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PubMedDate not supplied

[The family of env genes of avian retroviruses: molecular analysis of Rous sarcoma virus adapted to duck cells].

For the elucidation of the molecular basis of RSV adaptation to conditionally permissive host from the genome library of duck embryo fibroblasts, transformed by Rous sarcoma virus in 30 passages on these cells, recombinant bacteriophages that include provirus sequences, were obtained. Complete and transformation-defective proviruses were characterized, nucleotide sequences of their env-genes were compared with their counterparts the original RSV (Pr-RSV-C) and with viruses of other subgroups (A, B, D and E). The possible relation of the revealed changes in domains coding gp85 and gp37, with the changes of chicken RSV characteristics during adaptation to duck cells is discussed.

Animals↗
PubMed1989

[Ultrasonic scanning in the diagnosis of rheumatoid lesions of the knee joints].

A total of 60 patients with rheumatoid arthritis were examined. On the basis of ultrasound scanning of the knee joints 2 groups of patients were identified: with the prevalence of exudative-proliferative processes and with proliferative-sclerotic changes. Color coding of images was performed using a UAR-1 unit. A high informative value of ultrasound investigation was shown.

Adult↗
PubMed1984

Epidemiology of peptic ulcer disease.

In the United States about four million people have active peptic ulcers and about 350,000 new cases are diagnosed each year. Four times as many duodenal ulcers as gastric ulcers are diagnosed. Approximately 3000 deaths per year in the United States are due to duodenal ulcer and 3000 to gastric ulcer. There has been a marked decrease in reported hospitalization and mortality rates for peptic ulcer in the United States. Changes in criteria for selecting the underlying cause of death might account for some of the apparent decrease in ulcer mortality rates. Hospitalization rates for duodenal ulcers decreased nearly 50 per cent from 1970 to 1978, but hospitalization rates for gastric ulcers did not decrease. Although this decrease in hospitalization rates may reflect a decrease in duodenal ulcer disease incidence, it appears that changes in coding practices, hospitalization criteria, and diagnostic procedures have contributed to the reported declines in peptic ulcer hospitalization and mortality rates. There is no good evidence to support the popular belief that peptic ulcer is most common in the spring and autumn. The most consistent pattern appears to be low ulcer rates in the summer. There is strong evidence that cigarette smoking, regular use of aspirin, and prolonged use of steroids are associated with the development of peptic ulcer. There is some evidence that coffee and aspirin substitutes may affect ulcers, but most studies do not implicate alcohol, food, or psychological stress as causes of ulcer disease. Genetic factors play a role in both duodenal and gastric ulcer. The first-degree relatives of patients with duodenal ulcer have a two- to threefold increase in risk of getting duodenal ulcer and relatives of gastric ulcer patients have a similarly increased risk of getting a gastric ulcer. About half of the patients with duodenal ulcer have elevated plasma pepsinogen I. A small increase in risk of duodenal ulcer is found in persons with blood group O and in subjects who fail to secrete blood group antigens into the saliva. In most Western countries, morbidity from duodenal ulcer is more common than from gastric ulcer, even though deaths from gastric ulcer exceed or equal those from duodenal ulcer. In Japan, both morbidity and mortality are higher for gastric ulcer than for duodenal ulcer.

Adrenal Cortex Hormones↗
PubMed1994

Two alternatively spliced forms of the human insulin-like growth factor I receptor have distinct biological activities and internalization kinetics.

Two alternatively spliced human insulin-like growth factor I (IGF I) receptor mRNA transcripts have been described that differ by three nucleotides (CAG) starting at position 2829. This results in an amino acid coding sequence change from Thr-Gly to Arg in the extracellular portion of the receptor beta subunit. To investigate the functional significance of this sequence difference, we obtained full-length cDNAs for the CAG+ and CAG- receptor forms, transfected CHO cells, and isolated multiple clones expressing approximately equal numbers of receptors (0.57-0.73 x 10(6) receptors/cell). The two receptors bound IGF I with similar affinity (Kd approximately 1.7 nM), but the CAG- form exhibited an approximately 2-fold increase in IGF I stimulation of receptor autophosphorylation, insulin receptor substrate-1 (IRS-1) tyrosine phosphorylation, thymidine incorporation, and IRS-1-associated phosphatidylinositol 3-kinase activity. In contrast to its higher signaling activity, the rate of receptor-mediated internalization of IGF I by the CAG-receptor was decreased by 50% in comparison with the CAG+ receptor. We conclude that proteins corresponding to the two alternatively spliced human IGF I receptor transcripts are biologically active, but have distinct signaling properties. These experiments further indicate a previously unrecognized role for the extramembranous portion of the beta subunit in receptor signaling and internalization.

Alternative Splicing↗
PubMed1993

[The incidence of arterial hypertension and ischemic heart disease in workers manufacturing nitrogen and phosphorus fertilizers].

Examinations are performed on 120 workers from the plant for nitrogen and 253 workers from the plant for phosphorous fertilizers. For comparison is used a control group of 103 persons having no professional contact with chemical noxa. The measuring of the arterial pressure and assessment of the arterial hypertension rate is performed after the standardised method of the World Health Organization (1984). The probability of ischemic disease of the heart is determined on the basis of the electrocardiographic changes (Minnesota code) and the data of the questionnaire of G. A. Rose (WHO, 1984). The results point out, that the arterial hypertension incidence and that of the ischemic disease of the heart in the exposed workers in both plants is insignificantly higher than that of the controls. There is no effect of the specialized length of service on the dissemination of the registered cardio-vascular diseases. The data of the carried out investigation show no presence of heightened risk of arterial hypertension and ischemic heart disease in workers from the nitrogen and phosphorous fertilizers production.

Adult↗
PubMed1994

[Color velocity imaging for diagnosis in kidney transplants. Methods for interpretation of color coding].

Colour velocity imaging is a new technique in the field of colour-coded sonographic flow measurement. It measures blood flow directly by analysing ultrasound pulses' running time and has advantages over colour Doppler systems. Colour velocity imaging's colour code detects changes in arterial blood flow. Therefore it can be used in the diagnosis of kidney allografts in the same way as duplex ultrasound. Using the presented methods of colour interpretation, sensitivity of 66.6-100% and specificity of 72.7-91.7% are attained. Thus colour velocity imaging combines the attributes of duplex ultrasound and colour Doppler ultrasound.

Blood Flow Velocity↗
PubMed1983

Colour coding in the cerebral cortex: the responses of wavelength-selective and colour-coded cells in monkey visual cortex to changes in wavelength composition.

The reaction of wavelength-selective (WL), wavelength-opponent (WLO) and colour-coded (CO) cells in monkey visual cortex to changes in the wavelength composition of the light reflected from the area in their receptive fields was studied, using multicoloured displays. Wavelength-selective and wavelength-opponent cells were found to be very sensitive to changes in the wavelength composition of the light reflected from the areas in their receptive fields, irrespective of their perceived natural and void colours. Changes in the wavelength composition of the light reflected from surrounding areas did not affect their responses. They were also sensitive to the order in which lights of various wavelengths illuminated the areas in their receptive fields. Colour-coded cells were not affected by changes in the wavelength composition nor were they sensitive to the sequence with which the area in their receptive fields was illuminated by lights of different wavelengths. However, they required that the display, with the area of their preferred colour in their receptive fields, be trichromatically illuminated. This and other evidence suggested that such cells were sensitive not only to the illumination of the area in their receptive fields, but of surrounding areas as well. This evidence reinforces further the distinction between wavelength-selective and colour-coded cells and leads to the conclusion that one function of the wavelength-selective cells must be to register the changes in wavelength composition which occur throughout the day.

Animals↗
PubMed1990

Structural studies of the lysozyme coded by the pneumococcal phage Cp-1. Conformational changes induced by choline.

The CPL-1 lysozyme coded by the pneumococcal phage Cp-1 has been overproduced in Escherichia coli under the control of a modified lipoprotein lactose promoter. This result has provided the conditions to analyse the CPL-1 secondary structure by circular dichroism (CD). The CD spectra recorded in the far-ultraviolet region showed, at neutral pH, two minima at 210 nm and 230 nm and a shoulder at 217 nm, whereas two bands at 260 nm and 295 nm were observed in the near-ultraviolet region. It has been estimated, by using the CDPROT program, that the protein is composed of 19% alpha-helix, 32% beta-sheet, 28% beta-turn and 21% random coil. Minor changes in the CD spectra were detected either when the pH was varied over 6-10 or when the ionic strength was increased to 1 M NaCl. Choline, a well known modulator of the enzyme activity that is present in the pneumococcal cell wall, induced remarkable changes in the intensities of the bands at 210, 230 and 295 nm, with the appearance of an unusual positive band at 225 nm. The conformational change was reversible and correlated with the competitive inhibitory effect of choline on the lysozyme activity, supporting, by a new and direct experimental approach, the basic role of choline in the recognition of the cell wall substrate. The analyses of the secondary structure prediction and the CD data reported here are compatible with the two-domain structure of CPL-1 reinforce our hypothesis that the C-terminal region is directly involved in the binding of the enzyme to the pneumococcal teichoic and lipoteichoic acids.

Amino Acid Sequence↗
PubMed1994

Mutations in the helper component protease gene of zucchini yellow mosaic virus affect its ability to mediate aphid transmissibility.

The nucleotide sequence of the helper component protease (HC-Pro) genes of three zucchini yellow mosaic virus (ZYMV) strains has been compared with that of a helper-deficient strain of ZYMV-HC. The comparisons revealed three unique deduced amino acid differences. Two of these mutations were located in regions which are conserved in other potyviruses. The role of these mutations in aphid transmissibility was examined by exchanging DNA fragments of part of the deficient HC-Pro gene with the respective section within the gene of the infectious full-length clone of the aphid-transmissible ZYMV. The first exchange included two of the three mutations, the first coding for a change from Asp to Gly (in a non-conserved region) and the second coding for a change from Arg to Ile [within the Phe-Arg-Asp-Lys (FRNK) conserved box]. This exchange resulted in a reduced transmission (20.6% for the mutated virus compared with 57.4% in the normal ZYMV when acquired from plants and 37.2% compared with 83.1%, respectively, when acquired from membranes). The second exchange incorporated a single mutation [conferring a change from Thr to Ala within the Pro-Thr-Lys (PTK) conserved box]. This single mutation resulted in almost total loss of HC activity in aphid transmission both from plants and from membranes. The Lys residue in the conserved Lys-Ile-Thr-Cys (KITC) box, which is related to loss of HC activity in potato virus Y, tobacco vein mottling virus and in the Michigan strain of ZYMV, is unchanged in the helper-deficient ZYMV. It is therefore proposed that more than one site in HC-Pro may be functionally related to aphid transmissibility. The possible reasons for the role of these mutations in helper activity in aphid transmission of ZYMV are discussed.

Amino Acid Sequence↗
PubMed1990

The genetic code in mitochondria and chloroplasts.

The universal genetic code is used without changes in chloroplasts and in mitochondria of green plants. Non-plant mitochondria use codes that include changes from the universal code. Chloroplasts use 31 anticodons in translating the code; a number smaller than that used by bacteria, because chloroplasts have eliminated 10 CNN anticodons that are found in bacteria. Green plant mitochondria (mt) obtain some tRNAs from the cytosol, and genes for some other tRNAs have been acquired from chloroplast DNA. The code in non-plant mt differs from the universal code in the following usages found in various organisms: UGA for Trp, AUA for Met, AGR for Ser and stop, AAA for Asn, CUN for Thr, and possibly UAA for Tyr. CGN codons are not used by Torulopsis yeast mt. Non-plant mt, e.g. in vertebrates, may use a minimum of 22 anticodons for complete translation of mRNA sequences. The following possible causes are regarded as contributing to changes in the non-plant mt: directional mutation pressure, genomic economization, changes in charging specificity of tRNAs, loss of release factor RF2, changes in RF1, changes in anticodons, loss of lysidine-forming enzyme system, and disappearance of codons from coding sequences.

Animal Population Groups↗
PubMedDate not supplied

Molecular characterization of three mutations in katG affecting the activity of hydroperoxidase I of Escherichia coli.

Hydroperoxidase I (HPI) of Escherichia coli is a bifunctional enzyme exhibiting both catalase and peroxidase activities. Mutants lacking appreciable HPI have been generated using nitrosoguanidine and the gene encoding HPI, katG, has been cloned from three of these mutants using either classical probing methods or polymerase chain reaction amplification. The mutant genes were sequenced and the changes from wild-type sequence identified. Two mutants contained G to A changes in the coding strand, resulting in glycine to aspartate changes at residues 119 (katG15) and 314 (katG16) in the deduced amino acid sequence of the protein. A third mutant contained a C to T change resulting in a leucine to phenylalanine change at residue 139 (katG14). The Phe139-, Asp119-, and Asp314-containing mutants exhibited 13, less than 1, and 18%, respectively, of the wild-type catalase specific activity and 43, 4, and 45% of the wild-type peroxidase specific activity. All mutant enzymes bound less protoheme IX than the wild-type enzyme. The sensitivities of the mutant enzymes to the inhibitors hydroxylamine, azide, and cyanide and the activators imidazole and Tris were similar to those of the wild-type enzyme. The mutant enzymes were more sensitive to high temperature and to beta-mercaptoethanol than the wild-type enzyme. The pH profiles of the mutant catalases were unchanged from the wild-type enzyme.

Base Sequence↗
PubMed1983

Levels of translatable mRNA coding for rat liver glucokinase.

Changes in the level of translatable mRNA coding for glucokinase under different physiological conditions were determined using a reticulocyte lysate translation system and immunoprecipitation. Poly(A+) RNA isolated from livers of rats fed a high carbohydrate diet displayed a 10-fold increase in glucokinase template activity when compared to starved rats. Livers from streptozotocin-induced diabetic rats had only 9% of the glucokinase template activity displayed by controls. Administration of insulin to diabetic rats produced an increase in the level of mRNA coding for glucokinase within 20 min and reached a maximum 13-fold increase 1 h following insulin treatment. Under all experimental conditions examined, changes in the level of glucokinase mRNA were accompanied by similar changes in direction and magnitude of enzyme activity and the relative rate of synthesis of the enzyme in vivo. In addition, the developmental appearance of glucokinase activity at the 16th day following birth was accompanied by a corresponding increase in the amount of glucokinase mRNA. Thus, it appears that dietary, hormonal, and developmental changes in the activity of glucokinase arise as the result of changes in the amount of functional mRNA coding for the enzyme.

Animals↗
PubMed1990

Partial nucleotide sequence of South American yellow fever virus strain 1899/81: structural proteins and NS1.

We have partially cloned and sequenced the genome of a Peruvian yellow fever virus isolate (1899/81) and compared the nucleotide and deduced amino acid sequences of this strain with the previously published sequence of the West African yellow fever virus strain Asibi. In the 3594 base region sequenced, which contains the structural genes (C, M, E), all but the 72 3'-terminal nucleotides of the NS1 gene and 108 nucleotides of the 5' non-coding region, 515 nucleotide substitutions were detected. Nucleotide divergence was lowest in the 5' non-coding region, 2.8%, compared with an average rate of 14.7% in the coding regions. Over 91% of the 512 nucleotide changes in the coding region were silent; 44 amino acid substitutions resulted. The capsid protein was the least conserved, whereas the M protein was the most highly conserved (6.7% and 1.3% divergence, respectively). The envelope protein had 18 amino acid changes (3.7% divergence), one of which created an additional site for potential glycosylation of the 1899/81 virus. NS1 protein divergence (3.9%) was similar to that seen in the E protein. Of the 44 amino acid substitutions found, 34 (77%) were conservative. The highest number of nonconservative differences occurred in the envelope glycoprotein. These changes may significantly affect the antigenic and biological functions of the viruses.

Amino Acid Sequence↗
PubMed1988

Ischemia induces changes in the level of mRNAs coding for stress protein 71 and creatine kinase M.

Hyperthermia, hypoxia, and other conditions induce the appearance of heat shock or stress proteins in cells. We have previously shown that in the ischemic dog myocardium the level of a messenger RNA (mRNA) coding for a protein with migration characteristics similar to heat shock/stress protein 71 increases. Using a human heat-shock protein (hHSP) 70 genomic clone and anti-HSP70 antibodies as probes, we demonstrate in this report that heart stress protein (SP) 71 mRNA and its translational products (71 kDa polypeptides) are members of the stress protein family. In rabbit hearts, the ischemia-induced mRNAs translate into three isoforms with different isoelectric points (6.0, 6.1, and 6.15), in contrast to dog heart mRNA that translates into a protein with a pI of 5.8. The levels of SP71 mRNA in the dog and rabbit ischemic myocardium increased by sixfold and 18-fold, respectively. In the same samples, the levels of creatine kinase M mRNA decreased by about 40%, whereas those of myosin heavy chain mRNA remain unaltered. Our comparative analysis of three different mRNAs indicates that ischemia manifests its effects by differentially changing the levels of specific mRNAs coding for proteins with separate and distinct roles in the cell.

Animals↗
PubMed1990

[A method for the quantitative evaluation of the probability of ischemic heart disease in epidemiological research on workers exposed to harmful effects].

A method for quantitative evaluation of the probability for ischaemic disease of the heart in epidemiological studies is recommended and the state of risk is determined by riskogram, including 3 parts: 1. Assessment of the electrocardiographic changes after Minnesota code. 2. Integral quantitative interpretation of ECG-changes with the data from the Rose test. 3. Classified quantitative assessment of the probability for ischaemic disease of the heart. The quantitative interpretation of the probability for ischaemic disease of the heart allows the use of various statistical methods, mathematical models and computer processing of data, received at the epidemiological studies. By tracing the dependences "dose-effect" and "dose-response" the maximum admissible duration of the length of service could be predicted in specific conditions of professional exposure, in order to prevent injury of the cardiovascular system from harmful industrial factors.

Bulgaria↗
PubMed1990

Production of transgenic mice and application to immunology and autoimmunity.

During the last decade, transgenic animal technology has assumed an increasingly important role as a critical tool in animal biology, biomedical research, and pharmaceutical development. This technology allows virtually any fragment of DNA large enough to contain an entire gene to become integrated into the germline of the recipient animal. The newly inserted DNA will be inherited like endogenous genes, and will be expressed as RNA and protein at tissue locations and abundance depending on regulatory elements attached to the coding DNA. It is possible to clone a particular gene, change a regulatory coding sequence, and reinsert the gene to determine the effect of the change on expression and function of the gene.

Allergy and Immunology↗
PubMed1982

Changing faces: visual and non-visual coding processes in face recognition.

Two experiments examined the effect of recognition accuracy and latency of changing the view of faces between presentation and test. In Expt 1, all the faces were unfamiliar to the subjects. Faces at test were either unchanged, or changed in angle (e.g. full face to 3/4), expression (e.g. smiling to unsmiling) or both. Unchanged faces were recognized more quickly and accurately than faces with a change in angle or expression which were in turn better than faces with both changed. In Expt 2, half the faces were highly familiar to the subjects, and at test unfamiliar and familiar faces were either unchanged or changed in both angle and expression. Unfamiliar faces were recognized more slowly and less accurately if changed at test, while familiar faces were recognized more slowly though no less accurately if change (though performance was effectively at ceiling). Familiar faces were recognized more quickly and accurately than unfamiliar, though false positive rates and rejection latencies were similar for familiars and unfamiliars. The results are discussed in terms of the combination of information from "pictorial', "structural', and "semantic' and "name' codes.

Discrimination Learning↗