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Biomedical subjects

P A Ivanov

Publications and source records attributed to P A Ivanov.

At least 19 recordsLinked to original sources
PubMed2006

An internal ribosome entry site located upstream of the crucifer-infecting tobamovirus coat protein (CP) gene can be used for CP synthesis in vivo.

It was previously shown that, unlike the type member of the genus Tobamovirus (TMV U1), a crucifer-infecting tobamovirus (crTMV) contains a 148 nt internal ribosome entry site (IRES)(CP,148)(CR) upstream of the coat protein (CP) gene. Here, viral vectors with substitutions in the stem-loop (SL) region of CP subgenomic promoters (TMV U1-CP-GFP/SL-mut and crTMV-CP-GFP/SL-mut) were constructed and the levels of CP synthesis in agroinoculation experiments were compared. No CP-GFP (green fluorescent protein) synthesis was detected in Nicotiana benthamiana leaves inoculated with TMV U1-CP-GFP/SL-mut, whereas a small amount of CP-GFP synthesis was obtained in crTMV-CP-GFP/SL-mut-injected leaves. Northern blots proved that both promoters were inactive. It could be hypothesized that IRES-mediated early production of the CP by crTMV is needed for realization of its crucifer-infecting capacity.

Base Sequence↗
PubMed2005

[Immunological estimation of the degree and prognosis of acute pancreatitis].

An analysis of data of immunological investigation of blood of 89 patients with a severe acute pancreatitis (SAP) on the 2-3 day of the disease has revealed changes in immunogram characteristic also of other pathological conditions and pointing to a systemic inflammatory reaction. Among the patients who did not have purulent complications against the background of therapy of SAP, the character and degree of changes in immunogram were in line with average values, and so they could be considered as "a norm of pathology". A system of scores of impairments of the immune response to the destructive process was developed for an objective evaluation of the immune status of patients with SAP. In patients with a normal physiological immune response (sum of scores 0-5) the prognosis of the disease is considered to be good. No immunocorrectors should be included in the complex of treatment measures. In patients with an inadequate pathological immune response (sum of scores 9 and more) the prognosis is unfavorable. The complex of treatment measures for such patients should include immunocorrectors.

Adult↗
PubMed2004

Evidence for contribution of an internal ribosome entry site to intercellular transport of a tobamovirus.

Previously, it has been shown that tobacco mosaic virus (TMV) U1 and crucifer-infecting TMV contain a 75 nt internal ribosome entry site (IRES) upstream of movement protein (MP) gene (IRES(U1)(MP,75) and IRES(CR)(MP,75), respectively). A movement-deficient TMV mutant, KK6, has been constructed previously [Lehto, K., Grantham, G. L. & Dawson, W. O. (1990). Virology 174, 145-157] by insertion of the second coat protein subgenomic promoter (CP SGP-2) upstream of the MP gene, in addition to the natural CP SGP-1. Here, the authors compare the efficiency of movement function expression by KK6 and a derivative, K86, obtained by insertion of IRES(CR)(MP,75) between the CP SGP-2 and MP genes resulting in restoration of IRES(CR)(MP,75) function in the 5'-untranslated sequence of the I(2) subgenomic RNA of K86. The data indicate that the efficiency of K86 movement was largely restored by this insertion, which was apparently due to the translation-enhancing ability of IRES(CR)(MP,75).

Base Sequence↗
PubMed2004

[Surgery of cholelithiasis: from past to present].

Development of surgery of cholelithiasis is regarded. Classic surgical interventions on the gall bladder and bile ducts in complicated disease (acute cholecistitis, jaundice, cholangitis), postcholecistectomy syndrome, surgical trauma of the bile ducts are substantiated. To 1980s modern views on pathogenesis of the disease have been formed. However, unresolved problems of surgical policy, traumatism of open surgeries in complicated forms of the disease (postoperative lethality in acute cholecistitis was 37% and over) made results of treatment unsatisfactory. Correction of policy's problems, application of mini-invasive procedures, diapeutic approach and precision technique opened up-to-date period in surgery of cholelithiasis. It permitted to reduce postoperative lethality in acute and chronic course of the disease to 0.08 - 0.1%.

Cholecystectomy↗
PubMed2004

[Surgical tactics in duodenal trauma].

Results of surgical treatment of 61 patients with injuries of the duodenum are analyzed. The causes of injuries were stab-incised wounds in 24 patients, missile wound -- in 7, closed abdominal trauma -- in 26, trauma of the duodenum during endoscopic papillosphincterotomy -- in 4. All the patients underwent surgery. Complications were seen in 32 (52.5%) patients, 21 patients died, lethality was 34.4%. Within the first 24 hours since the trauma 7 patients died due to severe combined trauma, blood loss, 54 patients survived acute period of trauma, including 28 patients after open trauma, 26 -- after closed and 4 -- after trauma of the duodenum during endoscopic papillosphincterotomy. Diagnostic and surgical policies are discussed. Results of treatment depending on kind and time of surgery are regarded. It is demonstrated that purulent complications due to retroperitoneal phlegmona, traumatic pancreatitis, pneumonia are the causes of significant number of unfavorable outcomes. Therefore, it is important to adequately incise and drainage infected parts of retroperitoneal fat tissue with two-lumen drainages. Decompression through duodenal tube is the effective procedure for prophylaxis of suture insufficiency and traumatic pancreatitis. Suppression of pancreatic and duodenal secretion with octreotid improves significantly surgical treatment results.

Adolescent↗
PubMed2003

[Characteristic of combat trauma and treatment of gunshot fractures of long bones of the limbs].

Treatment of the patients with gunshot fractures of extremity long bones is one of the main problems of field surgery. The complex study of medical records obtained from 718 servicemen with gunshot fractures of extremity long bones who participated in counter-terrorist operation in the Republic of Chechnia (1994-1996) allowed to evaluate character and severity of the injuries, content of the treatment measures conducted at the stages of medical evacuation. The peculiarities of fighting trauma were the following: the high frequency of combined (22.5%) and multiple (25.9%) injuries, the high share of multi-fragmentation and splintered (76.4%), intra-articular fractures (17.3%), the primary defects of bones (7.1%) and soft tissues (4.8%), the injuries of main vessels (12.1%) and nerves (18.5%). Owing to the short periods of evacuation to the stage of specialized medical care (up to 18.2 +/- 5.3 h), high share of preserving variant of primary surgical treatment (82.3%); high quality of medical immobilization at the expense of wide introduction of functionally stable external osteosynthesis (51.2% of the casualties) it was possible to improve the treatment results.

Adult↗
PubMed2003

[Injuries of pancreatoduodenal organs].

Ten-year experience of treatment of 213 patients with trauma of the pancreas and 56 patients with trauma of the duodenum is analyzed. Combined injury of other organs was seen in 80% patients. Diagnostic policy included intraoperative revision in open abdominal trauma and dynamic observation with US, roentgenography, CT and laboratory tests in closed trauma wich doesn't require urgent surgery. The diagnosis was verified during laparoscopy and contrast duodenography. Surgical treatment results in patients with trauma of the pancreas depending on the variant of surgery are analyzed. The role of drug treatment of traumatic pancreatitis with 5-ftoruracil and octreotid is stressed. It is demonstrated that these principles allowed us to reduce complications rate to 11.7% and lethality to 6.7% from 71.7% and 37.0% respectively. It is established that suturing of duodenal wall on the decompressive nasoduodenal tube is effective within 6 hours after trauma. Later, for prophylaxis of suture insufficiency the duodenum must be switched off. Adequate drainage and depression of secretion with octreotid are very important for success of surgery. In this approach there were no cases of sutures insufficiency among 16 patients in the last 3 years.

Abdominal Injuries↗
PubMed2001

Interaction of an electromagnetic wave packet with an ionization front: copropagating configuration.

The interaction of a TM polarized wave packet with a moving ionization front is theoretically investigated. We extend our previous study [IEEE Trans. Plasma Sci. 27, 655 (1999)], where we considered the case when the wave packet is incident on the front, by including the case often used in experiments when the front overtakes the wave packet. We focus on the energy transformation into the generated waves-the point that is rarely addressed in literature due to complications arising from the presence of Langmuir waves. Our quantitative results show the importance of losses via Langmuir wave excitation compared to other possible losses due to the excitation of stationary transverse electron currents in the plasma. Applicability to the generation of frequency upshifted radiation is discussed.

Journal Article↗
PubMed1999

Internal initiation of translation directed by the 5'-untranslated region of the tobamovirus subgenomic RNA I(2).

Previously we reported that, unlike RNA of typical tobamoviruses, the translation of the coat protein (CP) gene of a crucifer-infecting tobamovirus (crTMV) in vitro occurred by an internal ribosome entry mechanism mediated by the 148-nt region that contained an internal ribosome entry site (IRES(CP,148)(CR)). The equivalent 148-nt sequence from TMV U1 RNA (U1(CP,148)(SP)) was incapable of promoting internal initiation. In the present work, we have found that the 228-nt region upstream of the movement protein (MP) gene of crTMV RNA (IRES(MP,228)(CR)) contained an IRES element that directed in vitro translation of the 3'-proximal reporter genes from chimeric dicistronic transcripts. Surprisingly, the equivalent 228-nt sequence upstream from the MP gene of TMV U1 directed translation of the downstream gene of a dicistronic transcripts as well. Consequently this sequence was termed IRES(MP,228)(U1). It was shown that IRES(MP,228)(CR), IRES(MP,228)(U1), and IRES(CP,148)(CR) could mediate expression of the 3'-proximal GUS gene from dicistronic 35S promoter-based constructs in vivo in experiments on transfection of tobacco protoplasts and particle bombardment of Nicotiana benthamiana leaves. The results indicated that an IRES element was located within the 75-nt region upstream of MP gene (IRES(MP,75)), which corresponded closely to the length of the 5'UTR of TMV subgenomic RNA (sgRNA) I(2). The RNA transcripts structurally equivalent to I(2) sgRNAs of TMV U1 and crTMV, but containing a hairpin structure (H) immediately upstream of IRES(MP,75) (HIRES(MP), (75)(CR)-MP-CP-3'UTR; HIRES(MP,75)(U1)-MP-CP-3'UTR), were able to express the MP gene in vitro. The capacity of HIRES(MP,75)(CR) sequence for mediating internal translation of the 3'-proximal GUS gene in vivo, in tobacco protoplasts, was demonstrated. We suggested that expression of the MP gene from I(2) sgRNAs might proceed via internal ribosome entry pathway mediated by IRES(MP) element contained in the 75-nt 5'UTR. Our results admit that a ribosome scanning mechanism of the MP gene expression from I(2) sgRNA operates concurrently.

5' Untranslated Regions↗
PubMed1999

[Diet regimes in acute pancreatitis].

A method of determination of the duration of curative fasting in acute pancreatitis, depending on the degree of severity of patients' condition is described. The dependence between the probability of exacerbation of the process after resumption of feeding, the degree of severity of the condition at admittance, the duration of the fast vs degree of the severity of the condition in which the feeding was resumed was studied, for this purpose the method for calculation of so called coefficient of the degree of severity of acute pancreatitis was developed. 130 patients with acute pancreatitis underwent the treatment according to this method.

Acute Disease↗
PubMed1999

[The dynamics of blood serum middle-molecule peptides in the prognosis of the course of acute pancreatitis].

The work is devoted to studying the dynamics of endogenous toxemia by the level of middle mass peptides of blood serum in patients with acute pancreatitis. The level of middle mass peptides was investigated in 116 patients spectrophotometrically after Gabriélian with the wave length 254 nm (1st fraction, MMP-1) and with the wave length 282 nm (2nd fraction, MMP-2). It was found that the ratio of these fractions could be used as a prognostic index of the complicated course of acute pancreatitis. When the initial ration MMp-2/MMP-1 is less that 1 the risk of the development of complications of the second phase of acute pancreatitis is real. The decrease of the level of MMP-1 and MMP-2 during treatment by the 3rd-4th days is considered to be an indicator of the favorable outcome of the disease. The elevation of the level of MMP-1 and MMP-2 by the 3rd-4th days despite the treatment predicts an unfavorable outcome of the disease.

Acute Disease↗
PubMed1998

[Choice of optimal policy for treatment of acute pancreatitis].

662 case records of patients with acute pancreatitis are analysed and principles for the choice of optimal treatment of patients with acute pancreatitis (AP) are established. The most justified policy in treatment of AD patients seems to be conservative-expectant. The treatment should satisfy the phases of the course of acute pancreatitis and severity of the disease. At the first stage of the disease the treatment should be aimed at correction of pancreatic toxemia and prophylaxis of pyogenic complications. Surgical interventions at this phase are risky and hardly justified. If there are indications for drainage, laparoscopy and small invasive interventions under US control are preferable. At the second stage conservative-expectant policy should be also used as a method of choice, and treatment should be aimed at prophylaxis of purulent complications. The presence of aseptic necroses are not an absolute indication for surgery if there are no clear signs of suppuration. The presence of purulent complications is an indication for surgical treatment; extraperitoneal approaches to pyogenous areas and their drainage by wide two-lumen tubes for the following use of aspiration--lavage treatment are more preferable.

Adult↗
PubMed1997

A tobamovirus genome that contains an internal ribosome entry site functional in vitro.

Most eukaryotic mRNAs are translated by a "scanning ribosome" mechanism. We have found that unlike the type member of the genus Tobamovirus, translation of the 3'-proximal coat protein (CP) gene of a crucifer infecting tobamovirus (crTMV) (Dorokhov et al., 1993; 1994) occurred in vitro by an internal ribosome entry mechanism. Three types of synthetic dicistronic RNA transcripts were constructed and translated in vitro: (i) "MP-CP-3'NTR" transcripts contained movement protein (MP) gene, CP gene and the 3'-nontranslated region of crTMV RNA. These constructs were structurally equivalent to dicistronic subgenomic RNAs produced by tobamoviruses in vivo. (ii) "deltaNPT-CP" transcripts contained partially truncated neomycin phosphotransferase I gene and CP gene. (iii) "CP-GUS" transcripts contained the first CP gene and the gene of Escherichia coli beta-glucuronidase (GUS) at the 3'-proximal position. The results indicated that the 148-nt region upstream of the CP gene of crTMV RNA contained an internal ribosome entry site (IRES(CP)) promoting internal initiation of translation in vitro. Dicistronic IRES(CP), containing chimeric mRNAs with the 5'-terminal stem-loop structure preventing translation of the first gene (MP, deltaNPT, or CP), expressed the CP or GUS genes despite their 3'-proximal localization. The capacity of crTMV IRES(CP) for mediating internal translation distinguishes this CP tobamovirus from the well-known-type member of the genus, TMV UI. The equivalent 148-nt sequence from TMV RNA was incapable of mediating internal translation. Two mutants were used to study structural elements of IRES(CP). It was concluded that integrity of IRES(CP) was essential for internal initiation. The crTMV provides a new example of internal initiation of translation, which is markedly distinct from IRESs shown for picornaviruses and other viral and eukaryotic mRNAs.

Base Sequence↗
PubMed1994

Complete nucleotide sequence and genome organization of a tobamovirus infecting cruciferae plants.

Genomic RNA sequence of a tobamovirus infecting cruciferae plants (cr-TMV) was determined. The RNA is composed of 6312 nucleotides and contains four ORFs encoding the proteins of 122K (ORF1), 178K (ORF2), 29K (ORF3) and 18K (capsid protein, ORF4). ORF4 overlaps ORF3 by 74 nucleotides and the overlapping region can be folded into a stable hairpin structure. The 3'-terminal region of the cr-TMV RNA preceding the tRNA-like structure was shown to form six potentially stable pseudoknots.

Amino Acid Sequence↗