Isolation of cytoplasts from Satsuma mandarin (Citrus unshiu Marc.) and production of alloplasmic hybrid calluses via cytoplast-protoplast fusion

Cytoplasm of Satsuma mandarin (Citrus unshiu Marc.) is known to influence seedlessness. Transfer of cytoplasm to a seedy cultivar could possibly lead to the production of seedless citrus fruits. In the present paper cytoplasts were isolated from cell suspension-derived protoplasts of Satsuma mandarin via ultra-centrifugation in a discontinuous gradient. No nucleus could be detected in the cytoplasts by DAPI (4', 6-diamidino-2-phenylindole) staining compared with normal protoplasts. The cytoplasts, with high viability and small size, did not divide during solid embedding culture. Cytoplasts of Satsuma mandarin were electrically fused with embryogenic protoplasts of Murcott tangor (C. reticulata x C. sinensis), which led to regeneration of several cell lines. Flow cytometry (FCM) indicated that the cell lines were diploids. Simple sequence repeats (SSR) and cleaved amplified polymorphism sequence (CAPS) showed that the cell lines got their nuclear DNA from the protoplast parent, whereas the cytoplast parent donated the mtDNA, confirming transfer of mtDNA from Satsuma mandarin into Murcott tangor via cytoplast-protoplast fusion though no polymorphism was detected in chloroplast DNA between the fusion partners. This is the first report on isolation and characterization of cytoplasts, together with cytoplast-protoplast fusion in Citrus, which has a potential for citrus cultivar improvement involving cytoplasm transfer via cytoplast-protoplast fusion.

Transcriptional profile of shrimp white spot syndrome virus (WSSV) genes with DNA microarray

In an attempt to obtain the transcriptional profile of shrimp white spot syndrome virus (WSSV) genes, DNA microarray analysis was performed using amplified DNA fragments of the WSSV genome that covered most of the presumptive open reading frames (ORFs). Total RNAs were extracted from WSSV-infected crayfish (Cambarus clarkii) and reverse transcribed into cDNA and labeled with 32P-dATP. The DNA microarray detected 81.1% of the ORFs, and 47 of these were transcribed at 6 h post infection, suggesting they may be early genes. Some early genes were further confirmed by temporal analyses of gene transcription. Results in this study indicated the effectiveness of DNA microarray for discovering early viral genes.

The differential effects of low dose and high dose concanavalin A on cytokine profile and their importance in liver injury

OBJECTIVE

Intravenous injection of concanavalin A (Con A) can cause mice to suffer from acute liver failure in a dose dependent manner and little is known about the difference between the high dose and the low dose of Con A regarding the immune response they initiate. The aim of this study was to analyze whether differential effects exist between the low dose and high dose of concanavalin A on the intrahepatic immune system and their importance in the development of liver injury.

MATERIALS AND METHODS

A high dose of Con A (15 microg/g) was injected intravenously to induce murine hepatitis. A low dose of Con A (3 microg/g) was injected intravenously 12 h before the injection of the high dose of Con A (15 microg/g). Liver injury was evaluated by serum transaminase assay and H&E staining. Serum cytokine concentrations were determined by enzyme-linked immunosorbent assay (ELISA), intrahepatic cytokine and Fas mRNA levels by reverse transcriptase polymerase chain reaction. Intracellular cytokine expression and FasL expression were analyzed by flow cytometry and Fas protein expression in hepatocytes by Western-blotting. Intrahepatic apoptosis was evaluated by terminal-deoxynucleotidyl transferase mediated nick end labeling (TUNEL).

RESULTS

Low dose Con A injection induced a distinct cytokine expression profile, characterized by a preferentially elevated serum IL-6 at the early stage of stimulation, whereas high dose Con A injection provoked significant elevation of various cytokines involved in Con A-induced hepatitis. Pretreatment with a low, nonhepatoxic dose of Con A (3 microg/g) significantly decreased production of proinflammatory cytokines induced by the high dose Con A (15 microg/g). Furthermore, low dose Con A pretreatment could significantly decrease the serum levels of transaminases and liver necrosis induced by high dose of Con A. The intrahepatic Fas expression was also apparently reduced, accompanied by a decrease in hepatocyte apoptosis.

CONCLUSION

Low dose Con A stimulation induced a different cytokine profile from high dose Con A stimulation resulting in differential importance in the development of liver injury.

The relationship between patient knowledge of hemoglobin levels and health-related quality of life

BACKGROUND

An anti-anemia drug may improve self-reported quality of life (QOL) partly because patients know their hemoglobin level is rising. In the absence of any published studies on this topic, the authors investigated the association between knowledge of hemoglobin levels and self-reported QOL.

METHODS

The study analyzed health-related QOL (HRQOL) data from five randomized clinical trials of erythropoietic therapy in patients with cancer-related anemia. Patients were asked whether they knew their hemoglobin level and, if so, to report its value. Patients (n=1007) were grouped into three categories depending on the extent and accuracy of hemoglobin level knowledge. HRQOL scale scores were compared between categories.

RESULTS

Only 23.2% of patients reported knowing their hemoglobin level at the end of the study; however, the value was accurate (within 1 g/dl) in 88.0% of these patients. On five of the 11 HRQOL scales studied, there was a significant association between knowledge of hemoglobin level and HRQOL score. However, the magnitude of the mean difference between those who knew vs. those who did not know their hemoglobin was generally below scale thresholds for minimally important differences.

CONCLUSIONS

Patient knowledge of hemoglobin level has a modest association with some aspects of self-reported HRQOL. The magnitude of this association, where it exists, would be unlikely to explain large group differences in HRQOL reports over time, even for patients who know their hemoglobin level.

Investigation of MR image distortion for radiotherapy treatment planning of prostate cancer

MR imaging based treatment planning for radiotherapy of prostate cancer is limited due to MR imaging system related geometrical distortions, especially for patients with large body sizes. On our 0.23 T open scanner equipped with the gradient distortion correction (GDC) software, the residual image distortions after the GDC were <5 mm within the central 36 cm x 36 cm area for a standard 48 cm field of view (FOV). In order to use MR imaging alone for treatment planning the effect of residual MR distortions on external patient contour determination, especially for the peripheral regions outside the 36 cm x 36 cm area, must be investigated and corrected. In this work, we performed phantom measurements to quantify MR system related residual geometric distortions after the GDC and the effective FOV. Our results show that for patients with larger lateral dimensions (>36 cm), the differences in patient external contours between distortion-free CT images and GDC-corrected MR images were 1-2 cm because of the combination of greater gradient distortion and loss of field homogeneity away from the isocentre and the uncertainties in patient setup during CT and MRI scans. The measured distortion maps were used to perform point-by-point corrections for patients with large dimensions inside the effective FOV. Using the point-by-point method, the geometrical distortion after the GDC were reduced to <3 mm for external contour determination and the effective FOV was expanded from 36 cm to 42 cm.

Hair follicle defects and squamous cell carcinoma formation in Smad4 conditional knockout mouse skin

Smad4 is the common mediator for TGFbeta signals, which play important functions in many biological processes. To study the role of Smad4 in skin development and epidermal tumorigenesis, we disrupted this gene in skin using the Cre-loxP approach. We showed that absence of Smad4 blocked hair follicle differentiation and cycling, leading to a progressive hair loss of mutant (MT) mice. MT hair follicles exhibited diminished expression of Lef1, and increased proliferative cells in the outer root sheath. Additionally, the skin of MT mice exhibited increased proliferation of basal keratinocytes and epidermal hyperplasia. Furthermore, we provide evidence that the absence of Smad4 resulted in a block of both TGFbeta and bone morphogenetic protein (BMP) signaling pathways, including p21, a well-known cyclin-dependent kinase inhibitor. Consequently, all MT mice developed spontaneous malignant skin tumors from 3 months to 13 months of age. The majority of tumors are malignant squamous cell carcinomas. A most notable finding is that tumorigenesis is accompanied by inactivation of phosphatase and tensin homolog deleted on chromosome 10 (Pten), activation of AKT, fast proliferation and nuclear accumulation of cyclin D1. These observations revealed the essential functions of Smad4-mediated signals in repressing skin tumor formation through the TGFbeta/BMP pathway, which interacts with the Pten signaling pathway.

Retinoic acid and oncostatin M combine to promote cartilage degradation via matrix metalloproteinase-13 expression in bovine but not human chondrocytes

OBJECTIVES

Retinoic acid (RetA) and oncostatin M (OSM) have both been shown to mediate potent effects with respect to extracellular matrix integrity. This study assesses the effects of a RetA + OSM combination on cartilage catabolism.

METHODS

Animal and human cartilage samples were used to assess the ability of RetA + OSM to promote the release of collagen and proteoglycan fragments, which was determined by measuring glycosaminoglycan and hydroxyproline, respectively. Total collagenolytic and tissue inhibitor of metalloproteinases (TIMP) inhibitory activities were determined by bioassay, whilst gene expression of matrix metalloproteinases (MMPs) and TIMP-1 were determined by northern blotting. Immunohistochemistry was used to assess the presence of MMP-1 and -13 in resorbing cartilage explants.

RESULTS

Both agents alone induced proteoglycan release from bovine cartilage, whilst RetA-induced collagen release was variable. Reproducible and synergistic collagenolysis was observed with RetA + OSM, which appeared to be due to MMP-13. Similar collagen release was observed from porcine cartilage. Conversely, no collagen release was seen with human articular cartilage. In primary human chondrocytes, RetA + OSM failed to induce MMP-1 or -13 but caused a significant increase in TIMP-1 expression.

CONCLUSIONS

These novel observations show that the combination of RetA + OSM has profound effects on cartilage matrix turnover, but these effects are species-specific. A better understanding of the mechanism by which this combination differentially regulates MMP and TIMP expression in human chondrocytes could provide valuable insight into new therapeutic strategies aimed at the prevention of cartilage destruction.

Serum DDT, age at menarche, and abnormal menstrual cycle length

BACKGROUND

Although dichlorodiphenyl trichloroethane (DDT) exposure is known to affect human endocrine function, few previous studies have investigated the effects of DDT exposure on age at menarche or menstrual cycle length.

METHODS

A cross sectional study was conducted to study the effects of DDT exposure on age at menarche and menstrual cycle length among 466 newly married, nulliparous female Chinese textile workers aged 20-34 years enrolled between 1996 and 1998. Serum was analysed for DDT and its major metabolites. Multivariate linear regression was used to estimate DDT exposure effects on age at menarche and multivariate logistic regression was used to estimate DDT exposure effects on odds of experiencing short or long cycles.

RESULTS

Relative to those in the lowest DDT quartile, the adjusted mean age at menarche was younger in those in the fourth quartile (-1.11 years). Modeled as a continuous variable, a 10 ng/g increase in serum DDT concentration was associated with an adjusted reduction in age at menarche of 0.20 years. Relative to those in the lowest DDT quartile, odds of any short cycle (<21 days) in the previous year were higher for those in the fourth quartile (odds ratio = 2.78; 95% CI 1.07 to 7.14). There were no associations between serum DDT concentrations and odds of experiencing a long cycle (>40 days).

CONCLUSION

Results suggest that DDT exposure was associated with earlier age at menarche and increased risk of experiencing a shortened menstrual cycle.

Protein S multimers and monomers each have direct anticoagulant activity

BACKGROUND AND OBJECTIVES

Plasma protein S (PS) is an essential anticoagulant that has activated protein C-independent, direct anticoagulant activity (PS-direct). It was reported that monomeric purified PS has poor PS-direct and that a subpopulation of multimeric purified PS has high PS-direct and high affinity for phospholipids. We independently examined the relative PS-direct and affinity for phospholipids of monomeric and multimeric PS and we obtained contrasting results.

METHODS AND RESULTS

Unpurified recombinant protein S (rPS) was monomeric and had PS-direct potency similar to that of both PS in plasma and multimeric affinity-purified PS, as measured in plasma assays for PS-direct and in thrombin-generation assays. Multimers of unpurified rPS were not induced by ethylenediaminetetraacetic acid (EDTA), pH 2.5, NaSCN, or barium adsorption/elution. Multimers were induced by chromatography in the presence of EDTA and thus may be concentration-dependent. In contrast to a different report, monomers, dimers, trimers, and higher-order PS forms were clearly separated in sedimentation velocity experiments and multimers were not dissociated by adding Ca(2+). Active plasma-derived and recombinant immunoaffinity-purified PS were fractionated into monomers and multimers. On a mass basis, monomers and multimers had similar specific PS-direct and ability to compete with prothrombinase components (factors Xa/Va) for limiting phospholipids. FXa ligand blotted to both monomers and multimers.

CONCLUSIONS

Plasma PS-direct is similar to that of affinity-purified PS and unpurified rPS. Under our conditions, monomeric and multimeric PS have similar PS-direct and ability to compete for phospholipids. Discordant earlier findings are likely due to loss of PS-direct during conventional purification procedures.

Effect of composition and packing configuration on the dichroic optical properties of coinage metal nanorods

When nanorods of Au, Ag and some other elements are aligned with a preferred orientation with respect to light, their optical extinction characteristics become dependent on the polarization and angle of incidence of the light. This effect is explored here and it is shown that it could potentially be exploited to produce a 'colour-change coating'. However, particle-particle interactions are also likely to occur in such coatings, with red shifting of extinction spectra occurring for end-on-end configurations of monodisperse rods, and blue shifting for side-by-side configurations. Surprisingly, the particle-particle interactions are attenuated if they are between rods of differing aspect ratios, and this offers a useful new means of control of the optical properties of coatings of nanorods.

Nanofluidic channels fabrication and manipulation of DNA molecules

Nanofluidic channel arrays, which have a width of about 40 nm, depth of 60 nm and length of 50 mum, were created using a focused-ion-beam milling instrument on a silicon nitride film swiftly and exactly, as is necessary. Stained -DNA molecules were put inside these sub-100 nm conduits by capillary force and they were stretched and transferred along these conduits, which were dealt with activating reagent Brij aqueous solution in advance. The movements of DNA molecules in these channels were discussed. These nano-structure channels may be useful in the study and analysis of the statics as well as the dynamics of single biomolecules.

BRCA1 germline mutations in Chinese patients with hereditary breast and ovarian cancer

The role of germline BRCA1 mutations in hereditary breast and ovarian cancer (HBOC) has been well established in women in Western countries. However, relatively few studies have been carried out in Chinese population. In the present study, we investigated the frequency and spectrum of germline BRCA1 mutations in Chinese HBOC patients, all of whom were from northern part of China. A total of 25 women with HBOC and ten relatives were analyzed. Mutation screening was performed by a combination of denaturing high-performance liquid chromatography and sequencing. Seven protein-truncating mutations were identified. They were 667delG, 3347A → T, 3478del5, 4255delCT, 1235A → G, 2064G → T, and 5589del8. The first four of the mutations were putative ones never reported before. The prevalence of the protein-truncating mutations in this HBOC series was 40.0%, which is similar to that observed in Western hereditary ovarian cancer patients but higher than that reported in Chinese women with sporadic breast and ovarian cancer. Among the ten relatives we analyzed, six shared the same mutations with their affected relatives. No ovarian cancer was detected after 19 months of follow-up. This study showed that BRCA1 mutations play an important role in Northern Chinese HBOC.