Apparent diffusion coefficient and its standard deviation from diffusion-weighted imaging in preoperative predicting liver invasion by T3-staged resectable gallbladder carcinoma.

AIM: To evaluate apparent diffusion coefficient (ADC) and its standard deviation (SDADC) in preoperative predicting liver invasion by T3-staged gallbladder carcinoma (GBC). MATERIALS AND METHODS: Forty-one consecutive patients with T3-staged resectable GBC were included and divided into two sets with (n=27) and without (n=14) liver invasion. All patients underwent DWI at b-values of 0, 20, 50, 80, 100, 200, 400, 600, 800, and 1,000 s/mm2 with a 3 T magnetic resonance imaging scanner before surgery. ADC and SDADC of tumour-adjacent and tumour-distant liver tissues were measured on DWI, and were compared by Mann-Whitney U-tests. If there was a significant difference in any derived parameter, the area under the receiver operating characteristic curve (AUC) was used to assess performance of this parameter to predict liver invasion. RESULTS: DWI could differentiate between patients with and without liver invasion when b = 0, 1,000 s/mm2 (AUCs of ADC and SDADC were 0.697 and 0.714, respectively). In patients with liver invasion, mean ADC and SDADC of tumour-adjacent liver tissue were lower than of tumour-distant liver tissue when b = 0, 800 s/mm2, and = 0, 1,000 s/mm2 (all p-values <0.05). To differentiate tumour-adjacent from tumour-distant liver tissues in patients with liver invasion, AUCs of ADC were 0.687 (b = 0, 800 s/mm2) and 0.680 (b = 0, 1,000 s/mm2), and AUCs of SDADC were 0.673 (b = 0, 800 s/mm2) and 0.731 (b = 0, 1,000 s/mm2). CONCLUSIONS: DWI could have potential value in preoperative predicting liver invasion by T3-staged GBC.

Risk factors for late-onset hypogonadism.

The European Male Aging Study (EMAS) has recently defined strict diagnostic criteria for late-onset hypogonadism (LOH) including the levels of serum total testosterone (TT), free testosterone (FT) and three sexual symptoms. However, there is no report on risk factors for LOH using these criteria. In this study, we investigated risk factors for LOH based on these criteria. We recruited 277 men (aged 36-80 years) who completed both a health check-up and two questionnaires (a health and lifestyle questionnaire, and a sexual function questionnaire). Data on parameters, such as systolic blood pressure (SBP), glucose, triglyceride (TG) and high-density lipoprotein (HDL), were obtained from medical records of the hospital in Shantou. TT and sex hormone-binding globulin (SHBG) were measured by chemiluminescent immunoassay, and FT was calculated. TT, FT, age, waist circumference, SBP and glucose showed significant differences between LOH-positive and LOH-negative individuals. Univariate regression analyses showed that age, waist circumference, SBP, glucose and health status were risk factors for LOH. Pearson's correlation analysis revealed that TT was inversely correlated with waist circumference, glucose and SBP, and FT was inversely correlated with age, SBP and health status. In conclusion, age, waist circumference, SBP, glucose and health status were risk factors for LOH.

Impact of endocrine-disrupting chemicals on reproductive function in zebrafish (Danio rerio).

The prevalence of endocrine-disrupting chemicals (EDCs) in the aquatic environment has been associated with the wide detection of alterations in the development and physiology of vertebrates. Zebrafish, as a model species, has been extensively used in toxicological research. In this review, we focus on recent published evidence of the harmful effects of EDCs on reproductive function in zebrafish, including skewed sex ratio, immature gonads, diminished sexual behaviour, decreased sperm count, reduced spawning and fertilization. These impairments mostly result from disruption to sex-steroid hormones induced by endocrine disruptors. We also discuss other effects of exposure to EDCs. In EDC exposure research, despite incomplete assessments of altered gonad histopathology and sexual behaviour, these present potential effective biomarkers or pathways for evaluating the reproductive function in zebrafish on EDC exposure. To date, the pernicious effects of some EDCs on the reproductive performance in laboratory zebrafish are well understood; however, similar alterations remain for further determination in wild-type fish and more kinds of EDCs. More studies should be performed under established scientific regulatory criteria to investigate the impact of EDCs on reproduction in zebrafish. Moreover, further research is required to explain the definite mechanism of sexual differentiation, which helps in understanding the shift of sexual phenotype with EDC exposure.

Respiratory syncytial virus pneumonia treated with lower-dose palivizumab in a heart transplant recipient.

Respiratory syncytial virus (RSV) is an important community-acquired pathogen that can cause significant morbidity and mortality in patients who have compromised pulmonary function, are elderly, or are immunosuppressed. This paper describes a 70-year-old man with a remote history of heart transplantation who presented with signs and symptoms of pneumonia. Chest computed tomography (CT) imaging demonstrated new patchy ground glass infiltrates throughout the upper and lower lobes of the left lung, and the RSV direct fluorescence antibody (DFA) was positive. The patient received aerosolized ribavirin, one dose of intravenous immunoglobulin, and one dose of palivizumab. After two months of followup, the patient had improved infiltrates on chest CT, improved pulmonary function testing, and no evidence of graft rejection or dysfunction. There are few data on RSV infections in heart transplant patients, but this case highlights the importance of considering this potentially serious infection and introduces a novel method of treatment.

Soluble CD30 as a prognostic factor for outcome following renal transplantation.

AIMS: To determine whether measurement of soluble CD30 (sCD30) levels predicts for early rejection in a cohort of first deceased kidney transplant recipients. METHODS: Pre-transplant serum samples were analysed for sCD30 levels using a commercial ELISA kit (Biotest). A 100 U/ml cut-off for "high sCD30" was applied. Clinical outcome parameters were biopsy-proven rejection episodes, creatinine levels and glomerular filtration rate. RESULTS: In the cohort of patients who experienced at least one episode of rejection in the first 6 months post-transplant, levels of pre-transplant sCD30 were significantly higher than in those who did not experience rejection. Despite this association, the occurrence of a high sCD30 level did not predict for rejection on an individual basis. CONCLUSIONS: The prognostic value of pre-transplant sCD30 testing is diminished by the large number of patients with high sCD30 levels who do not develop rejection. Although this limits the utility of the test in informing clinical management of individual patients, a high pre-transplant sCD30 level should still be considered a risk factor for poorer outcome.

Giant nonlinear optical properties of bismuth thin films grown by pulsed laser deposition.

Thin films of Bi were grown by pulsed laser deposition on glass substrates at room temperature. The thickness and roughness of the films were characterized by grazing-incidence x-ray reflectivity, and the complex refractive indices were measured in the range from 1.5 to 4 eV by spectroscopic ellipsometry. We performed Z-scan measurements to study the third-order optical nonlinearity of the films. It was found that the Bi films exhibited an unusually large nonlinear refractive coefficient, n(I)~1.24x10(-1) cm(2)/kW and nonlinear absorption coefficient, alpha(I)~-3.97 cm/W , at low laser intensity, ~60 kW/cm(2) . This anomaly is believed to have an origin related to melting of the Bi films at the focus spot by the laser beam.

tA single amino acid difference distinguishes resistant and susceptible alleles of the rice blast resistance gene Pi-ta.

The rice blast resistance (R) gene Pi-ta mediates gene-for-gene resistance against strains of the fungus Magnaporthe grisea that express avirulent alleles of AVR-Pita. Using a map-based cloning strategy, we cloned Pi-ta, which is linked to the centromere of chromosome 12. Pi-ta encodes a predicted 928-amino acid cytoplasmic receptor with a centrally localized nucleotide binding site. A single-copy gene, Pi-ta shows low constitutive expression in both resistant and susceptible rice. Susceptible rice varieties contain pi-ta(-) alleles encoding predicted proteins that share a single amino acid difference relative to the Pi-ta resistance protein: serine instead of alanine at position 918. Transient expression in rice cells of a Pi-ta(+) R gene together with AVR-Pita(+) induces a resistance response. No resistance response is induced in transient assays that use a naturally occurring pi-ta(-) allele differing only by the serine at position 918. Rice varieties reported to have the linked Pi-ta(2) gene contain Pi-ta plus at least one other R gene, potentially explaining the broadened resistance spectrum of Pi-ta(2) relative to Pi-ta. Molecular cloning of the AVR-Pita and Pi-ta genes will aid in deployment of R genes for effective genetic control of rice blast disease.

Abundance, polymorphism and genetic mapping of microsatellites in rice.

Dinucleotide microsatellites have been characterized and used as genetic markers in rice. Screening of a rice genomic library with poly(dG-dA).(dC-dT) and poly(dG-dT).(dC-dA) probes indicated that (GA)n repeats occurred, on average, once every 225 kb and (GT)n repeats once every 480 kb. DNA sequencing of ten randomly selected microsatellites indicated that the numbers of repeats ranged from 12 to 34 and that the patterns of microsatellites in rice were similar to those of humans and other mammals. Primers to these microsatellite loci as well as to four published microsatellite-containing sequences have been designed and degrees of polymorphism has been examined with 20 rice accessions. Multiple alleles, ranging from 5 to 11, have been observed at all the microsatellite loci in 20 rice accessions. Alleles specific to two cultivated subspecies, indica and japonica, were found in some microsatellite loci. Heterozygosity values of all the microsatellite markers were significantly higher than those of RFLP markers, based upon a parallel comparison. Ten microsatellite loci have been genetically mapped to four rice chromosomes. The genomic distribution of microsatellites appears to be random in rice.

PFGE analysis of the rice genome: estimation of fragment sizes, organization of repetitive sequences and relationships between genetic and physical distances.

Pulsed-field gel electrophoresis (PFGE) has been applied to analyze the rice nuclear genome. Probing 56 RFLP probes selected from the 12 rice chromosomes to PFGE blots of nine rare-cutting restriction enzymes revealed that there are relatively high numbers of 'rare-cutting' restriction sites in the rice genome. The average sizes of restriction fragments detected by single-copy probes are smaller than 200 kb for all of the rare-cutting restriction enzymes examined. Sizes of fragments detected by repetitive probes are variable, depending on the probes analyzed. By using PFGE, a tandemly repeated sequence, Os48, was found to be tightly linked to telomeric tandem repeats but not physically linked to r5s genes with which sequence homology had been observed. Relationships between genetic and physical distances have been established for three different chromosomal segments. In these regions 1 cm corresponds to ca. 260 kb on average. Analysis of a cluster of RFLP markers on chromosome 3 revealed that genetically clustered RFLP markers are also physically closely linked, suggesting that clustering of genetic markers may result in part from uneven distribution of single-copy sequences.

Genetic and physical mapping of telomeres and macrosatellites of rice.

Telomeres and telomere-associated satellites of rice were genetically and physically analyzed by pulsed-field gel electrophoresis (PFGE) using Arabidopsis telomeric DNA and rice satellite sequences as probes. We demonstrate that Arabidopsis telomeric sequences hybridize to rice telomeres under the conditions of high stringency. Using the Arabidopsis probe, multiple, discrete telomeric fragments could be identified on pulsed-field gel blots of rice DNAs digested with rare-cutting restriction enzymes. Most of the telomeric bands larger than 300 kb are physically linked with satellite bands as revealed by PFGE. Some of the telomeric and satellite bands segregate in a Mendelian fashion and are highly reproducible. Three such telomeric bands have been mapped to the distal ends of RFLP linkage groups: Telsm-1 on chromosome 8, Telsa-1 on chromosome 9 and Telsm-3 on chromosome 11. One segregating satellite band was mapped to an internal region of chromosome 10. Telomeric fragments were shown not only to be genetically linked to but also physically linked (based on PFGE) to the terminal RFLP markers. The physical distance from telomeric sequences to a distal RFLP marker, r45s gene, on chromosome 9, is 200 kb while the distance from telomeric sequences to RG98, a terminal RFLP marker on chromosome 11, is 260 kb. Physical maps of the telomere regions of chromosome 9 and chromosome 11 are presented.

Genetic and physical analysis of the rice bacterial blight disease resistance locus, Xa21.

Nearly isogenic lines (NILs) of rice (Oryza sativa) differing at a locus conferring resistance to the pathogen Xanthomonas oryzae pv. oryzae were surveyed with 123 DNA markers and 985 random primers using restriction fragment length plymorphism (RFLP) and random amplified polymorphic DNA (RAPD) analysis. One chromosome 11 marker (RG103) detected polymorphism between the NILs that cosegregated with Xa21. All other chromosome 11 DNA markers tested were monomorphic between the NILs, localizing the Xa21 introgressed region to an 8.3 cM interval on chromosome 11. Furthermore, we identified two polymerase chain reaction (PCR) products (RAPD2148 and RAPD818) that detected polymorphisms between the NILs. Genomic sequences hybridizing with RAPD818, RAPD248 and RG103 were duplicated specifically in the Xa21 NIL. All three markers cosegregated with the resistance locus, Xa21, in a F2 population of 386 progeny. Based on the frequency with which we recovered polymorphic Xa21-linked markers, we estimated the physical size of the introgressed region to be approximately 800 kb. This estimation was supported by physical mapping (using pulsed field gel electrophoresis) of the sequences hybridizing with the three Xa21-linked DNA markers. The results showed that the three Xa21-linked markers are physically close to each other, with one copy of the RAPD818 sequences located within 60 kb of RAPD248 and the other copy within 270 kb of RG103. None of the enzymes tested generated a DNA fragment that hybridized with all three of the markers indicating that the introgressed region containing the resistance locus Xa21 is probably larger than 270 kb.

Isolation of plant DNA for pulsed-field gel electrophoresis.

A prerequisite for physical mapping by pulsed-field gel electrophoresis (PFGE) is the saturation of a given genome or chromosomal region with single copy markers. One possible way to achieve this goal is by construction of a saturated restriction fragment length polymorphism (RFLP) map. Although RFLP maps are now available for many plant species, only a few systems provide the high density of markers (at least one marker every 1000 kb) required for long-range physical mapping using PFGE. At present, only four plant systems, Arubidofm (1,2), tomato (3), potato (4,5), and rice (6), have a sufftcient density of markers. These species are characterized by relatively small genomes when compared to other plants, with an average distance between individual RFLP markers of 400-800 kb. PFGE in combination with the digestion of DNA, using rare-cutting restriction enzymes, is able to bridge these gaps, and will allow the construction of long-range physical maps for regions of these plant genomes (7). PFGE has already been used in a number of species to construct long-range restriction maps of a number of gene families and repeated DNA sequences (8-12).

Chromosomal locations of ten isozyme loci in rice (Oryza sativa L.) through trisomic analysis.

Chromosomal locations of 10 isozyme loci in rice (Oryza sativa L.) were determined through trisomic analysis. All 10 genes produced altered allozyme banding patterns in specific F1 trisomics. This served as the primary source of evidence for chromosome locations of Est-5, Icd-1, Acp-1, and Pgd-1. The locations of Amp-1, Amp-2, Amp-4, Pox-5, Got-1, and Cat-1 were further confirmed from segregation data in BC1 generations, as the ratios deviated significantly from 1:1 in the critical trisomics but agreed with the expected trisomic ratios. Triallelic heterozygotes were recovered for Amp-1 and Amp-2. On the basis of these data Got-1, Est-5, and Icd-1 were located to chromosome 1, Amp-1 to chromosome 2, Cat-1 and Pox-5 to chromosome 3, Acp-1 to chromosome 6, Amp-2 and Amp-4 to chromosome 8, and Pgd-1 to chromosome 11. Because Acp-2 and Pox-2 are known to be linked with Acp-1, they must also be on chromosome 6. The gene order and recombination values between isozyme loci on chromosomes 3, 6, 8, and 11 are presented.