Effect of dexamethasone on the expression of binding sites for high-density lipoproteins in cultured rat hepatocytes (Independence of the hormone effect on the intracellular cholesterol pool)

It is shown that glucocorticoids play a key regulatory role directed toward the maintenance of an optimal level of binding and internalization of HDL₃ in hepatocytes. Their stimulatory effect on the expression of HDL receptors proves to be independent of changes in the CH content in parenchymal cells. Translated fromByulleten' Eksperimentalnoi Biologii i Meditsiny, Vol. 117, N ^o 1, pp. 50–53, January, 1994     

Respiratory response to CO2 by controlled alveolar hypercapnia

A method of assessing the respiratory response to a hypercapnic stimulus after an increase in alveolar pCO₂ in accordance with an assigned program is suggested. The results are independent of the metabolic level, resistance to respiration, and other factors. Unlike the widely used rebreathing method, this new method enables the ventilatory sensitivity to CO₂ to be compared at rest, during muscular work, when the resistance to respiration is changed, and so on. It can also be used for both clinical and experimental investigations.Respiratory Physiology Group, I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. (Presented by Academician of the Academy of Medical Sciences of the USSR V. N. Chernigovskii.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 89, No. 1, pp. 6–7, January, 1980.     

Lymphocyte response in the early period after heart transplantation

The quantitative and qualitative composition of the leukocytes and dehydrogenase activity of the lymphocytes were determined in blood entering and leaving the transplanted heart at different times after grafting in dogs. A decrease in the lymphocyte count in blood flowing from the grafted heart was found, on account of retention of the lymphocytes in the graft; the activities of the mitochondrial dehydrogenases also were reversed as the result of contact of the lymphocytes with the foreign antigens of the transplanted heart. It is suggested that the mechanism of reversal is connected with the functions of the lymphocytes as immunocompetent cells.A. N. Bakulev Institute of Cardiovascular Surgery, Academy of Medical Sciences of the USSR, Moscow. Institute of Experimental Surgery, Slovak Academy of Sciences, Bratislava, Czechoslovakia. (Presented by Academician of the Academy of Medical Sciences of the USSR, P. A. Vershilova.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 85, No. 6, pp. 704–708, June, 1978.     

Arrhythmogenic right ventricular dysplasia: polymorphism of clinical manifestations

We observed 15 patients with arrhythmogenic right ventricular dysplasia (ARVD): 9 with definite and 5 with probable ARVD (modified European Criteria, 2010). Eight patients had typical ARVD (frequent right ventricular extrasystoles, nonsustained right ventricular tachycardia without heart failure with or without myocarditis). Five patients had ARVD with progressive heart failure (right- or biventricular with or without myocarditis). Two patients had full scale arrhythmic form (sustained right ventricular tachycardia without or with right ventricular dilation, with or without myocarditis). In 3 cases diagnosis was confirmed morphologically or with DNA-diagnostics. This material allowed us to highlight the following specific points related to diagnostics of ARVD. Detection of fat at MRT is not obligatory for diagnosis, fat can be detected by MSCT; ventricular arrhythmias can move backwards in the picture of the disease; leading clinical manifestation can be unexplained right ventricular insufficiency; ARVD can be combined with other genetic cardiomyopathies as well as with infectious immune myocarditis (up to 50% of patients); elevated titer of anticardiac antibodies is not characteristic for isolated ARVD; myocardial biopsy allows to verify both ARVD and concomitant myocarditis. The paper also contains discussion of the role of myocarditis in various forms of ARVD and possibilities of its diagnosis and treatments.     

The proapoptotic factor HLDF in the normal, hyperplastic and neoplastic endometrium

Antibodies to the factor HLDF are shown to be specific markers of apoptosis and permit the estimation of the rate of programmed cell death in the course of a normal menstrual cycle and in pathologic endometrial processes. HLDF expression in the epitheliocytic cytoplasm makes it possible to evaluate apoptosis at early stages, before the emergence of the first morphological signs and after apoptotic body formation. The study shows increased apoptotic processes at the end of a normal menstrual cycle and during neoplastic cell transformation. Antibodies to the HLDF factor may be used as a new immunohistochemical marker for the differential diagnosis of benign and malignant endometrial processes.     

Enhancement of protein expression by alphavirus replicons by designing self-replicating subgenomic RNAs

Since the development of infectious cDNA clones of viral RNA genomes and the means of delivery of the in vitro-synthesized RNA into cells, alphaviruses have become an attractive system for expression of heterologous genetic information. Alphaviruses replicate exclusively in the cytoplasm, and their genetic material cannot recombine with cellular DNA. Alphavirus genome-based, self-replicating RNAs (replicons) are widely used vectors for expression of heterologous proteins. Their current design relies on replacement of structural genes, encoded by subgenomic RNAs (SG RNA), with heterologous sequences of interest. The SG RNA is transcribed from a promoter located in the alphavirus-specific RNA replication intermediate and is not further amplified. In this study, we have applied the accumulated knowledge of the mechanism of alphavirus replication and promoter structures, in particular, to increase the expression level of heterologous proteins from Venezuelan equine encephalitis virus (VEEV)-based replicons. During VEEV infection, replication enzymes are produced in excess to RNA replication intermediates, and a large fraction of them are not involved in RNA synthesis. The newly designed constructs encode SG RNAs, which are not only transcribed from the SG promoter, but are additionally amplified by the previously underused VEEV replication enzymes. These replicons produce SG RNAs and encoded proteins of interest 10- to 50-fold more efficiently than those using a traditional design. A modified replicon encoding West Nile virus (WNV) premembrane and envelope proteins efficiently produced subviral particles and, after a single immunization, elicited high titers of neutralizing antibodies, which protected mice from lethal challenge with WNV.Alphaviruses are a group of enveloped viruses with a positive-strand RNA genome that replicate in most commonly used cell lines to titers exceeding 10¹⁰ infectious units (inf.u)/mL (1, 2). Upon infection, the genomic RNA serves as a template for translation of viral nonstructural proteins that form replication complexes (3). Within a few hours postinfection, these complexes synthesize large amounts of viral genomic and subgenomic (SG) RNA (3). The SG RNA is transcribed from the SG promoter and serves as a template for translation of viral structural proteins: capsid, E2 and E1, which ultimately assemble with genomic RNA into infectious viral particles. This highly efficient virus-specific RNA and protein synthesis, coupled with the availability of infectious cDNA clones, have made alphaviruses an attractive system for designing self-replicating vectors for delivery and expression of heterologous genetic information. The most widely used alphavirus-based expression systems are based on replacement of viral structural genes by a gene(s) of interest (4). These modified viral genomes, termed replicons, can be synthesized in vitro and delivered into cells either by transfection or in infectious viral particles, which deliver essentially every packaged RNA molecule into the cells both in vivo and in vitro.In recent years, significant progress has been made in our understanding of the mechanism of alphavirus replication. Detailed studies have elucidated the structure and function of the RNA promoters, critical aspects of virus–host cell interactions, and the composition of the replication complexes (5–12). These mechanistic studies of alphavirus replication raised the question of whether we are using their entire expression potential, and whether the traditional replicon design can be further improved to achieve higher levels of heterologous protein production. In this project, we sought to apply the latest advances in understanding of alphavirus RNA replication to design a new generation of Venezuelan equine encephalitis virus (VEEV) genome-based expression systems. The distinguishing feature of these constructs is the modification of the SG RNAs. These SG RNAs have been engineered to contain the cis-acting promoter elements, which are normally present at the 5′ end of the viral genome and mediate genomic RNA replication (8, 13, 14). Thus, in these newly designed VEEV replicons (VEErep), the SG RNAs were not only transcribed from the SG promoter, but were capable of replication/amplification by the VEEV replication complexes. As a result, the heterologous gene expression was more efficient than that of the existing constructs, which use replicons with the standard SG RNAs. The expression level of heterologous protein encoded by the improved replicons was also found to be dependent on coexpression of VEEV capsid protein. The VEEV replicons, which use both amplification of the SG RNA and express capsid protein, provide a platform for development of a variety of more efficient expression systems and have numerous applications. To illustrate this, we have generated a VEEV replicon encoding the premembrane and envelope (prM/E) proteins of West Nile virus (WNV). Particles containing the newly designed replicons induced high levels of WNV E protein expression in vitro and elicited robust protective immunity in mice.     

肿瘤相关基因Cap43在胰腺癌中的表达及意义

目的研究肿瘤相关基因Cap43在胰腺癌组织中的表达情况,探讨其对胰腺癌的诊断价值。方法收集1999年4月～2002年8月长海医院外科手术切除胰腺癌标本和癌旁正常组织33例,诊断均由病理证实。男性22例,女性11例,年龄30～73岁,平均58．1岁。所有组织标本按肿瘤、癌旁(正常)配对。采用RT-PCR和Northern杂交方法研究Cap43 mRNA表达情况。结果 RT-PCR结果显示,Cap43在肿瘤组织中表达显著上调,其在肿瘤组织和癌旁正常组织的扫描值分别为4 033±1 986和2 244±1 145,有显著差异(P<0．001)。Northern杂交亦显示Cap43在肿瘤组织中表达显著上调,相同病例的RT-PCR结果与Northern杂交的结果有较好的一致性,经回归分析,没有显著性差异(P>0．1)。结论 Cap43在胰腺癌组织中呈显著高表达,其有可能成为胰腺癌早期诊断的重要标志物。