PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Thoracica”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1995

The genetic link between the Chinese bamboo partridge (Bambusicola thoracica) and the chicken and junglefowls of the genus Gallus.

Further comparison of mitochondrial control-region DNA base sequences of 16 avian species belonging to the subfamily Phasianinae revealed the following: (i) Generalized perdicine birds (quails and partridges) are of ancient lineages. Even the closest pair, the common quail (Coturnix coturnix japonica) and the Chinese bamboo partridge (Bambusicola thoracica), maintained only 85.71% identity. (ii) The 12 species of phasianine birds previously and presently studied belonged to three distinct branches. The first branch was made exclusively of members of the genus Gallus, while the second branch was made of pheasants of the genera Phasianus, Chrysolophus, and Syrmaticus. Gallopheasants of the genus Lophura were distant cousins to these pheasants. The great argus (Argusianus argus) and peafowls of the genus Pavo constituted the third branch. The position of peacock-pheasants of the genus Polyplectron in the third branch was similar to that of the genus Lophura in the second branch. Members of the fourth phasianine branch, such as tragopans and monals, were not included in the present study. (iii) The one perdicine species, Bambusicola thoracica, was more closely related to phasianine genera Gallus and Pavo than to members of other perdicine genera. The above might indicate that Bambusicola belong to one-stem perdicine lineage that later splits into two sublineages that yielded phasianine birds, one evolving to Gallus, and the other differentiating toward Pavo and its allies.

Animals↗
PubMed2004

Growth and molting in epizoic pedunculate barnacles genus Octolasmis (Crustacea: Thecostraca: Cirripedia: Thoracica).

Scanning electron microscopy, light microscopy, and histology were used to study growth in species of the pedunculate barnacle genus Octolasmis (O. angulata, O. cor, O. californiana, O. mülleri). These species are epizoic in the gill chamber of portunid crabs and have highly reduced capitular shell plates, with large areas of general cuticle in between. The external integument grows by means of a system of narrow growth zones, one encircling the peduncle and a Y-shaped system on either side of the capitulum. Growth is by a regular series of molts, but shedding of old cuticle and production of new layers is entirely restricted to the growth zones. Just prior to ecdysis, the new cuticle lies in a highly folded fashion beneath the old cuticle that is about to be shed. At ecdysis, the old cuticle breaks along the margins of the growth zones and the resulting scars remain as a system of "ecdysial lines" along either side of the zone. Once exposed after ecdysis, the new cuticle remains as a part of the permanent external integument. The growth zones divide the externa into five cuticular areas, two on the peduncle and three on the capitulum. The calcareous shell plates (carina, paired scuta, and, when present, paired terga) all lie within the capitular regions and the ecdysial lines pass across, not around, these mineralized areas. The number, relative spacing, and topology of the ecdysial lines form a record of the growth history of the specimen. These and other growth patterns demonstrate that size increase is due to the formation of new cuticle by molting in the growth zones, while expansion of the shell plates by mineralization follows only after production of the new cuticle. Thus, although specialized, growth in Octolasmis still complies with the general crustacean model, complicated only by the mineralization of parts of the capitular cuticle into shell plates. The results are compared with the very scarce information on molting in other barnacles. We argue that at least the circular peduncular growth zone is omnipresent in the Cirripedia Thoracica.

Animals↗
PubMed1983

The circadian locomotor rhythm of Hemideina thoracica (Orthoptera; Stenopelmatidae): a population of weakly coupled feedback oscillators as a model of the underlying pacemaker.

A control systems model consisting of a population of weakly-coupled feedback oscillators has been developed to simulate the circadian locomotor rhythm of the insect, Hemideina thoracica (Orthoptera; Stenopelmatidae). The model is an extension of a previously published single oscillator feedback model (Gander and Lewis, 1979) which successfully simulates entrainment, phase response curves, temperature compensation and Aschoff's Rule for Hemideina activity rhythms. The population model described here has the additional properties of predicting some of the free-run period lability (Pavlidis, 1978a, b) observed in the Hemideina rhythm (Christensen and Lewis, 1982) which is unexplained by single oscillator systems. Model behaviour is compared with the experimental data derived from the insect activity rhythms.

Animals↗
PubMed1975

Thoracic collapse as affected by the retia thoracica in the dolphin.

The carcass of a subadult female Delphinus was placed in a hyperbaric chamber and subjected to two simulated dives each equivalent to 69.7 m. In one dive the thorax was in its natural state, and in the other 100 ml of water had been injected into each pleural cavity. Various morphometric measurements of the thorax were taken before, during, and after each dive. Results indicate that if fluid is located in the same position as the retia thoracica, the shape of the thorax is affected when submitted to diving, but not surface, pressures. The overall collapse of the chest is greater during partial infusion of the pleura, exhibiting exceptional compression in the ventral area. The engorged thoracic rete apparently affects the degree and pattern of thoracic collapse and thereby reduces the amount of displacement stress exerted upon the abdominal organs when the animal is subjected to the high ambient hydrostatic pressures encountered during normal diving.

Animals↗
PubMed2000

Characterization of a hybrid zone between two chromosomal races of the weta Hemideina thoracica following a geologically recent volcanic eruption.

Two chromosomal races (2n=17 and 2n=15; XO) of the weta Hemideina thoracica meet at the centre of a volcanic region in North Island, New Zealand. Five independent polymorphic genetic markers showed broadly coinciding, steep frequency clines from north to south across this zone beside the flooded crater, Lake Taupo. Three unlinked nuclear gene markers provide estimates of zone width that are at least twice the width of the chromosomal and mitochondrial clines, with cline centres displaced at least 2.5 km. The different zone widths and centres suggest that this hybrid zone is a semipermeable barrier reducing the introgression of the chromosomal markers more than genic markers. We estimate that this species of weta must have a dispersal rate of at least 100 m per generation using the time since the last Taupo eruption (1850 years ago), which covered an area of about 20 000 km2 with pyroclastic flow.

Animals↗
PubMed2003

A comparison of five hybrid zones of the weta Hemideina thoracica (Orthoptera: Anostostomatidae): degree of cytogenetic differentiation fails to predict zone width.

Tension zones are maintained by the interaction between selection against hybrids and dispersal of individuals. Investigating multiple hybrid zones within a single species provides the opportunity to examine differences in zone structure on a background of differences in extrinsic factors (e.g., age of the zone, ecology) or intrinsic factors (e.g., chromosomes). The New Zealand tree weta Hemideina thoracica comprises at least eight distinct chromosomal races with diploid numbers ranging from 2n = 11 (XO) to 2n = 23 (XO). Five independent hybrid zones were located that involve races differing from one another by a variety of chromosomal rearrangements. The predicted negative correlation between extent of karyotypic differentiation (measured in terms of both percent of genome and number of rearrangements) and zone width was not found. Conversely, the widest zones were those characterized by two chromosome rearrangements involving up to 35% of the genome. The narrowest zone occurred where the two races differ by a single chromosome rearrangement involving approximately 2% of the genome. The five estimates of chromosomal cline width ranged from 0.5 km to 47 km. A comparative investigation of cline width for both chromosomal and mitochondrial markers revealed a complex pattern of zone characteristics. Three of the five zones in this study showed cline concordance for the nuclear and cytoplasmic markers, and at two of the zones the clines were also coincident. Zones with the widest chromosomal clines had the widest mitochondrial DNA clines. It appears that, even within a single species, the extent of karyotypic differentiation between pairs of races is not a good predictor of the level of disadvantage suffered by hybrids.

Animals↗
PubMed1990

Localization of the circadian pacemakers of Hemideina thoracica (Orthoptera; Stenopelmatidae).

The location of the circadian pacemakers of the orthopteran Hemideina thoracica (White) has been investigated through observation of the effects of surgical removal of brain tissues (principally optic lobes and tracts) on free-running and entrained locomotor rhythms. Bilobectomy and severance of optic tracts invariably resulted in arrhythmicity, whereas rhythmicity was sustained following unilateral lobectomy, generally with increases in the free-running period (FRP) and decreases in both the active-phase lengths and activity-to-rest ratios of the rhythm. Bilobectomized subjects could be entrained by temperature cycles, but exhibited no transients or residual rhythmicity, indicating that temperature brought about a direct response or masking effect. These results support the hypothesis that the circadian locomotor pacemakers of Hemideina are located within each optic lobe, and that there are no extraoptic centers for the control of the timing of locomotor activity. Although confirmation of the pacemaker role of the optic lobes requires transplantation of the tissues, the conclusion may be drawn by inference from other studies (e.g., Leucophaea maderae--Page, 1983; Gryllus bimaculatus--Tomioka and Chiba, 1986). Light entrainment continued after surgical binding and blackening of the compound eyes and ocelli, supporting the view that direct illumination of neural tissue through the cuticle may be one possible pathway for light entrainment.

Animals↗
PubMed1999

Control systems models for the circadian clock of the New Zealand weta, Hemideina thoracica (Orthoptera: Stenopelmatidae)

The New Zealand weta, Hemideina thoracica, is a nocturnal orthopteran insect which emerges from holes in trees or from under bark soon after sunset to forage for several hours on plant and animal material before returning to its refuge before dawn. In tests of the internal clock hypothesis it exhibits clear circadian locomotor rhythms in which the period is initially somewhat less than 24 h, but frequently spontaneously increases to over 25 h. The rhythms are entrainable by light and temperature cycles, obey Aschoff's Law and are temperature compensated. A single oscillator feedback model accounts for these basic properties of the weta clock, but does not explain a variety of examples of rhythm lability, such as day skipping, spontaneous change in period, scalloping and desynchrony typically found in the real data. To account for these characteristics the model is expanded into two linked populations of oscillators, which retain the basic properties of the simple model and in addition interact through their coupling to show the various types of free-run lability. To make these control systems models compatible with the molecular interpretation of circadian biology, each of the components in the feedback loop is matched with molecular function and structure.

Animals↗
PubMed1989

[Use of the internal mammary vessels (vasa thoracica interna) forirradiation of the parasternal region in breast cancer. 1].

The topographic-anatomical situation of parasternal lymph-nodes, of a. and v. thoracica interna were studied and a method for local irradiation of parasternal lymph-nodes was elaborated introducing discrete linear 60Co-radiation-sources into inner breast vessels. This is the prerequisite to use a radiosurgical method treating mammary carcinoma in central and medial localisation. With this in 463 patients with mammary carcinoma the inner breast vessels were used to introduce radioactive radiation sources. This allowed the irradiation of parasternal lymph-nodes in shortest time with simultaneous substantial decrease of radiation exposure of heart, lung, and mediastinal organs, and of spinal marrow.

Brachytherapy↗
PubMed2004

Antennulary sensory organs in cyprids of Octolasmis and Lepas (Crustacea: Thecostraca: Cirripedia: Thoracica): a scanning electron microscopic study.

Cypris larvae of the pedunculate barnacles Octolasmis angulata (Poecilasmatidae), Lepas australis, L. pectinata, and Dosima fascicularis (Lepadidae) were studied with scanning electron microscopy, focusing on the sensory setae and the attachment disc on the antennules. The antennules of O. angulata did not exhibit any remarkable trait, but carry the same number of setae as seen in most other thoracicans. The third segment is bell-shaped and quite distinct from the second and its attachment disc is surrounded by a skirt. We found several potential synapomorphies in antennulary morphology between cyprids of the lepadid species but none of them were shared with the cyprids of Octolasmis; the list of unique lepadid characters includes: one additional, preaxial seta on the second segment; multiple similar (up to eight) postaxial setae (PS3) on the third segment, unlike all other thoracicans, where there is only a single PS3; the third segment consists almost entirely of the attachment disc, which is distended and surrounded by two parallel rows of radial setae; on the fourth segment the terminal seta E is diminutive. We found no traits in cyprids of Octolasmis that seem to be adaptations to their attachment site within the branchial chamber of swimming crabs and, in particular, no similarities with cyprids of rhizocephalan barnacles, many of which also attach in the gill chamber. The synapomorphies between cyprids of the lepadid species may be adaptations to their life in the neuston.

Animals↗
PubMedDate not supplied

[Larvae of barnacles (Cirripedia: Thoracica) in the White sea plankton].

The barnacle fauna in the White Sea is briefly described. The morphology of barnacle larvae in this water body is comparatively analyzed. The characters important for the larvae identification are given particular attention. A classification key was developed for the nauplius and cyprid larvae of barnacles in the White Sea.

Animals↗
PubMed1998

Morphology and development of the thoracic part of the sympathetic trunk (pars thoracica trunci sympathici) in the pig (Sus scrofa L.) during the prenatal period.

The aim of the experiment was to establish, on the basis of morphometric and statistic analysis, the changes occurring in the thoracic part of the sympathetic trunk of the pig during its prenatal period. The experiment was conducted on 36 swine fetuses divided into three age groups. The standard variation (s) and the coefficient of variation (CV%) of the length of sympathetic components were calculated. The rates of standard variation increased with the age of the fetuses and it was found that the most dynamic development of the elements examined took place during the terminal period of gestation. Also the coefficient of correlation of the length of those elements investigated with the length of the fetuses was calculated. The part of the sympathetic trunk in question was found to be negatively allometric in relation to the body length during the whole of gestation. A gradual emergence of an increasing domination of the right side of the body, in relation either to the ganglia or to the interganglionic branches was observed. There was no perceptible influence of sex on the rate of development of the part of the sympathetic trunk studied. Also an emergence of an increasing domination of the fetuses originating from the left uterine horn at the end of gestation was noted.

Animals↗
PubMed1989

Changes in nucleus tractus spinalis nervi trigemini after temporary occlusion of aorta thoracica in dog.

In a group of seven dogs the thoracic aorta was occluded by means of tourniquet for 30 minutes. After the release of aorta the animals were left living for 6-7 days. The spinal cord and brain stem were treated by Nauta-Gygax method after sacrificing the animals, then the preterminal and terminal degenerations of some ascending spinal systems were analysed. Distinct degenerations in nucleus tractus spinalis nervi trigemini were detected. They originated in lower thoracic and lumbosacral segments of spinal cord. Degenerations were localised in the caudal part of nuclei of trigeminal complex. It looks like the above mentioned projections terminating in nucleus tractus spinalis nervi trigemini are related to tractus spinocerebellaris posterior.

Afferent Pathways↗