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B Olofsson

Publications and source records attributed to B Olofsson.

71 records · Page 4Linked to original sources
PubMed1988

Expression of the ras-related ralA, rho12 and rab genes in adult mouse tissues.

The expression of recently isolated mammalian ras-related ral, rho, and rab genes was examined in adult mouse tissues. Most of the genes studied were transcribed into two major messenger RNAs. The transcription of each gene appeared to be regulated in a complex manner with a tissue-specific modulation of the two transcripts. One member of the rab gene family, rab3, showed an RNA expression restricted to brain-tissues. Ral, rho, and three other rab genes had a more ubiquitous expression in murine tissues. However, the expression level of each gene showed a high degree of variation depending upon the organ. Among all the members of the enlarged ras gene family examined so far, the rab3 gene is the first example showing an expression restricted to a distinct organ.

DNA↗
PubMed1988

Human cDNAs rap1 and rap2 homologous to the Drosophila gene Dras3 encode proteins closely related to ras in the 'effector' region.

We have characterized two new ras-related genes rap1 and rap2 from a human cDNA library, by hybridization with the Drosophila Dras3 gene at low stringency conditions. The rap1 and rap2 genes encode proteins of 184 and 183 amino acid respectively with molecular weights of 20.9 kd and 20.7 kd. These proteins are 53% and 46% identical to the human K-ras protein and share several properties with the classical ras proteins. The C-terminal cysteine involved in the membrane anchoring as well as the GTP binding regions of the p21 ras proteins are present in the rap proteins suggesting that these proteins could bind GTP/GDP and have a membrane localization. The most striking difference between the rap and ras proteins resides in their 61st amino acid. As in the Drosophila Dras3 protein, both rap proteins have a threonine instead of the glutamine found at position 61 of the classical ras proteins. Furthermore the putative effector domain of the ras proteins is strictly conserved in the rap1 protein whereas only one amino acid difference is found in the rap2 protein. This suggests that the rap proteins might interact with the same effector as the ras proteins.

Amino Acid Sequence↗
PubMed1987

Arrhythmogenicity from combined bronchodilator therapy in patients with obstructive lung disease and concomitant ischemic heart disease.

Twenty-four patients (five women) aged 53-72 yr with both ischemic heart disease and asthma or chronic bronchitis receiving oral beta 2-agonists also received additional bronchodilating therapy with theophylline (600 mg daily), enprofylline (600 mg daily) or placebo. The study was double-blind, randomized, triple-crossover with each regimen given for two weeks. Holter monitoring was used during 48 consecutive hours in each period. Compared with placebo, addition of theophylline and enprofylline were associated with an increased mean hourly heart rate of 6 bpm (p less than 0.001). A small, but statistically significant (p less than 0.05) increase in mean hourly frequency of premature ventricular beats (PVBs) occurred with enprofylline as compared with placebo. However, in only two patients with enprofylline (and one patient with theophylline) the increase in PVBs was such that a clinically relevant proarrhythmic effect seems possible. Furthermore, ventricular tachycardia was not more frequently observed with any xanthine than with placebo. Thus, combined oral bronchodilator therapy is not contraindicated in patients with obstructive lung disease and concomitant ischemic heart disease. Holter monitoring is recommended to assess the individual patient's response to such therapy.

Aged↗
PubMed1986

Structure and expression of the chicken epidermal growth factor receptor gene locus.

Similarity between the carboxyl-terminal portion of the human epidermal growth factor (EGF) receptor and the deduced protein sequence of the chicken-derived oncogene v-erbB, of avian erythroblastosis virus strain H, has suggested that the chicken cellular erbB locus, c-erbB, might be part of a longer EGF-receptor gene in the chicken, whose entire coding capacity remained to be defined. The c-erbB locus spans more than 20 X 10(3) base pairs (20 kbp) of DNA and contains at least 1.8 kbp homologous to the v-erbB oncogene. We show here that human EGF receptor cDNA and chicken genomic DNA share homology not only within the c-erbB locus but also within a 25.1-kbp DNA region situated 5' to this locus. The 3' region of the EGF receptor overlaps, in sequence homology, the c-erbB locus. The EGF receptor/c-erbB locus in chicken generates six related but distinctly different mRNAs of sizes 12, 9, 5, 3.6, 3.2 and 2.6 kb. The transcripts of 12, 9, and 3.6 kb contain sequences coding for both the extracellular EGF-binding domain of the receptor and the intracellular tyrosine kinase domain. The 12-kb and 9-kb transcripts, which have already been shown to contain the sequences coding for the v-erbB, were found to possess, in addition, sequences that encode the entire chicken EGF receptor. The 3.2-kb and 2.6-kb mRNAs are homologous only to the 5' portion of the EGF receptor gene. These results therefore indicate that the c-erbB locus, initially defined by homology to the viral transforming gene, corresponds to the 3' region of the EGF receptor gene in the chicken genome. The multiple, related, chicken EGF receptor RNA transcripts reported here are reminiscent of the various human EGF receptor RNA transcripts observed in normal and transformed cells.

Alpharetrovirus↗
PubMed1985

The mosaic genome of warm-blooded vertebrates.

Most of the nuclear genome of warm-blooded vertebrates is a mosaic of very long (much greater than 200 kilobases) DNA segments, the isochores; these isochores are fairly homogeneous in base composition and belong to a small number of major classes distinguished by differences in guanine-cytosine (GC) content. The families of DNA molecules derived from such classes can be separated and used to study the genome distribution of any sequence which can be probed. This approach has revealed (i) that the distribution of genes, integrated viral sequences, and interspersed repeats is highly nonuniform in the genome, and (ii) that the base composition and ratio of CpG to GpC in both coding and noncoding sequences, as well as codon usage, mainly depend on the GC content of the isochores harboring the sequences. The compositional compartmentalization of the genome of warm-blooded vertebrates is discussed with respect to its evolutionary origin, its causes, and its effects on chromosome structure and function.

Animals↗
PubMed1985

Cardiac arrhythmias in patients with mild-to-moderate obstructive lung disease. Comparison of beta-agonist therapy alone and in combination with a xanthine derivative, enprofylline or theophylline.

Long-term ambulatory Holter-monitoring was used to evaluate the arrhythmogenic effects of beta 2-agonist therapy, alone and in combination with a xanthine derivative, theophylline or enprofylline. Twenty patients (mean age 51 years) with mild-to-moderate obstructive lung disease (bronchial asthma or chronic bronchitis), but without concomitant ischemic heart disease were studied. Compared with beta 2-agonist therapy alone, both combined regimens were associated with a small but significant increase in the frequency of ventricular arrhythmias. Few serious arrhythmias were observed, however, and the clinical significance of these findings is thought to be minor. Although adenosine has been suggested to have an antiarrhythmic effect, a difference between theophylline and enprofylline in the effect on adenosine (theophylline but not enprofylline being an adenosine antagonist) would appear to be of less cardiac relevance in patients without ischemic heart disease.

Adrenergic beta-Agonists↗
PubMed1983

The distribution of CR1, and Alu-like family of interspersed repeats, in the chicken genome.

We have studied the distribution of CR1, a family of short interspersed repeats, in the chicken genome; this family is homologous to the AluI family of man and to the B1-B2 families of mouse. Hybridization with a suitable probe showed that the vase majority of CR1 are located on the heaviest major component (1.708) of the genome which only represents 9% of chicken DNA. Some repeats were also found on the 1.702 and 1.704 components, but none on the 1.699 component (components are denoted by their buoyant densities in CsCl). The GC content of the repeats, 48%, matches that, 47%, of the major component mainly harboring it.

Animals↗
PubMed1983

Organization of nucleotide sequences in the chicken genome.

The four major components of chicken DNA were prepared by density gradient centrifugation and characterized in several basic properties: relative amounts, dG + dC content, buoyant densities, compositional heterogeneity, and reassociation kinetics. While the relative amounts and the compositions of the major components of chicken DNA were similar to those found in mammalian genomes, their compositional heterogeneities were found to be narrower. The relative amounts of interspersed repeated and unique sequences were strikingly different in different components and also different from those found in the corresponding major components of mouse and human DNAs. If one takes into consideration that major DNA components (a) account for practically all of main-band DNA and (b) derive by preparative breakage from very long DNA segments of fairly homogeneous composition, the isochores, our findings indicate that the distribution of interspersed repeats is different in different chromosomal regions and is species-specific.

Animals↗
PubMed1979

THE DNA components of the chicken genome.

The organization of the chicken genome was investigated by centrifuging chicken DNA (Mr = 57 X 10(6) in preparative Cs2SO4/Ag+ and Cs2SO4/BAMD density gradients [BAMD = 3.6-bis(acetato-mercurimethyl)dioxane]. An analysis by CsCl density gradient of the DNA fractions obtained from the preparative experiments revealed that 88% of the genome is made up of four DNA components, characterized by buoyant densities of 1.699, 1.702(5), 1.704(5) and 1.708 g/cm3 and representing 39%, 25%, 15%, and 9%, respectively, of the total DNA. The remaining 12% of the genome is formed by seven minor and/or satellite components. The distribution of the ovalbumin gene in a Cs2CO4/BAMD density gradient, as tested with a cloned cDNA probe, coincides with the distribution of the 1.702(5)-g/cm3 component. This shows that the DNA regions flanking the ovalbumin gene are homogeneous in base composition over along distances and that the gene is located on a DNA segment belonging to the 1.702(5)-g/cm3 component.

Animals↗
PubMed1974

Extent of transcription of mouse sarcoma-leukemia virus by RNA-directed DNA polymerase.

The DNA product obtained from the endogenous RNA-directed DNA polymerase (deoxynucleosidetriphosphate:DNA deoxynucleotidyltransferase, EC 2.7.7.7) reaction of the Moloney sarcoma:leukemia viruses produced by the 78 A-1 cell line was analyzed and characterized. The extent of transcription of viral 70S RNA was measured by RNA.DNA hybridization ((32)P-viral RNA-(3)H product DNA). No double-stranded DNA was obtained. The product consisted of 95-99% single-stranded DNA with an average length of 200 nucleotides. In contrast to the results reported with avian and other RNA oncogenic viruses, it was found that the entire 70S viral RNA genome was transcribed into DNA pieces and that a small excess of the product DNA was sufficient to anneal the 70S RNA and render it totally resistant to single-stranded-specific enzyme digestion.

Animals↗
PubMedDate not supplied

Influence of food on the bioavailability of an enteric-coated tablet formulation of omeprazole 20 mg under repeated dose conditions.

The objective of this study was to investigate the influence of food on the bioavailability of omeprazole (20 mg) given as an enteric-coated tablet under repeated dose conditions. This open randomized crossover study consisted of three seven-day treatment periods, each separated by a drug-free period. During each treatment period an enteric-coated tablet of omeprazole was taken once daily either under fasting conditions, or immediately before or after a standardized breakfast. On the last day of each treatment period, blood samples for the determination of plasma omeprazole concentrations were collected at baseline and at predetermined intervals over the 24 h period following drug administration. Fifty-seven male and female subjects, aged 18 to 52 years, completed the study according to the protocol. No statistically significant differences were found when comparing either the before breakfast or after breakfast treatment regimens with the fasting regimen for the estimated mean area under the plasma concentration-time curve (AUC). The maximum plasma concentration was not found to differ significantly among any of the treatment regimens. However, the lower limit of the CI for the comparison of fasting/before breakfast was not contained within the limits of bioequivalence. The time to reach maximum plasma concentration was significantly different when fasting and after breakfast regimens were compared. Thus, under repeated dose conditions, food has no influence on the bioavailability (expressed as AUC) of omeprazole given as the enteric-coated tablet formulation.

Adolescent↗
PubMedDate not supplied

Pharmacokinetics and pharmacodynamics during treatment with the omeprazole 20 mg enteric-coated tablet and 20 mg capsule in asymptomatic duodenal ulcer patients.

This study compared the 24 h intragastric pH profile and bioavailability at repeated dosing conditions of the omeprazole 20 mg enteric-coated tablet versus the 20 mg capsule. Forty duodenal ulcer patients in asymptomatic remission completed this randomized open two-way crossover study. Omeprazole 20 mg tablets or capsules were administered for seven days in each period. A 24 h pH recording was performed before the start of treatment and on day 7 of each treatment period. Plasma concentrations of omeprazole were determined 24 h after the dose. The treatment periods were separated by two to four weeks. The difference in percentage of time with pH of at least 3 was less than 16% in favour of the tablet (not significant). The estimated mean area under the plasma concentration-time curve as well as the maximum plasma concentration (Cmax) for omeprazole were 18% and 41% higher, respectively, for the tablet versus the capsule, with the latter percentage being statistically significant. The time to reach Cmax (tmax) with the tablet was, on average, about 0.5 h longer than to reach the tmax of the capsule. This study indicates that the enteric-coated tablet formulation of omeprazole is biodynamically equivalent to the capsule regarding their effects on intragastric pH during repeated dosing.

Adult↗