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Biomedical subjects

S Bergström

Publications and source records attributed to S Bergström.

At least 199 records · Page 11Linked to original sources
PubMed1991

A prospective study on the perinatal outcome in Mozambican pregnant women with preterm rupture of membranes using two different methods of clinical management.

Antenatal care of women with preterm rupture of membranes is controversial, particularly in countries with high prevalence figures for sexually transmitted diseases and other genital infections. In order to assess the value of conservative and active management routines, 92 women with singleton pregnancies and gestational lengths between 27 and 34 weeks were adopted into the two respective groups. The first group comprised 40 cases who were treated conservatively and the second comprised 52 cases who were treated actively with induction. The first group received amoxicillin (100 mg) and metronidazole (500 mg), both drugs given three times daily. All patients were also routinely treated with an antimalarial dose of chloroquine. The second group was not given any pharmaceutical treatment, and labor was induced 3-24 h after membrane rupture. The two groups differed significantly regarding birth weight, the average birth weights being 2,168 and 1,780 g in the first and second groups, respectively (p less than 0.05). While the intrauterine mortality was approximately the same in both groups, the neonatal mortality differed significantly (2.6 vs. 19.2%; p less than 0.05). It is concluded that an expectant attitude, rather than an active and induction-oriented one, is most favorable in cases with preterm rupture of membranes, also in settings in which prevalence figures of sexually transmitted diseases and other genital infections are high.

Adult↗
PubMed1991

Genetics of Borrelia burgdorferi.

Structural analysis by electronmicroscopy and pulsed field agarose gel electrophoresis of the genome of Borrelia burgdorferi has revealed a 1000 kilobase (kb) chromosome and a unique type of extra chromosomal linear DNA, as well as supercoiled circular DNA. The plasmid DNA ranged in size from 1.5 to 50 kb. Gene mapping of the ospA and ospB genes have placed them on the 49 kb linear plasmid molecule. The osp operon of B. burgdorferi has been extensively characterized at the molecular level.

Animals↗
PubMed1990

Cloning and sequencing of a cDNA encoding human milk beta-casein.

A cDNA of 1065 bp encoding the human milk beta-casein was cloned and sequenced using a synthetic oligodeoxyribonucleotide probe and a human mammary gland library. The nucleotide (nt) sequence contained an open reading frame sufficient to encode the entire amino-acid (aa) sequence of a beta-casein precursor protein consisting of 210 aa and a signal peptide of 15 aa. The nt sequence shows 45-62% homology to those of bovine, ovine, rat, and mouse beta-caseins. The highly phosphorylated site, which is responsible for the calcium-binding capacity of beta-casein, the signal peptide, and a sequence encoding for an inhibitor to the angiotensin-converting enzyme seem highly conserved among the beta-caseins with known sequences.

Amino Acid Sequence↗
PubMed1990

The variable antigens Vmp7 and Vmp21 of the relapsing fever bacterium Borrelia hermsii are structurally analogous to the VSG proteins of the African trypanosome.

The relapsing fever agent Borrelia hermsii avoids the host's immune response by the strategy of multiphasic antigenic variation. A given Borrelia cell can express one of a number of alleles for polymorphic outer-membrane proteins, known as Vmp proteins. The genes for the variant-specific Vmp proteins of serotypes 7 and 21 of B. hermsii strain HS1 were sequenced. The genes, which were designated vmp7 and vmp21, were obtained from populations of borreliae before and after a switch in serotypes from 7 to 21. The analysis showed that vmp7 and vmp21 are 77% identical in terms of their coding sequence. The deduced translation products of vmp7 and vmp21 are polypeptides of 369 (37.2 kD) and 364 amino acids (37.1 kD), respectively. Vmp7 and Vmp21 have sequence features of prokaryotic lipoproteins and are processed as such during expression in E. coli. The secondary structure predictions of the Vmp proteins reveals analogous structures to the VSG proteins of the African trypanosome.

Amino Acid Sequence↗
PubMed1990

Cloning and sequence analysis of linear plasmid telomeres of the bacterium Borrelia burgdorferi.

Borrelia burgdorferi, the Lyme disease agent, has double-stranded linear plasmids with covalently closed ends. DNA at the ends, or telomeres, of two linear plasmids of B. burgdorferi strain B31 was examined. Telomeric sequences from both ends of a 16 kb linear plasmid and from one end of a 49 kb linear plasmid were cloned and sequenced. An 18 bp AT-rich inverted repeat was found at each end of the 16 kb linear plasmid. The sequences of the two ends of this plasmid were different beyond these short inverted terminal repeats. The cloned end of the 49 kb linear plasmid had sequence identity with one end of the 16 kb linear plasmid. The end sequence common to both plasmids contained a series of phased, short direct repeats and a 52 bp palindrome adjacent to a highly AT-rich region. These findings indicate that Borrelia linear plasmid telomeres have structural features different from those of other known replicons.

Base Sequence↗
PubMed1990

DNA content and nuclear size of megakaryocytes in thrombocythaemia.

Total nuclear DNA content and nuclear size of megakaryocytes were studied in biopsies of the iliac bone marrow of individuals with normal or increased platelet counts. The DNA content was determined using Feulgen cytophotometry of bone marrow smears and the nuclear area by morphometric analysis of megakaryocytes of bone marrow sections. The mean DNA content and the mean nuclear area were both significantly larger in megakaryocytes of patients with thrombocytosis as a result of myeloproliferative disease than in patients with secondary thrombocytosis as well as in two control groups of individuals with normal platelets counts, one comprising healthy volunteers, the other with various non-haematological disorders. There was a statistically significant correlation between the DNA content and nuclear area of the megakaryocytes (r = 0.92) in the entire group of bone marrows studied.

Adolescent↗
PubMed1990

Genital infections and reproductive health: infertility and morbidity of mother and child in developing countries.

Genital infections in impoverished countries take a heavy toll both in the etiology of childlessness and in pregnancy-related morbidity, both for the carrier (mother) and the passenger (fetus/newborn). Tubal damage is by far the most common single etiology in cases of childlessness. Among the three factors principally contributing to childlessness, infertility, pregnancy wastage and child loss, tubal infertility is the predominant one. Prevalence figures of N. gonorrhoeae among women in reproductive ages range between 5 and 15% in several countries. Similar figures prevail among pregnant/puerperal women. Preliminary figures indicate that prevalence of Chlamydia trachomatis is similar. Genitally acquired infections during pregnancy contribute to pregnancy wastage in the second and third trimesters of pregnancy. There is virtually no data to support that HBV, HSV and HPV significantly contribute to transmitted intra-uterine disease leading to pregnancy wastage. In the third category of childlessness, child loss, HSV and HIV play a well-known role. Maternal and neonatal morbidity is adversely affected by genital infections acquired during pregnancy. While hepatitis in some places is an important contributor to maternal mortality and morbidity, other viral diseases like HSV and HPV do not appear important in pregnancy-related maternal morbidity. Gonorrhea and chlamydia infection give few maternal problems during pregnancy but may be more important as a cause of puerperal endometritis-myometritis, which constitutes one of the leading causes of maternal death in many developing countries. The fetal/neonatal infant morbidity is affected by gonorrhea and chlamydia infection, while HSV is less frequent but extremely serious when it appears.(ABSTRACT TRUNCATED AT 250 WORDS)

Developing Countries↗
PubMed1989

Parturient fundal height and its relation to fetal weight.

Fundal heights of parous and non-parous women were measured in early singleton labour and grouped according to level of presenting fetal part. The birth-weights were recorded and related to fundal heights in each group. Regression lines were drawn corresponding to different probabilities of a given minimum birth-weight. It was concluded that a single measurement particularly in early pre-term labour might give a useful and simple estimate of expected fetal weight.

Birth Weight↗
PubMed1989

Molecular analysis of linear plasmid-encoded major surface proteins, OspA and OspB, of the Lyme disease spirochaete Borrelia burgdorferi.

The ospA and ospB genes encode the major outer membrane proteins of the Lyme disease spirochaete Borrelia burgdorferi. The deduced translation products from the ospA and ospB genes were: (OspA) 273 amino acids long with a molecular weight of 29,334, and (OspB) 296 amino acids long with a molecular weight of 31,739. The two Osp proteins showed a great degree of sequence similarity indicating a recent evolutionary event. Molecular analysis and sequence comparison of OspA and OspB with other proteins revealed a sequence similarity to the signal peptides of prokaryotic lipoproteins. These are the first sequences from Borrelia and provide interesting data on the evolutionary relationship between spirochaetes and other species as well as providing potential for spirochaete diagnostics and vaccines.

Amino Acid Sequence↗
PubMed1989

On mast cell-mediated mitogenesis in normal and hyperplastic mesenterial windows in female rats.

The outcome of the mast cell-mediated mitogenesis in hyperplastic membranous mesenterial windows of lactating rats as well as in normal mesenterial windows of age-matched and young virgin female rats was studied quantitatively in vivo and in organ culture. Besides elucidating the effect of age and tissue hyperplasia on mitogenic responsiveness, this approach should provide some insight into the pathogenic mechanics of the previously reported supranormal mast cell-mediated mitogenic reaction that emerges in similarly hyperplastic mesenterial windows of diabetic rats. Mast cell secretion was elicited by Compound 48/80 and the histamine release, which was quantified fluorometrically, was unaffected by lactation. The young female rats showed a statistically significant mast cell-dependent mitogenesis taken as the mitotic index and the fraction of the predominating fibroblasts and mesothelial cells in the (S+G2) cell cycle phases after Feulgen-DNA absorption analysis of the cells in situ. Although there was an age-dependent decrease in mitogenesis, the older lactating and non-lactating virgin control rats also showed mast cell-mediated mitogenesis measured as the specific DNA activity. The hyperplastic mesenterial tissue of the lactating animals showed a virtually normal mitogenic reactivity following local mast cell secretion, but at a lower level than in the age-matched controls. This finding suggests that the supranormal mast cell-mediated mitogenesis previously found in the hyperplastic mesenterial windows of diabetic animals is causally related to the diabetic condition rather than to the hyperplastic state of the test tissue.

Animals↗
PubMed1989

Effect of nedocromil sodium on the compound exocytosis of mast cells.

The secretory activity of peritoneal mast cells was studied in vitro after challenge with compound 48/80 of cells obtained from normal rats and with anti-rat IgE of cells obtained from rats hyperimmunised with Nippostrongylus brasiliensis. Peritoneal mast cells were isolated from 2 groups of rats aged 2 to 3 months and 5 to 6 months. After purification, the cells were preincubated with or without nedocromil sodium for 5 minutes followed by addition of secretagogue and incubation for an additional period of 5 minutes (compound 48/80) or 15 minutes (anti-IgE). The secretory response was analysed by measurement of the release of endogenous histamine and serotonin (5-hydroxytryptamine) into the medium using high performance liquid chromatography, and by the assay of the heparin content of individual mast cells by cytofluorometry, using the fluorescent dye berberine as a quantitative marker. Concentrations of secretagogues which gave 30 to 40% amine release in controls without inhibitor were selected. In agreement with previous reports, the degree of release of histamine was slightly higher than that of serotonin, but nedocromil sodium suppressed the release of both amines in a parallel manner, without any differential effect, after stimulation with both compound 48/80 and anti-IgE. The effect of nedocromil sodium was concentration-dependent, with the lowest effective concentration in the range of 10(-8) to 10(-7) mol/L, and reduced release to about 40% of control values. Mast cells from young rats responded with a significantly higher amine release than mast cells from old rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗