Study on the application of the Internet + nursing service in family rehabilitation of common bone and joint diseases in the elderly.

OBJECTIVE: To explore the feasibility of the Internet + nursing service mode in family rehabilitation of elderly patients with osteoarthritic diseases. PATIENTS AND METHODS: The control group (n=50) received routine rehabilitation treatment procedures and discharge guidance. For the observation group (n=50), extended nursing rehabilitation service was conducted through the Internet + nursing service platform based on the routine treatment in the control group. RESULTS: (1) The compliance with follow-up of the patients in the observation group was significantly higher than that in the control group; (2) The total satisfaction of patients in the observation group was significantly higher than that in the control group; (3) The VAS (1 month: 4.36±1.15 vs. 5.86±1.61, p<0.05; 3 months 4.36±1.15 vs. 5.86±1.61, p<0.05), SAS (1 month: 37.21±14.16 vs. 49.31±13.45, p<0.05; 3 months 26.73±8.25 vs. 40.33±9.50, p<0.05), SDS (1 month: 32.36±10.15 vs. 46.32±12.61, p<0.05; 3 months 27.11±8.08 vs. 40.62±11.40, p<0.05) and PSQI (1 month: 13.64 ± 1.13 vs. 16.31 ± 3.45, p<0.05; 3 months 11.54 ± 1.87 vs. 15.74 ± 1.36, p<0.05) scores in the observational group were significantly lower than that in control group at one month and three months after discharge. The ADL (1 month: 86.86 ± 4.13 vs. 74.33 ± 3.44, p<0.05; 3 months 90.34 ± 7.87 vs. 78.52 ± 6.36, p<0.05) scores in the observational group were significantly higher than that in control group at one month and three months after discharge. CONCLUSIONS: The extended rehabilitation nursing management for family rehabilitation of elderly patients with osteoarthritic diseases through the Internet + nursing service is a family rehabilitation model suitable for elderly patients with osteoarthritic diseases in China and has positive significance in developing a diversified medical nursing model.

[The clinical application of two-complex and one-plane technique for renal artery location in transperitoneal laparoscopic radical nephrectomy].

Objective: To examine the clinical application effects of two-complex and one-plane technique for the renal artery dissected location in transperitoneal laparoscopic radical nephrectomy(LRN). Methods: Clinical data of patients diagnosed as renal tumor between January 2016 and December 2019 that treated with transperitoneal LRN and the two-complex and one-plane technique was performed to locate and dissect the renal arteries were analyzed retrospectively. A total of 206 qualified patients were enrolled, included 71 cases from Kaifeng Central Hospital and 135 cases from the First Affiliated Hospital of Zhengzhou University. There were 126 males and 80 females with median age of 54 years (range: 35 to 82 years). Renal tumor lived at left kidney in 102 cases and at the right in 104 cases, with a maximum tumor diameter of (6.8±2.5)cm (range: 3.0 to 12.7 cm). During the procession of transperitoneal LRN, The genital veins was followed to locate renal veins, soon the renal vein complex and renal lower pole complex and psoas major muscle plane that named as "two-complex and one-plane"anatomical markers were applied to the dissected location of renal arteries. The established application of two-complex and one-plane technique for renal artery location, and the anatomical features along with its locational time of renal artery, as well as vascular-related complications were recorded and analysed. The χ2 test or t test was used to compare the results of different lateral operations. Results: The surgical procedures were successful in all 206 patients. The operation time was (54.4±13.6) minutes (range:22 to 116 minutes), no injury to liver, spleen or intestine. Two-complex and one-plane technique was used to complete renal arteries location of 206 patients that accompanied with one or more arterial branch in the procession of transperitoneal LRN. Single renal artery branch was found in 163 cases, two or more renal artery branches were found in 43 cases, and 60 branches of accessory renal artery that in addition to the main trunks were detected in 14 cases (13.7%, 14/102) on left-side and 29 cases (27.9%, 29/104) on the right(χ²=6.251, P=0.012).The main branch of renal artery that directly been located inferior or posterior to renal vein in 165 cases, and the other 41 cases that born with higher-position of main branch been located through an upper"window-opening"of renal veins complex. Of the 60 accessory renal artery, 46 branch (76.6%, 46/60) been located inferior or posterior to renal veins, and the other 14 branch with higher-position (23.3%, 14/60) been located by a"window-opening"technique. The renal artery dissected location time was (21.2±9.4) minutes (range:11 to 43 minutes) in left-side and (17.5±9.3) minutes (range:9 to 32 minutes) in the right (t=2.840, P=0.005).The intraoprative bleeding was (51.8±25.2) ml (range:20 to 400 ml). There were 4 cases of vascular injury occured and treated with laporoscopy, only one need blood transfusion. Conclusions: The anatomical markers of renal vein complex and renal lower pole complex and psoas major muscle plane that can apply to locate various anatomical position types of renal artery in transperitoneal LRN effectively. The exactly application of two-complex and one-plane technique that could shorten the operational time of renal artery location and reduce the complications of vascular injury.

MicroRNA-29b Promotes Subchondral Bone Loss in TMJ Osteoarthritis.

Abnormal subchondral bone remodeling plays important roles during osteoarthritis (OA) pathology. Recent studies show that bone marrow mesenchymal stem cells (BMSCs) in osteoarthritic subchondral bones exhibit a prominent pro-osteoclastic effect that contributes to abnormal subchondral bone remodeling; however, the pathologic mechanism remains unclear. In the present study, we used a mouse model with OA-like change in the temporomandibular joint (TMJ) induced by an experimentally unilateral anterior crossbite (UAC) and found that the level of microRNA-29b (miR-29b), but not miR-29a or miR-29c, was markedly lower in BMSCs from subchondral bones of UAC mice as compared with that from the sham control mice. With an intra-articular aptamer delivery system, BMSC-specific overexpression of miR-29b by aptamer-agomiR-29b rescued subchondral bone loss and osteoclast hyperfunction in UAC mice, as demonstrated by a significant increase in bone mineral density, bone volume fraction, trabecular thickness, and the gene expression of osteocalcin and Runx2 but decreased trabecular separation, osteoclast number and osteoclast surface/bone surface, and the gene expression of cathepsin K, Trap, Wnt5a, Rankl, and Rank as compared with those in the UAC mice treated by aptamer-NC (all P < 0.05). In addition, BMSC-specific inhibition of miR-29b by aptamer-antagomiR-29b exacerbated those responses in UAC mice. Notably, although it primarily affected miR-29b levels in the subchondral bone (but not in cartilage and synovium), BMSC-specific overexpression of miR-29b in UAC mice largely rescued OA-like cartilage degradation, including decreased chondrocyte density, cartilage thickness, and the percentage areas of proteoglycans and type II collagen, while BMSC-specific inhibition of miR-29b aggravated these characteristics of cartilage degradation in UAC mice. Moreover, we identified Wnt5a, but not Rankl or Sdf-1, as the direct target of miR-29b. The results of the present study indicate that miR-29b is a key regulator of the pro-osteoclastic effects of BMSCs in TMJ-OA subchondral bones and plays important roles in the TMJ-OA progression.

[Hospitalization burden of hand, foot and mouth disease in Anhua county of Hunan province, 2013-2016].

Objective: To estimate the serotype and age-specific hospitalization burden associated with hand, foot and mouth disease (HFMD) in Anhua county of Hunan province, between October 2013 and September 2016. Methods: We collected hospitalization records of HFMD patients from 6 virological surveillance hospitals, and reimbursement records through new rural cooperative medical system from 23 township health centers to estimate the age-specific hospitalization burden of HFMD in Anhua. Combined with the results of virological surveillance, the serotype-specific hospitalization burden of HFMD in Anhua, was estimated. Results: During the three years, it was estimated that 3 541 clinical diagnosed HFMD cases, including 3 146 laboratory-confirmed HFMD cases, were hospitalized in Anhua, but only one was diaguosed as being severe. The estimated average hospitalization rate was 723/100 000(95%CI: 699/100 000-747/100 000) for clinical diagnosed HFMD and 642/100 000 (95%CI: 620/100 000-665/100 000) for laboratory-confirmed HFMD between October 2013 and September 2016. The cases caused by Cox A16 (208/100 000) and Cox A6 (202/100 000) had higher hospitalization rates compared with the cases caused by EV71 (130/100 000), Cox A10 (38/100 000) and other enterovirus (64/100 000), and the difference was statistically significant (P<0.001). HFMD-associated hospitalization rates peaked in children aged 1 year (3 845/100 000), and then decreased with age. Compared with the hospitalized HFMD caused by EV71 and Cox A16, Cox A6-associated hospitalizations mainly occurred in younger age groups (P<0.001). Conclusion: Our study revealed a substantial hospitalization burden associated with mild HFMD caused by EV71, Cox A16, Cox A6 and Cox A10, especially in young children, in Anhua.

Calcium-/calmodulin-dependent protein kinase II in occlusion-induced degenerative cartilage of rat mandibular condyle.

Activated calcium-/calmodulin-dependent protein kinaseII (CaMKII) is important to promote chondrocytes from proliferative to pre-hypertrophic state, which probably plays a role in osteoarthritis (OA), a widespread degeneration disease with enhanced aberrant chondrocyte differentiation. Our aim was to detect the role of CaMKII, and its relationship with the feedback loop of Indian hedgehog (Ihh) and Parathyroid-related peptide (PTHrP) in the temporomandibular joints (TMJs) OA. KN93, the competitive inhibitor of CaMKII, was added to the culture medium in vitro and was locally injected to rats TMJs (n = 54, female) every other day for 4 weeks from the beginning of the 5th and 9th week after installing of unilateral anterior crossbite (UAC), termed as 4 wk+4 wk and 8 wk+4 wk, accordingly. The RNA expression of CaMKII α (1.49 ± 0.09), CaMKII ß (3.36 ± 0.20), Ihh (1.88 ± 0.06) and PTHrP (1.87 ± 0.12) was all enhanced, especially at 24 dyn/cm2 in vitro (all P < .05), accompanied with downregulated expression of cartilage matrix, but upregulated markers of chondrocytes differentiation (all P < 0.05). Similarity was observed in the 4 wk+4 wk group in vivo. In the 8 wk+4 wk group, UAC upregulated the RNA expression of CaMKII α (1.81 ± 0.24), CaMKII ß (1.36 ± 0.07) and Ihh (1.70 ± 0.21), however, down-regulated PTHrP (0.53 ± 0.04) (all P < .05), in consonance with the protein expression. All these changes were attenuated by KN93 (all P < .05). In conclusion, CaMKII took a role, via Ihh and PTHrP pathways, in promoting biomechanically induced TMJ chondrocytes differentiation, the initiation issue of UAC stimulated osteoarthritic changes in rodent TMJs. Inhibiting CaMKII is helpful to rescue the biomechanically stimulated cartilage degradation and prospective to be a target treatment of OA.

Effect of TGF-ß1/SDF-1/CXCR4 signal on BM-MSCs homing in rat heart of ischemia/perfusion injury.

OBJECTIVE: Heart ischemia/reperfusion (I/R) injury is a common cause of heart failure. However, there is no effective method to treat the disease presently. The present research was to investigate the effects of transforming growth factor-ß1 (TGF-ß1) on homing of bone marrow mesenchymal stem cells (MSC) in heart I/R injury. MATERIALS AND METHODS: Effects of TGF-ß1 on the expression of CXCR4 [Chemokine (C-X-C Motif) Receptor 4] and chemotactic effect to SDF-1 (stromal cell-derived factor 1) in MSCs were investigated by in vitro transmembrane chemotaxis. Anti-TGF-ß1 was incubated with I/R injury's heart tissue of mice. In addition, effects of TGF-ß1 and anti-CXCR4 treatment using MSCs on the expression of SDF-1/CXCR4 in heart tissue and on I/R injury repair were further explored. RESULTS: CXCR4 and TGF-ß1 expression were significantly increased after TGF-ß1 treatment in MSCs; TGF-ß1 treatment increased MSCs cell migration, and anti-CXCR4 and anti-TGF-ß1 treatment blocked MSCs/TGF-ß1cell migration. Expression of TGF-ß1 in the I/R injury's myocardial tissue of mice was increased, and MSCs transplantation could enhance the protein expression of CXCR4 in the I/R injury's myocardial tissue of mice, and the expression of CXCR4 was decreased by the anti-TGF-ß1 and the anti-CXCR4 treatment. TGF-ß1 induced homing of MSCs in the repair of myocardial injury by regulating expression of CXCR4 on the cell membranes. Blue fluorescence of DAPI-positive MSCs cells of myocardial in the I/R+MSC group was enhanced significantly, which was significantly inhibited by anti-TGF-ß1 and anti-CXCR4 antibody, and the inhibitory effect of anti-CXCR4 antibody was more evident than that of anti-TGF-ß1 antibody. CONCLUSIONS: TGF-ß1 promotes homing of bone marrow (BM) MSCs in I/R injury's myocardial. The study provided useful data on the role of TGF-ß1 in regulating SDF-1/CXCR4 axis-induced MSCs homing.

Clinical effects and safety review of self-expanding stent surgery for extracranial carotid artery stenosis treatment.

This study aimed to investigate the clinical effects and safety review of self-expanding stent surgery in the treatment of extracranial carotid artery stenosis. Seventy-eight patients with carotid artery stenosis were applied with the self-expanding stent for endovascular interventional therapy. Eighty-one stents were implanted into 80 blood vessels of the 78 patients, in which protective umbrellas were used in 56 cases, and the success rate of stent implantation was 100%. The stenosis degree decreased from the preoperative (86.72 ± 9.5%) to the postoperative (13.43 ± 5.62%) stage, and the blood peak velocity of the stenosed vessels decreased from 189.58 ± 13.5 to 83.73 ± 5.61 cm/s. Transient blood pressure and heart rate decreases occurred in 21 cases, continuously low blood pressure and heart rate decreasing occurred in 29 cases, and acute occlusion of the ipsilateral middle cerebral artery occurred in 1 case, which was resolved through thrombolysis and thrombus breaking in time. Over-perfusion symptoms were observed in 13 cases, although without serious complications such as cerebral hemorrhage. The follow-up period continued for 6-32 months, and ultrasonography revealed that 77 cases had no stent-restenosis, while 1 case had restenosis. The application of self-expanding stents had good clinical effects, with fewer complications and higher safety for the treatment of extracranial carotid artery stenosis.

Selective 14-3-3γ induction quenches p-ß-catenin Ser37/Bax-enhanced cell death in cerebral cortical neurons during ischemia.

Ischemia-induced cell death is a major cause of disability or death after stroke. Identifying the key intrinsic protective mechanisms induced by ischemia is critical for the development of effective stroke treatment. Here, we reported that 14-3-3γ was a selective ischemia-inducible survival factor in cerebral cortical neurons reducing cell death by downregulating Bax depend direct 14-3-3γ/p-ß-catenin Ser37 interactions in the nucleus. 14-3-3γ, but not other 14-3-3 isoforms, was upregulated in primary cerebral cortical neurons upon oxygen-glucose deprivation (OGD) as measured by quantitative PCR, western blot and fluorescent immunostaining. The selective induction of 14-3-3γ in cortical neurons by OGD was verified by the in vivo ischemic stroke model. Knocking down 14-3-3γ alone or inhibiting 14-3-3/client interactions was sufficient to induce cell death in normal cultured neurons and exacerbate OGD-induced neuronal death. Ectopic overexpression of 14-3-3γ significantly reduced OGD-induced cell death in cultured neurons. Co-immunoprecipitation and fluorescence resonance energy transfer demonstrated that endogenous 14-3-3γ bound directly to more p-ß-catenin Ser37 but not p-Bad, p-Ask-1, p-p53 and Bax. During OGD, p-ß-catenin Ser37 but not p-ß-catenin Ser45 was increased prominently, which correlated with Bax elevation in cortical neurons. OGD promoted the entry of 14-3-3γ into the nuclei, in correlation with the increase of nuclear p-ß-catenin Ser37 in neurons. Overexpression of 14-3-3γ significantly reduced Bax expression, whereas knockdown of 14-3-3γ increased Bax in cortical neurons. Abolishing ß-catenin phosphorylation at Ser37 (S37A) significantly reduced Bax and cell death in neurons upon OGD. Finally, 14-3-3γ overexpression completely suppressed ß-catenin-enhanced Bax and cell death in neurons upon OGD. Based on these data, we propose that the 14-3-3γ/p-ß-catenin Ser37/Bax axis determines cell survival or death of neurons during ischemia, providing novel therapeutic targets for ischemic stroke as well as other related neurological diseases.

Occlusal effects on longitudinal bone alterations of the temporomandibular joint.

The pathological changes of subchondral bone during osteoarthritis (OA) development in the temporomandibular joint (TMJ) are poorly understood. In the present study, we investigated the longitudinal alterations of subchondral bone using a rat TMJ-OA model developed in our laboratory. Changes in bone mass were examined by micro-CT, and changes in osteoblast and osteoclast activities were analyzed by real-time PCR, immunohistochemistry, and TRAP staining. Subchondral bone loss was detected from 8 weeks after dental occlusion alteration and reached the maximum at 12 weeks, followed by a repair phase until 32 weeks. Although bone mass increased at late stages, poor mechanical structure and lower bone mineral density (BMD) were found in these rats. The numbers of TRAP-positive cells were increased at 12 weeks, while the numbers of osteocalcin-expressing cells were increased at both 12 and 32 weeks. Levels of mRNA expression of TRAP and cathepsin K were increased at 12 weeks, while levels of ALP and osteocalcin were increased at both 12 and 32 weeks. These findings demonstrated that there is an active bone remodeling in subchondral bone in TMJs in response to alteration in occlusion, although new bone was formed with lower BMD and poor mechanical properties.

Complex genetic networks underlying the defensive system of rice (Oryza sativa L.) to Xanthomonas oryzae pv. oryzae.

Complete resistance (CR) and partial resistance (PR) of rice (Oryza sativa L.) to its bacterial pathogen, Xanthomonas oryzae pv. oryzae (Xoo), was genetically dissected by using 2 mapping populations and 10 Xoo races. Two CR genes, 50 quantitative resistance loci, and 60 digenic interactions were identified, which showed various degrees of race specificity to the Xoo races. The complex epistasis between these loci led us to the discovery of complex genetic networks underlying the rice defensive system to Xoo. The networks consisted of two major components: one representing interactions between alleles at the R loci of rice and alleles at the corresponding avirulence loci of Xoo for CR and the other comprising interactions between quantitative resistance loci in rice and their corresponding aggressiveness loci in Xoo for PR. The race specificity of PR and its strong genetic overlap with CR indicate that PR is essentially "weaker" CR. The genetic networks discovered are expected to maintain a high level of the allelic diversity at avirulent loci in the pathogen by stabilizing selection, which may maintain a high allelic diversity at R loci in the host by the frequency-dependent selection.

QTL x environment interactions in rice. I. heading date and plant height.

One hundred twenty six doubled-haploid (DH) rice lines were evaluated in nine diverse Asian environments to reveal the genetic basis of genotype x environment interactions (GEI) for plant height (PH) and heading date (HD). A subset of lines was also evaluated in four water-limited environments, where the environmental basis of G x E could be more precisely defined. Responses to the environments were resolved into individual QTL x environment interactions using replicated phenotyping and the mixed linear-model approach. A total of 37 main-effect QTLs and 29 epistatic QTLs were identified. On average, these QTLs were detectable in 56% of the environments. When detected in multiple environments, the main effects of most QTLs were consistent in direction but varied considerably in magnitude across environments. Some QTLs had opposite effects in different environments, particularly in water-limited environments, indicating that they responded to the environments differently. Inconsistent QTL detection across environments was due primarily to non- or weak-expression of the QTL, and in part to significant QTL x environment interaction effects in the opposite direction to QTL main effects, and to pronounced epistasis. QTL x environment interactions were trait- and gene-specific. The greater GEI for HD than for PH in rice were reflected by more environment-specific QTLs, greater frequency and magnitude of QTL x environment interaction effects, and more pronounced epistasis for HD than for PH. Our results demonstrated that QTL x environment interaction is an important property of many QTLs, even for highly heritable traits such as height and maturity. Information about QTL x environment interaction is essential if marker-assisted selection is to be applied to the manipulation of quantitative traits.

Molecular diversity and multilocus organization of the parental lines used in the International Rice Molecular Breeding Program.

One hundred and ninety three parental lines obtained from 26 countries for an international rice molecular breeding program were evaluated using 101 well-distributed simple sequence repeat (SSR) markers. An overall genetic diversity of 0.68 and an average of 6.3 alleles per locus were revealed, indicating a high level of genetic variation in these lines. Cluster analysis of the 193 accessions showed three major groups and nine subgroups. Group I corresponded to the classical indica subspecies, whereas groups II and III belong to the japonica subspecies. Indica and japonica differentiation accounted for only 6.5% of the total variation in the entire sample and 93.5% was due to within-subspecies diversity. Differentiation among eco-geographic regions accounted for 24% of the diversity within the subspecies. Larger amounts of the eco-geographical differentiation were resolved within japonica than within indica. The largest indica-japonica differentiation based on the single locus level was detected by markers on chromosomes 9 and 12, while the smallest differentiation was detected by markers on chromosomes 4 and 8. Furthermore, genetic differences at the single-locus and two-locus levels, as well as components due to allelic and gametic differentiation, were revealed between indica and japonica and among the main geographic regions. The multilocus analysis in genetic diversity showed a higher proportion of variation caused by predominant non-random associations of different loci within and among the classified subspecies and geographic subdivisions. The results suggest that selection for eco-geographical adaptation on multilocus associations was largely responsible for the maintenance of the extensive variation in the primary gene pool of rice.

Twenty-year trends of primary liver cancer incidence rates in an urban Chinese population.

The objective of this study was to describe trends in the incidence rates of primary liver cancer in a geographically defined Chinese population. Primary liver cancer cases (N=13 685) were diagnosed between 1981 and 2000 and identified by the Tianjin Cancer Registry. Age-adjusted and age-specific incidence rates were examined in both males and females. Poisson regression was employed to assess the incidence rate trends. Crude and age-adjusted incidence rates in the study period were: 27.4/100 000 and 16.4/100 000 in males and 11.5/100 000 and 6.4/100 000 in females, respectively. While the results from Poisson regression analyses suggest statistically significant trends of declining incidence rates of primary liver cancer overall, trends were not consistent across age and sex groups. The decline in incidence was observed, for the most part, in the 40-69 age group, with a greater decrease in males. Our findings provide a new evidence of a downward trend in incidence rates of this disease in China for a period of 20 years. As the observed decline is relatively small and inconsistent across sex and age groups, a continued epidemiological observation on this condition is required.

Molecular dissection of the genetic relationships of source, sink and transport tissue with yield traits in rice.

Source, sink, and translocation capacity of assimilates play important roles during the formation of grain yield. The present study was conducted to characterize the genetic bases of traits representing source, sink and transport tissue, and their relationships with yield traits in rice, by analyzing QTLs for these traits and various ratios among them. The genetic materials were a recombinant inbred population derived from a cross between two indica cultivars Zhenshan 97 and Minghui 63, the parents of the most-widely grown hybrid rice in China. Using a linkage map that covers a total of 1,796 cM based on 221 molecular marker loci, a total of 81 QTLs were identified for the 15 traits studied (three leaf areas as the source, total spikelets per panicle as the sink, the number of large vascular bundles in the stem as transport tissue, three source to sink ratios, three transport tissue to source ratios, one transport tissue to sink ratio and three yield traits). The amount of variation explained by individual QTLs ranged from 1.12% to 24.14%. Five QTLs were identified to show interaction effects with the environment, which explained from 3.19% to 9.15% of the variation. The results showed that close linkage or pleiotropy is the genetic basis for the correlations of grain yield traits with source, sink, transport tissue and the various ratios among them. Of the 25 QTLs identified for source-sink-transport tissue trait, and 43 for various ratios, 8 and 22 QTLs, respectively, were mapped to the similar genomic blocks harboring QTLs for yield traits, especially for grain weight. Co-location of QTLs for yield traits with those for ratios among source, sink and transport tissue may provide a genetic explanation for the physiological expression of yield traits, and also suggest that improvement in ratios among source, sink and transport tissue may result in improvement in yield potential.

Genetic dissection of an elite rice hybrid revealed that heterozygotes are not always advantageous for performance.

We introduced an experimental design that produced an "immortalized F(2)" population allowing for complete dissection of genetic components underlying quantitative traits. Data for yield and three component traits of the immortalized F(2) were collected from replicated field trials over 2 years. Using 231 marker loci, we resolved the genetic effects into individual components and assessed relative performance of all the genotypes at both single- and two-locus levels. Single-locus analysis detected 40 QTL for the four traits. Dominance effects for about one-half of the QTL were negative, resulting in little "net" positive dominance effect. Correlation between genotype heterozygosity and trait performance was low. Large numbers of digenic interactions, including AA, AD, and DD, were detected for all the traits, with AA as the most prevalent interaction. Complementary two-locus homozygotes frequently performed the best among the nine genotypes of many two-locus combinations. While cumulative small advantages over two-locus combinations may partly explain the genetic basis of heterosis of the hybrid as double heterozygotes frequently demonstrated marginal advantages, double heterozygotes were never the best genotypes in any of the two-locus combinations. It was concluded that heterozygotes were not necessarily advantageous for trait performance even among genotypes derived from such a highly heterotic hybrid.

Identification of quantitative trait loci and epistatic interactions for plant height and heading date in rice.

Appropriate heading date and plant height are prerequisites for attaining the desired yield level in rice breeding programs. In this study, we analyzed the genetic bases of heading date and plant height at both single- locus and two-locus levels, using a population of 240 F(2:3) families derived from a cross between two elite rice lines. Measurements for the traits were obtained over 2 years in replicated field trials. A linkage map was constructed with 151 polymorphic marker loci, based on which interval mapping was performed using Mapmaker/QTL. The analyses detected six QTLs for plant height and six QTLs for heading date; collectively the QTLs for heading date accounted for a much greater amount of phenotypic variation than did the QTLs for plant height. Two-way analyses of variance, with all possible two-locus combinations, detected large numbers (from 101 to 257) of significant digenic interactions in the 2 years for both traits involving markers distributed in the entire genome; 22 and 39 were simultaneously detected in both years for plant height and heading date, respectively. Each of the interactions individually accounted for only a very small portion of the phenotypic variation. The majority of the significant interactions involved marker loci that did not detect significant effects by single-locus analyses, and many of the QTLs detected by single-locus analyses were involved in epistatic interactions. The results clearly demonstrated the importance of epistatic interactions in the genetic bases of heading date and plant height.

Dimeric W3SO3 cluster complexes: synthesis, characterization, and potential applications as X-ray contrast agents.

Our continued research on the use of heavy metal cluster complexes as a new class of X-ray contrast agents in medical diagnostic imaging is described. A series of 2:3 cluster-ligand complexes, [(W(IV)3SO3)2L3]4- (L = linear polyaminopolycarboxylate ligands), were isolated from the reaction of aqua ion [W(IV)3SO3(H2O)9]4- (prepared in large quantities through an improved literature process) with respective ligands in refluxing DMF. The salts of [(W(IV)3SO3)2L3]4- complex anions were fully characterized using routine techniques such as elemental analysis, MS, HPLC, UV-vis, IR, and NMR. The solid structures of two complex anions, [(W(IV)3SO3)2(PDTA)3]4- and [(W(IV)3SO3)2(HO-PDTA)3]4-, were determined by X-ray crystallography. They are the first examples wherein two W(IV)3SO3 clusters are complexed and linked by three ligands that contain two terminal iminodiacetate (bis-IDA) groups. Complexation of the unstable aqua ion [W(IV)3SO3(H2O)9]4- with ligands has imparted desired biological compatibility to the tungsten metal cluster. These complexes are stable and highly soluble in H2O. The potential utility of such tungsten cluster complexes as X-ray contrast agents was evaluated in both in vitro and in vivo animal studies. In addition, the syntheses of several new linear polyaminopolycarboxylate ligands used in this study are reported.

The three important traits for cooking and eating quality of rice grains are controlled by a single locus in an elite rice hybrid, Shanyou 63.

The cooking and eating quality of the rice grain is one of the most serious problems in many rice-producing areas of the world. In this study, we conducted a molecular marker-based genetic analysis of three traits, amylose content (AC), gel consistency (GC) and gelatinization temperature (GT), that are the most important constituents of the cooking and eating quality of rice grains. The materials used in the analysis included F(2) seeds, an F(2:3) population, and an F(9) recombinant inbred-line population from a cross between the parents of 'Shanyou 63', the most widely grown hybrid in rice production in China. Segregation analyses of these three generations showed that each of the three traits was controlled by a single Mendelian locus. Molecular marker-based QTL (quantitative trait locus) analyses, both by one-way analysis of variance using single marker genotypes and by whole-genome scanning with MAPMAKER/QTL, revealed a single locus that controls the expression of all three traits. This locus coincided with the Wx region on the short arm of chromosome 6, indicating that all three traits were either controlled by the Wx locus or by a genomic region tightly linked to this locus. This finding has provided clues to resolving the molecular bases of GC and GT in future studies. The results also have direct implications for the quality improvement of rice varieties.

Differentiation and classification of parental lines and favorable genic interactions affecting F1 fertility in distant crosses of rice (Oryza sativa L.).

This study was intended to investigate the extent of genetic differentiation in parental lines of rice hybrids and to analyze the genetic basis underlying the fertility phenomenon in distant crosses. Two subsets of rice material (111 entries in total) were used, including 81 doubled-haploid (DH) lines and 30 Indica and Japonica rice varieties or lines (as a control). The DH lines was derived from a heterotic Indica/Japonica cross (Gui630/02428) by anther culture. The materials in the control represent a broad spectrum of the Asian cultivated rice gene pool including landraces, primitive cultivars, historically important cultivars, modern elite cultivars, super rice and parents of superior hybrids. In accordance with the NC II design, 57 out of the DH lines were test-crossed to two important wide compatibility lines: photoperiod-sensitive genetic male sterile (PGMS) line N422s and thermo-sensitive genetic male sterile (TGMS) line Peiai64s. The F1s and their parents, 182 entries in total, were examined for the performance of seven traits in a replicated field trial. All the rice materials was surveyed for polymorphisms using 92 RFLP markers selected from two published molecular marker linkage maps. Genotypes of the F1 hybrids at the molecular-marker loci were deduced from the parental genotypes. The analysis showed that there were two types of genetic differentiation in the two subsets of rice material; that is, qualitative differentiation in the control and quantitative differentiation in the DH lines. In addition, favorable genic interactions (both intra- or inter-locus) contributed to better increase the fertility in hybrids of distant crosses through incorporation of a wide-compatibility line as the female parent. Favorable genic interactions can be applied in hybrid rice breeding programs by selecting parents with an appropriate extent of genetic differentiation.