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PubMed2006

Bioaccumulation and trophic transfer of polychlorinated biphenyls by aquatic and terrestrial insects to tree swallows (Tachycineta bicolor).

Insectivorous passerines often bioaccumulate polychlorinated biphenyls (PCBs) via trophic transfer processes. Tree swallows (Tachycineta bicolor) frequently are used for estimating PCB bioaccumulation, yet the focus on specific trophic links between contaminated sediment and bird has been limited. Bioaccumulation of PCBs from sediment to tree swallows was examined with focus on trophic pathways by simultaneously examining PCBs in emergent aquatic and terrestrial insects and gut contents of nestlings. Total PCB concentrations increased from sediment (123.65 +/- 15.93 microg/kg) to tree swallow nestlings (2,827.76 +/- 505.67 microg/kg), with emergent aquatic insects, terrestrial insects, and gut content samples having intermediate concentrations. Biota-sediment accumulation factors (BSAFs) varied among congeners for tree swallow nestlings and for male and female Chironomus spp. For nestlings, the highest BSAF was for the mono-ortho-substituted congener 118. Nestling biomagnification values were similar for gut contents and female Chironomus spp., suggesting this diet item may be the main contributor to the overall PCB transfer to nestlings. However, gut content samples were highly variable and, on a PCB congener pattern basis, may have been influenced by other taxa, such as terrestrial insects. Considering dietary plasticity of many insectivorous birds, the present study suggests that a variety of potential food items should be considered when examining PCB accumulation in insectivorous passerines.

Animals↗
PubMed1988

Health family trees: a tool for finding and helping young family members of coronary and cancer prone pedigrees in Texas and Utah.

We report on the feasibility and utility of a new approach for identifying the small percentage of families in the general population with strong familial predisposition to early coronary heart disease, strokes, and common familial cancers (breast, colon, lung), using the "Health Family Tree," a medical family history. A total of 24,332 "trees" were completed by parents and students in 37 high schools in 14 urban and rural communities in Texas and Utah during the years 1980-86. Completed "trees" were obtained from 68 per cent of all enrolled students. High-risk families, included 1,796 families with early coronary disease (7.5 per cent of all student families or 3.7 per cent of their parents' families), 870 stroke families (3.6 per cent), and 415 cancer prone families (1.7 per cent). Among these 3,081 high-risk families there were 8,245 family members already reported to have been diagnosed by a physician to have the familial disease of interest and 43,269 high risk unaffected siblings and offspring of these persons. The average cost per identified high-risk unaffected person was under $10. We conclude that the "Health Family Tree" is a feasible and cost-effective way to find high-risk families.

Adolescent↗
PubMed2003

Interaction between Japanese flowering cherry trees and some wild animals observed during physiological experiment in fields.

We have studied the weeping habit of Japanese flowering cherry tree in the field of Tama Forest Science Garden, Forestry and Forest Products Research Institute at the foot of Mt. Takao. Since cherry trees at various age were the materials for our plant physiology experiments, our studies were conducted in the fields where we experienced certain difficulties. Even under such difficult environment that was rather unexpected and uncontrollable, we could obtain fruitful results on the growth of cherry tree, and found them scientifically significant, especially in terms of biological effects of gravity on earth. Moreover, a lot of interesting interactions of cherry trees with various kinds of animals were observed in parallel to the plant physiology.

Animals↗
PubMed1998

Morphology of the tracheobronchial tree and the route of the pulmonary artery in the fetal minke whale (Balaenoptera acutorostrata).

Molecular and statistical studies support the close phylogenetic relation between Cetacea and Artiodactyla. The presence of the tracheal bronchus has been pointed out as one of the common traits between only these groups. Nakakuki (1980) has investigated the mammalian tracheobronchial trees in 50 species based on his new nomenclature, and his study has consequently demonstrated the above-mentioned indication. Therefore, comparative anatomy of the tracheobronchial tree based on the nomenclature seems to be useful for investigations of the cetacean phylogeny. Three pairs of fetal lungs of the minke whale (Balaenoptera acutorostrata) were supplied from the Institute of Cetacean Research, Tokyo (1991) to observe their tracheobronchial trees and the ramification of the pulmonary artery. The fetal tracheobronchial tree consisted of one tracheal, four lateral, four dorsal and one medial secondary bronchi in the right lung, and five or six lateral and four or five dorsal secondary bronchi in the left, using the new nomenclature. The right pulmonary artery crossed the right axial bronchus from the ventral side to the dorsal over the third lateral bronchus. The tracheal bronchus in the fetal minke whale seems to belong to the type II of Nakakuki's nomenclature, and this type is seen in one species of the river dolphins. The other conspicuous traits of the fetal lungs are the defect of the second lateral broncus and the route of the pulmonary artery in the right side. This route is very different from that of many other mammals.

Animals↗
PubMed2000

Ontogenetic changes in the fractal geometry of the bronchial tree in Rattus norvegicus.

Respiration and metabolism change dramatically over the course of the development of vertebrates. In mammals these changes may be ascribed to organogenesis and differentiation of structures involved in gas exchange and transport and the increase in size. Since young as well as mature individuals must be well-designed if the species is to survive, the physiological changes during the development should be matched with geometrical or structural adjustments of the respiratory system. The aim of this study was to evaluate changes in the fractal geometry of the bronchial tree during the postnatal development of the rat. The average fractal dimension of the bronchial tree of the rats was 1.587, but that of juveniles was larger than that of the adults. We found a significant negative correlation between age and fractal dimension. This correlation could be considered be misleading because of the difficulty of separating age/body size effects. Nevertheless, because fractal dimensions of the bronchial tree of rabbits and humans are known to be similar, 1.58 and 1.57 respectively, the body size effect may be nil. To our knowledge, this is the first report of ontogenetic changes in the fractal dimension of the bronchial tree in mammals.

Animals↗
PubMed1999

The expression of insulin-like growth factor II, hepatitis B virus X antigen and p21 in experimental hepatocarcinogenesis in tree shrews.

The purpose of this paper was to study the mechanism of synergistic effect in hepatocarcinogenesis induced by hepatitis B virus (HBV) infection and aflatoxin B1 (AFB1) intake. Immunohistochemical staining was used in formalin-fixed, paraffin-embedded sections of cancer and liver tissues. The incidence of hepatocellular carcinomas (HCCs) was 52.9% in experimental tree shrews that received both HBV and AFB1. It was significantly higher than that of animals exposed to HBV (11.1%, Group B), or (AFB1) (15.8%, group C) alone. HCC was not found in the control animals (group D). The expressions of insulin-like growth factor II (IGF-II) were 82.4%, 22.2%, 26.3% and 0 in groups A, B, C and D, respectively. The significant differences of IGF-II were observed between groups A and B, C and D (P < 0.05). The expressions of p21 were 29.4%, 11.1%, 15.8% and 0 in group A, B, C and D, respectively. The positive rate of hepatitis B x antigen (HbxAg) was significantly higher in the group A than that in the group B (52.9% vs. 11.1%, P < 0.05). The parallel relations between the incidence of HCC and the overexpressions of these genes protein have been found in each group. On the other hand, the expressions of these genes in tumour-bearing tree shrews were significantly higher than that in nontumour-bearing animals. These findings suggest a synergistic effects of HBV and AFB1 in activation of these genes in tree shrews. Overexpressions of these genes may take an important role in the course of hepatocarcinogenesis in tree shrews.

Aflatoxin B1↗
PubMed1999

The genomic tree as revealed from whole proteome comparisons.

The availability of a number of complete cellular genome sequences allows the development of organisms' classification, taking into account their genome content, the loss or acquisition of genes, and overall gene similarities as signatures of common ancestry. On the basis of correspondence analysis and hierarchical classification methods, a methodological framework is introduced here for the classification of the available 20 completely sequenced genomes and partial information for Schizosaccharomyces pombe, Homo sapiens, and Mus musculus. The outcome of such an analysis leads to a classification of genomes that we call a genomic tree. Although these trees are phenograms, they carry with them strong phylogenetic signatures and are remarkably similar to 16S-like rRNA-based phylogenies. Our results suggest that duplication and deletion events that took place through evolutionary time were globally similar in related organisms. The genomic trees presented here place the Archaea in the proximity of the Bacteria when the whole gene content of each organism is considered, and when ancestral gene duplications are eliminated. Genomic trees represent an additional approach for the understanding of evolution at the genomic level and may contribute to the proper assessment of the evolutionary relationships between extant species.

Animals↗
PubMed2000

Incidence of testicular lesions in a population of tree shrews (Tupaia belangeri).

BACKGROUND AND PURPOSE: The sexual activity of male tree shrews is socially influenced; therefore, the testicular lesions in adult male tree shrews were of interest. METHODS: The testes of 229 adult and 9 subadult male tree shrews were obtained during routine necropsy and were subjected to light microscopy. At one time, 138 animals were experimentally exposed to social conflicts. RESULTS: Hypospermatogenesis (testicular inactivity) was observed in social stress-exposed males up to two years of age. Seasonality of hypospermatogenesis could not be statistically supported. Testicular atrophy, observed in 21 animals, was neither stress- nor age-related; it developed unilaterally, with the left testis preferred. Testicular tumors developed in animals older than 2 years, with increasing frequency particularly of Leydig cell tumors in animals more than four year old. CONCLUSION: Testicular lesions were more frequently found in male tree shrews than they were observed in nonhuman primates kept at the German Primate Center. Connections to social stress were statistically supported, particularly with respect to hypospermatogenesis. Testicular tumors, in contrast, were distinctly age related.

Age Factors↗
PubMed2000

Tools for community-oriented primary care: use of key informant trees in eleven practices.

Physicians increasingly need information about their communities to use in care of the individual patient. Busy practitioners need feasible methods for collecting this information before they can begin to gather and use it, however. Our objective was to study key informant trees as a practical approach for practice-based gathering of qualitative data from a community. Following a standard protocol, key informant trees were set up in 11 different practices to study the costs, advantages, and problems with their use for this purpose. Time studies showed that each tree took 7 to 11 hours of physician time and 7 hours of clerical time to organize and conduct. The technique appeared to be best suited for two qualitative informational needs: idea generation and explanatory data gathering. Trees appeared most productive where there was stability of physician staff in the practice, where the practice had been present in the community for some years, and where community residents were relatively stable. Response and selection biases are important considerations in use of this technique.

Community Participation↗
PubMed2001

Tree models for dependent copy number changes in bladder cancer.

We analyzed comparative genomic hybridization data on a collection of 237 bladder cancer tumors with the aim of identifying sets of copy number aberrations (CNAs) that tend to occur together. A test based on Fisher's exact test for pairs, but taking into account multiple testing, showed strong dependencies amongst several pairs of aberrations including (+1q, -11p), (+17q, +20q), (+10p, -17p), (-8p, -17p), (+5p, +10p). To determine whether co-occurrence of CNAs may characterize tumor subtypes, we used two recently proposed methods to construct tree models of tumor progression. We constructed tree models for all the tumors, the tumors of stage pT1, and the tumors of stages pT2-4. The tree models confirmed that most of the non-random events and the associations are the same for different stages. We conclude that the combination of large data sets and tree models provide a useful approach to systematically identifying tumor subgroups characterized by more than a single chromosomal aberration.

Algorithms↗
PubMed2001

Ontogenetic wood anatomy of tree and subtree species of Nepalese Rhododendron (Ericaceae) and characterization of shrub species.

Ontogenetic trends in the wood structure of Nepalese Rhododendron were studied in 15 specimens of two tree and four subtree species. Average growth ring width was constant from pith to bark in spite of occurrences of extremely narrow, false, or discontinuous rings. Vessel density, vessel area, vessel element length, and multiseriate ray height generally had an initial increase or decrease to 1.5 cm radius and near plateau or slight decrease or increase outward. Multiseriate ray density and area percentage were variable between specimens without a clear pattern. Ontogenetic trends from pith to fully mature wood in trees plus subtrees were inferred by treating the measurements in the present study with those of mature individuals in a previous study. Comparison of trends in trees plus subtrees and those in shrubs lead to ecological or systematic groupings. Vessel features showed that alpine shrub species have distinctly small, numerous vessels composed of short vessel elements. Multiseriate ray features indicated a systematic difference between the trees plus subtrees of subgenus Hymenanthes and the shrubs of subgenus Rhododendron. Vessel features of alpine shrubs may be an adaptation against frequent freeze-thaw cycles or the result of growth stress imposed by the severe alpine environment.

Journal Article↗
PubMed2001

Survival analysis with time-varying relative risks: a tree-based approach.

A tree-based method for estimating time-varying effects of baseline patient characteristics on survival is introduced. A Cox-type model for censored survival data is used in which the time-varying relative risks are modelled as piecewise constants. The tree method consists of three steps: 1. Growing the tree, in which a fast algorithm using maximized score statistics is utilized to determine the optimal change points; 2. A pruning algorithm is applied to obtain more parsimonious models; 3. Selection of a final tree, which may be either via bootstrap resampling or based on a measure of explained variation. The piecewise constant model is more suitable for clinical interpretation of the regression parameters than the more continuously time-varying models (spline, loess, etc.) that have been proposed previously.

Algorithms↗
PubMed1975

A study of absorption of compounds from the rat biliary tree by retrograde intrabiliary injection (RII).

Absorption of compounds from the biliary tree of rats was studied by a retrograde intrabiliary injection (RII) technique. After RII of a number of compounds in volumes that exceeded the maximum distended capacity of the biliary tree, only that volume of RII solution which corresponded to biliary tree capacity remained therein. Furthermore, this latter portion of RII solution was absorbed by a first-order process when the duration of bile duct cannula occlusion was extended. Thus, the present study demonstrates that absorption of retrogradely injected compounds continues during occlusion. Since excretion of i.v. administered compounds into the biliary system was also shown to continue during occlusion, we propose in the present study a concept of bidirectional exchange of solute within the biliary tree during occlusion. As an additional finding, after RII and occlusion, a temporary increase in bile flow was obtained. If the occlusion duration was 3 minutes or less, the bile flow response was of sufficient magnitude to repay alomst exactly the volume of bile that would have been expected to be produced. If the occlusion was 6 and 9 minutes the increased magnitude of the bile flow response was not great enough to repary the larger bile volumes expected and underpayments of -48 and -96 mul were incurred.

Absorption↗
PubMed2000

[Effect of elevated CO2 concentration on growth of dominant tree species in pine broadleaf forest of Changbai mountain].

Potted saplings of Pinus koraiensis, Picea koraiensis, Larix olgensis, Populus ussuriensis, Betula platyphylla, Tilia amurensis, Traxinus mandshurica, and Acer mono, the eight dominant species in the Korean pine broadleaf forest at Changbai Mountain, were grown in open-top chambers with ambient(400 microliters.L-1) and elevated (700 microliters.L-1) CO2 concentration under natural sunlight for two growing seasons. The average height growth of these eight species under elevated CO2 increased by 10%-40%, compared with the control at ambient CO2. The response of transpiratory rate to the higher CO2 concentration was different among the species, and the water use efficiency of the saplings of the 8 species growing under elevated CO2 concentration was higher than that under ambient CO2. Soluble sugar and chlorophyll contents were not related to the CO2 concentration under which the saplings grew, indicating that the complicacy was existed in the acclimation of tree species to high CO2 concentration. The response of broad-leaved tree species to the elevated CO2 concentration was more sensitive than that of conifer tree species. Saplings of all tree species showed a photosynthetic acclimation to higher CO2 under long-term elevated CO2 concentration.

Carbohydrate Metabolism↗
PubMed2002

[Light quality effect on the seeds germination in tropical pioneer tree Heliocarpus appendiculatus (Tiliaceae)].

The objective of this study was to determine whether seeds of the pioneer tree Heliocarpus appendiculatus possess photoblastic dormancy. Seeds from nine trees were collected in Los Tuxtlas, Mexico. In order to test for the presence of photoblastic dormancy, germination experiments were carried out separately on seeds of each individual tree. The seeds from each tree were sown and subjected to four light treatments: fluorescent white light, red light (660 nm), far red light (730 nm), and darkness. A total of 50 seeds were sown in each plastic Petri dish (three replicates per treatment) on an agar solution. Experiments were carried out at a constant temperature of 20 degrees C, and a 12:12 hr (L:D) photoperiod. In addition, seeds of three individuals were sown on agar and subjected to a light quality gradient from red to far red (1.1-0.2). Results show that final germination percentages of seeds were unaffected by light quality in all individuals. Nevertheless, germination was delayed by 24 hr in the seeds of four individuals under the far red light treatment. By the end of fourth day, final germination did not differ among treatments. Further, germination of the three individuals under the red/far red gradient was unaffected. Seeds of H. appendiculatus lack photoblastic dormancy and germination behavior can not be used to explain the absence of seedlings below the canopy. We propose that this absence is due to the failure of the seedlings to establish themselves under the canopy.

Chi-Square Distribution↗
PubMed2003

[Human hepatitis B virus infection of tree shrews and Macaca assamensis in vivo].

OBJECTIVE: To examine sensitivity of the tree shrews and Macaca assamensis to human hepatitis B virus (HHBV) by serologic methods. METHODS: Totally 233 tree shrews and 28 Macaca assamensis were inoculated with human sera containing HBV. After inoculation, the sera were collected weekly from them and HBV markers were detected with HBV ditecting ELISA kits. RESULTS: Ninety percent of the tree shrews developed acute infection, among them, 44.4 % persisted for over one year, 33.3% of them developed chronic infection persisted for 2 years and one month; the persistence of HBV in Macaca assamensis was much shorter. CONCLUSION: These data clearly indicated that tree shrew may be used as an animal model for study of chronic HBV infection, whereas, Macaca assamensis, showed only a transient sensitivity to HHBV.

Animals↗
PubMed2000

Estimation of mating-compatibility of the wild service tree (Sorbus torminalis L. Crantz) by observing pollen tube germination.

Cross-compatibility and self-compatibility in trees of Sorbus torminalis (L.) Crantz were evaluated. Degree of mating-compatibility between three trees was determined by means of fluorescence microscope. Self-compatibility evaluated on the basis of the pollen tube germination index showed that one tree is fully self-incompatible and the other two are self-compatible. Observations of pollen tube germination showed full cross-compatibility between trees under investigation.

Journal Article↗
PubMed2004

[Nitrogen cycling and its dynamic feature in fine roots of poplar trees and herbs].

The nitrogen cycling and its dynamic feature in fine roots of poplar trees and herbs were studied in Shenyang of Liaoning Province. The results showed that the nitrogen content in the standing biomass of fine roots of poplar trees and herbs was 20.3 kg.hm-2, and its net accumulation was 10.0 kg.hm-2. With regard to the biological cycling of nitrogen, the annual uptake was 14.6 kg.hm-2 of which, the retention and the return was 9.6 and 5.1 kg.hm-2.yr-1 respectively, and the turnover period was 4 year. The relationship between total nitrogen in roots of poplar trees, and herbs and the available nitrogen in soil was also studied, which indicated that there were similar dynamic trends between total nitrogen in herb roots and the NH3-N in soil in growth season. The total nitrogen in fine roots of poplar trees was positively related to the biomass.

Ammonia↗