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V V Tkach

Publications and source records attributed to V V Tkach.

At least 19 recordsLinked to original sources
PubMed2004

Taxonomic revision of Hilmylepis Skryabin & Matevosyan, 1942 (Cyclophyllidea: Hymenolepididae).

Three species of Hilmylepis Skryabin & Matevosyan, 1942 are redescribed: H. nagatyi (Hilmy, 1936) from shrews Crocidura foxi, C. theresae, C. giffardi and C. occidentalis in the Ivory Coast; H. raillieti (Joyeux & Baer, 1950) on the basis of syntypes from C. russula in France; and H. prokopici Genov, 1970 from C. leucodon and C. suaveolens in Bulgaria. The holotype of H. sharpiloi Tkach & Velikanov, 1990 from Diplomesodon pulchellum in Turkmenistan is figured and a brief description of the species, based on that of Tkach & Velikanov (1990), is presented. The major reliable diagnostic characters of Hilmylepis are re-evaluated. The number and length of the rostellar hooks, the shape of the rostellum and the host-range of Hilmylepis spp. are considered as the main distinguishing characters applicable at the species level. An amended generic diagnosis and an identification key to Hilmylepis spp. are presented.

Animals↗
PubMed2003

Phylogeny and classification of the Digenea (Platyhelminthes: Trematoda).

Complete small subunit ribosomal RNA gene (ssrDNA) and partial (D1-D3) large subunit ribosomal RNA gene (lsrDNA) sequences were used to estimate the phylogeny of the Digenea via maximum parsimony and Bayesian inference. Here we contribute 80 new ssrDNA and 124 new lsrDNA sequences. Fully complementary data sets of the two genes were assembled from newly generated and previously published sequences and comprised 163 digenean taxa representing 77 nominal families and seven aspidogastrean outgroup taxa representing three families. Analyses were conducted on the genes independently as well as combined and separate analyses including only the higher plagiorchiidan taxa were performed using a reduced-taxon alignment including additional characters that could not be otherwise unambiguously aligned. The combined data analyses yielded the most strongly supported results and differences between the two methods of analysis were primarily in their degree of resolution. The Bayesian analysis including all taxa and characters, and incorporating a model of nucleotide substitution (general-time-reversible with among-site rate heterogeneity), was considered the best estimate of the phylogeny and was used to evaluate their classification and evolution. In broad terms, the Digenea forms a dichotomy that is split between a lineage leading to the Brachylaimoidea, Diplostomoidea and Schistosomatoidea (collectively the Diplostomida nomen novum (nom. nov.)) and the remainder of the Digenea (the Plagiorchiida), in which the Bivesiculata nom. nov. and Transversotremata nom. nov. form the two most basal lineages, followed by the Hemiurata. The remainder of the Plagiorchiida forms a large number of independent lineages leading to the crown clade Xiphidiata nom. nov. that comprises the Allocreadioidea, Gorgoderoidea, Microphalloidea and Plagiorchioidea, which are united by the presence of a penetrating stylet in their cercariae. Although a majority of families and to a lesser degree, superfamilies are supported as currently defined, the traditional divisions of the Echinostomida, Plagiorchiida and Strigeida were found to comprise non-natural assemblages. Therefore, the membership of established higher taxa are emended, new taxa erected and a revised, phylogenetically based classification proposed and discussed in light of ontogeny, morphology and taxonomic history.

Animals↗
PubMed2001

Intraspecific variability among NADH dehydrogenase subunit 1 sequences of Taenia hydatigena.

This paper describes intraspecific variability of the partial sequences of the mitochondrial ND1 gene among isolates of Taenia hydatigena from pigs in Poland, Ukraine and Wales. The differences between studied isolates ranged from 0.4 to 5.5%, which exceeds the variability within the same fragment between the different genetic variants of Echinococcus multilocularis and is comparable with the variability between the most closely related strains (G5/G6/G7) of E. granulosus. The biggest difference (5.5%) was found between the geographically most distant Ukrainian and Welsh samples of T. hydatigena while the samples collected from the neighbouring locations in Poland, were most similar to each other.

Animals↗
PubMed2001

Allassogonoporus callosciuri n. sp. (Digenea: Allassogonoporidae) from the plantain squirrel Callosciurus notatus (Boddaert) (Rodentia: Sciuridae) in Borneo.

A new digenean, Allassogonoporus callosciuri n. sp. from the plantain squirrel Callosciurus notatus from the Malaysian state of Sarawak, Borneo, is described. The new species differs from: A. amphoraeformis by the size of the ventral sucker and the position of the vitellarium and uterus; and from A. marginalis by the smaller oral sucker, the position of the testes and vitellarium; from A. vespertilionis by the position of the vitellarium, testes and ovary; from A. asymmetrica by the position of the testes and uterus. Gilford's (1955) and Dubois' (1963) opinions on the synonymy of Allassogonoporus and Myotitrema is supported. No representatives of the family Allassogonoporidae have been reported previously from sciurids or South-East Asia.

Animals↗
PubMed2001

Phylogenetic and biogeographical relationships among some holarctic frog lung flukes (Digenea: Haematoloechidae).

A phylogenetic study of 8 North American and European species of frog lung flukes belonging to Haematoloechus was conducted using approximately 850 to 1,000 bases of the intemal transcribed spacer region (ITS 1 + 5.8S + ITS 2) and 1,250 bases of the large subunit (LSU) of the nuclear ribosomal DNA. Adequate phylogenetic resolution could not be obtained from 5.8S or ITS 2 data. Analysis of ITS 1 data produced 2 equally parsimonious trees that differed only in the position of Haematoloechus breviplexus relative to H. medioplexus and H. varioplexus. Single, identical trees were produced by analysis of both LSU sequence data and a data set comprised of all ITS and LSU data. All trees demonstrated 3 distinct evolutionary lineages within the Holarctic Haematoloechus examined. The results confirmed the taxonomic validity of H. abbreviatus and demonstrated that the presence or absence of extracecal uterine loops is not a character meaningful to the recognition of evolutionary lineages or differentiation of genera. Examination of ITS sequence data revealed almost no intraspecific variation within 5 species of Haematoloechus and demonstrated an approximately 150-base indel common to the North American H. longiplexus and the European H. asper. Two of 3 clades revealed by the phylogenetic analyses are comprised of both European and North American species, indicating that lineages of Haematoloechus arose before the breakup of Laurasia and radiated after Eurasia and North America split. Within each of 3 evolutionary lineages, members share similar patterns of arthropod host specificity distinct from patterns found in the other lineages. This suggests that second intermediate host specificity may be a trait that has been conserved through evolutionary time.

Animals↗
PubMed2000

Molecular and morphological differentiation between species of the Plagiorchis vespertilionis group (Digenea, Plagiorchiidae) occurring in European bats, with a re-description of P. vespertilionis (Müller, 1780).

The taxonomic history of the species of Plagiorchis Lühe, 1899 occurring in European bats has been very confused because of high morphological similarity between different forms/species and the inadequate initial description of P. vespertilionis (Müller, 1780). As morphological data alone have not provided enough convincing arguments to solve the problem, the sequences from the nuclear rDNA ITS region (ITS1, 5.8S and ITS2) of three species of the P. vespertilionis group (P. vespertilionis, P. muelleri Tkach & Sharpilo, 1990 and P. koreanus Ogata, 1938) occurring in European bats were used to test the validity of these species and evaluate some of the morphological characters used for the species differentiation within this group. P. elegans from birds was used as the outgroup in the analysis. All three ingroup species were clearly distinguishable using ITS sequences. Among them, P. koreanus occupied a basal position, while P. vespertilionis and P. muelleri appeared as a cluster of two closely related, derived species. ITS sequences of the specimens obtained from different hosts and/or geographical areas did not exhibit any intraspecific variability. Morphological study of the material in collections revealed characters which enable the species of Plagiorchis from bats in Europe to be distinguished. Taking into account that the type-material of P. vespertilionis. described during the 18th Century, has been lost, for nomenclatural stability, a neotype is established and described. An amended description of the type-material of P. muelleri and keys for the determination of Plagiorchis spp. from European bats are presented.

Animals↗
PubMed2000

[Effect of intraventricular infusion of Licvorin on general convulsive activity of rats].

It was studiet anticonvulsive action of the biopreparation licvorin had been made from a cerebrospinal fluid (CSF) of a cattle on the epiliptic activity provoking by korasol. The preparation was infused intraventriculary. Research showed preparation had the antiepileptic effect. It was manifested by decreasing expressiveness of convulsions, averting of general epileptic fit and mortality. Anticonvulsive action of the biopreparation licvorin was registrated in 2 hours and was achieved maximum effect 24 hours after injection. Anticonvulsive properties of the biopreparation licvorin realized by influence his active factors on structures of a brain, specifically on the GABAdependent systems.

Animals↗
PubMed1998

Maritrema neomi n. sp. (Digenea: Microphallidae) from water shrews (Neomys).

Maritrema neomi n. sp. is described based on specimens found in the intestine of the Mediterranean water shrew (Neomys anomalus) from the Ukrainian part of the Carpathian Mountains. The most important diagnostic features of M. neomi are the body size, sucker ratio, shape and length of the cirrus sac, the cirrus sac/body length ratio, and the topography of the intestinal ceca. Maritrema neomi differs from Maritrema carpathica in the length and shape of body, size of eggs and vitelline follicles, and length of uterus; from Maritrema feliui, in length of cirrus sac, the cirrus sac/body length ratio, and length of intestinal ceca; from Maritrema pyrenaica, in the suckers ratio, shape of body, and size of some internal organs; and from metacercariae of Maritrema galloprovinciale, by much smaller size of body and internal organs, size of vitelline follicles, and topography of the vitellarium. The life cycle of M. neomi involves as intermediate hosts prosobranch snails (Terrestribythinella) and gammarid crustaceans (Gammarus (Rivulogammarus) balcanicus).

Animals↗
PubMed1996

Scanning electron microscopy of the rare nematode species Pterygodermatites bovieri (Nematoda:Rictatuliriidae), a parasite of bats.

External morphology of the nematode Pterygodermatites bovieri (Blanchard, 1886), a very rare parasite of bats in the Palaearctic region, was studied by scanning electron microscopy. Special attention was paid to the cephalic end structure and cuticular armament, which are of great systematic importance in this group of nematodes. The mouth opening of P. bovieri is subterminal and oriented dorsally. Numerous sclerotized denticles, arranged in two rows, are situated in the buccal cavity around the mouth opening. They are better developed in its ventral part. In females there are 12-14 ventral denticles. Cephalic papillae are arranged in two rows: internal (six papillae--two dorsal, two lateral and two ventral) and external (four papillae). Amphids are small, situated close to lateral, cephalic papillae of the internal row. Males possess 40-41 cuticular combs in each ventro-lateral plate row, and, in addition, a short row of four ventral, unpaired precloacal fans. Females in our material possessed 68 cuticular elements represented by combs and spines, in each row. Changes of the cuticular elements shape along the nematode body length are described. Results of SEM observations are compared with previous descriptions of P. bovieri based on the light microscopical observations.

Animals↗
PubMed1994

Description of cysticercoid of Coronacanthus vassilevi Genov, 1980 (Cestoda:Hymenolepididae).

Genus Coronacanthus Spassky, 1954 contains three species--C. integra (Hamann, 1891), C. omissa (Baer et Joyeux 1943) and C. vassilevi Genov, 1980--but larval stages of only first two species were described before. During 1991-1993 cysticercoids of all three species were found from gammarid crustaceans in Eastern Carpathians. The article contains an illustrated description of the cysticercoid of C. vassilevi. It differs considerably from the formerly known Coronacanthus larvae by the egg-shaped (not lens-shaped) form of the cyst, absence of marginal thickening of the cyst wall, by the shape and length of cercomer and besides, by the invagination of the anterior part of the scolex. Microvilli on the cyst surface were not detected with light microscope. Cercomer of C. vassilevi is narrow and very long as for mammalian hymenolepidid (4.7 to 8 times longer than cyst). The number (37-38), length (8-9 microns) and shape of rostellar hooks well correspond to those of adult worms (Genov, 1980).

Animals↗
PubMed1991

Pseudhymenolepis turkestanica sp. n. (Cestoda: Hymenolepididae), a new cestode from shrews.

An illustrated description of the Pseudhymenolepis turkestanica sp. n., a new cestode from piebald shrew (Diplomesodon pulchellum) from Middle Asia is given. P. turkestanica differs from the most similar species P. papillosa Hunkeler, 1970 by the measures of the scolex and rostellum, the number of rostellar hooks and the size of embryonic hooks. P. turkestanica is considered as a specific parasite of D. pulchellum.

Animals↗
PubMed1982

[Structure and physicomechanical properties of the human dura mater from the age aspect].

The reconstructive surgery embracing a wide range of operations, when the dura mater is used as plastic material, requires a profound study of its physico-mechanical and structural properties. The dura mater obtained from 150 human corpses of persons at the age of 1 month of embryogenesis up to 90 years has been studied by means of morphological, histochemical methods and using the device for mechanical testing of various biological materials. In ontogenesis of the dura mater three states are arbitrary distinguished: development, stabilization of morphological structures and involutional-degenerative changes. Specific feature of each stage are described. Owing to the investigations performed, it is possible to state optimal time range for taking transplants and widening the limits for choosing for plastic material with the reference to the required strength, thickness,, stretching and elasticity.

Adolescent↗
PubMed1981

[Changes in vessels of the microcirculatory bed following parenteral administration of xenogeneic cerebrospinal fluid obtained in vivo to normal animals and animals with experimental hypercholesterolemia].

Effect of parenteral administration of xenogenic liquor, vitally obtained, on the state of the microcirculatory bed, as well as its biostimulating action for cellular metabolism activation have been studied. The number of actively functioning capillaries increases, microvessels dilate, vascular permeability intensifies not only under normal conditions, but under experimental hypercholesteremia, as well. How the changes observed in the microcirculatory bed depend on various doses and total amount of the preparation administered, as well as means of its conservation have been analysed and stated. The dynamics of indices on lipid metabolism have been studied.

Animals↗
PubMed1980

[Experimental-morphological reasons for using dura mater for plastic surgery of defects of the anterior abdominal wall].

A possibility to use preserved dura mater (in 2% formalin) for substituting various abdominal wall layers under both sterile and infectious conditions has been studied experimentally in 126 dogs. Morphological investigation has been performed at various postoperative time (1 day--2 years). It has been stated that the dura mater implantation produces minimal aseptic inflammatory reaction in the abdominal wall tissues. The transplant is gradually disorganized and resolved and simultaneously substituted with the connective tissue. There are no commissurae between the transplant and the abdominal organs. The dura mater is resistive to infections. Application of the dura mater for surgery of hernia of the abdominal wall is substantiated.

Abdominal Muscles↗
PubMed1979

[Prevention of asphyxia in tracheomalacia after operations of the thyroid gland].

A new technique for prevention of asphyxia in tracheomalacia has been developed. The technique consists in suturing the softened portion of the trachea to the dura mater graft which had been previously fixed to its healthy portions. Such a technique allows performing reliable fixation of the tracheomalacia portion in an extended state and thereby to prevent asphyxia, The technique was used in 11 operated patients and gave good results.

Asphyxia↗