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At least 1,693 records · Page 94Linked to original sources
PubMed2005

The role of cathelicidins in the innate host defenses of mammals.

The cathelicidin peptides comprise one of several families of antimicrobial peptides that are found in neutrophils and epithelia as components of the early host defenses of mammals against infection. All cathelicidin family members are synthesized and stored in cells as two-domain proteins. These are split on demand to produce a cathelin protein and an antimicrobial peptide. Accumulating evidence indicates that both the cathelin portion and the C-terminal peptide exert biological activities connected with host protection. This review presents an overview of the structure and biology of cathelicidins and discusses recent progress in cathelicidin research with emphasis on the functional properties and role in host defense of the human cathelicidin hCAP18/LL-37. Although investigators initially concentrated their attention on antibiotic activity, it is becoming clear now that LL-37 is a multifunctional molecule that may mediate various host responses, and thus represents an essential component of the innate immune system in humans.

Animals↗
PubMedDate not supplied

A study on 'Vermiform Appendix'--a caecal appendage in common laboratory mammals.

The vermiform appendix, a small structure without any known function in human being has been regarded as a vestigial remnant of a more developed distal caecum in man's herbivorous ancestors. A detailed study of the morphological and histological changes in the appendix and the caecum of different mammals with varying dietary habits revealed a distinctly well-defined vermiform appendix in rabbit only. However, the apical part of caecum among the carnivorous animals like cat and dog showed a clear histological picture with heavy infiltration of lymphoid tissue in the mucous & sub-mucous coats as seen in rabbit or human being. Thus, the vermiform appendix is in no way a vestigial organ but a specialized structure without any definitely known function, probably concerned with the establishment and maintenance of the body defence and immunity of the body.

Animals↗
PubMed2005

[Differentiation, protection and regeneration of hair cells and auditory neurons in mammals].

Perception deafness, as opposed to transmission deafness, results from a lesion of the sensory cells and/or of the neurons of the auditory part of inner ear. There is currently no treatment able to stop the progression of a hearing loss or to restore a lost auditory function. We review here the progress which has been made with respect to the regeneration and the protection of neurosensory structures in the inner ear. A spontaneous post-lesional regeneration of hair cells in the sensory epithelium has been observed in amphibians and birds as well as in the vestibular part of the mammalian inner ear. In contrast, hair cells regeneration in the auditory portion of the inner ear of mammals appears to be limited to the developmental stages. The objective of this first part of our work is to try to identify progenitor cells in the cochlea and to characterize factors that are able to induce their proliferation and differentiation. Otoprotection of the sensory epithelium is another therapeutical strategy aimed at preventing further degradation of the auditory function. The prevention of the deleterious effect on hair cells of several drugs such as aminoglycosides and platin derivatives has been obtained using free radical scavengers or growth factors. Studies of the development of the innervation of the inner ear suggest the potential therapeutic interest of various growth factors, mostly the neurotrophins, to maintain the innervation of the adult Corti's organ.

Animals↗
PubMed2006

Recent achievements in in vitro culture and preservation of ovarian follicles in mammals.

The mammalian ovary contains a large number of follicles that are in various developmental stages. The largest portion of them are primordial follicles. However, throughout the female reproductive lifespan only a small proportion of these follicles will produce oocytes competent to undergo successful maturation and ovulation. The rest of the ovarian oocytes (>99.9%) undergo atresia. It would be of great practical benefit to rescue some of these follicles by growing them in culture in order to provide an extra source of gametes. There is considerable interest in developing technologies that aim to produce fully-grown, developmentally competent oocytes from a pool of early developmental stages of follicles. Two methods have been used: 1/ long-term in vitro culture of either follicles or oocytes, and 2/ transplantation of ovarian tissue grafts. The development of efficient technologies may provide an additional source of oocytes for livestock production and reproduction in humans and rare or endangered species. The aim of this paper is to present a comprehensive review of recent achievements in the utilization of small ovarian follicles (primordial, preantral and early antral) by long-term in vitro culture and/or transplantation of ovarian tissue grafts (fresh and cryopreserved) in mammals including humans.

Animals↗
PubMedDate not supplied

[The evidence for the existence of an endogenous factor with digitalis activity in mammals: a physiological regulator of the sodium pump?].

In the last years a great deal of reports on the presence of endogenous digitalis-like activity in mammals have appeared in the literature. The active factor could be an endogenous ligand of the digitalis receptor and thus a physiological humoral regulator of sodium pump activity. Such an agent would necessary have a whole series of physiological and physiopathological implications. It has been proposed that the factor is a natriuretic hormone, that it participates in blood pressure regulation and in the genesis of arterial hypertension, that it plays a role in pregnancy and that it regulates cardiac contractility. These hypotheses are discussed in the present review.

Animals↗
PubMed2006

Aspects of central and peripheral regulation of reproduction in mammals.

To increase our knowledge concerning the central and peripheral regulation of reproduction in mammals a series of studies were performed. In the first experiment, we found that exogenous leptin altered the activity of the hypothalmo-pituitary-gonadotropic axis in sheep during insufficient feeding. The action of leptin appears to be mediated by changes in GnRH and LH secretion as well as NPY immunoreactivity. The aim of the second experiment was to investigate the role of the adipoinsular axis hormones during pregnancy in rats. The elevated levels of plasma leptin as wells as the increased mRNAs expression of the leptin receptors in placenta indicate the significant role of the hormone in fetal growth and development. On the other hand, a decrease in leptin receptors mRNA content within hypothalamus and pituitary together with unchanged plasma insulin level may suggest that during rat pregnancy leptin resistance was developed in the hypothalamus, pituitary and pancreatic islets. The third experiment was carried out to establish the role of opioids and glucocorticoids in the regulation of the hypothalmo-pituitary-gonadal axis in ewes during natural or synchronized estrous cycle. Prolonged treatment with progesterone resulted in significant changes in plasma levels of Met-enkephalin, cortisol and steroids and altered the expression of proenkephalin mRNA in the hypothalamus, pituitary, ovary and adrenals. Injections of Met-enkephalin or naltrexone (blocker of opioid receptors) modulated the progesterone influence in tested tissues. The data clearly suggest that opioids are involved in the regulation of the estrous cycle at the hypothalamo-pituitary-gonadal/adrenal axes.

Animals↗
PubMedDate not supplied

[Change in the antigenic structure of surface glycoprotein E of tick-borne encephalitis virus during its adaptation to ticks and mammals].

Enzyme immunoassay and immunoprecipitation test of viral proteins, by applying a tick-borne encephalitis (TBE) viral protein E monoclonal antibody kit, have shown that TBE adaptation to ticks and mammals may cause a considerable change in the antigenic structure of surface glycoprotein E, by involving different antigenic domains, including a neutralizing epitope that seems to participate at the early stages of interaction of virions with the cell membrane.

Adaptation, Physiological↗
PubMedDate not supplied

[The macrosystematics of mammals according to energy metabolism criteria].

Criteria of evolutionary progress and complexity of organization have been proposed on the basis of the data on energetic metabolism. These criteria can serve as a basis of macrosystematics of mammals at the level of orders. The orders with the known data on energetic metabolism have been ranged.

Animals↗
PubMedDate not supplied

[Spectral properties of myoglobins from aquatic mammals].

Spectral characteristics of ferri- and ferroderivatives of myoglobins have been studied in semiwater mammals. Extinction coefficients in the visible range of the spectrum have been determined for different derivatives of the studied heme proteins. It is established that variations in the maxima and minima of different absorption bands are inconsiderable. Close positions of isobestic points have been revealed for a system of oxyglobin and reduced myoglobin obtained from the muscles of the studied animals. Changes in spectral characteristics of methmyoglobins, induced by the effect of different pH, are identical, which evidences for similarity of the surroundings of active site of the studied heme proteins.

Animals↗
PubMed1991

[Pulvina-lateralis posterior nucleus complex of mammals and the visual function].

It is now well established that the lateral posterior-pulvinar (LP-P) complex of mammals is involved in visual processing. However, the actual function of these large nuclei of the thalamus remains unknown. In contrast to the nearby lateral geniculate nucleus, the LP-P complex does not receive any substantial direct projections from the retina. Its main visual inputs come from the mesencephalon and the neocortex. Most cells in the LP-P complex behave like cortical units. They are tuned to the orientation, direction, spatial and temporal frequencies of the visual stimulus. In addition, most units are binocular and sensitive to relative retinal disparity. Despite their multiple inputs, the LP-P complex cells form an homogeneous population and their overall properties do not reflect those of a given cortical or subcortical area. On the basis of its afferent and efferent connectivity, it has been proposed that the LP-P complex may serve as a relay of an extrageniculate ascendant pathway which originates from the superior colliculus, and/or provide another route for the geniculo-striate input to reach the extrastriate areas. Despite the fact that there is some electro-physiological evidence of such functions, it is now often suggested that the LP-P complex may integrate its multiple inputs and be involved in functions which go beyond those of a simple thalamic relay. Recent findings suggest that the LP-P complex might play a role in visual spatial attention.

Animals↗
PubMed1991

Beta-carbolines and tetrahydroisoquinolines: detection and function in mammals.

beta-Carbolines occur in man and rat. The concentration in various tissues is about 100 to 1000 times lower than that of classical neurotransmitters. Administration of beta-carbolines in animals induces overlapping but not identical activity profiles. The molecular modes of action differ. For example, harman (1-methyl-beta-carboline) acts as an endogenous inhibitor of monoamine oxidase [E.C. 1.4.3.4.], subtype A, whereas norharman (beta-carboline) probably acts by stimulation of a specific beta-carboline receptor which is different from the benzodiazepine-GABA receptor complex. There is substantial evidence that tetrahydroisoquinolines occur under physiological conditions as well. Whether tetrahydropapaveroline serves as a precursor of morphinanes in mammals, as has been found in opium poppies, remains to be elucidated.

Animals↗
PubMedDate not supplied

Synthesis and characterization of a novel gonadotropin hormone releasing hormone analog which stimulates reproductive functions in fish and mammals.

A novel gonadotropin hormone releasing hormone analog, (D-Phe6,Gln8,des-Gly10)GnRH ethylamide, has been developed in our laboratory which stimulates not only ovulation but also follicular maturation in various kinds of fish and mammals. A large-scale liquid phase synthesis has been worked out for this analog. The synthetic product was characterized for structure and purity by various physicochemical methods. Though its structure was derived from the native chicken type I sequence, this peptide was one of the most effective analogs among those reported so far in the literature for artificial propagation of fish. The peptide was effective both during and out of spawning season. It was also potent in treating various sexual disorders such as anestrous, inactive ovaries and follicular cysts in cows.

Amino Acid Sequence↗
PubMed1990

[Various mechanic characteristics of bony structures of the temporo-mandibular joint in several classes of mammals studied by measurement of hardness and resistance to penetration].

Applying the principles of mechanics, the authors have studied and compared the bony structures of the temporo-mandibular joint. Using the means of investigation usually implemented in the metallurgical sector, they have tried to establish a link between the morphology and mechanical strength of the various components of this joint in some subjects belonging to the mammals classification and with various feeding modes. The results obtained by hardness micrometry tend to show that during masticatory movements, the temporo-mandibular joint works in a hanging rather than in a compressed mode.

Animals↗
PubMedDate not supplied

[A comparative study of the effect of vinyl phosphoric acid esters on cholinesterase and carboxylesterase activities in mammals and arthropods].

Studies have been made of the effect of organophosphorus inhibitors on cholinesterase and carboxylesterase from various mammals (human erythrocytes, mouse brain, blood serum of mouse and rat, blood serum of horse) and arthropods (Calliphora vicina, Schizaphis graminum, Myzus persicae, Sitophilus oryzae, Pseudococcus maritimus, Tetranychus urticae). Organophosphorus inhibitors were presented by esters of vynylphosphoric acid containing normal and branched alkyls in the phosphoryl part of the molecule. The increase of the radical up to a propyl one increased the effect of organophosphorus inhibitors with respect to cholinesterase from the majority of the arthropods investigated. Organophosphorus compound with an isopropyl radical was found to be weaker for all the enzymes studied. Extremely high sensitivity of carboxylesterase from all arthropods to all organophosphorus inhibitors was noted; in some of the cases, anticarboxylesterase activity of all drugs was 2-3 orders higher than anticholinesterase one (P. maritimus, T. urticae). Regularities established for cholinesterase practically completely were confirmed on carboxylesterase. This finding evidently reveals similar structure of catalytic surface at the vicinity of esterase center in both enzymes.

Animals↗
PubMed1990

[Importance of masseter insertion surface in different mammal groups].

The objective of this study is to compare the strength of the masseter muscle in various mammals by calculating the ratio between insertion area of the masseter and total mandibular surface. We will also determine the factors capable of modifying the insertion area of this masticatory muscle.

Anatomy, Comparative↗
PubMedDate not supplied

[Circulation of the virus of hemorrhagic fever with renal syndrome among small mammals in the territory of the USSR].

Over 55,000 small mammals of 72 species trapped in 62 administrative territories practically in all landscape-geographical zones of the USSR were examined in 1980-1985. The use of current laboratory methods demonstrated a wide spread of HFRS virus in the territory of this country, involvement in the epizootic process of most species of forest and steppe murine rodents and insectivora. In each landscape zone, the main carriers of the HFRS agent were established, represented, as a rule, by the basic species having a high and stable population density.

Animals↗
PubMed1989

[Genetic variability of antigenic structure of the Lpm-protein and alpha2-macroglobulin among non-mustelid mammals].

The data on interspecific distribution and antigenic variability of homologues of mink Lpm-protein (Lpm) and alpha 2M-globulin (alpha 2M) among 43 species of 6 orders of mammals are presented. Strong variability of antigenic structure of Lpm and alpha 2M of Rodentia and Artiodactyla orders was established. This fact allows to classify the macroglobulins studied as belonging to the group of evolutionary high-speed plasma globulins. In the plasma of human and green marmoset (Cercopithecus aephiops) the only homologue of alpha 2M was found. The lack of reaction to Lpm in above-mentioned species allows to postulate significant differences between Carnivora and Primates in the organization of this gene cluster. Unique features of antigenic variability of Lpm and alpha 2M were also fixed among other systematical groups tested. Taken together, the data obtained stimulate scientific interest to the study of molecular organization of the Lpm and alpha 2M gene families.

Animals↗
PubMed1989

Parabrachial nuclear complex. A comparative study of its cytoarchitectonics in birds and some mammals including man.

The cytoarchitectonic structure of the ncl. parabrachialis of 20 bird species, 17 mammals and man was studied in sections stained with cresyl violet. This comparative study showed the six cytoarchitectonic subnuclei of the ncl. parabrachialis (subncl. medialis, dorsomedialis, dorsalis, lateralis, dorsolateralis and ventralis) to be unevenly developed in the vertebrates under study. The degree of development of the subnuclei was tabulated to bring out the developmental trends of the ncl. parabrachialis in different groups of vertebrates. Only three of the six subnuclei were found enlarged in higher primates and in man--the subncl. dorsolateralis, lateralis and medialis, the latter two (subncl. lateralis and medialis) being also larger in insectivores. The most primitive structure is that of the subncl. ventralis with features very much like those of a small-cell reticular formation. Cytoarchitectonically speaking, the parabrachial subnuclei appear to be of polyphyletic origin: the medial and dorsomedial subnuclei being close to the substantia grisea centralis, the ventral subnucleus to the small-cell lateral reticular formation, and the lateral and dorsolateral subnuclei to the ncl. pedunculo-pontinus.

Animals↗