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A L Iudin

Publications and source records attributed to A L Iudin.

At least 19 recordsLinked to original sources
PubMed2006

[Mating types in the ciliate Dileptus anser. Inheritance and genetic determination].

Hybridological analysis of mating types (MTs) has been first made for the lower ciliate Dileptus anser. Clones of an initially unknown genotype belonging to three MTs (MT I, MT II and MT III), characteristic of D. anser, were isolated from natural reservoirs and further used for crosses. In one group crosses, synclonal inheritance and typical Mendelian behaviour of the character were observed over sexual generations of ciliates. The results suggest that MTs in D. anser may be directly controlled by a single mat locus with three alleles showing peck-order dominance (mat1 > mat2 > mat3). In other words, cells with mat1/mat1, mat1/mat2 and mat1/mat3 genotypes belong to MT I, those with mat2/mat2 and mat2/mat3, and the mat3/mat3 belong to MT II and MT III, respectively. Sexually mature exconjugant clones stably retain their MTs corresponding to their genotypes on vegetative reproduction. The progeny of other group crosses showed various deviations from typical Mendelian behaviour of the character. In some cases, standard Mendelian ratios were more or less violated. Most typical was instability of differentiation for MT in maturing exconjugant clones. Shortly after their maturation, the majority of clones change their MT, rather frequently more than once, although the finally established MT is stably inherited afterwards, during vegetative reproduction. When unstable, exconjugant clones can successively express two or even three MTs characteristic of this species, including MTs that should not have been expected on the basis of parental genotypes available in a given cross. It looks likely that the mat locus in D. anser is complex and multipotential; it is inherited as a whole providing for expression of any MT characteristic of the species (in this respect bearing similarity with Tetrahymena thermophila). Other mechanisms, epigenetic in particular (Nanney, 1958), determine the final expression of one of the three MT potentialities by a given exconjugant clone. Stable, persistent functioning of these mechanisms ensures a stable differentiation for MT and Mendelian behaviour of the character in sexual generations and in crosses. Any disturbances in differentiation control may trigger MT instability in maturing exconjugant clones and violation of regular Mendelian behaviour.

Animals↗
PubMed2004

[Mating types in the ciliate Dileptus anser. Shortening of maturation period after micrurgical bisection of exconjugant cells].

In many ciliates, young exconjugant clones demonstrate sexual immaturity: they are not able to conjugate with mature cells of complementary mating types (MTs). After several scores of cell divisions, a short period of adolescence (partial maturity) commonly occurs followed by maturation, after which these cells are able to conjugate with cells of other, i.e. complementary, MTs again. Tavrovskaja (1981) reported a significant reduction in the maturity period in Dileptus anser clones, grown from exconjugant ciliates regenerated from small cell fragments. To verify this, in the present study exconjugant D. anser cells were bisected with glass needle after 3 to 4 cell divisions following conjugation. The same procedure was performed with survived and regenerated cells on the 2nd and 3rd days. The clones thus obtained were cultivated, and their ability to mate with each of the three standard clones of MT I, II and III was tested week by week. Indeed, in 22 F1 clones from cross N 7C (MT I) x N 2 (MT II) the immaturity period was reduced 1.4-3.4-fold (2.18 in average) after a threefold bisection, as compared with that in intact subclones. Similarly, in 27 F1 clones from cross N 20 (MT I) x N 14 (MT II) this period was shortened 1.6-3.0-fold (2.19 in average). 12 of these clones showed a 0.9-2.4-fold (1.53 in average) reduction after a single bisection, and 1.6-2.8 (2.12 in average) after a threefold operation. Thus, micrurgical fragmentation of young exconjugant cells can be used to accelerate maturation in D. anser.

Animals↗
PubMed2003

[Mating types in the ciliate Dileptus anser. Genetical instability in the mating type system].

In F1 and F2 from a cross between two clones of Dileptus anser isolated from natural sources (MT 1 x x MT III; MT = mating type), along with "normal" clones, many clones were observed demonstrating abnormal phenotype with respect to the MT-character. Irregular features of the latter were as follows: a) a delay in maturation; b) temporary reversion to immature or adolescent state, which means instability of maturity state; c) expression of MT I and MT III, rather than MT II as in properly matured clones; d) changes in MT (i.e., MT instability); e) appearance of totally unexpected MTs in terms of the scheme of genetic control of MTs in D. anser previously suggested by Afon'kin and Yudin (1987)--e.g., of all three MTs in F1 from the initial (analysing!) cross. Amazingly, these abnormal D. anser clones closely resembled some selfer-clones of Tetrahymena pigmentosa, previously reported as an example of genetic instability in the ciliate MT system (Simon, 1980; Simon, Orias, 1987).

Animals↗
PubMed2001

[Re-expression of various i-antigens in Dileptus anser after temporary transformation of serotype].

RNP particles containing 20S prosomes (alpha RNP) isolated from human epidermoid carcinoma cell line A-431 are shown to posses strong and regulated endonuclease activity specific for high-molecular-weight RNA, particularly, specific mRNAs. Furthermore, alpha-RNP destabilize the 3'-untranslated regions of c-myc mRNA, creating a specific cleavage pattern. Cleavage point within Alu sequence in high-molecular-weight RNA has been localized by primer-extension method. This RNase activity is induced under the action of EGF. alpha-RNP involvement in the coordinated control of processing and stability of specific messenger RNA molecules is suggested. The endoribonuclease activity of alpha-RNP can represent a link between EGF signalling pathway and RNA processing and degradation.

Animals↗
PubMed2000

[Mode of serotype inheritance in exoconjugant progeny of the ciliate Dileptus anser].

Two clones of Dileptus anser, originally isolated from natural reservoirs and referred to below as B and D clones, were found to display different serotypes, when cultured under identical laboratory conditions. On being tested with two different polyclonal rabbit immune sera against each particular clone (the classic immobilization test) these clones showed no cross-reaction. At a standard dilution (1:50) and at a standard exposure time (4 h), either of the two immune sera immobilized 100% or commonly 0% of homologous and heterologous clone cells, respectively. In addition, the difference in serotypes was confirmed by the immunofluorescence analysis. By crossing (conjugation) between B (mating type I) and D (mating type III) cells, exconjugant F1 clones were obtained. Their serotypes were then tested (the same immobilization test) with antisera against both the "parental" clones: some clones were tested before their sexual maturation in ca. one month after conjugation, while others were examined in approximately 4 months after conjugation, i.e. after reaching maturity. Each of the F1 clones could react with both immune sera, which means that they possessed the intermediate, "hybrid" phenotype. Five different F1 clones were selected, and each of them was back-crossed to both "parental" clones, B and D. We succeeded in raising 25 exconjugant F2 (B1, to be more exact) clones from F1 x B crosses and 26 clones from F1 x D crosses. The conventional testing of these clones in 5-10 weeks after conjugation provided quite unexpected results, since among them no segregation for "parental" serotypes was observed. Each of the 51 tested clones demonstrated the "hybrid" serotype--seemingly the same as that of F1 clones. Such a non-Mendelian inheritance of the character is hardly to explain from the standard, canonical assumptions on the genetic control of serotype difference between original "parental" clones (different alleles in one locus? different loci?). Also it does not seem likely that the absence of segregation could result from differential survival of various phenotypes in F2 (although the total viability of exconjugant clones appeared rather low). The above data obviously need further confirmations and experimental analyses. We attempt to discuss the obtained results in terms of the epigene hypothesis (Tchuraev, 1975) and in relation to the epigenetic control of serotype expression in species of the Paramecium aurelia complex and in Tetrahymena thermophila, which are "the chosen few" subjects in ciliate genetics.

Animals↗
PubMed1991

[New methods of image creation in the diagnosis of superior vena cava syndrome].

A program for the examination of patients with the superior vena caval syndrome, including digital subtraction angiography and computed-tomographic phlebography, is discussed. A combination of these methods is optimal and makes it possible to obtain detailed diagnostic information which is necessary for determining the therapeutic tactics in cases with the compression syndrome.

Adolescent↗
PubMed1991

[Computerized tomography in the diagnosis of heart neoplasms].

Computed tomography (CT) was used to study 56 and 4 patients with primary and secondary cardiac blastomas, respectively. CT allows differentiation between a racemose and dense endocardial tumor, localization of myxoma pedicle, recording its prolapse into the adjacent chamber, identification of extra-, intracardiac and intramyocardial tumor growth as well as changes in adjacent vessels. CT image of cardiac myxoma is similar to a filling defect of diminished density, that of extra-endocardial tumors display polymorphism. Blastomatous invasion of the heart is characterized by blurring of cardiovascular elements boundaries, pericardial thickening and fluid accumulation. CT is advocated as a new, noninvasive and highly efficient diagnostic modality in cardiac tumors.

Adolescent↗
PubMed1991

[Various clinical and roentgenological aspects of diagnosis of postoperative empyema in pulmonary surgery].

The results of a 10-year follow-up of 101 patients with pyothorax that developed after operations on the lungs, bronchi, and trachea (5.4% of all patients who underwent operation) show a stable fever of 38 degrees C and higher, pain in the chest, leucocytosis, and a shift of the peripheral blood leucocyte count to the left to be the most constant clinical signs of suppuration of the pleura in the postoperative period. Experience convinces the authors that the initial radiological signs of pyothorax are early fragmentation of the pleural cavity after pneumonectomy and a rigid residual pleural cavity after partial lung resection. Computed tomography complements the classical radiological examination and is conductive to timely diagnosis and successful treatment of postoperative pyothorax.

Adolescent↗
PubMed1990

[The role of computerized tomography in preoperative evaluation of disseminated esophageal cancer].

The authors characterize signs of the spread of carcinoma of the esophagus to the neighboring and remote structures, which were revealed by computerized+ tomography. The value of the method in identifying the stage of esophageal carcinoma is discussed. It is shown that the complex of signs must be taken into account in determining growth of the tumor into the neighboring organs. It is concluded that computerized+ tomography helps in dividing the patients into 3 main groups: patients with curable tumors; inoperable patients; patients in whom the volume of the operative intervention can be determined only during the operation. Conduction of computerized+ tomography in patients with carcinoma of the esophagus before the operation is considered expedient.

Cardia↗
PubMed1990

[Diagnosis of spherical shadows in the lungs].

From analysis of the results of scrupulous examination of 66 patients with pathological shadows up to 3 cm in diameter found in the lungs during X-ray examination the authors established that peripheral carcinoma of the lung accounts for 65.2% of all asymptomatic accidentally revealed structures in the lungs. Computerized tomography is a valuable method of differential diagnosis of small spherical shadows in the lungs, which also makes it possible to determine the spread of the disease during a single examination of the patient. The method of fine-needle aspiration biopsy under control of computerized tomography with subsequent cytological examination of the aspired material is simple, relatively safe, and highly informative in peripheral carcinoma of the lung. The method is of less diagnostic value in cases with benign structures in the lungs.

Adult↗
PubMed1989

[Computerized tomography in evaluating the function of aortocoronary shunts].

An examination was made of 38 patients undergone aortocoronary bypass surgery. Comparing the density of content in the aorta and shunt before and after bolus contrast in computerized tomography makes it possible to evaluate the patency of the aortocoronary shunt. A shunt patency coefficient (SPC) was proposed, which fitted the ratio of density differences in the shunt to those in the lumen of the ascending aorta before and after the injection of a contrast agent. SPC equal to 0.5 or more is indicative of a good patency of the aortocoronary shunt, but that being 0.3 or less suggests no or extremely poor function of the shunt. SPCs that are equal to 0.3-0.5 are transient indicators of its patency.

Adult↗
PubMed1989

[Macrostructural analysis of peripheral lung cancer by computed tomography].

The macrostructure of peripheral cancer of the lung was studied using computed tomography-based densitometric data in 47 patients. The study was concerned with detecting epicenters of tumor growth and identifying necrosis and calcinosis. It was found that the presence of microcalcinates in tumor cannot be considered an absolute criterion of benignity. However, it may be used as indicator of the degree of lung tumor malignancy. Densitometric analysis of the said structure provides means for identifying histologic pattern of tumor, making prognosis, carrying out computed tomography-controlled aiming biopsy and improving it.

Biopsy, Needle↗
PubMed1986

[Diagnosis of heart myxomas using computerized tomography].

Procedures for computed tomography of the heart are discussed. Serial or dynamic computed tomography involving intravenous injection of contrast substance as well as application of computed tomography in synchronism with ECG provide exhaustive information on the site, size, type and mobility of heart myxomas. The latter lesion was diagnosed in 4 (left auricle--2; right auricle--2) out of 250 patients suffering different diseases of the heart and aorta. Two clinical cases are reported. Particular mention is made of the sparing nature of the procedure and its high diagnostic potential for heart myxoma detection.

Adult↗