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At least 865 records · Page 48Linked to original sources
PubMed1992

[The correlation of the segments of the extremities as a biomechanical constant in man and mammals].

The length of human extremity segments at different stages of age development, beginning from newborns up to far-advanced age, was studied. Under examination there were 1505 humans. In addition, bone segments of the extremities were studied in 100 human skeletons and 225 skeletons of mammals from 8 orders. On the basis of a functional analysis of the length of bone segments and the detected high correlative dependence two homogeneous (homodynamic) pairs in extremities of the man and animals were identified mainly performing the supporting, static and repulsive functions. An equality between the length of these pairs was established called the biomechanical constant. The biomechanical constant regulates the proportionality of bone links as a mechanical lever in the process of age development of man as well as in the process of evolution of mammals in changing the types of locomotion from foot-walking up to phalanx-walking.

Aging↗
PubMedDate not supplied

[The MB1 family of repeats in clones from the genomes of mammals].

Members of MB1 family repeats are revealed in genomes of many mammals (cow, rabbit, opossum, horse, ...). The MB1 repeats from cow and rabbit genomes are mirror-reflected about the SINE families repeats from cow and rabbit genomes. The life time of MB1 repeats are no less than 100 million years. Classification of MB1 repeats from human genome using the information similarity was performed. This classification has revealed two subfamily MB1 repeats in human genome. Possible processes of creation of MB1 family repeats common for many mammals are discussed.

Animals↗
PubMed2003

Occurrence of Orientia tsutsugamushi in small mammals from Thailand.

Extensive sampling of small mammals was conducted in eight provinces of Thailand between September 9, 1992 and April 29, 2001. A total of 3,498 specimens representing 22 species were collected. Eighty-eight percent (3,089 of 3,498) of the animals were collected from a region in Chiangrai Province, which is commonly recognized as endemic for human scrub typhus. Blood and tissue samples from each animal were tested for the presence of Orientia tsutsugamushi, the etiologic agent of scrub typhus. The predominant species collected were Rattus rattus (53%, n = 1,863), R. losea (18%, n = 638), Bandicota indica (16%, n = 564), and R. exulans (4%, n = 146). Orientia tsutsugamushi was detected in 10 of the 22 species of mammals that included R. bukit (25% infected, 1 of 4), R. rattus (23%, 419 of 1,855), R. argentiventer (22%, 5 of 23), R. berdmorei (22%, 2 of 9), R. losea (13%, 82 of 638), B. indica (9%, 52 of 564), R. koratensis (8%, 1 of 12), B. savilei (3%, 1 of 30), R. exulans (1%, 2 of 146), and Tupaia glis (2%, 1 of 49). Infected animals were found in Chiangrai (18% infected, 563 of 3,084), Bangkok (11%, 1 of 9), Sukothai (3%, 1 of 30), and Nonthaburi (1%, 1 of 69) Provinces. The implications towards scrub typhus maintenance and transmission are discussed.

Animals↗
PubMedDate not supplied

[Genetic control of spermatogenesis and sex determination in mammals].

The material was analyzed on the main problems of genetics of mammalian spermatogenesis, sex determination, its reversion and other defects from the standpoint of current cytological and molecular-genetic concepts of functional activity of the parental genomes after fertilization and behavior of their chromosomes at the early embroyonic stages. On the basis of this analysis, a hypothesis has been proposed, which explains a high percentage (50% or more) of early embryonic mortality in placental mammals under the conditions of natural and extracorporeal fertilization, as well as regular appearance of defects in the course of natural sex determination, including the appearance of representatives of both sex minorities. We do not make pretense to comprehensive and deep analysis of male gametogenesis and sex determination in mammals.

Animals↗
PubMedDate not supplied

[Communication and auditory behavior obtained by auditory evoked potentials in mammals, birds, amphibians, and reptiles].

METHODS ANIMALS: amphibians, Frog catesbiana (frog bull, 30 animals); reptiles, Sceloporus torcuatus (common small lizard, 22 animals); birds: Columba livia (common dove, 20 animals), and mammals, Cavia porcellus, (guinea pig, 20 animals). With regard to lodging, all animals were maintained at the Institute of Human Communication Disorders, were fed with special food for each species, and had water available ad libitum. Regarding procedure, for carrying out analysis of auditory evoked potentials of brain stem SPL amphibians, birds, and mammals were anesthetized with ketamine 20, 25, and 50 mg/kg, by injection. Reptiles were anesthetized by freezing (6 degrees C). Study subjects had needle electrodes placed in an imaginary line on the half sagittal line between both ears and eyes, behind right ear, and behind left ear. Stimulation was carried out inside a no noise site by means of a horn in free field. The sign was filtered at between 100 and 3,000 Hz and analyzed in a computer for provoked potentials (Racia APE 78). RESULTS: In data shown by amphibians, wave-evoked responses showed greater latency than those of the other species. In reptiles, latency was observed as reduced in comparison with amphibians. In the case of birds, lesser latency values were observed, while in the case of guinea pigs latencies were greater than those of doves but they were stimulated by 10 dB, which demonstrated best auditory threshold in the four studied species. Last, it was corroborated that as the auditory threshold of each species it descends conforms to it advances in the phylogenetic scale. CONCLUSIONS: Beginning with these registrations, we care able to say that response for evoked brain stem potential showed to be more complex and lesser values of absolute latency as we advance along the phylogenetic scale; thus, the opposing auditory threshold is better agreement with regard to the phylogenetic scale among studied species. These data indicated to us that seeking of auditory information is more complex in more evolved species.

Amphibians↗
PubMedDate not supplied

[Structure, occurrence and functional significance of nonlinear phenomena in sounds of terrestrial mammals].

Subharmonics, deterministic chaos, biphonations, sidebands and frequency jumps, known under joining name nonlinear phenomena, represent acoustical appearances that occur in calls of various mammals, from insectivorous to humans. Although the physical basis for appearances of the nonlinear phenomen is known in principle, such aspects as occurrence and functional significance of nonlinear phenomena, are poorly understood. We described here the structural peculiarities of these appearances based on domestic dogs' whines demonstrating all kinds of the nonlinear phenomena. The nonlinear phenomena result directly from the work of mammalian vocal apparatus--lunges, vocal folds, and vocal tract, which are responsible for its inherent functional characteristics. The mammalian vocal folds represent a system of two coupled oscillators functioning in different vibratory regimes depending on degree of synchronization in their vibrations and occurrence of coupling between the vocal folds. This functioning does not need in direct neural control for turning on the complex regimes of vocal folds' vibration and switching from one regime to another. Besides, many mammals possess anatomical structures, such as vocal membranes, pads on vocal folds, or laryngeal air sacs, that are to participate in sound production as additional oscillators extend the range of possibilities for arising of nonlinear phenomena in vocalization. On the basis of published and own data, we provide and overview of the occurrence of nonlinear phenomena in sounds of humans, nonhuman primates, canids, and rodents, and discuss the supposed functional significance of these acoustical appearances in mammalian vocal communication systems. From one side, nonlinear phenomena may be related to various physiological disorders in humans and animals. In such cases, their appearance in calls may be nonadaptive, because they permit conspecifics' to avoid owners of such "ill" voices, and points easy prey to predators. From another side, in some cases the nonlinear phenomena may arise especially for performing of some signal functions in species communication system: to enhance reliability of individual recognition, to transmit information about size of a caller over the large distance, to permit individuals of not great size mimicry acoustically under more larger animal, to introduce variety into monotonous vocal sequences in order to force other group members to pay attention to a caller, and to facilitate distance estimation to a caller and direction of its movement.

Animal Communication↗
PubMed2005

Detection of Bartonella species from ticks, mites and small mammals in Korea.

We investigated the prevalence of Bartonella infections in ticks, mites and small mammals (rodents, insectivores and weasels) collected during 2001 through 2004, from various military installations and training sites in Korea, using PCR and sequence analysis of 16S rRNA, 23S rRNA and groEL heat shock protein genes. The prevalence of Bartonella spp. was 5.2% (n = 1,305 sample pools) in ticks, 19.1% (n = 21) in mesostigmatid mites and 13.7% (n = 424 individuals) in small mammals. The prevalence within the family Ixodidae was, 4.4% (n = 1,173) in Haemaphysalis longicornis (scrub tick), 2.7% (n = 74) in H. flava, 5.0% (n = 20) in Ixodes nipponensis, 11.1% (n = 9) in I. turdus, 33.3% (n = 3) in I. persulcatus and 42.3% (n = 26) in Ixodes spp. ticks. In rodents, the prevalence rate was, 6.7% (n = 373) in Apodemus agrarius (striped field mouse) and 11.1% (n = 9) in Eothenomys regulus (Korean red-backed vole) and in an insectivore,Crocidura lasiura, 12.1% (n = 33). Neither of the two weasels were positive for Bartonella spp. Phylogenetic analysis based on amino acid sequence of a portion of the groEL gene amplified from one A. agrarius spleen was identical to B. elizabethae species. We demonstrated the presence of Bartonella DNA in H. longicornis, H. flava and I. nipponensis ticks, indicating that these ticks should be added to the growing list of potential tick vectors and warrants further detailed investigations to disclose their possible roles in Bartonella infection cycles.

Animals↗
PubMed2006

Antibodies to West Nile virus in asymptomatic mammals, birds, and reptiles in the Yucatan Peninsula of Mexico.

Surveillance for evidence of West Nile virus (WNV) infection in taxonomically diverse vertebrates was conducted in the Yucatan Peninsula of Mexico in 2003 and 2004. Sera from 144 horses on Cozumel Island, Quintana Roo State, 415 vertebrates (257 birds, 52 mammals, and 106 reptiles) belonging to 61 species from the Merida Zoo, Yucatan State, and 7 farmed crocodiles in Ciudad del Carmen, Campeche State were assayed for antibodies to flaviviruses. Ninety (62%) horses on Cozumel Island had epitope-blocking enzyme-linked immunosorbent assay (ELISA) antibodies to flaviviruses, of which 75 (52%) were seropositive for WNV by plaque reduction neutralization test (PRNT). Blocking ELISA antibodies to flaviviruses also were detected in 13 (3%) animals in the Merida Zoo, including 7 birds and 2 mammals (a jaguar and coyote) seropositive for WNV by PRNT. Six (86%) crocodiles in Campeche State had PRNT-confirmed WNV infections. All animals were healthy at the time of serum collections and none had a history of WNV-like illness.

Animals↗
PubMed2004

[Ectoprasitic mites of the families Myocoptidae and Listrophoridae (Acari: Astigmata) infecting mammals in Poland].

Mites of the family Myocoptidae and Listrophoridae (Acari: Astigmata) are permanent, mono- or oligoxenous ectoparasites of mammals. Only 9 species from 4 genera of Myocoptidae are reported in Poland, as well 6 species from 4 genera of Listrophoridae, which are only a small fraction of huge number of these mites known in the world. This paper summarize known data about morphological features being adaptation of Myocoptidae and Listrophoridae to parasitize fur of mammals.

Animals↗
PubMed2006

[Genomic imprinting in the epigenetics of mammals].

Genomic imprinting is one of the most remarkable and important epigenetic phenomena. A biological ban on parthenogenetic and androgenetic development of mammals is an obvious consequence of genomic imprinting. Genomic imprinting defects may cause malformations, clinical syndromes, and tumor growth in humans and to the large offspring syndrome and an increased mortality after in vitro manipulations with early embryos in mammals. Differential expression of parental alleles during ontogeny implies a mechanism of reversible, selective marking of gene alleles. These relatively stable epigenetic modifications, which do not affect the primary nucleotide sequence of DNA, may be transmitted in somatic cell lines and reproduced in the germ line. The genomic imprinting mechanism may be involved in other epigenetic processes, such as epigenetic inheritance, nonrandom allele segregation, meiotic drive, etc. Artificial modulation of genomic imprinting effects with the use of growth factors and demethylating agents permits partial "normocoping" during the development of parthenogenetic mouse embryos. Targeted changes in the transcriptional activity of imprinted genes provide prerequisites for epigenetic correction of syndromes and diseases caused by genomic imprinting defects.

Animals↗
PubMed1991

Parasites of domestic and wild animals in South Africa. XXVI. The mosaic of ixodid tick infestations on birds and mammals in the Mountain Zebra National Park.

Sixteen species of ixodid ticks were collected over varying periods of time from 6 species of ground-frequenting birds and 15 species of small and large mammals in the Mountain Zebra National Park, Karoo, Cape Province. Margaropus winthemi followed by Rhipicephalus glabroscutatum and Rhipicephalus evertsi evertsi were the most abundant species. The host preferences of 14 tick species and the seasonal abundances of 13 species were determined. Small numbers of immature stages of only a few tick species were generally recovered from ground-frequenting birds, mice and rats. Amongst the slightly larger animals the smallest number of ticks and species were recovered from springhares and the largest numbers from scrub hares. Amongst the larger mammals, very few ticks were harboured by springbuck and black wildebeest, while heavy infestations of several species were encountered on Cape mountain zebras and eland.

Animals↗
PubMedDate not supplied

[Energy metabolism and the direction of evolutionary progress in the class of mammals].

The data on dependence of standard metabolism on body weight in 518 mammalian species have been summarized. Standard metabolism differs in representatives of different classes and families. The higher it is, the more complicated is the organization of the animals. Comparison of standard metabolism in different classes of mammals with the time of their paleontological origin demonstrates that evolutionary process in mammals was directed towards the increase in energetic metabolism of animals.

Animals↗
PubMed1990

Susceptibility of wild mammals to infection with Naegleria fowleri.

Animals of 4 families of small wild mammals were live-trapped and inoculated intranasally with Naegleria fowleri to determine patterns of susceptibility. Of the 7 species of animals examined, only rodents were susceptible to N. fowleri. Susceptible animals were eastern gray squirrel, hispid cotton rat, muskrat, and house mouse. Mammals that were not susceptible at a dose of 10(6) were opossum, raccoon, and eastern cottontail rabbit. Perhaps rodents and humans share a common anatomical or physiological determinant that makes them susceptible to infection with N. fowleri.

Amebiasis↗
PubMed1990

Comparative cytoarchitectonics of the parabrachial nuclear complex in mammals.

The cytoarchitectonics of the parabrachial nuclear complex (PBNC) were studied in brain stem sections, stained with cresyl violet, from laboratory and phylogenetically interesting mammals. In all the animals studied, the PBNC can be separated into the following subnuclei: dorsal (D), dorsomedial (DM), dorsolateral (DL), lateral (L), medial (M), ventral (Ve) and the less distinct interstitial subnucleus (I). According to the nomenclature used hitherto, D, DM, DL, I and L belong to the ncl. parabrachialis lateralis (or dorsalis) and M and Ve to the ncl. parabrachialis medialis (or ventralis). In most laboratory animals (rodents, the rabbit), the individual subnuclei are roughly all the same size. In other phylogenetically interesting mammals, however, the size of some subnuclei deviates from the laboratory animal "norm". A comparison among these animals shows that in higher primates three of the six parabrachial subnuclei are enlarged. In insectivores the subncl. lateralis and subncl. medialis are also enlarged--possibly as an expression of a definite phylogenetic trend. In the discussion, the previously known connections of the PBNC are included and it is shown that each subnucleus has its characteristic connections.

Animals↗
PubMedDate not supplied

[The extracellular epidermal compartment of mammals].

The structure and function of the intercorneocyte cement of the corneal layer of epidermis in mammals has been reviewed on the basis of the author's and published data. Two functions of the layer have been considered: a water-tight barrier and a desquamation. Chemical structure of the barrier has been characterized. Comparison of the barrier in water and terrestrial mammals suggest that the peculiarities of the barrier correlate with different pathways of keratinization. Factors that determine the adhesion have been described. The authors show the possibility to use natural models for studying the processes of keratinization and, in particular, functioning the intercellular compartment of the corneal layer.

Amphibians↗
PubMed1988

Man, apes, and Old World monkeys differ from other mammals in the expression of alpha-galactosyl epitopes on nucleated cells.

The study of the expression of alpha-galactosyl epitopes on various mammalian cells is of particular interest, since as much as 1% of circulating IgG antibodies in humans interact with this carbohydrate residue. This natural antibody, designated "anti-Gal," was previously found to bind to terminal Gal alpha 1----3Gal beta 1----4GlcNAc-R on biochemically defined glycolipids (Galili, U., Macher, B. A., Buehler, J., and Shohet, S. B. (1985) J. Exp. Med. 162, 573-582; Galili, U., Buehler, J., Shohet, S. B., and Macher, B. A. (1987) J. Exp. Med. 165, 693-704). The expression of anti-Gal binding epitopes on nucleated cells from various mammalian species was studied by immunostaining with this antibody. The binding of anti-Gal to various cells was correlated with the binding of the lectin Bandeiraea (Griffonia) simplicifolia IB4 (BS lectin). The BS lectin also interacts with alpha-galactosyl residues and particularly with high affinity with Gal alpha 1----3Gal beta 1----4GlcNAc residues. We observed a striking evolutionary pattern in the expression of these epitopes on mammalian nucleated cells. Fibroblasts, epithelial cells, endothelial cells, smooth muscle cells, and lymphoid cells of nonprimate mammals, prosimians, and New World monkeys readily bound both anti-Gal and BS lectin. However, no such binding was detectable on cells of Old World monkeys, apes, and humans. Measurment of the binding of radiolabeled BS lectin to the various nucleated cells suggests that cells binding anti-Gal express 10(6) to 3.5 x 10(7) alpha-galactosyl epitopes, most of which, based on the anti-Gal specificity, seem to have the structure of Gal alpha 1----3Gal beta 1----4GlcNAc-R. The absence of these epitopes from human cells results from diminished activity of the enzyme alpha 1----3 galactosyltransferase, which catalyzes the following reaction. Gal beta 1----4GlcNAc-R + UDP-Gal(alpha 1----3-galactosyltransferase)----Gal alpha 1----3Gal beta 1----4GlcNAc-R + UDP This enzyme, which participates in the glycosylation of cell membrane glycoconjugates in nonprimate mammals, prosimians, and New World monkeys, appears to have been suppressed in Old World primates as a result of evolutionary events which occurred 20-30 million years ago. It is argued that an anomalous activity of this enzyme in man may result in initiation of autoimmune diseases because of the de novo expression of Gal alpha 1----3Gal beta 1----4GlcNAc-R epitopes recognized by anti-Gal.

ABO Blood-Group System↗
PubMedDate not supplied

[An attempt to search for the correlations between the indices of plague infectivity in small mammals and fleas].

On the basis of faunal analysis of 1.2 mln fleas collected from about 300,000 individuals belonging to 30 species of small mammals were obtained average indices of abundance and similarity between faunas of ectoparasites of different animals in a number of autonomous plague nidi of the Aral sea area. Their comparison with published earlier average data on the infection of mammals with plague has revealed notable statistical connections between these indices in all nidi under study. Thus, has been shown a leading role of transmission of plague microbe by fleas in the maintenance of natural nidality of this zoonosis. At the same time a new confirmation of the multiple-host nature of Middle Asian natural nidus of plague has been obtained.

Animals↗
PubMed1988

Ultrastructural studies on the boundary tissue of the seminiferous tubules of different mammals.

The aims of our studies were to compare the ultrastructure of the boundary tissue of seminiferous tubules of various mammals (rat, mouse, hamster, guinea pig, rabbit, ram, bull and man). Visual analysis of electron micrographs revealed the similarity of structure of all layers at investigated animals. The boundary tissue consists of 4 layers: 1) amorphous inner lamina, 2) cellular inner lamina, 3) amorphous outer lamina, 4) cellular outer lamina. The outer lamina of boundary tissue of rat, mouse and hamster revealed in histochemical reactions meshes resembling honey-combs. The wall of seminiferous canalicules of bull and ram consists of more bigger and different structure than one at the other laboratory animals. The most different structure of boundary tissue in man was observed. The capillary vessels penetrate in the myofibroblastic layer, when comparted to that found in other mammals on the surface of the wall.

Adenosine Triphosphatases↗