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PubMed2002

Inter-ictal- and ictal-like epileptic discharges in the dendritic tree of neocortical pyramidal neurons.

Dendritic mechanisms have been implied to play a key role in the formation of epileptic discharges. However, presently only a handful of direct dendritic recordings have been reported during epileptic discharges. In this study, I performed simultaneous voltage recordings from the soma and apical dendrite of the same neuron combined with calcium-imaging measurements to investigate inter-ictal- and ictal-like epileptic discharges in dendrites of layer 5 pyramidal neurons. Neocortical brain slices treated with bicuculline (BCC) produced both isolated "inter-ictal" paroxysymal depolarization shift (PDS) responses and electrographic seizures. Concomitant voltage recordings from the soma and apical dendrite revealed that PDS responses developed in both the apical dendrites and soma. However, the two responses differed from one another. In apical dendrites, the PDS was significantly higher in amplitude and shorter in duration compared with the somatic PDS. The PDS response in dendrites had a peak amplitude of 68.9 +/- 2.2 (SD) mV, peak voltage value of 9.3 +/- 2.7 mV, and half-width of 203.8 +/- 38.4 ms. In contrast, the somatic PDS had a peak amplitude of 48.7 +/- 2.7 mV, peak voltage value of -11.9 +/- 3.1 mV, and half-width of 247.8 +/- 57.3 ms (P < 0.01, n = 18). In addition the apical dendritic PDS always preceded the somatic counterpart in all 18 neurons examined. Concomitant calcium-imaging measurements showed the PDS evoked large calcium influx into the entire dendritic tree including the apical tuft, basal, and oblique dendrites. The PDS evoked [Ca(2+)](i) were not uniform along the dendritic tree, being highest in the oblique dendrites (71.3 +/- 14.5 microM) and lowest at the distal tuft branches (9.3 +/- 0.7 microM). The PDS responses persisted after blockade of voltage-gated sodium channels by intracellular QX-314 but became narrower (by 69.6 +/- 9.7%) following intracellular administration of the voltage-gated calcium channel blocker D600. Electrographic seizures recorded in the soma and apical dendrites were composed of recurrent bursts. The initial bursts represented PDS responses. During the seizure the amplitude of bursts gradually attenuated and reached an average value of 26 +/- 13% of the initial ictal PDS burst. Double recordings during electrographic seizures revealed the initial one to four ictal bursts appeared first at the apical dendrite while later ictal bursts were always observed first at the soma. In conclusion, the results of this study show "inter-ictal" PDS responses originated in the apical dendritic tree, were partially mediated by voltage-gated calcium channels and spread throughout the dendritic tree including the fine tuft, basal, and oblique dendrites. During electrographic seizures the origin of epileptic bursts shifted from the apical dendritic tree to the soma-basal region.

Animals↗
PubMed2005

Multiclass cancer classification by using fuzzy support vector machine and binary decision tree with gene selection.

We investigate the problems of multiclass cancer classification with gene selection from gene expression data. Two different constructed multiclass classifiers with gene selection are proposed, which are fuzzy support vector machine (FSVM) with gene selection and binary classification tree based on SVM with gene selection. Using F test and recursive feature elimination based on SVM as gene selection methods, binary classification tree based on SVM with F test, binary classification tree based on SVM with recursive feature elimination based on SVM, and FSVM with recursive feature elimination based on SVM are tested in our experiments. To accelerate computation, preselecting the strongest genes is also used. The proposed techniques are applied to analyze breast cancer data, small round blue-cell tumors, and acute leukemia data. Compared to existing multiclass cancer classifiers and binary classification tree based on SVM with F test or binary classification tree based on SVM with recursive feature elimination based on SVM mentioned in this paper, FSVM based on recursive feature elimination based on SVM can find most important genes that affect certain types of cancer with high recognition accuracy.

Journal Article↗
PubMed2004

Wall shear stress gradient topography in the normal left coronary arterial tree: possible implications for atherogenesis.

OBJECTIVE: Wall shear stress gradient (WSSG) in vitro has shown its importance in atherogenesis, probably as a local modulator of endothelial gene expression. The purpose of this study is to numerically analyse the WSSG distribution over the normal human left coronary artery (LCA) tree. RESEARCH DESIGN AND METHODS: A three-dimensional computer generated model of the LCA tree, based on an averaged human data set extracted from angiographies, was adopted for finite-element analysis. The LCA tree includes the left main coronary artery (LMCA), the left anterior descending (LAD), the left circumflex artery (LCxA) and their major branches. RESULTS: In proximal LCA tree regions where at bifurcations in regions opposite the flow atherosclerosis frequently occurs, low WSSG appears. At distal segments, the WSSG increases substantially due to increased velocity resulting from increased vessel tapering. Low WSSG occurs dividers, which are anatomic sites predisposed for atherosclerotic development. CONCLUSIONS: This computational work determines, probably for the first time, the topography of the WSSG in the normal human LCA tree. Spatial WSSG differentiation indicates that low values of this parameter probably correlate to atherosclerosis localization. However, further studies are needed to clarify the role of WSSG in atherogenesis.

Blood Flow Velocity↗
PubMed2006

Construction of phylogenetic trees by kernel-based comparative analysis of metabolic networks.

BACKGROUND: To infer the tree of life requires knowledge of the common characteristics of each species descended from a common ancestor as the measuring criteria and a method to calculate the distance between the resulting values of each measure. Conventional phylogenetic analysis based on genomic sequences provides information about the genetic relationships between different organisms. In contrast, comparative analysis of metabolic pathways in different organisms can yield insights into their functional relationships under different physiological conditions. However, evaluating the similarities or differences between metabolic networks is a computationally challenging problem, and systematic methods of doing this are desirable. Here we introduce a graph-kernel method for computing the similarity between metabolic networks in polynomial time, and use it to profile metabolic pathways and to construct phylogenetic trees. RESULTS: To compare the structures of metabolic networks in organisms, we adopted the exponential graph kernel, which is a kernel-based approach with a labeled graph that includes a label matrix and an adjacency matrix. To construct the phylogenetic trees, we used an unweighted pair-group method with arithmetic mean, i.e., a hierarchical clustering algorithm. We applied the kernel-based network profiling method in a comparative analysis of nine carbohydrate metabolic networks from 81 biological species encompassing Archaea, Eukaryota, and Eubacteria. The resulting phylogenetic hierarchies generally support the tripartite scheme of three domains rather than the two domains of prokaryotes and eukaryotes. CONCLUSION: By combining the kernel machines with metabolic information, the method infers the context of biosphere development that covers physiological events required for adaptation by genetic reconstruction. The results show that one may obtain a global view of the tree of life by comparing the metabolic pathway structures using meta-level information rather than sequence information. This method may yield further information about biological evolution, such as the history of horizontal transfer of each gene, by studying the detailed structure of the phylogenetic tree constructed by the kernel-based method.

Archaeal Proteins↗
PubMed2005

Rooting a phylogenetic tree with nonreversible substitution models.

BACKGROUND: We compared two methods of rooting a phylogenetic tree: the stationary and the nonstationary substitution processes. These methods do not require an outgroup. METHODS: Given a multiple alignment and an unrooted tree, the maximum likelihood estimates of branch lengths and substitution parameters for each associated rooted tree are found; rooted trees are compared using their likelihood values. Site variation in substitution rates is handled by assigning sites into several classes before the analysis. RESULTS: In three test datasets where the trees are small and the roots are assumed known, the nonstationary process gets the correct estimate significantly more often, and fits data much better, than the stationary process. Both processes give biologically plausible root placements in a set of nine primate mitochondrial DNA sequences. CONCLUSIONS: The nonstationary process is simple to use and is much better than the stationary process at inferring the root. It could be useful for situations where an outgroup is unavailable.

Animals↗
PubMed2003

Can a decision tree help nurses to grade and treat pressure ulcers?

OBJECTIVE: This study investigated whether a decision tree can aid pressure ulcer management. It hypothesised that nurses who use a decision tree in pressure ulcer care assess wound grade more accurately and select more appropriate dressings. METHOD: Sixty-six nurses were randomly assigned to two groups. Each nurse reviewed written information and pictures of three cases of pressure ulceration, and then graded and selected a dressing for the lesions. The absence or presence of a decision tree was used as an independent variable. Measurements included: mean and standard deviation; confidence intervals; percentages; Chi-square test, Pearson's correlation and Kruskal-Wallis test. RESULTS: Baseline characteristics were comparable for both groups. There was no statically significant difference between the grades selected by the two groups. But significantly more of the decision tree users selected an appropriate dressing (p < 0.02). Joint scores (ranging from 0 to 6) were assigned for each accurate decision. The mean score for the experimental group was 4.47 +/- 1.14 (95% CI: 0.95 [4.06-4.88]) and for the control group, 3.35 +/- 1.30 (95% CI: 0.95 [2.90-3.81]). CONCLUSION: Decision trees could help nurses to make complex clinical decisions. Further studies undertaken in a clinical setting are needed.

Adult↗
PubMed2006

Rubber Tree (Hevea brasiliensis Muell. Arg).

Rubber tree (Hevea brasiliensis Muell. Arg.) is an important industrial crop for natural rubber production. At present, more than 9.5 million hectares in about 40 countries are devoted to rubber tree cultivation with a production about 6.5 million tons of dry rubber each year. The world supply of natural rubber is barely keeping up with a global demand for 12 million tons of natural rubber in 2020. Tapping panel dryness (TPD) is a complex physiological syndrome widely found in rubber tree plantations, which causes severe yield and crop losses in natural rubber producing countries. Currently, there is no effective prevention or treatment for this serious malady. As it is a perennial tree crop, the integration of specific desired traits through conventional breeding is both time-consuming and labour-intensive. Genetic transformation with conventional breeding is certainly a more promising tool for incorporation of agronomically important genes that could improve existing Hevea genotype. This chapter provides an Agrobacterium-mediated transformation protocol for rubber tree using immature anther-derived calli as initial explants. We have applied this protocol to generate genetically engineered plants from a high yielding Indian clone RRII 105 of Hevea brasiliensis (Hb). Calli were co-cultured with Agrobacterium tumefaciens harboring a plasmid vector containing the Hb superoxide dismutase (SOD) gene and the reporter gene used was beta-glucuronidase (GUS) gene (uidA). The selectable marker gene used was neomycin phosphotransferase (nptII) and kanamycin was used as selection agent. We found that a suitable transformation protocol for Hevea consists of a 3-d co-cultivation with Agrobacterium in the presence of 20 mM acetosyringone, 15 mM betaine HCl, and 11.55 mM proline followed by selection on medium containing 300 mg/L kanamycin. Transformed calli surviving on medium containing 300 mg/L kanamycin showed a strong GUS-positive reaction. Upon subsequent subculture into fresh media, we obtained somatic embryogenesis and germinated plantlets, which were found to be GUS positive. The integration of uidA, nptII, and HbSOD transgenes into Hevea genome was confirmed by polymerase chain reaction (PCR) as well as Southern blot analysis.

Acetophenones↗
PubMed1995

The photoperiodic control circuit in euthyroid American tree sparrows (Spizella arborea) is already programmed for photorefractoriness by week 4 under long days.

The aim of this investigation was to determine whether spontaneous testicular regression in male American tree sparrows (Spizella arborea) that were thyroidectomized at week 4 of photostimulation manifests photorefractoriness, as it does in chronically photostimulated euthyroid controls. On the basis of our demonstration that exogenous thyroxine stimulates the gonads only when recipient birds are photosensitive, male tree sparrows were thyroidectomized at week 4 of photostimulation (20 h light:4 h dark) and given thyroxine periodically to assay for photosensitivity. When initiated at weeks 4, 7, 10, 13 and 16 of photostimulation, thyroxine replacement therapy had no effect on testis size until week 16, when most recipient birds showed robust testicular growth. The inductive effect of exogenous thyroxine at week 16 confirms that chronic thyroidectomy dissipates photorefractoriness and simulates the effect of short days. The failure of replacement thyroxine to halt spontaneous testicular regression between week 7 and week 13 establishes that spontaneous testicular regression after thyroidectomy manifests photorefractoriness. Moreover, the failure of replacement thyroxine to induce testicular growth between week 4 and week 7 indicates that by week 4 of photostimulation, at least 3 weeks before photoinduced testicular growth ends, male tree sparrows are programmed for photorefractoriness. This conclusion is strengthened by the finding that thyroidectomy at week 4 of photostimulation does not uncouple photorefractoriness and postnuptial moult, which in euthyroid tree sparrows are tightly linked. In another experiment, photosensitive thyroid-intact tree sparrows were moved from 8 h light:16 h dark to 20 h light:4 h dark and given exogenous thyroxine or vehicle through week 6 of photostimulation. Exogenous thyroxine augmented testicular growth.

Animals↗
PubMed2003

Survival and development of Lymantria monacha (Lepidoptera: Lymantriidae) on North American and introduced Eurasian tree species.

Lymantria monacha (L.) (Lepidoptera: Lymantriidae), the nun moth, is a Eurasian pest of conifers that has potential for accidental introduction into North America. To project the potential host range of this insect if introduced into North America, survival and development of L. monacha on 26 North American and eight introduced Eurasian tree species were examined. Seven conifer species (Abies concolor, Picea abies, P. glauca, P. pungens, Pinus sylvestris with male cones, P. menziesii variety glance, and Tsuga canadensis) and six broadleaf species (Betula populifolia, Malus x domestica, Prunus serotiaa, Quercus lobata, Q. rubra, and Q. velutina) were suitable for L. monacha survival and development. Eleven of the host species tested were rated as intermediate in suitability, four conifer species (Larix occidentalis, P. nigra, P. ponderosa, P. strobus, and Pseudotsuga menziesii variety menziesii) and six broadleaf species (Carpinus caroliniana, Carya ovata, Fagus grandifolia, Populus grandidentata, Q. alba, and Tilia cordata) and the remaining 10 species tested were rated as poor (Acer rubrum, A. platanoidies, A. saccharum, F. americana, Juniperus virginiana, Larix kaempferi, Liriodendron tulipfera, Morus alba, P. taeda, and P. deltoides). The phenological state of the trees had a major impact on establishment, survival, and development of L. monacha on many of the tree species tested. Several of the deciduous tree species that are suitable for L. monacha also are suitable for L. dispar (L.) and L. mathura Moore. Establishment of L. monacha in North America would be catastrophic because of the large number of economically important tree species on which it can survive and develop, and the ability of mated females to fly and colonize new areas.

Animals↗
PubMed2005

Reproductive success and contaminants in tree swallows (Tachycineta bicolor) breeding at a wastewater treatment plant.

The uptake and effects of contaminants were measured in the insectivorous tree swallow (Tachycineta bicolor) at a wastewater treatment site. The study examined reproductive, immunological, and growth endpoints in tree swallows exposed to chlorinated hydrocarbon contaminants and to 4-nonylphenol in wastewater lagoons at the Iona Wastewater Treatment Plant, Vancouver (BC, Canada). Clutch size was significantly lower in tree swallows breeding at Iona Island in 2000 and 2001 compared to the reference site. In 2000, fledging success was significantly lower and mean mass of nestling livers was significantly higher in the tree swallows breeding at the Iona Island Wastewater Treatment Plant. Additional factors that may influence reproductive success, such as parental provisioning and diet composition, did not differ significantly between sites. Levels of 4-nonylphenol detected in sediment and insects were elevated at the Iona Island Wastewater Treatment Plant (2000: lagoon sediment 82,000 ng/g dry wt, insects 310 ng/g wet wt; 2001: lagoon sediment 383,900 ng/g dry wt, insects 156 ng/g wet wt) compared to the reference site (2000: pond sediment 1,100 ng/g dry wt, insects not sampled; 2001: pond sediment 642 ng/g dry wt, insects 98 ng/g wet wt). These results indicate that tree swallows might be a useful indicator species for exposure to 4-nonylphenol at wastewater treatment sites: however, further work is necessary to determine the extent of uptake and effects of 4-nonylphenol in riparian insectivorous birds.

Animals↗
PubMed2004

Effects of ECG gating and postprocessing techniques on 3D MDCT of the bronchial tree.

OBJECTIVE: Our goal was to determine the impact of ECG gating and different postprocessing techniques on 3D imaging of the bronchial tree. SUBJECTS AND METHODS. Retrospective ECG-gated MDCT and non-ECG-gated MDCT of the chest were performed in 25 patients. ECG-gated MDCT data were reconstructed mid diastole using a fixed interval of -400 msec in 25 patients and then additionally at -200, -300, and -500 msec in 10 of those patients. Shaded surface display and volume rendering of the bronchial tree combined with virtual bronchoscopy were performed using all data sets. The extent of bronchial tree visualization in shaded surface display-virtual bronchoscopy and volume rendering-virtual bronchoscopy and the presence of artifacts in volume-rendered images were scored by three blinded reviewers. The effective radiation doses of the ECG-gated and nongated acquisitions were compared. RESULTS: The summary scores of all bronchial segments for gated shaded surface display-virtual bronchoscopy and gated volume rendering-virtual bronchoscopy did not differ significantly. The summary scores for nongated shaded surface display-virtual bronchoscopy and nongated volume rendering-virtual bronchoscopy were not significantly different. Non-gated acquisition yielded significantly better visualization of the bronchial tree for both post-processing techniques, regardless of the time interval used for reconstruction of the ECG-gated series. Artifact scores in volume-rendered images were significantly higher for ECG-gated MDCT compared with nongated MDCT. Effective radiation dose was significantly higher for the ECG-gated acquisition. CONCLUSION: Given the advantage of volume rendering for representing the entire data set and given the lower radiation dose and better 3D image quality of nongated acquisition, volume rendering performed on nongated MDCT data is the method of choice for 3D visualization of the bronchial tree.

Bronchography↗
PubMed1977

The House-Tree-Person Test as a measure of intelligence and creativity.

The House-Tree-Person test and a verbal test of mental ability, the Basic Word Vocabulary Test, were administered to 23 male and 27 female, university undergraduates and to 27 boys and 38 girls in Grades 3 to 8. The drawings were given three separate and independent scorings by judges who computed intelligence scores according to the House-Person manual; rated them impressionistically on intelligence, using a forced-distribution method; or rated them impressionistically on creativity, using the same forced-distribution method. The three House-Tree-Person measures were highly intercorrelated for all groups of subjects. All three House-Tree-Person scores also correlated positively and significantly with vocabulary test scores for female university students, as did both Impressionistically derived House-Tree-Person scores for grade-school girls. Male students' and boys' vocabulary scores were unrelated to any of the House-Tree-Person scores. Results suggest that competence in graphic expression operates independently of verbal intelligence in males but validity as a nonverbal test of mental ability and that it can be scored efficiently and reliably by using a global, impressionistic method.

Adult↗
PubMed2006

Application of classification and regression trees for sensitivity analysis of the Escherichia coli O157:H7 food safety process risk model.

Microbial food safety process risk models are simplifications of the real world that help risk managers in their efforts to mitigate food safety risks. An important tool in these risk assessment endeavors is sensitivity analysis, a systematic method used to quantify the effect of changes in input variables on model outputs. In this study, a novel sensitivity analysis method called classification and regression trees was applied to safety risk assessment with the use of portions of the Slaughter Module and Preparation Module of the E. coli O157:H7 microbial food safety process risk as an example. Specifically, the classification and regression trees sensitivity analysis method was evaluated on the basis of its ability to address typical characteristics of microbial food safety process risk models such as nonlinearities, interaction, thresholds, and categorical inputs. Moreover, this method was evaluated with respect to identification of high exposure scenarios and corresponding key inputs and critical limits. The results from the classification and regression trees analysis applied to the Slaughter Module confirmed that the process of chilling carcasses is a critical control point. The method identified a cutoff value of a 2.2-log increase in the number of organisms during chilling as a critical value above which high levels of contamination would be expected. When classification and regression trees analysis was applied to the cooking effects part of the Preparation Module, cooking temperature was found to be the most sensitive input, with precooking treatment (i.e., raw product storage conditions) ranked second in importance. This case study demonstrates the capabilities of classification and regression trees analysis as an alternative to other statistically based sensitivity analysis methods, and one that can readily address specific characteristics that are common in microbial food safety process risk models.

Consumer Product Safety↗
PubMed1999

Changes in the factor of safety within the superstructure of a dicot tree.

The objective of this study was to determine whether the factor of safety for mechanical stability varied among stems differing in size and age within the superstructure of a large dicot tree. Two factors of safety were selected for study: the quotient of the critical buckling height and the actual length of stems, Hcrit/L, and the quotient of the modulus of rupture (the force per unit area required to break a stem) and the working stress (the force per unit area resulting from the biomass measured distal to a stem), M(R)/σ(w). These two dimensionless safety factors were determined for a total of 420 shoot segments comprising much of the aboveground biomass of a Robinia pseudoacacia (Fabaceae) tree measuring 18.7 m in height and 1347 kg in mass, and 0.46 m in diameter (40 yr old) at 1.2 m from the ground.An S-shaped trend was observed when each of the two factors of safety was plotted as a function of stem age. Each factor decreased from a local maximum for the most distal (peripheral) stems in the canopy to a local minimum value for stems ∼10 yr old; each factor increased again to another local maximum for stems 11-18 yr old, and then decreased steadily toward the base of the trunk. This trend was the result of the allometric relationships among stem diameter, length, biomass, and material properties (stiffness and strength) with respect to stem age. Although they were disproportionately more slender than their older counterparts, peripheral stems were sufficiently stiff and strong to sustain the stresses resulting from their weight and that of foliage without deflecting under these loads, yet they were sufficiently flexible to easily bend and thereby presumably provide a mechanism to reduce the drag forces acting on the entire tree. In contrast, the internally imposed mechanical forces acting on progressively older stems increased at a greater rate than the observed rate of increase in stem stiffness, strength, or diameter. The probability of mechanical failure, which must be considered from a demographic perspective (i.e., an age-dependent phenomenon), thus increased from older branches to the base of the trunk. Reports of similar allometric trends based on interspecific comparisons among diverse dicot species comply with the allometry observed for the R. pseudoacacia tree and suggest that the S-shaped trend for the factor of safety holds for stems differing in age drawn from individual trees and for the trunks of conspecifics differing in age drawn from a dense population.

Journal Article↗
PubMed2001

Incongruence of mitochondrial and nuclear gene trees in the Carabid beetles Ohomopterus.

We studied the molecular phylogeny of the carabid subgenus Ohomopterus (genus Carabus), using two mitochondrial (mt) DNA regions (16SrRNA and NADH dehydrogenase subunit 5) and three nuclear DNA regions (wingless, phosphoenolpyruvate carboxykinase, and an anonymous locus). We revisited the previously reported incongruence between the distribution of mtDNA markers and morphologically defined species (Su et al., 1996; J. Mol. Evol. 43:662-671), which those authors attributed to "type switching", a concerted change in many morphological characters that results in the repeated evolution of a particular morphological type. Our mtDNA gene tree obtained from 44 individuals representing all 15 currently recognized species of Ohomopterus revealed that haplotypes isolated from individuals of a single "species" were frequently separated into distant clades, confirming the previous report. The three nuclear markers generally conformed better-with the morphologically defined species than did the mitochondrial markers. The phylogenetic signal in mtDNA and nuclear DNA data differed strongly, and these two partitions were significantly incongruent with each other according to the incongruence length difference test of Farris et al. (1994; Cladistics 10:315-320), although the three nuclear partitions were not homogeneous either. Our results did not support the type-switching hypothesis that had been proposed to fit the morphological data to the mitochondrial gene tree: The incongruence of the mtDNA tree with other nuclear markers indicates that the mtDNA-based tree does not reflect species history any better than the morphological data do. Incongruence of gene trees in Ohomopterus may have been promoted by the complex processes of geographic isolation and hybridization in the Japanese Archipelago that have led to occasional gene flow and recombination between separated entities. The occurrence of reticulate patterns in this group is intriguing, because species of Ohomopterus exhibit extremely divergent genitalic structures that represent a highly efficient reproductive isolation mechanism.

Animals↗
PubMed2002

[Prediction of the total Japanese cedar pollen counts based on male flower-setting conditions of standard trees].

We made a prediction of the Japanese cedar (Cryptomeria japonica) pollen counts at Tsu city based on male flower-setting conditions of standard trees. The 69 standard trees from 23 kinds of clones, planted at Mie Prefecture Science and Technology Promotion Center (Hakusan, Mie) in 1964, were selected. Male flower-setting conditions for 276 faces (69 trees x 4 points of the compass) were scored from 0 to 3. The average of scores and total pollen counts from 1988 to 2000 was analyzed. As the results, the average scores from standard trees and total pollen counts except two mass pollen-scattered years in 1995 and 2000 had a positive correlation (r = 0.914) by linear function. On the mass pollen-scattered years, pollen counts were influenced from the previous year. Therefore, the score of the present year minus that of the previous year were used for analysis. The average scores from male flower-setting conditions and pollen counts had a strong positive correlation (r = 0.994) when positive scores by taking account of the previous year were analyzed. We conclude that prediction of pollen counts are possible based on the male flower-setting conditions of standard trees.

Cedrus↗
PubMed2003

Alteration of the p53 gene during tree shrews' hepatocarcinogenesis.

OBJECTIVE: To detect the expression and variation of the p53 gene in hepatocarcinogenesis of tree shrews induced by hepatitis B virus (HBV) and aflatoxin B1 (AFB1). METHODS: Tree shrews were divided into four groups: group A, infected with HBV and fed with AFB1; group B, only infected with HBV; group C, fed with AFB1 alone; and group D normal control. The tree shrews underwent liver biopsy every 15 weeks. Liver and tumor tissues were detected by immunohistochemistry and molecular biotechnologies. RESULTS: The incidence of hepatocellular carcinoma (HCC) was higher in group A (66.7%) than in groups B (0) and C (30%). HCC occurrence was earlier in group A than in group C (120.0+/-16.6 wk vs 153.3+/-5.8 wk, t=3.336, P<0.01). Mutated p53 protein was not found in all groups before 75 weeks of experiment. At the 105th week, the expression rates of mutated p53 protein were 78.6%, 60.0% and 71.4% in groups A, B and C respectively, which were significantly higher than that in group D (10%) (chi2> or =5.03, P<0.05). An abnormal band of the p53 gene was detected in groups A and C. The mutational points of the p53 gene in liver cancer of tree shrews were at codon 275, 78 and 13. Nucleotide sequence and amino acids sequence of tree shrew's wild-type p53 were 91.7% and 93.4% in homology compared with those of human p53, respectively. CONCLUSIONS: Remarkable synergistic effect on HCC exists between HBV and AFB1. Mutated p53 protein expressed before occurrence of HCC promotes the development of HCC. HBV and AFB1 may synergistically induce p53 gene mutation.

Animals↗
PubMed2004

[Cloning and sequencing of the introns of UCP gene and construction of molecular phylogenetic tree in chicken].

The UCP genes were the newly discovered genes that can increase the energy expenditure and involve in the metabolism of fat and regulation of energy. Four pairs of primers in chicken UCP exon region were designed to amplify the introns of chicken UCP gene according to the splice ways of the mouse UCP2 gene (Accession No.AF096288). The sequence results showed that the chicken UCP gene also had five GT-AG type introns. The molecular phylogenetic tree was constructed based on the sequence of cds, intron 2 and intron 3 region, respectively. The phylogenetic tree based on the UCP cds region was consistent with the species phylogenetic tree. This result implicated that UCP gene can be regarded as the useful gene for the study of animal phylogenesis. On the contrast, the phylogenetic tree based on the intron 2 and intron 3 region was different from the species phylogenetic tree, which showed that the evolution of intron and cds region is different.

Animals↗