Disorders in the act of feeding in psychopharmacotherapy.
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Adult↗
Biomedical subjects
I Ivanov
Publications and source records attributed to I Ivanov.
Two methods for rapid assembly and oligomerization of synthetic genes: construction of human calcitonin-encoding sequences.
Two fast, simple and reliable methods for construction of synthetic genes are described. The first represents a one-vial method for assembly and cloning of monomeric genes, and the second allows a simultaneous assembly, oligomerization and cloning of synthetic genes. Both methods consist of ligation of the synthetic oligodeoxyribonucleotides (oligos) building up the gene directly into the cloning vector, followed by screening of the recombinant clones for the presence of specific gene constructs. The average length of the oligomeric genes thus constructed is directly proportional to the molar ratio between the vector DNA and the synthetic oligos used. Both methods are illustrated by the construction of a series of human calcitonin-encoding genes.
Amino Acid Sequence↗
Construction of a Co1E1 plasmid bearing inducible high-copy-number phenotype.
In order to construct plasmids bearing inducible high-copy-number phenotype, the cloning plasmid pBR322 was modified as follows: a DNA fragment containing a strong synthetic promoter (P1), synthetic lac operator (O1), DNA sequence corresponding to the RNAI/RNAII region of the Co1E1 replicon and the CAT gene transcription terminator was substituted for the 29 bp EcoRI/HindIII DNA fragment. Two types of plasmids were constructed in this way, differing in the orientation of the RNAI/RNAII fragment. Depending on the orientation these plasmids coded for RNA molecules representing either RNAI or RNAII domains. It was found that when RNAII molecules were overproduced the plasmid copy number was about 4 times higher than that of pBR322 and only negligible change in the plasmid copy-number value was observed upon overproduction of RNAI molecules.
Bacteriocin Plasmids↗
Interleukin production by human colostral cells after in vitro mitogen stimulation.
Human colostral cells were pulsed with PHA, Con A, or LPS and cultivated in serum-free medium. The culture supernatants were tested for IL-1 activity in C3H/HeJ thymocyte assay and for IL-2 activity on human lymphoblasts. The IL-1 activity was the highest at the 24th h of cultivation and IL-2 activity at the 48th h of cultivation.
Biological Assay↗
Incidence and character of lipoproteinemia in underground and surface workers at the Goroubso Works, Zlatograd.
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Adult↗
Avian bone-derived cell line infected with osteopetrosis virus pts-56.
Cell culture derived from embryonal turkey bone was infected with osteopetrosis virus pts-56. After 13 passages the morphology of the infected cells was changed and later a cell line was established. Some features of this cell line are described and compared with a non-infected cell culture.
Alkaline Phosphatase↗
Stable line of turkey bone marrow cells transformed by the myelocytomatosis virus strain MC31.
A stable bone marrow-derived cell line LSTC-SF2, producing transforming avian acute leukaemia virus, was established. The cell line has been maintained in culture for over 4 years, and 450 passages can be frozen and easily recovered in viable form. The cells grow rapidly in monolayers with multilayer clumps, have low serum requirements, display specific morphology, form colonies in semisolid medium and release transforming MC31 virus. A helper virus was also detected by the reverse transcriptase assay.
Animals↗
[The interrelationship between calcium and magnesium homeostasis and its significance for the relapse-prevention treatment of calcium nephrolithiasis].
The correlation between the renal excretion of calcium and magnesium after an overload with 1000 mg of calcium is studied. The significant interrelations between the calcium and magnesium urine excretion point that there are close interrelations between their active tubular transport in the kidneys. The significantly higher magnesuria and the tendency toward a low serum magnesium level in patients with renal hypercalciuria require to take into account the hypermagnesuria. The oral treatment with magnesium which was prescribed in the past indiscriminantly to all patients with relapsing calcium nephrolithiasis is necessary only for patient with renal hypercalciuria.
Adolescent↗
[The effect of oral calcium loading on the serum concentrations and urinary excretion of uric acid in patients with recurrent calcium nephrolithiasis and hypercalciuria].
The authors have established that to higher calciuria in patients with calcium nephrolithiasis correspond higher vales of uric acid serum concentrations and urine excretion than in the controls. In the oral calcium tolerance test a significant correlation was found between the changes in the uric acid urine excretion and those in the diuresis. The following conclusions are put forward. I. In the patients with recurrent calcium nephrolithiasis and hypercalcinosis one should look for active impairment of uric acid metabolism which should be kept in mind when an antirecurrence treatment is planned. 2. The established parallel increase of uricosuria and calciuria in the oral calcium tolerance test means that to patients with recurrent calcium nephrolithiasis and gout a rich calcium diet should not be prescribed since it increases the risk of formation of calcium oxalate stones.
Administration, Oral↗
Chemical synthesis and characteristics of a hybrid phage T5-lac promoter.
A new P1O1R9 inducible promoter (where P1 is a promoter sequence analogous to that of the phage T5 early promoter; O1 is lac-operator; and R9 is a ribosome binding site) was synthesized. We studied the efficiency of this promoter in controlling and inducible gene expression using two model genes: human calcitonin tetrameric (hCT[4]) and human interferon alpha 1 (hIFN alpha 1). The synthetic lac-operator O1 was found to repress P1 activity in media free of lac-operon inducers which was derepressed in the presence of IPTG. The levels of expression of both genes (evaluated by quantitating mRNA and protein) in the presence of lac-inducers were close to those obtained with the P1R9 constitutive promoter.
Base Sequence↗
Constitutive expression of a native human interferon-alpha 1 gene in Escherichia coli.
1. A plasmid for constitutive expression of the human interferon-alpha 1 (hIFN-alpha 1) gene in Escherichia coli is constructed on the basis of the cloning plasmid pBR322 using a strong synthetic promoter, synthetic ribosome binding site and a native hIFN-alpha 1 gene excised from a chromosomal clone. 2. The yield of recombinant hIFN-alpha 1 from E. coli LE392 cells transformed with the expression plasmid pJP1R9-hIFN-alpha 1 is evaluated to be 2-6 x 10(7) U/l bacterial culture for metabolic shaker and 6-8 x 10(7) U/l for fermentor.
Cloning, Molecular↗
Expression of synthetic calcitonin genes in plasmid vectors containing tandemly repeated non-overlapping ribosome binding sites.
1. Expression plasmids containing non-overlapping tandemly repeated ribosome binding sites (RBS) were constructed in order to stabilize mRNA and enhance translation. 2. Two synthetic genes (human calcitonin tetramer gene and a fusion gene human gamma-interferon-human calcitonin) were cloned in these vectors and the effect of multiplicity of Shine-Dalgarno (S/D) sequence on heterologous gene expression was studied. 3. It was found that duplication and triplication of RBS had no effect on the stability of mRNA but led to a strong decrease in the level of recombinant protein and mRNA in the cell. 4. Plasmids bearing four times repeated S/D sequences gave longer-lived mRNAs and maintained a level of protein and mRNA very close to the values obtained with a single S/D containing plasmids.
Base Sequence↗
Amplification of bacterial plasmids without blocking protein biosynthesis.
The effect of amino acids (presence or absence from the growth media) and metal ions on the replication of Escherichia coli plasmids in rel A+ strains was studied. It was found that: (i) The absence of one amino acid from the growth media had no effect on the plasmid copy number in prototrophic E. coli strains: (ii) The presence of only one amino acid in artificial media free of amino acids had a negligible effect on the plasmid copy number for the amino acids Ala, Arg, Glu, His, Leu, Phe, Thr, Trp, and Tyr: (iii) The combination of Met and Thr caused a rise in pBR322 plasmid copy number up to 90-100 plasmid copies per cell: (iv) The Fe3+ concentration had an amplification effect on E. coli plasmids. The pBR322 plasmid copy number for media free of amino acids and supplemented with 0.2-0.4 mM FeCl3 was 60-80 plasmid copies per cell: (v) The combination of Fe3+ with certain amino acids (Ala, Arg, Glu, Leu, Thr, and Trp) leads to a dramatic increase in the plasmid copy number reaching 180-270 plasmid copies per cell for the plasmid pBR322 and 20-24 for the plasmid pR100.
Amino Acids↗
[Effect of beta-adrenergic blockaders and nitrates on left ventricular diastolic function in patients with ischemic heart disease].
By means of M-type electrocardiography the anapriline (propranolol--40 mg) and nitrosorbide (isosorbide dinitrate--10 mg) action on the left ventricular diastolic function was studied in the conditions of acute experiment in 55 patients with stable stenocardia. It was established that anapriline lengthens the diastole (at the expense of diastasis), decreases the myocardial relaxation speed and the fast filling and causes an increase of the telediastolic volume. Nitrosorbide decreases the filling velocity in the three diastolic phases without changing its duration and leads to a decrease of the telediastolic volume. In the combination of the two drugs anaprilin acts mainly on the duration, volume and speed indices of the left ventricular diastolic function while nitrosorbide acts mainly on the venous flow towards the heart and reduces the unfavourable action of anapriline on myocardial relaxation.
Administration, Oral↗
Expression of repetitive human calcitonin genes in Escherichia coli.
In order to stabilize recombinant human calcitonin (rhCT) against Escherichia coli proteases a series of concatemeric hCT genes with varying degrees of repetition were synthesized and expressed in E. coli under the control of a constitutive synthetic phage promoter. The series of expression vectors thus constructed was used as a model to study the effect of gene repetition on the efficiency of expression (both transcription and translation), stability of mRNA, proteolytic stability of recombinant protein, genetic stability of expression plasmids, etc. The oligomerization of the hCT gene resulted in stabilization of the mRNA increasing its half-life from 60-70 s (as in the hCT monomer, dimer, and trimer genes) to 100-120 s (for the hCT tetramer gene). This effect held true as well for the proteins coded by the corresponding repetitive hCT genes. The genetic stability (segregation and recombination) of the expression plasmids containing hCT oligomeric genes also depended on the number of hCT gene repeats. The expression plasmid containing the hCT tetramer gene segregated from one of the best producers of rhCT (E. coli LE392) up to 100% after 100 cell generations in nonselective media (free of antibiotics). One of the plasmids most sensitive to recombination events was that containing the hCT pentamer gene. The series of expression plasmids bearing hCT oligomeric genes was used for transformation of various E. coli strains in order to find the optimal host for production of rhCT. The highest yield (44-100 mg rhCT per 1 liter of bacterial culture) was obtained with the strains LE392, JM107, and DH1.
Calcitonin↗
[The effect of oral calcium loading on the serum magnesium concentration and its urinary excretion in patients with recurrent calcium nephrolithiasis and hypercalciuria--differential diagnostic potentials].
The study deals with 13 healthy controls with normal basic indices for calcium-phosphorus metabolism and 25 patients with recurrent calcium nephrolithiasis and hypercalciuria, 13 of them with renal hypercalciuria and 12 patients with absorptive hypercalciuria. The oral calcium-tolerance test was carried out in all persons. The changes in the serum and urine calcium and magnesium concentrations following the calcium loading are recorder. A statistically significant increase of magnesium urine excretion was found in all persons examined, the highest being in the patients with renal hypercalciuria, considerably higher than in the healthy controls. The conclusion is reached that the magnesium urine excretion gives valuable information for the diagnosis of patients with renal hypercalciuria.
Administration, Oral↗
What does the homology between E. coli tRNAs and RNAs controlling ColE1 plasmid replication mean?
Nucleotide sequences of E. coli tRNAs and RNA I or RNA II (controlling replication of ColE1 plasmids) were compared using the computer. The homology between some of these molecules is over 60%. The distribution of homologous nucleotides among the functional elements (stems and loops) of either RNA I or RNA II and the tRNAs molecules was studied. It was found that the homologous domains are located mainly in the loop regions of RNA I or RNA II. A consensus sequence, the nonanucleotide AGUUGGUAG, was discovered in loop II of RNA I and in the dihydrouridylic loop of tRNAs showing homology with RNA I. Based on this observation, a hypothesis was drawn for a possible role of the tRNAs in the regulation of plasmid DNA replication.
Base Sequence↗
A conditional high-copy-number plasmid derivative of pBR322.
A spontaneous high-copy-number plasmid derivative of plasmid pBR322 was isolated. This plasmid bears two point mutations adjacent to the unpaired region in the stem of loop II of RNA I and expresses its high-copy-number phenotype only when the harboring cells grow on solid support (L-agar).
Base Sequence↗