Analyzing the response of rice to tefuryltrione herbicide: Haplotype variation and evolutionary dynamics of the HIS1 gene

Weeds pose multifaceted challenges in rice cultivation, leading to substantial economic losses through reduced yield and poor grain quality. Harnessing the natural genetic diversity in germplasm collections becomes crucial for identifying novel herbicide resistance loci in crops. A comprehensive analysis was conducted on 475 rice accessions from the KRICE depository, assessing their response to TFT (tefuryltrione) and probing the underlying HIS1 (HPPD INHIBITOR SENSITIVE 1) genotypic variations. The HIS1 gene, responsible for detoxifying benzobicyclon (BBC) and imparting broad-spectrum herbicide resistance, holds significant promise in rice breeding. This study explores the genetic landscape of HIS1 within Korean rice collection (KRICE), aiming to unveil genetic variations, haplotype diversity, and evolutionary relationships across diverse rice ecotypes. The indica ecotype showed the highest nucleotide diversity, while the wild and temperate japonica groups exhibited low diversity, hinting at selective sweeps and possible population expansion. Negative Tajima's D values in temperate japonica and wild groups indicate an excess of low-frequency mutations, potentially resulting from selective sweeps. In contrast, with positive Tajima's D values, admixture, indica, and aus groups suggest balancing selection. Furthermore, haplotype analysis uncovered 42 distinct haplotypes within KRICE, with four shared haplotypes between cultivated and wild accessions, four specific to cultivated accessions, and 34 specific to wild types. Phenotypic assessments of these haplotypes revealed that three haplotypes, viz., Hap_1 (predominant in japonica), Hap_2 (predominant in indica), and Hap_3 (specific to indica), displayed significant differences from aus-specific Hap_4 and indica-specific Hap_5. This study offers insights into genetic diversity, selective pressures, and ecotype-specific responses, ultimately paving the way for developing HPPD-inhibiting herbicide-resistant rice cultivars.

Harnessing γ-TMT Genetic Variations and Haplotypes for Vitamin E Diversity in the Korean Rice Collection

Gamma-tocopherol methyltransferase (γ-TMT), a key gene in the vitamin E biosynthesis pathway, significantly influences the accumulation of tocochromanols, thereby determining rice nutritional quality. In our study, we analyzed the γ-TMT gene in 475 Korean rice accessions, uncovering 177 genetic variants, including 138 SNPs and 39 InDels. Notably, two functional SNPs, tmt-E2-28,895,665-G/A and tmt-E4-28,896,689-A/G, were identified, causing substitutions from valine to isoleucine and arginine to glycine, respectively, across 93 accessions. A positive Tajima's D value in the indica group suggests a signature of balancing selection. Haplotype analysis revealed 27 haplotypes, with two shared between cultivated and wild accessions, seven specific to cultivated accessions, and 18 unique to wild types. Further, profiling of vitamin E isomers in 240 accessions and their association with haplotypes revealed that Hap_2, distinguished by an SNP in the 3' UTR (tmt-3UTR-28,897,360-T/A) exhibited significantly lower α-tocopherol (AT), α-tocotrienol (AT3), total tocopherol, and total tocotrienol, but higher γ-tocopherol (GT) in the japonica group. Additionally, in the indica group, Hap_2 showed significantly higher AT, AT3, and total tocopherol, along with lower GT and γ-tocotrienol, compared to Hap_19, Hap_20, and Hap_21. Overall, this study highlights the genetic landscape of γ-TMT and provides a valuable genetic resource for haplotype-based breeding programs aimed at enhancing nutritional profiles.

Telemedicine acceptance by older adults in Hong Kong during a hypothetical severe outbreak and after the COVID-19 pandemic: a cross-sectional cohort survey

INTRODUCTION

Telemedicine services worldwide have experienced unprecedented growth since the early days of the coronavirus disease 2019 (COVID-19) pandemic. Multiple studies have shown that telemedicine is an effective alternative to conventional in-person patient care. This study explored the public perception of telemedicine in Hong Kong, specifically among older adults who are most vulnerable to COVID-19.

METHODS

Medical students from The Chinese University of Hong Kong conducted in-person surveys of older adults aged ≥60 years. Each survey collected socio-demographic information, medical history, and concerns regarding telemedicine use. Univariate and multivariate logistic regression analyses were conducted to identify statistically significant associations. The primary outcomes were acceptance of telemedicine use during a hypothetical severe outbreak and after the COVID-19 pandemic.

RESULTS

There were 109 survey respondents. Multivariate logistic regression analyses revealed that the expectation of government subsidies for telemedicine services was the strongest common driver and the only positive independent predictor of telemedicine use during a hypothetical severe outbreak (P=0.016) and after the COVID-19 pandemic (P=0.003). No negative independent predictors of telemedicine use during a hypothetical severe outbreak were identified. Negative independent predictors of telemedicine use after the COVID-19 pandemic included older age and residence in the New Territories (both P=0.001).

CONCLUSION

Government support, such as telemedicine-specific subsidies, will be important for efforts to promote telemedicine use in Hong Kong during future severe outbreaks and after the COVID-19 pandemic. Robust dissemination of information regarding the advantages and disadvantages of telemedicine for the public, especially older adults, is needed.

Genomic landscape of the OsTPP7 gene in its haplotype diversity and association with anaerobic germination tolerance in rice

Early season flooding is a major constraint in direct-seeded rice, as rice genotypes vary in their coleoptile length during anoxia. Trehalose-6-phosphate phosphatase 7 (OsTPP7, Os09g0369400) has been identified as the genetic determinant for anaerobic germination (AG) and coleoptile elongation during flooding. We evaluated the coleoptile length of a diverse rice panel under normal and flooded conditions and investigated the Korean rice collection of 475 accessions to understand its genetic variation, population genetics, evolutionary relationships, and haplotypes in the OsTPP7 gene. Most accessions displayed enhanced flooded coleoptile lengths, with the temperate japonica ecotype exhibiting the highest average values for normal and flooded conditions. Positive Tajima's D values in indica, admixture, and tropical japonica ecotypes suggested balancing selection or population expansion. Haplotype analysis revealed 18 haplotypes, with three in cultivated accessions, 13 in the wild type, and two in both. Hap_1 was found mostly in japonica, while Hap-2 and Hap_3 were more prevalent in indica accessions. Further phenotypic performance of major haplotypes showed significant differences in flooded coleoptile length, flooding tolerance index, and shoot length between Hap_1 and Hap_2/3. These findings could be valuable for future selective rice breeding and the development of efficient haplotype-based breeding strategies for improving flood tolerance.

Development of an inclusive 580K SNP array and its application for genomic selection and genome-wide association studies in rice

Rice is a globally cultivated crop and is primarily a staple food source for more than half of the world's population. Various single-nucleotide polymorphism (SNP) arrays have been developed and utilized as standard genotyping methods for rice breeding research. Considering the importance of SNP arrays with more inclusive genetic information for GWAS and genomic selection, we integrated SNPs from eight different data resources: resequencing data from the Korean World Rice Collection (KRICE) of 475 accessions, 3,000 rice genome project (3 K-RGP) data, 700 K high-density rice array, Affymetrix 44 K SNP array, QTARO, Reactome, and plastid and GMO information. The collected SNPs were filtered and selected based on the breeder's interest, covering all key traits or research areas to develop an integrated array system representing inclusive genomic polymorphisms. A total of 581,006 high-quality SNPs were synthesized with an average distance of 200 bp between adjacent SNPs, generating a 580 K Axiom Rice Genotyping Chip (580 K _ KNU chip). Further validation of this array on 4,720 genotypes revealed robust and highly efficient genotyping. This has also been demonstrated in genome-wide association studies (GWAS) and genomic selection (GS) of three traits: clum length, heading date, and panicle length. Several SNPs significantly associated with cut-off, -log₁₀ p-value >7.0, were detected in GWAS, and the GS predictabilities for the three traits were more than 0.5, in both rrBLUP and convolutional neural network (CNN) models. The Axiom 580 K Genotyping array will provide a cost-effective genotyping platform and accelerate rice GWAS and GS studies.

Multi-omics analysis reveals the genetic basis of rice fragrance mediated by betaine aldehyde dehydrogenase 2

INTRODUCTION

Fragrance is an important economic and quality trait in rice. The trait is controlled by the recessive gene betaine aldehyde dehydrogenase 2 (BADH2) via the production of 2-acetyl-1-pyrroline (2AP).

OBJECTIVES

Variation in BADH2 was evaluated at the population, genetic, transcriptional, and metabolic levels to obtain insights into fragrance regulation in rice.

METHODS

Whole-genome resequencing of the Korean World Rice Collection of 475 rice accessions, including 421 breeding lines and 54 wild accessions, was performed. Transcriptome analyses of a subset of 279 accessions, proteome analyses of 64 accessions, and volatile profiling of 421 breeding lines were also performed.

RESULTS

We identified over 3.1 million high-quality single nucleotide polymorphisms (SNPs) in Korean rice collection. Most SNPs were present in intergenic regions (79%), and 190,148 SNPs (6%) were located in the coding sequence, of which 53% were nonsynonymous. In total, 38 haplotypes were identified in the BADH2 coding region, including four novel haplotypes (one in cultivated and three in wild accessions). Tajima's D values suggested that BADH2 was under balancing selection in japonica rice. Furthermore, we identified 316 expression quantitative trait loci (eQTL), including 185 cis-eQTLs and 131 trans-eQTLs, involved in BADH2 regulation. A protein quantitative trait loci (pQTL) analysis revealed the presence of trans-pQTLs; 13 pQTLs were mapped 1 Mbp from the BADH2 region. Based on variable importance in projection (VIP) scores, 15 volatile compounds, including 2AP, discriminated haplotypes and were potential biomarkers for rice fragrance.

CONCLUSION

We generated a catalog of haplotypes based on a resequencing analysis of a large number of rice accessions. eQTLs and pQTLs associated with BADH2 gene expression and protein accumulation are likely involved in the regulation of 2AP variation in fragrant rice. These data improve our understanding of fragrance and provide valuable information for rice breeding.

Functional Haplotypes and Evolutionary Insight into the Granule-Bound Starch Synthase II (GBSSII) Gene in Korean Rice Accessions (KRICE_CORE)

Granule-bound starch synthase 2 (GBSSII), a paralogous isoform of GBSSI, carries out amylose biosynthesis in rice. Unlike GBSSI, it mainly functions in transient organs, such as leaves. Despite many reports on the starch gene family, little is known about the genetics and genomics of GBSSII. Haplotype analysis was conducted to unveil genetic variations (SNPs and InDels) of GBSSII (OS07G0412100) and it was also performed to gain evolutionary insight through genetic diversity, population genetic structure, and phylogenetic analyses using the KRICE_CORE set (475 rice accessions). Thirty nonsynonymous SNPs (nsSNPs) were detected across the diverse GBSSII coding regions, representing 38 haplotypes, including 13 cultivated, 21 wild, and 4 mixed (a combination of cultivated and wild) varieties. The cultivated haplotypes (C_1-C_13) contained more nsSNPs across the GBSSII genomic region than the wild varieties. Nucleotide diversity analysis highlighted the higher diversity values of the cultivated varieties (weedy = 0.0102, landrace = 0.0093, and bred = 0.0066) than the wild group (0.0045). The cultivated varieties exhibited no reduction in diversity during domestication. Diversity reduction in the japonica and the wild groups was evidenced by the negative Tajima's D values under purifying selection, suggesting the domestication signatures of GBSSII; however, balancing selection was indicated by positive Tajima's D values in indica. Principal component analysis and population genetics analyses estimated the ambiguous evolutionary relationships among the cultivated and wild rice groups, indicating highly diverse structural features of the rice accessions within the GBSSII genomic region. FST analysis differentiated most of the classified populations in a range of greater FST values. Our findings provide evolutionary insights into GBSSII and, consequently, a molecular breeding program can be implemented for select desired traits using these diverse nonsynonymous (functional) alleles.

Haplotype Variations and Evolutionary Analysis of the Granule-Bound Starch Synthase I Gene in the Korean World Rice Collection

Granule-bound starch synthase I (GBSSI) is responsible for Waxy gene encoding the, which is involved in the amylose synthesis step of starch biosynthesis. We investigated the genotypic and haplotypic variations of GBSSI (Os06g0133000) gene, including its evolutionary relatedness in the nucleotide sequence level using single-nucleotide polymorphisms (SNPs), indels, and structural variations (SVs) from 475 Korean World Rice Collection (KRICE_CORE), which comprised 54 wild rice and 421 cultivated represented by 6 ecotypes (temperate japonica, indica, tropical japonica, aus, aromatic, and admixture) or in another way by 3 varietal types (landrace, weedy, and bred). The results revealed that 27 of 59 haplotypes indicated a total of 12 functional SNPs (fSNPs), identifying 9 novel fSNPs. According to the identified novel fSNPs, we classified the entire rice collection into three groups: cultivated, wild, and mixed (cultivated and wild) rice. Five novel fSNPs were localized in wild rice: four G/A fSNPs in exons 2, 9, and 12 and one T/C fSNP in exon 13. We also identified the three previously reported fSNPs, namely, a G/A fSNP (exon 4), an A/C fSNP (exon 6), and a C/T fSNP (exon 10), which were observed only in cultivated rice, whereas an A/G fSNP (exon 4) was observed exclusively in wild rice. All-against-all comparison of four varietal types or six ecotypes of cultivated rice with wild rice showed that the GBSSI diversity was higher only in wild rice (π = 0.0056). The diversity reduction in cultivated rice can be useful to encompass the origin of this gene GBSSI during its evolution. Significant deviations of positive (wild and indica under balancing selection) and negative (temperate and tropical japonica under purifying selection) Tajima's D values from a neutral model can be informative about the selective sweeps of GBSSI genome insights. Despite the estimation of the differences in population structure and principal component analysis (PCA) between wild and subdivided cultivated subgroups, an inbreeding effect was quantified by F _ST statistic, signifying the genetic relatedness of GBSSI. Our findings of a novel wild fSNPS can be applicable for future breeding of waxy rice varieties. Furthermore, the signatures of selective sweep can also be of informative into further deeper insights during domestication.

Functional Haplotype and eQTL Analyses of Genes Affecting Cadmium Content in Cultivated Rice

BACKGROUND

Rice is a major food resource for Asian countries including Korea. However, most Asian countries are facing food safety problems due to cropland contamination by heavy metals. Thus, this study was conducted to investigate genetic factors affecting the expression of cadmium (Cd) gene, and to confirm differences in Cd translocation among cultivars because the current molecular understanding of Cd uptake-transport mechanisms remains insufficient. Associations between genotypes and gene expression level of Cd-related genes such as NRAMP, MTP, and HMA gene families in the rice core collection were analyzed at the genomic level.

RESULTS

Os01g0956700, Os05g0128400 and Os11g0485200 showed strong associations between expression level and genotype in the rice core collection, the regulatory factors that associated with these genes in cis and trans were founded. The association between the expression level and genotype of the candidate gene (Os01g0611300: metal tolerance protein) predicted to affect Cd content in rice by a previous genome-wide association study (GWAS) was also analyzed. Furthermore, as a result of the phylogeny and haplotype analyses of the candidate gene, high-Cd tolerance cultivars were selected. The correlations between Cd and other inorganic components (Mg, Mn, Fe, Cu and Zn) in the roots, stems, leaves and unpolished grain of selected rice cultivars were analyzed.

CONCLUSION

Therefore, these results may be useful for understanding the uptake-transport mechanisms of Cd and other inorganic components via molecular genetics and may help rice breeders develop new low-Cd cultivars in the near future.

Genome-Wide Association Study for Squalene Contents and Functional Haplotype Analysis in Rice

Squalene is an isoprenoid compound that acts as the intermediate metabolite in cholesterol synthesis. Squalene is not very susceptible to peroxidation, and it quenches singlet oxygen in the skin, which is caused by UV exposure and other ionizing radiation sources. Squalene is a precursor to phytosterol synthesis, and it has been widely studied for its ability to reduce oxidation, cancer activity, and cholesterol levels. We performed a genome-wide association study for squalene in rice using 1.6 million high-quality SNPs extracted from 295 accessions' resequencing data. The candidate gene locus Os09g0319800-an orthologue of terpene synthase in Arabidopsis-showed up as the most likely candidate gene amongst the identified loci. Nucleotide variations in the promoter were associated with squalene content variations within the japonica group. The results of this study can provide clues for understanding the mechanisms of squalene biosynthesis in rice.

Signatures of differential selection in chloroplast genome between japonica and indica

BACKGROUND

The domestication process of Asian rice (Oryza sativa L.) is complicated. It's well established that Oryza rufipogon is the ancestor of Asian rice, although the number of domestication events still controversial. Recently, numerous types of studies based on rice nuclear genome have been conducted, but the results are quite different. Chloroplasts (cp) are also part of the rice genome and have a conserved cyclic structure that is valuable for plant genetics and evolutionary studies. Therefore, we conducted chloroplast-based studies, aiming to provide more evidence for the domestication of Asian rice.

RESULTS

A total of 1389 variants were detected from the chloroplast genomes of 412 accessions obtained through the world. Oryza sativa L. ssp. japonica exhibited slightly less diversity (π) than Oryza sativa L. indica and wild rice. The fixation index values (F_ST) revealed that indica and japonica exhibited farther genetic distances compared with wild rice. Across cp genome, Tajima's D test demonstrated that different selection sites occurred in Asian rice. Principal component analyses (PCA) and multidimensional scaling (MDS) clearly classify the Asian rice into different groups. Furthermore, introgression patterns identified that indica and japonica shared no introgression events in cp level, and phylogenetic studies showed cultivated rice were well separated from different type of wild rice.

CONCLUSIONS

Here, we focus on the domestication of Asian rice (indica and japonica). Diversity and phylogenetic analyses revealed some selection characteristics in the chloroplast genome that potentially occurred in different Asian rice during the domestication. The results shown that Asian rice had been domesticated at least twice. In additional, japonica may experience a strong positive selection or bottleneck event during the domestication.

Low Adherence to Immunosuppressants Is Associated With Symptom Experience Among Kidney Transplant Recipients

PURPOSE

The purpose of this study was to investigate the relationship between immunosuppressant-related symptom experience (SE) and adherence to immunosuppressant regimens among kidney transplant (KT) recipients.

METHODS

A total of 239 KT recipients on an immunosuppressant regimen who were followed up after transplantation participated in this study. Data was collected through a self-reported questionnaire survey (medication adherence, SE, and quality of life) and medical record review.

RESULTS

Low adherence in the immunosuppressant group was associated with longer time since KT, less comorbidity (<3), and a higher rehospitalization rate. Low adherence among KT recipients showed significantly greater overall symptom occurrence (P = .001) and symptom distress (P = .002) levels than patients with high or medium adherence after adjusting for a number of covariates. The most common symptom both in terms of occurrence (96.4%) and distress (91.1%) among poorly adherent KT recipients was tiredness.

CONCLUSION

Low adherence to an immunosuppressant regimen was significantly associated with high SE among KT recipients. Strategies to decrease immunosuppressant-related SE are needed to improve adherence to immunosuppressants.

Needs assessment for master of nursing programmes among Bangladesh nurses

AIM

This study aimed to assess the intent to enrol in a master of nursing programme among Bangladesh nurses, identify preferred programme options and measure the association among intent to enrol in the programme, clinical competency and job satisfaction.

BACKGROUND

Personal and professional aspects of potential students pursuing graduate education are beneficial in devising educational strategies. However, considering the pressing needs for higher nursing education, there are no masters of nursing programmes in Bangladesh.

METHODS

This study used a descriptive correlational design. Nurses working in Bangladesh public sector were recruited to participate in a self-administered survey (n = 260). The questionnaire consisted of perception of job satisfaction, clinical competency and the need for educational options, including the intent to enrol in a master of nursing programme, preferred specialty area, curriculum content and career goals after graduation. Data were analysed using descriptive statistics and point-biserial correlation.

RESULTS

Ninety per cent of the respondents reported that they intended to enrol in a master of nursing programme. Intention was significantly correlated with clinical competency but not with job satisfaction. The most preferred specialty areas were nursing management and education. Half of the respondents responded that teaching at nursing schools was a career goal after graduation.

DISCUSSION

The results of the needs assessment for the programme reflected the unique interest and priorities of the current status of Bangladesh.

CONCLUSIONS

The results indicate a strong motivation to enrol in a master of nursing programme, confidence in clinical competence and high demand for programme in nursing management and education. These findings should be considered to design the programme in order to meet the interest of Bangladesh nurses.

IMPLICATIONS FOR NURSING AND HEALTH POLICY

Educational needs assessments should take precedence to ensure the best possible educational outcome and to produce competent nurses who will contribute in achieving the Millennium Development Goals of Bangladesh.

Analysis of segregation distortion and its relationship to hybrid barriers in rice

BACKGROUND

Segregation distortion (SD) is a frequently observed occurrence in mapping populations generated from crosses involving divergent genotypes. In the present study, ten genetic linkage maps constructed from reciprocal F2 and BC1F1 mapping populations derived from the parents Dasanbyeo (indica) and Ilpumbyeo (japonica) were used to identify the distribution, effect, and magnitude of the genetic factors underlying the mechanisms of SD between the two subspecies.

RESULTS

SD loci detected in the present study were affected by male function, female function, and zygotic selection. The most pronounced SD loci were mapped to chromosome 3 (transmitted through male gametes), chromosome 5 (transmitted through male gametes), and chromosome 6 (transmitted through female gametes). The level of SD in BC1F1 populations which defined by chi-square value independence multiple tests was relatively low in comparison to F2 populations. Dasanbyeo alleles were transmitted at a higher frequency in both F2 and BC1F1 populations, suggesting that indica alleles are strongly favored in inter-subspecific crosses in rice. SD loci in the present study corresponded to previously reported loci for reproductive barriers. In addition, new SD loci were detected on chromosomes 2 and 12.

CONCLUSION

The identification of the distribution of SD and the effect of genetic factors causing SD in genetic mapping populations provides an opportunity to survey the whole genome for new SD loci and their relationships to reproductive barriers. This provides a basis for future research on the elucidation of the genetic mechanisms underlying SD in rice, and will be useful in molecular breeding programs.

Loss of speech after living-related donor liver transplantation: detection of the lesion by diffusion tensor image

INTRODUCTION

Loss of speech after living-related liver transplantation is uncommon. Either immunosuppressive agents, related sequelae, or a neurological event may cause it.

CASE REPORT

A 46-year-old man developed dysarthria and dysphagia on the 10th day after living-related donor liver transplantation for alcoholic cirrhosis with Child-Pugh class C. Brain magnetic resonance images and electroencephalograms could not detect any lesion, but the diffusion tensor image showed a subacute lacunar infarction at right midbrain. The patient's speech improved 1 month after rehabilitation.

CONCLUSIONS

Some unexpected neurological events, such as loss of speech, may occur after liver transplantation. The differential diagnosis becomes very important before active treatment. Magnetic resonance imaging supplemented with diffusion tensor imaging is an effective imaging study in establishing the diagnosis.

Right mini-parasternotomy may be a good minimally invasive alternative to full sternotomy for cardiac valve operations-a propensity-adjusted analysis

AIM

Limited realworld data existed for miniparasternotomy approach with good sample size in Asian cohorts and most previous studies were eclipsed by case heterogeneity. The goal of this study was to compare safety and quality outcomes of cardiac noncoronary valve operations by miniparasternotomy and full sternotomy approaches on riskadjusted basis.

METHODS

From our hospital database, we retrieved the cases of non-coronary valve operations from 1 January 2005 to 31 December 2012, including re-do, emergent, and combined procedures. Estimated EuroScore-II and propensity score for choosing mini-parasternotomy were adjusted for in the regression models on hospital mortality, complications (pneumonia, stroke, sepsis, etc.), and quality parameters (length of stay, ICU time, ventilator time, etc.). Non-complicated cases, defined as survival to discharge, ventilator use not over one week, and intensive care unit stay not over two weeks, were used for quality parameters.

RESULTS

There were 283 miniparasternotomy and 177 full sternotomy cases. EuroScore-II differed significantly (medians 2.1 vs. 4.7, p<0.001). Propensity scores for choosing miniparasternotomy were higher with lower EuroScore-II (OR=0.91 per 1%, p<0.001), aortic regurgitation (OR=2.3, p=0.005), and aortic non-mitral valve disease (OR=3.9, p<0.001). Adjusted for propensity score and EuroScore-II, mini-parasternotomy group had less pneumonia (OR=0.32, p=0.043), less sepsis (OR=0.31, p=0.045), and shorter non-complicated length of stay (coefficient=7.2 (day), p<0.001) than full sternotomy group, whereas Kaplan-Meier survival, non-complicated ICU time, non-complicated ventilator time, and 30-day mortality did not differ significantly.

CONCLUSION

The propensity-adjusted analysis demonstrated encouraging safety and quality outcomes for mini-parasternotomy valve operation in carefully selected patients.

Map-based cloning of the ERECT PANICLE 3 gene in rice

Panicle architecture in rice can have a strong influence on yield. Using N-methyl-N-nitrosourea mutagenesis, we isolated an erect panicle mutant, Hep, from Hwasunchalbyeo, a glutinous japonica rice cultivar. Genetic analysis revealed that the erect panicle phenotype was controlled by a single recessive mutation designated erect panicle 3 (ep3). Genetic mapping revealed that the ep3 mutation was located on the short arm of chromosome 2 in a 0.1 cM region delimited by the STS markers STS5803-5 and STS5803-7. The ep3 locus corresponded to 46.8 kb region and contained six candidate genes. Comparison of the DNA sequences of the candidate genes from wild-type and erect panicle plants revealed a single base-pair change in the second exon of LOC_Os02g15950, which is predicted to result in a nonsense mutation. LOC_Os02g15950 encodes a putative F-box protein containing 515 amino acids and is expressed throughout the plant during all growth stages. A line carrying a T-DNA insertion in LOC_ Os02g15950 was obtained and shown to have the same phenotype as the ep3 mutant, thus confirming the identification of LOC_Os02g15950 as the ERECT PANICLE 3 (EP3) gene. The ep3 mutation causes a significant increase in the number of small vascular bundles as well as the thickness of parenchyma in the peduncle, which results in the erect panicle phenotype.

PCR marker-based evaluation of the eating quality of japonica rice ( Oryza sativa L.)

Evaluation of eating quality in early breeding generations of rice is critical to developing varieties with better palatability. This paper reports DNA markers associated with eating quality of temperate japonica rice and an evaluation method aided by multiple regression analysis. A total of 30 markers comprising STSs, SNPs, and SSRs were tested for their association with palatability using 22 temperate japonica varieties with different palatability values. Eating quality-related traits of the 22 varieties were also measured. Of the 30 markers, 18 were found to be significantly associated with palatability and, consequently, a model regression equation with an R(2) value of 0.99 was formulated to estimate the palatability by the marker data set. Validation of the model equation using selected breeding lines indicated that the marker set and the equation are highly applicable to evaluation of the palatability of cooked rice in temperate japonica varieties.

Comparison of molecular linkage maps and QTLs for morphological traits in two reciprocal backcross populations of rice

Comparison of maps and QTLs between populations may provide us with a better understanding of molecular maps and the inheritance of traits. We developed and used two reciprocal BC1F1 populations, IP/DS//IP and IP/DS//DS, for QTL analysis. DS (Dasanbyeo) is a Korean tongil-type cultivar (derived from an indica x japonica cross and similar to indica in its genetic make-up) and IP (Ilpumbyeo) is a Korean japonica cultivar. We constructed two molecular linkage maps corresponding to each backcross population using 196 markers for each map. The length of each chromosome was longer in the IP/DS//IP population than in the IP/DS//DS population, indicating that more recombinants were produced in the IP/DS//IP population. Distorted segregation was observed for 44 and 19 marker loci for the IP/DS//IP and IP/DS//DS populations, respectively; these were mostly skewed in favor of the indica alleles. A total of 36 main effect QTLs (M-QTLs) and 15 digenic epistatic interactions (E-QTLs) were detected for the seven traits investigated. The phenotypic variation explained (PVE) by M-QTLs ranged from 3.4% to 88.2%. Total PVE of the M-QTLs for each trait was significantly higher than that of the E-QTLs. The total number of M-QTLs identified in the IP/DS//IP population was higher than in the IP/DS//DS population. However, the total PVE by the M-QTLs and E-QTLs together for each trait was similar in the two populations, suggesting that the two BC1F1 populations are equally useful for QTL analysis. Maps and QTLs in the two populations were compared. Eleven new QTLs were identified for SN, SF, GL, and GW in this study, and they will be valuable in marker-assisted selection, particularly for improving grain traits in tongil-type varieties.

Fine mapping and candidate gene analysis of hwh1 and hwh2, a set of complementary genes controlling hybrid breakdown in rice

Hybrid breakdown (HB), a phenomenon of reduced viability or fertility accompanied with retarded growth in hybrid progenies, often arises in the offspring of intersubspecific hybrids between indica and japonica in rice. We detected HB plants in F8 recombinant inbred lines derived from the cross between an indica variety, Milyang 23, and a japonica variety, Tong 88-7. HB plants showed retarded growth, with fewer tillers and spikelets. Genetic analysis revealed that HB was controlled by the complementary action of two recessive genes, hwh1 and hwh2, originating from each of both parents, which were fine-mapped on the short arm of chromosome 2 and on the near centromere region of the long arm of chromosome 11, respectively. A comparison of the sequences of candidate genes among both parents and HB plants revealed that hwh1 encoded a putative glucose-methanol-choline oxidoreductase with one amino acid change compared to Hwh1 and that hwh2 probably encoded a putative hexose transporter with a six amino acid insertion compared to Hwh2. Investigation of the distribution of these alleles among 54 japonica and indica cultivars using candidate gene-based markers suggested that the two loci might be involved in developing reproductive barriers between two subspecies.

Inactivation of the UGPase1 gene causes genic male sterility and endosperm chalkiness in rice (Oryza sativa L.)

A rice genic male-sterility gene ms-h is recessive and has a pleiotropic effect on the chalky endosperm. After fine mapping, nucleotide sequencing analysis of the ms-h gene revealed a single nucleotide substitution at the 3'-splice junction of the 14th intron of the UDP-glucose pyrophosphorylase 1 (UGPase1; EC2.7.7.9) gene, which causes the expression of two mature transcripts with abnormal sizes caused by the aberrant splicing. An in vitro functional assay showed that both proteins encoded by the two abnormal transcripts have no UGPase activity. The suppression of UGPase by the introduction of a UGPase1-RNAi construct in wild-type plants nearly eliminated seed set because of the male defect, with developmental retardation similar to the ms-h mutant phenotype, whereas overexpression of UGPase1 in ms-h mutant plants restored male fertility and the transformants produced T(1) seeds that segregated into normal and chalky endosperms. In addition, both phenotypes were co-segregated with the UGPase1 transgene in segregating T(1) plants, which demonstrates that UGPase1 has functional roles in both male sterility and the development of a chalky endosperm. Our results suggest that UGPase1 plays a key role in pollen development as well as seed carbohydrate metabolism.

Single-center experience of pediatric heart transplantation in taiwan

Heart transplantation (HTx) is a treatment for end-stage heart failure or a complex or inoperable congenital defect. The long-term survival and the adequate donor to recipient body weight (D/R BW) ratio remain to be determined. From March 1995 to May 2004, 14 children (6 months-16 years of age) underwent HTx due to underlying diseases of idiopathic dilated cardiomyopathy (n = 10; 71.4%), congenital heart disease (n = 3; 21.4%), and Kawasaki disease (n = 1; 7.1%). Donor-recipient body weight ratio ranged from 0.89 to 3.9. Big heart syndrome was present in one patient when D/R BW ratio was more than 3. Actuarial survival was 92.9% at 5 years after transplantation. Only the one patient who had Kawasaki disease died due to early primary graft failure. HTx is a feasible method with good long-term survival rates for end-stage heart failure or for complex or inoperable congenital defects. After careful pretransplant evaluation, a high D/R BW ratio (more than 3) is acceptable.

Heart retransplantation for heart allograft failure in Chinese heart transplant recipients: NTUH experience

We investigated the short- and long-term results after heart retransplantation in terms of different causes of heart allograft failure. We sought to establish the data of heart retransplantation in Chinese compared with Western counterparts due to differences in heart allograft vasculopathy. From March 1995 to May 2005, eight heart transplantation recipients with allograft failure underwent retransplantation. Heart allograft failure was due to coronary vasculopathy (CAV) in six patients (75%) and acute rejection in two patients (25%). The mean interval to retransplantation was 32 to 84 months (mean 54.3 months). There were five patients who survived after heart retransplantation for CAV and no patient survived after an earlier diagnosis of acute rejection. Heart retransplantation is a feasible method with acceptable long-term survival rate for heart allograft failure. After careful pretransplant evaluation, retransplantation is acceptable. The survival after retransplantation for CAV is notably great than that after acute rejection. Heart retransplantation is the only way for patients who have cardiac allograft failure to achieve long-term survival.

Successful Treatment of Hepatitis B Virus Infection With Lamivudine After Heart Transplantation

Patients with hepatitis B virus (HBV) infection have a higher morbidity and mortality after heart transplantation (HT). HBV infection is endemic in Taiwan. We studied the effect of lamivudine treatment of HBV infection after HT. From July 1987 to July 2005, 252 patients underwent HT. All recipients and donors underwent routine screening of hepatitis B surface antigen (HBsAg), hepatitis B e antigen, antibody to hepatitis B surface antigen, antibody to hepatitis B core antigen, antibody to hepatitis B e antigen, and an alanine aminotransferase (ALT) level before HT. When ALT was two times greater than the upper limit of normal or serum bilirubin was higher than 3 mg/dL in HBsAg-positive patients, HBV-DNA were checked by a branched DNA assay or polymerase chain reaction. When HVB-DNA was greater than 100,000 copies/mL, lamivudine (100 mg per day) was prescribed indefinitely. There were 14 patients under lamivudine treatment after HT, among whom, none suffered severe adverse reactions from lamivudine. Four patients died: one due to end-stage cirrhosis while awaiting liver transplantation at 14 months after HT. Two died of sudden death at 54 months and 138 months after HT. Another died of diffuse B cell lymphoma at 62 months after HT. All the survivors have normal ALT and undetectable HBV-DNA after lamivudine treatment. But the YMDD mutant was detected in two patients. With successful treatment of HBV infection in HT, it is not necessary to exclude HBV infection patients from HT.

Sparing Immunosuppression in Heart Transplant Recipients With Severe Sepsis

This study described an analysis of severe sepsis among heart transplantation recipients who were treated by sparing all immunosuppressants. Sepsis leading to multiple organ failure (MOF) in heart transplantation has a high mortality. This retrospective study of 190 patients who underwent heart transplantation from 1993 to 2004 included 12 who had severe sepsis with MOF who were treated by sparing all immunosuppressants. Half of them survived after sparing all immunosuppressants with intensive endomyocardial biopsy. Only one case needed pulse therapy for an acute rejection episode. The most common bacterial infectious episodes were caused by methicillin-resistant Staphylococcus aureus (n = 3). All sepsis episodes occurred in the first month after heart transplantation except in one case, which occurred 6 years after heart transplantation. There was a 50% survival rate of heart transplantation recipients who experienced MOF due to severe sepsis and were treated by sparing all immunosuppressants under a program of intensive endomyocardial biopsy.

Simultaneous Heart and Kidney Transplantation for Combined Cardiac and Renal Failure

Simultaneous heart and kidney transplantation (SHKT) is feasible for combined cardiac and renal failure. Herein we reviewed our 10-year experience in SHKT. Six patients underwent SHKT from June 1995 to December 2004. Their ages ranged from 13 to 63 years old with a mean of 45.5 +/- 15.8 years. They were all men except one girl, who was the youngest (aged 13) who suffered from dilated cardiomyopathy with congestive heart failure and chronic renal failure due to systemic lupus erythematosus. Because of aggravating heart failure, she changed from hemodialysis to peritoneal dialysis. Because of intractable heart failure, she underwent SHKT from a 24-year-old female donor. All received hemodialysis before SHKT. The indications for heart transplantation included dilated cardiomyopathy (n = 3), ischemic cardiomyopathy (n = 1), cardiac allograft vasculopathy (n = 1), and cardiac allograft failure (n = 1). The immunosuppressive protocol and rejection surveillance were these employed for heart transplantation. No operative mortality was noted in this study. The 1-year and 5-year survival rates were the same, 83%. The 10-year survival rate was 55%. No cardiac or renal allograft rejection was noted. No renal allograft loss was noted. There were two late mortalities: the one, who underwent redo heart transplantation for coronary artery vasculopathy died of cardiac allograft failure 1 year after SHKT. The other patient died of massive ischemic necrosis of the intestine at 6 years after SHKT. Our experience showed that SHKT had good short- and long-term results without increasing immunosuppressive doses. End-stage failure of either the heart or the kidney did not preclude heart plus kidney transplantation.

Characterization and mapping of a shattering mutant in rice that corresponds to a block of domestication genes

Easy shattering reduces yield due to grain loss during harvest in cereals. Shattering is also a hindrance in breeding programs that use wild accessions because the shattering habit is often linked to desirable traits. We characterized a shattering mutant line of rice, Hsh, which was derived from a nonshattering japonica variety, Hwacheong, by N-methyl-N-nitrosourea (MNU) treatment. The breaking tensile strength (BTS) of the grain pedicel was measured using a digital force gauge to evaluate the degree of shattering of rice varieties at 5, 10, 15, 20, 25, 30, 35, and 40 days after heading (DAH). The BTS of Hwacheong did not decrease with increasing DAH, maintaining a level of 180-240 gf, while that of Hsh decreased greatly during 10-20 DAH and finally stabilized at 50 gf. Optical microscopy revealed that Hsh had a well-developed abscission layer similar to the wild rice Oryza nivara (accession IRGC105706), while Hwacheong did not produce an abscission layer, indicating that the shattering of Hsh was caused by differentiation of the abscission layer. On the basis of the BTS value and morphology of the abscission layer of F(1) plants and segregation data in F(2) populations, it was concluded that the easy shattering of Hsh was controlled by the single recessive gene sh-h. The gene sh-h was determined to be located on rice chromosome 7 by bulked segregant analysis. Using 14 SSR markers on rice chromosome 7, the gene sh-h was mapped between the flanking markers RM8262 and RM7161 at distances of 1.6 and 2.0 cM, respectively. An SSR marker Rc17 cosegregated with the gene sh-h. The locus sh-h for shattering was tightly linked to the Rc locus conferring red pericarp, as well as a QTL qSD(s)-7-1 for seed dormancy, implying that this region might represent a domestication block in the evolutionary pathway of rice.

Constitutional activation of IL-6-mediated JAK/STAT pathway through hypermethylation of SOCS-1 in human gastric cancer cell line

The interleukin-mediated Janus kinase (JAK)/STAT pathway plays a crucial role in carcinogenesis. Recently, increased STAT3 activity was found in hepatocellular carcinoma and multiple myeloma in which there was silencing of SOCS-1 (suppressor of cytokine signalling-1) by gene promoter hypermethylation. We investigated the expression level of interleukin-6 (IL-6) and SOCS-1 in gastric cancer cell lines. Expression of SOCS-1 correlated with IL-6 level in most of the cell lines, except for AGS cells in which SOCS-1 was absent despite a high level of IL-6 production. Methylation analysis by methylation-specific polymerase chain reaction and bisulphite sequencing revealed that CpG island of SOCS-1 was densely methylated in AGS cells. Demethylation treatment by 5'aza-deoxycytidine restored SOCS-1 expression and also suppressed constitutive STAT3 phosphorylation in AGS cells. Moreover, methylation of SOCS-1 was detected in 27.5% (11 of 40) of primary gastric tumours samples, 10% (one of 10) of adjacent noncancer tissues but not in any (zero of nine) normal gastric mucosa. Methylation of SOCS-1 also correlated with the loss of mRNA expression in some primary gastric cancers. In conclusion, this is the first report to demonstrate that hypermethylation of SOCS-1 led to gene silencing in gastric cancer cell line and primary tumour samples. Downregulation of SOCS-1 cooperates with IL-6 in the activation of JAK/STAT pathway in gastric cancer.

Management of aortic aneurysm infected with Salmonella

BACKGROUND

This study reviewed the clinical outcomes of patients with an aortic aneurysm infected with Salmonella treated by a single centre over 6 years.

METHODS

Data were collected by a retrospective case-note review.

RESULTS

Between September 1995 and December 2001, 121 patients with non-typhoid Salmonella bacteraemia were treated, of whom 24 patients had an aortic aneurysm infected with Salmonella. Ten had a suprarenal and 14 an infrarenal aortic infection. The most common responsible pathogen was group C Salmonella (12 patients). All of the 20 patients who had combined medical and surgical therapy survived, whereas two of four who had medical therapy alone died. There were two late deaths during a mean follow-up of 23 (range 3-63) months.

CONCLUSION

The incidence of aortic infection in patients with non-typhoid Salmonella bacteraemia was high in Taiwan. Timely surgical intervention and prolonged intravenous antibiotic therapy resulted in excellent outcomes.

Fish allergy in atopic children

The prevalence of fish allergy among 11 atopic children with elevated levels of specific immunoglobulin (Ig) E for cod was determined. None of the children had a history of fish allergy. All of the children had asthma and allergic rhinitis and 5 of them had also atopic dermatitis. The children underwent allergy skin tests (codfish, tuna, catfish, salmon, flounder, and bass), specific IgE tests (salmon, trout, tuna, eel, and mackerel), and food challenge tests. Skin tests in cod-specific IgE-positive children were positive for codfish in 4 children, tuna in 2, catfish in 2, salmon in 6, flounder in one, and bass in 2. Three children had elevated specific IgE for salmon, 5 for trout, 8 for tuna, 4 for eel, and 4 for mackerel. Oral fish challenge with 10 g of fish did not result in positive reaction in any of the children. In conclusion, a positive food challenge test provided the only definitive confirmation of fish allergy, whereas positive allergy skin tests or positive specific IgE tests were less reliable. Skin tests and in vitro specific IgE assays were not correlated with clinical symptoms of fish allergy, and the results of these 2 tests did not correlate with each other in this study.

Reactive oxygen species activity, mucosal lipoperoxidation and glutathione in Helicobacter pylori-infected gastric mucosa

BACKGROUND AND AIM

Helicobacter pylori is considered as the major pathogen in Helicobacter pylori-associated gastroduodenal disease, but the mechanism of its action has not been fully explained. This study was performed to assess the reactive oxygen species activity and the damage in Helicobacter pylori-infected gastric mucosa.

METHODS

Gastric biopsy specimens were obtained from 308 patients undergoing endoscopy. Gastric mucosal damage was assessed by using luminol enhanced chemiluminescence, thiobarbituric acid-reactive substance, and mucosal glutathione.

RESULTS

The chemiluminescence and thiobarbituric acid-reactive substance-equivalent levels in the mucosa of patients with Helicobacter pylori-positive gastric mucosa (43.8 +/- 134.9 c.p.m./microg tissue, 157.0 +/- 96.2 nmol/g tissue, respectively) were significantly higher than in those with Helicobacter pylori-negative mucosa (6.8 +/- 20.3 c.p.m./microg tissue, 110.0 +/- 51.6 nmol/g tissue, respectively; P=0.000, P=0.016, respectively). The glutathione levels in the mucosa of patients with Helicobacter pylori-positive gastric mucosa (159.3 +/- 76.6 nmol/microg tissue) were significantly lower than in those with Helicobacter pylori-negative gastric mucosa (212.3 +/- 134.3 nmol/microg tissue; P=0.008). After the data were divided according to the presence of Helicobacter pylori, there were no significant differences in chemiluminescence, thiobarbituric acid-reactive substance, and glutathione among the different macroscopic findings within Helicobacter pylori-positive and -negative gastric mucosa.

CONCLUSIONS

Helicobacter pylori infection plays a pathological role in many gastrointestinal diseases through excessive mucosal-reactive oxygen species production, pronounced membrane damage, and the depletion of gastric anti-oxidants.

Survival after early surgical revascularization in patients with both acute myocardial infarction and cardiogenic shock

BACKGROUND AND PURPOSE

Previous studies have reported encouraging results with percutaneous transluminal coronary angioplasty (PTCA) in patients with acute myocardial infarction (AMI) complicated by cardiogenic shock. However, PTCA is often unsuccessful and the mortality rate is more than 80%. The success rate of early surgical revascularization in patients with cardiogenic shock and failed PTCA is not clear. This study assessed the effect of early surgical revascularization on survival chances in patients with cardiogenic shock and failed PTCA.

PATIENTS AND METHODS

Nineteen patients referred to our hospital by cardiologists due to cardiogenic shock and failed PTCA were included in this study. During the period from February 1995 through August 1997, seven patients were treated using mechanical circulatory support with extracorporeal membrane oxygenation (ECMO) and no surgical revascularization, and from August 1997 through June 1999, 12 patients underwent emergency surgical revascularization. The patient characteristics and in-hospital mortality were compared between groups.

RESULTS

Ten patients were treated after acute infarction and nine were treated after cardiac intervention. No significant differences were found between the two groups in age, sex, hypertension, diabetes, smoking, and previous infarction. The in-hospital mortality rates were 100% in patients receiving mechanical circulatory support with ECMO and 25% in patients who underwent emergency surgical revascularization (p = 0.003). In the emergency revascularization group, four of 12 patients had surgical revascularization more than 18 hours after AMI and the in-hospital mortality rate was 25%.

CONCLUSION

Surgical revascularization improved survival in patients with cardiogenic shock and failed PTCA.

The dilemma of "to-be or not-to-be": needs and expectations of the Taiwanese cadaveric organ donor families during the pre-donation transition

There has been little study of the Chinese cadaveric donor family's decisions to donate organs within the Chinese cultural framework. A convenience sample of 25 cadaveric donor family members (12 men, 13 women) who gave their consent to donation at National Taiwan University Hospital agreed to participate in this study and completed in-depth interviews. Data were analyzed by a three-steps within-method qualitative triangulation method. The factors influencing the donor family's decisions to donate organs, the needs of donor families, and their expectations of health care providers during the pre-donation transition--the critical period of time between signing a donation and consent to organ harvesting--were examined. The background context and a conceptual framework were further developed to discuss and depict this phenomenon. This project aims to broaden the horizon on organ donation and contribute to the understanding of some of the psychodynamic issues in the Chinese family in Taiwan.

Lamivudine treatment for hepatitis B reactivation in HBsAg carriers after organ transplantation: a 4-year experience

BACKGROUND

Reactivation of hepatitis B after organ transplantation in hepatitis B surface antigen (HBsAg) carriers may be fatal. In this study, we reported our experience of lamivudine treatment in HBsAg carriers who had post-transplant reactivation of hepatitis B.

METHODS

The patients were 15 men and one woman. Nine received kidney transplants, six received heart transplants, and one received a lung transplant. They developed a reactivation of hepatitis B 1-101 months (median, 14 months) after transplantation. They received lamivudine 100 mg daily on a compassionate-use basis, and had regular follow ups. The median pretreatment total serum bilirubin level was 3.0 mg/dL, and the alanine aminotransferase level was 357 U/L. Four of the 16 patients were positive for HBeAg. The serum hepatitis B virus (HBV) DNA levels were > 3000 pg/mL in 13 (81%) patients. Three were coinfected with hepatitis C virus.

RESULTS

The overall survival rate was 75%. All four fatal cases had a pretreatment total serum bilirubin level of > or = 3 mg/dL. Serum HBV-DNA soon became undetectable in 12 survivors. Of the 12 survivors, after a median treatment period of 101 weeks, a lamivudine-resistant strain with variation in the YMDD motif of the HBV polymerase gene developed in three (25%). None had significant adverse reactions to lamivudine treatment.

CONCLUSIONS

These results indicated that lamivudine is effective in the treatment of post-transplant hepatitis B reactivation, including patients with dual chronic hepatitis B and C. Early recognition of HBV reactivation and prompt lamivudine treatment are important to prevent mortality.

Hepatitis B virus infection in heart transplant recipients in a hepatitis B endemic area

BACKGROUND

Hepatitis B virus (HBV) infection is hyperendemic in Taiwan. It is almost impossible for us to reject organ donors or recipients with positive serum hepatitis B surface antigen (HBsAg). We report our experience with HBV infection in heart transplant recipients with particular attention to outcome of recipients who were HBsAg+ or who had received donor hearts from HBsAg+ donors.

METHODS

We performed a retrospective review of medical records.

RESULTS

In the study, we included 101 heart recipients with post-transplant survival of more than 6 months. According to pre-transplant HBV serology markers, we divided patients into 4 groups. Group 1 (n = 8) had been HBsAg+ at the time of heart transplantation. Of these, 6 patients had HBV reactivation in the post-transplant follow-up and needed lamivudine treatment. Complete response was achieved in all 6 patients; however, HBV recurrence occurred in 1 patient after 8 months of lamivudine treatment. The recurrence remained under partial control. Group 2 (n = 16) was HBV naïve at the time of heart transplantation. Of these, 2 received HBsAg+ donor hearts under perioperative hepatitis B immunoglobulin prophylaxis. HBV infection was successfully prevented in 1 patient, but the other contracted HBV hepatitis, which was successfully treated with lamivudine. In Group 2, 10 patients received donor hearts from anti-HBs+ donors, and none contracted HBV hepatitis after transplantation. Group 3 (n = 55) had protective anti-HBs antibody at the time of heart transplantation either from previous HBV vaccination (n = 10) or from natural HGB infection (n = 45). HBsAg+ donor hearts were transplanted into 2 patients with anti-HBs from previous HBV vaccination, and into 8 patients with anti-HBs form natural HBV infection. However, none of these 10 patients who received HBsAg+ donor hearts had HBV hepatitis after transplantation. Group 4 (n = 22) was HBs-, anti-HBs-, and anti-HBc+ at the time of heart transplantation. Of these, 7 patients received HBsAg+ donor hearts. Six patients experienced no HBV hepatitis after heart transplantation, and serum HBV DNA by polymerase chain reaction (PCR) at the time of heart transplantation was negative in all 6 patients. One patient had HBV hepatitis after transplantation, and serum HBV DNA by PCR at the time of heart transplantation also was positive.

CONCLUSION

HBV reactivation after the heart transplantation was common but usually well controlled with lamivudine treatment. Therefore, HBV carrier status should not contraindicate heart transplantation. HBsAg+ donor hearts were safely transplanted into anti-HBs+ recipients; therefore, HBsAg+ itself was not a contraindication to heart donation. Patients with HBsAg-, anti-HBs-, anti-HBc+, and negative HBV DNA in the serum by PCR could be protected from HBV infection from HBsAg+ donor hearts. However, patients with HBsAg-, anti-HBs-, anti-HBc+, and positive HBV DNA in the serum by PCR should be recognized as HBV carriers and closely followed for potential HBV flare-up after heart transplantation.

Mechanical bridge with extracorporeal membrane oxygenation and ventricular assist device to heart transplantation

The aim of this study was to evaluate the effect of double bridges with extracorporeal membrane oxygenation (ECMO) and ventricular assist devices (VADs) in clinical heart transplantation. Between May 1994 and October 2000, 134 patients underwent heart transplantation at the National Taiwan University Hospital. Ten patients received ECMO or VAD support as bridges to transplantation. The ages ranged from 3 to 63 years. The indications included cardiac arrest under cardiopulmonary resuscitation in 2 and profound cardiogenic shock refractory to conventional therapy in 8 patients. Usually ECMO was first set up as rescue therapy. If ECMO could not be weaned off after short-term (usually 1 week) support, suitable VADs (HeartMate or Thoratec VAD) were implanted for medium-term or long-term support. Five patients received ECMO support as emergency rescue for 2 to 9 days, and then moved to Thoratec VAD for 8, 49, and 55 days, respectively, or centrifugal VAD for 31 days, or HeartMate VAD for 224 days. They all survived. The survival rate of double bridges with ECMO and VAD was 100%. In postcardiotomy cardiogenic shock, circulatory collapse from acute myocardial infarction or myocarditis, ECMO is the device of choice for short-term support. If heart transplantation is indicated, VADs should replace ECMO for their superiority as a bridge to heart transplantation. Our preliminary data of double bridges with ECMO and VAD revealed good results and were reliable and effective bridges to transplantation.

Conversion of extracorporeal membrane oxygenation to non-pulsatile left ventricular assist device. Is it out-of-date for non-pulsatile LVAD?

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) provides an immediate support for acute deterioration of hemodynamic and pulmonary status, but what is the best decision for these critical patients? Biventricular assist device (BVAD) or left ventricular assist device (LVAD)? We proposed a protocol of step-by-step conversion from ECMO to LVAD after assurance of the reversibility of right ventricle and pulmonary function.

METHODS

After femoral venoarterial ECMO was inserted for the critical patients, the left atrial drainage was added to the ECMO firstly and the femoral arterial inflow was shifted to the ascending aorta for preventing possible peripheral vascular complications. Temporary clamp of right heart drainage was tried to test right heart function 24 to 48 hours later. The sweep gas flow of oxygenator could be reduced gradually to test the pulmonary function. Therefore, the right heart drain and the oxygenator could be withdrawn to become a non-pulsatile LVAD or shift to pneumatic LVAD directly. There were four clinical experiences with successful conversion without temporary right ventricular assist device.

RESULTS

All of them were able to convert their ECMO to LVAD smoothly in 8.0+/-2.5 days. Three of them were shifted to non-pulsatile LVAD, and one was converted to HeartMate. All but one could be weaned from the ventilator. No BVAD was needed in these patients. Due to the shortage of donor hearts, only one had the chance to undergo heart transplantation.

CONCLUSIONS

The protocol did provide a good guideline for decision-making for those under ECMO support necessitating bridge to transplantation.

Development of a totally implantable pulsatile centrifugal pump as a ventricular assist device

The Taita No. 1 ventricular assist device (T-VAD) is a totally implantable pulsatile impeller centrifugal pump driven by a magnetically suspended motor. The flow can achieve 2.01 +/- 0.17 L/min against a pressure of 100 mm Hg under 0.266 +/- 0.017 amp and 13.55 +/- 0.41 voltage. The speed was around 3,500 rpm. It consumed less than 6 W of power, resulting in less heat production and mechanical bearing complications. The impeller vane was designed to have both radial and axial curves according to the stream surface and stream lines to reduce thrombosis and hemolysis. Eight calves weighing 80 to 100 kg (mean 87 +/- 12 kg) were used for experiments. With the calves under general anesthesia, left posterolateral thoracotomy was performed to connect the inflow tube with the atrial appendage and to anastomose the outflow tube with the descending aorta. The calves usually awoke and stood up within hours after discontinuation of anesthetics. The mean survival of the calves was 75 +/- 42 days (range 33-148 days). The terminations of experiments were mainly due to infection. During the course of pumping, no significant deterioration of liver or renal function was noted. The evaluation of serum samples from the implanted calves indicated that hemolysis was not associated with use of the T-VAD. The average daily free hemoglobin level was 8.08 +/- 3.05 mg/dl, which was less than the set limit of 20 mg/dl. The red blood cell and platelet count and hemoglobin of implanted animals were within the normal range. In our results, the T-VAD provided competent pulsatile function without severe blood damage or organ dysfunction.

Physiologic analysis of cardiac cycle in an implantable impeller centrifugal left ventricular assist device

The purpose of this study was to determine the physiologic relationship between the cardiac cycle and the nonpulsatile impeller centrifugal Taita No.1 left ventricular assist device (T-LVAD) in a chronic animal study. The relationship of the cardiac cycle, pump flow, aortic pressure, left ventricle pressure, and pump power were analyzed by 5 phases in 4 stages. The isovolumetric ventricular phase is from mitral valve closure (MVC) to aortic valve opening (AVO) and is called Stage 1. The ejection phase is from AVO to aortic valve closure (AVC) and is called Stage 2. The isovolumetric relaxation phase is from AVC to MVC and is called Stage 3. The passive filling and atrial contraction phase is from MVC to mitral valve opening (MVO) and called Stage 4. Based on evidence from the physiologic volume change of the left ventricle, the change of pump flow of the T-LVAD in a cardiac cycle by variable voltages of pump control was evaluated using animal models. After left posteriolateral thoracotomy via the fifth intercostal space under general anesthesia, the nonpulsatile centrifugal T-LVAD was implanted into 2 healthy calves. The inflow of the T-LVAD was inserted into the left ventricle through the mitral valve via the left atrial appendage. The arterial blood pressure waveform was measured and recorded on the outflow of the T-LVAD. The 4 phases of a cardiac cycle were defined as MVC-AVO (Stage 1), AVO-AVC (Stage 2), AVC-MVO (Stage 3) and MVC-MVO (Stage 4) according to the outflow pressure of the outflow of the T-LVAD and differential pressure between the outflow and inflow of the T-LVAD. We carried out the real-time waveform measurement for electrocardiogram, the outflow pressure, the T-LVAD flow and the speed, as well as open loop and constant voltage (V). In a cardiac cycle, the sensing current of the T-LVAD was inverse to the speed. The flow of the T-LVAD at the 4 stages was measured individually and analyzed with different control voltages from 10 to 18 V. The highest flow ratio of MVC-AVC/AVC-MVC was noted when the T-LVAD worked on 14 V. By using analysis methodology of the flow ratio of a cardiac cycle, the optimal physiologically effective control of the T-LVAD might be achieved.

Application of extracorporeal membrane oxygenation in adult burn patients

Adult respiratory distress syndrome (ARDS) has been the major cause of mortality in burn injury. The authors reported the experience of using extracorporeal membrane oxygenation (ECMO) to treat adult burn patient with ARDS. Three patients with burn or electric injury, around 48.9% of body surface area over second-degree burns, developed ARDS after resuscitation. All had positive blood culture and depended on a ventilator more than 5 days before ECMO. Venovenous (VV) ECMO was started at the beginning of severe respiratory failure with an oxygen index of 61.6 +/- 15.5 cm H2O/mm Hg (> or =40 cm H2O/mm Hg), partial arterial oxygen tension to inspired oxygen fraction (Pa(O2)/Fi(O2)) of 46.1 +/- 7.0 mm Hg (< or =200 mm Hg), positive end expiratory pressure (PEEP) of 15.7 +/- 1.6 cm H2O (> or =10 cm H2O), alveolar-arterial difference in oxygen concentration (A-a D(O2)) of 618.9 +/- 19.3 mm Hg (> or =300 mm Hg), and lung compliance of 17.3 +/- 4.6 ml/cm H2O (< or =30 ml/cm H2O). The VV type had to be converted to the newly designed veno-venoarterial (V-VA) ECMO due to the myocardial dysfunction. Two of three patients survived. The duration of ECMO was 160.2 +/- 51.1 h. Two patients received debridement of escar during ECMO support and desmopressin infusion, and no increased bleeding or coagulopathy was found. The respiratory parameters were significantly improved after ECMO, especially in the survivors. ECMO is also suitable for ARDS in adult burn injury.

Growth of endothelial cells on different concentrations of Gly-Arg-Gly-Asp photochemically grafted in polyethylene glycol modified polyurethane

To improve endothelial cell adhesion and growth on the surface of polyethylene glycol modified polyurethane (PU-PEG), cell adhesive peptide Gly-Arg-Gly-Asp (GRGD) was photochemically grafted to the surface. The surface grafted GRGD-N-Succinimidyl-6-[4'-azido-2'-nitrophenylamino]hexanoate (SANPAH) on a PU-PEG surface was performed by adsorption and subsequent ultraviolet irradiation. Fourier transform infrared spectra (FTIR) and electron spectroscopy for chemical analysis (ESCA) confirmed the GRGD grafted to form a PU-PEG-GRGD surface. The composition fraction of nitrogen calculated from ESCA analysis for the PU-PEG-GRGD surface was well correlated with the concentration of GRGD to be immobilized. Human umbilical vein endothelial cells (ECs) were well adhered and growing on the PU-PEG-GRGD surface. Moreover, the viability of ECs growing on PU-PEG-GRGD surfaces, analyzed by MTT test, was also well correlated with the GRGD concentrations immobilized on the surface. With photochemical techniques, we could manipulate different contents of GRGD to form multiple regions of PU-PEG-GRGD surface that could enhance the growth of ECs on the surface, and the enhancement efficiency was well correlated with GRGD contents.

Preliminary result of an algorithm to select proper ventricular assist devices for high-risk patients with extracorporeal membrane oxygenation support

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is not suitable for long-term support because of its high incidence of complications. Conversion from ECMO to ventricular assist device (VAD) is reasonable, and we have developed a simple algorithm for selecting proper VADs for these ECMO-supported patients.

METHODS

We converted 12 patients who were receiving ECMO support to VAD for bridge to transplantation. Group I (n = 6) was converted directly from ECMO to VAD. Group II (n = 6) underwent stage conversion. We added left atrial drainage to ECMO because of lung edema or marked left heart distension. We discontinued drainage after recovery of right heart function. Group II had more unfavorable risk factors for VAD before ECMO.

RESULTS

Three patients (50%) in Group I received biventricular VADs. The other 3 patients were converted to left ventricular assist device (LVAD), but only 1 (16.7%) experienced successful conversion. We successfully converted 5 patients (83.3%) in Group II to LVAD without right VAD, and 4 of them could be weaned from the ventilator. The multiple-organ dysfunction score gradually improved in Group II despite additional surgery. Two patients in each group received heart transplantation and survived long term.

CONCLUSION

Using a conversion protocol provides a good guideline for making decisions. According to the protocol, right heart and pulmonary function can be clearly assured before shifting to LVAD in these critical ECMO-supported patients.

Successful resuscitation of acute massive pulmonary embolism with extracorporeal membrane oxygenation and open embolectomy

Acute massive pulmonary embolism is usually fatal if not treated aggressively, but the management is not standardized. Open pulmonary embolectomy retains a role in the treatment of this disastrous disease. Extracorporeal membrane oxygenation has been used for cardiopulmonary support in some patients with life-threatening pulmonary embolism. This article details our experience of a 58-year-old woman suffering from acute cardiopulmonary collapse caused by massive pulmonary embolism. Under extracorporeal membrane oxygenation support, the patient received pulmonary angiography and underwent open embolectomy for a definitive treatment.

Heart transplantation and the Batista operation for children with refractory heart failure

Medically refractory heart failure may be present in children with cardiomyopathy (CMP) or complex congenital heart disease (CHD). In adults, the surgical management of this condition is either heart transplantation or the Batista operation. From March 1995 to January 2000, a total of 6 children, aged from 1 to 16 years, with medically refractory heart failure associated with CMP or complex CHD underwent cardiac transplantation and one of them also had the Batista operation as a bridge to transplantation. One of the 6 patients died of intractable sepsis 17 days after the operation, but the other 5 were discharged with satisfactory hemodynamics. Immunosuppressive agents, including azathioprine, cyclosporin or FK-506, were given. One patient experienced moderate acute rejection, but it was controlled by FK-506, OKT-3 and solumedrol. However, another suffered from lymphoproliferative disease 8 months after transplant, but it was controlled by intravenous immunoglubulin, alpha-interferon and acyclovir. Cardiac function during serial follow-up (range, 1 month to 5 years) revealed normal systolic and diastolic function and none received any anticongestive medications. Almost all patients received an oversized donor heart. The left ventricle (LV) mass was remodeled, initially as an decrease and later as an increase. The patient who underwent the Batista operation was discharged 1 month after the operation with an increased LV ejection fraction (from 10% to 22%). She was successfully bridged to heart transplantation 7 months after the Batista operation. The results of cardiac transplantation in growing children are satisfactory and remain the mainstay of surgical treatment for medically refractory heart failure in these patients. However, with a shortage of donor hearts, the Batista operation may be adopted as a bridge to heart transplant with a fair response.

Impact of cadaveric organ donation on Taiwanese donor families during the first 6 months after donation

OBJECTIVE

Organ donation is a complex decision for family members of Asian donors. The impact of cadaveric organ donation on both Chinese and Western donor families has not been well investigated within a cultural framework. The purposes of this study were to follow Chinese family members' appraisal of their decision to donate organs, to explore the possible negative and positive impacts of organ donation on their family life, and to determine what help they expected from healthcare providers during the first 6 months after donation.

METHODS

Twenty-two family members (10 men and 12 women) of cadaveric organ donors who signed consent forms at an organ transplant medical center in Taiwan participated in this project and completed in-depth interviews during the sixth month after donation.

RESULTS

Participants were 25 to 56 years old (mean = 48.15 +/- 8.31 years). The type of kinship of the participants included the donor's parents, older sister, and spouse. Subjects reported several negative impacts: worry about the donor's afterlife (86%), stress due to controversy among family members over the decision to donate (77%), and stress due to others' devaluation of the donation (45%). Positive impacts reported by the subjects included having a sense of reward for helping others (36%), having an increased appreciation of life (32%), having closer family relationships (23%), and planning to shift life goals to the study of medicine (9%). Subjects expected the transplant team to provide information about organ recipients (73%), to submit the necessary documents so that family members could receive healthcare payments from the insurance company (68%), to help resolve legal proceedings and settlements associated with accidents (64%), and to not overly publicize their decision to donate (64%).

CONCLUSIONS

Although all of the subjects reported that organ donation was the right decision, the decision to donate did not protect Taiwanese donor families from negative psychocognitive bereavement. The impacts of organ donation were affected by the subject's social cultural, spiritual, and legal context and the nature of their bereavement.