controls. Assessment was done before treatment with rituximab, and 4 weeks after initiation of therapy. Patients were randomly assigned to receive infusion of rituximab in a full dose of 2.0 g divided into two doses of 1.0 g on days I and 15. The lymphocytes from periphereal blood was cultured by the Moorhead method. Results： Normal male and female Karyograms were observed after full courses of therapy with rituximab. In one female patient who had been receiving longstanding cytotoxic therapy with methotrexate, 2% of chromosomal mitosis showed structural abnormalities. Following the discontinuation of methotrexate and the administration of rituximab, her karyogram became normal. Conclusion： The results from this study indicated that rituximab therapy was safe for the number and structure of human chromosomes, while methotrexate showed chromosomal aberration in one female RA patient. After discontinuation of this longstanding treatment, the karyogram of the same patient returned to normal.展开更多
文摘The genus Pistacia L. belongs to the Anacardiaceae family and includes at least eleven species. Cytogenetic studies addressing the genus Pistacia are rather few. Chromosome numbers of the different Pistacia species, revealed by these studies, are questionable due to the fact that poor chromosome counting protocols were used, and these protocols are hampered by the extremely small-sized chromosomes of Pistacia species. The aim of this study was to develop a more effective method to resolve the chromosome numbers in Pistacia species using a fluorescent microscope. The method described here is modified from the Sigma Plant Protoplast Digest/Wash Solution protocol. The method used here is highly effective for karyotyping analysis and studying population genetics of Pistacia species. Moreover, it is easy and can be reproduced for other species that have smaller chromosomes. This method can be used for plant herbarium specimens or field plants. This study provides valuable chromosomal data for cytogeneticists and plant breeders who are working on this genus. It provides additional insight into understanding the taxonomic and phylogenetic relationships among Pistacia species. The chromosomes described here are also suitable for gene and genome mapping.
文摘适当降低株高可以提高植物的养分利用效率和抗倒伏性,对高粱的高产和稳产具有重要意义。为揭示高粱株高遗传机制,本研究以242份中国高粱为研究对象,利用2,015,850个单核苷酸多态性(SNP)标记,在7个不同环境条件下对株高、节间数及节间长度进行全基因组关联分析(Genome-wide association study,GWAS)。表型调查表明,株高、节间数和节间长度的表型变异系数在13.47%~30.06%之间,在所有环境下的偏度和峰度的绝对值均小于1。利用2种不同的关联模型(Blink和FarmCPU)对株高、节间数及节间长度进行GWAS分析,在10条染色体上共鉴定出118个与这3个性状显著相关的数量性状核苷酸(QTN)。其中,与株高、节间数及节间长度显著相关的QTN分别为60个、37个和32个,株高与节间数、节间长度共定位QTN分别有8个和3个。通过对候选基因的序列分析和功能注释,在12个QTN置信区间或附近鉴定出14个候选基因,它们与水稻和玉米中参与糖代谢、激素合成与信号传递以及细胞分裂的基因同源。选择性消除分析揭示,位于1号染色体的候选基因Sobic.001G510400在中国南北高粱群体中受到强烈选择,形成了以北方矮秆高粱为主的单倍型Hap1和以南方高秆高粱为主的单倍型Hap2。携有Hap1的北方种质871255和携有Hap2的南方种质红缨子之间,该基因表达存在显著差异。本研究结果为中国高粱品种株高遗传改良提供了理论依据。
基金Supported by the Key New Products Development Program of Science and Technology Agency of Yunnan Province(2011BB012)~~
文摘[Objective] This study aimed to clarify the correlation between changes of Apis mel ifera and the nectar secretion characteristics of nectariferous plants. [Method] Considering the nectar secretion characteristics of major and auxiliary nec-tariferous plants, six Apis mel ifera colonies were selected for measure the number of eggs, larvae, pupae and adult bees from Jan. to Dec. in 2012; based on that, their annual change curves were also plotted. [Result] The results showed that there were three peaks of the total number of A. mel ifera workers throughout the year：the first occurred on May 15th, with bees developed into an ideal population for col-lecting pomegranate nectar, and the second and third peaks occurred on July 15th and Oct. 15th, respectively, with bees developed into an ideal population for col ect-ing E. ciliate （Thuab） Hyland. [Conclusion] Prevention of Varroa jacobsoni should be carried out with two or more types of acaricides at the late nectar flow stages of the two nectariferous plants（pomegranate and E. ciliate （Thuab） Hyland） when there was a nectar deficiency. Prevention of Tropilaelaps clareae should be timely per-formed with sublimed sulfur in conjunction with acaricides. This study provides a theoretical basis for the high-quality and high-yielding production of honey, as wel as for the product safety.
基金supported by grants from the National High Technology Research and Development Program of China(2013AA102403)the National Natural Science Foundation of China (30921091, 31200274)+1 种基金the Program for New Century Excellent Talents in University (NCET-10-0386)the Fundamental Research Funds for the Central Universities (2013PY034, 2014BQ010)
文摘Plant phenomics has the potential to accelerate progress in understanding gene functions and environmental responses. Progress has been made in automating high-throughput plant phenotyping. However, few studies have investigated automated rice panicle counting. This paper describes a novel method for automatically and nonintrusively determining rice panicle numbers during the full heading stage by analyzing color images of rice plants taken from multiple angles. Pot-grown rice plants were transferred via an industrial conveyer to an imaging chamber. Color images from different angles were automatically acquired as a turntable rotated the plant. The images were then analyzed and the panicle number of each plant was determined. The image analysis pipeline consisted of extracting the i2 plane from the original color image, segmenting the image, discriminating the panicles from the rest of the plant using an artificial neural network, and calculating the panicle number in the current image. The panicle number of the plant was taken as the maximum of the panicle numbers extracted from all 12 multi-angle images. A total of 105 rice plants during the full heading stage were examined to test the performance of the method. The mean absolute error of the manual and automatic count was 0.5, with 95.3% of the plants yielding absolute errors within ± 1. The method will be useful for evaluating rice panicles and will serve as an important supplementary method for high-throughput rice phenotyping.
基金supported by the National Key Research Plan Project (2017YFD0101107)the Chongqing Science and Technology Commission Special Project (cstc2016shmsztzx0032)the Southwest University Innovation Team Project (XDJK2017A004)
文摘A chromosome segment substitution line (CSSL) is a powerful tool for combining quantitative trait locus (QTL) mapping with the pyramiding of desirable alleles. The rice CSSL Z1364 with increased kernel number was identified in a BC3F8 population derived from a cross of Nipponbare as the recipient with Xihui 18 as the donor parent. Z1364 carried three substitution segments distributed on chromosomes 1, 6, and 8. The mean substitution length was 1.19 Mb. Of 17 QTL identified on the substitution segments, qSP1 for spikelets per panicle, qSSD1 for seed-set density, and qNSB1 for number of secondary branches explained respectively 57.34%, 87.7%, and 49.44% of the corresponding phenotypic variance and were all linked to RM6777. Chi-square analysis showed that the increased kernel number in Z1364 was inherited recessively by a single gene. By fine mapping, qSP1 was delimited to a 50-kb region on the short arm of chromosome 1. Based on DNA sequence, a previously uncharacterized rice homolog of Arabidopsis thaliana AT4G32551 was identified as a candidate gene for qSP1 in which mutation increases the number of spikelets and kernels in Z1364. qSP1 was expressed in all tissues, but particularly in 1-cm panicles. The expression levels of OsMADS22, GN1A, and DST were upregulated and those of LAX2, GNP1, and GHD7 were downregulated in Nipponbare. These results provide a foundation for functional research on qSP1.
基金received from the National Natural Science Foundation of China(32070274,32072014 and 31971899)the China Postdoctoral Science Foundation(2020M681072)+4 种基金the Natural Science Foundation for the Excellent Youth Scholars of Heilongjiang Province,China(YQ2019C008)the Europe Horizon 2020(EUCLEG and 727312)the Youth Science and Technology Innovation Leader,China(2018RA2172)the National Key Research&Development Program of China(2016YFD0100500,2016YFD0100300 and 2016YFD0100201)the Heilongjiang Postdoctoral Science Foundation,China(LBH-Q16014)。
文摘Soybean is one of the most important food crops worldwide.Like other legumes,soybean can form symbiotic relationships with Rhizobium species.Nitrogen fixation of soybean via its symbiosis with Rhizobium is pivotal for sustainable agriculture.Type Ⅲ effectors(T3Es)are essential regulators of the establishment of the symbiosis,and nodule number is a feature of nitrogen-affected nodulation.However,genes encoding T3Es at quantitative trait loci(QTLs)related to nodulation have rarely been identified.Chromosome segment substitution lines(CSSLs)have a common genetic background but only a few loci with heterogeneous genetic information;thus,they are suitable materials for identifying candidate genes at a target locus.In this study,a CSSL population was used to identify the QTLs related to nodule number in soybean.Single nucleotide polymorphism(SNP)markers and candidate genes within the QTLs interval were detected,and it was determined which genes showed differential expression between isolines.Four candidate genes(GmCDPK28,GmNAC1,GmbHLH,and GmERF5)linked to the SNPs were identified as being related to nodule traits and pivotal processes and pathways involved in symbiosis establishment.A candidate gene(GmERF5)encoding a transcription factor that may interact directly with the T3E NopAA was identified.The confirmed CSSLs with important segments and candidate genes identified in this study are valuable resources for further studies on the genetic network and T3Es involved in the signaling pathway that is essential for symbiosis establishment.
文摘The somaclone, C39, derived by tissue culture from the obligate apomict Paspalum dilatatum cv Raki (2n=50), had 50 chromosomes and a karyotype apparently identical to Raki.SC2 seedlings of C39 showed a high degree of phenotypic variation which was of ten associated with increased chromosome numbers, but some of the variant seedlings were karyotypically indistinguishable from Raki or C39. Plants with increased chromosome numbers exhibited a high degree of intraplant chromosome variation (aneusomaty). In one of the SC2seedlings, the chromosome number of root tip cells varied from 58 to 82 and in several other seedlings the range was more than 10. The results suggested that the ability to form seed apomictically was much reduced in C39 and that this plant showed some capacity for sexual reproduction and the resulting seedlings, with a chromosome number of about 70, were genetically unstable. Of 11 SC2 seedlings examined cytolog ically, 6 did not produce any viable seed. Seedlings grown from seed of the remaining 5 plants showed that aneusomaty persisted in the SC3 generation. SC3 seedlings which were phenotypically similar to their maternal parent showed a similar range of chromosome numbers to that parent. Some of the SC3 seedlings exhibited an even wider range of chromosome numbers (e.g.56-136), and these plants were all dwarfs.
文摘This article proves the existence of a hyper-precise global numerical meta-architecture unifying, structuring, binding and controlling the billion triplet codons constituting the sequence of single-stranded DNA of the entire human genome. Beyond the evolution and erratic mutations like transposons within the genome, it’s as if the memory of a fossil genome with multiple symmetries persists. This recalls the “intermingling” of information characterizing the fractal universe of chaos theory. The result leads to a balanced and perfect tuning between the masses of the two strands of the huge DNA molecule that constitute our genome. We show here how codon populations forming the single-stranded DNA sequences can constitute a critical approach to the understanding of junk DNA function. Then, we suggest revisiting certain methods published in our 2009 book “Codex Biogenesis”. In fact, we demonstrate here how the universal genetic code table is a powerful analytical filter to characterize single-stranded DNA sequences constituting chromosomes and genomes. We can then show that any genomic DNA sequence is featured by three numbers, which characterize it and its 64 codon populations with correlations greater than 99%. The number “1” is common to all sequences, expressing the second law of Chargaff. The other 2 numbers are related to each specific DNA sequence case characterizing life species. For example, the entire human genome is characterized by three remarkable numbers 1, 2, and Phi = 1.618 the golden ratio. Associated with each of these three numbers, we can match three axes of symmetry, then “imagine” a kind of hyperspace formed by these codon populations. Then we revisit the value (3-Phi)/2 which is probably universal and common to both the scale of quarks and atomic levels, balancing and tuning the whole human genome codon population. Finally, we demonstrate a new kind of duality between “form and substance” overlapping the whole human genome: we will show that—simultaneously with the duality between genes and junk DNA—there is a second layer of embedded hidden structure overlapping all the DNA of the whole human genome, dividing it into a second type of duality information/redundancy involving golden ratio proportions.
文摘Objectives： An open-label prospective, combined basic and clinical controlled study was done to investigate the effects of biological therapy using rituximab, and cytotoxic drug treatment with methotrexate on morphology and quantifitiation of chromosomes in rheumatoid arthritis patients. Methods： This study is follow-up of a prior publication, with new observations in comparison with control subjects. A total of 16 subjects were divided into two groups. Group I comprised 8 seropositive rheumatoid arthritis patients who were analysed for the primary end point of possible cytotoxic effects of rituximab and methotrexate. Group II included 8 healthy individuals who served as controls. Assessment was done before treatment with rituximab, and 4 weeks after initiation of therapy. Patients were randomly assigned to receive infusion of rituximab in a full dose of 2.0 g divided into two doses of 1.0 g on days I and 15. The lymphocytes from periphereal blood was cultured by the Moorhead method. Results： Normal male and female Karyograms were observed after full courses of therapy with rituximab. In one female patient who had been receiving longstanding cytotoxic therapy with methotrexate, 2% of chromosomal mitosis showed structural abnormalities. Following the discontinuation of methotrexate and the administration of rituximab, her karyogram became normal. Conclusion： The results from this study indicated that rituximab therapy was safe for the number and structure of human chromosomes, while methotrexate showed chromosomal aberration in one female RA patient. After discontinuation of this longstanding treatment, the karyogram of the same patient returned to normal.
