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Biomedical subjects

S Bergström

Publications and source records attributed to S Bergström.

At least 109 records · Page 6Linked to original sources
PubMed1996

Amniotic fluid interleukins in Swedish and Mozambican pregnant women.

The aim of the study was to investigate inflammatory cytokines, interleukin-1 beta (IL-1 beta), interleukin-1 receptor antagonist (IL-1ra), IL-6, IL-8 in amniotic fluid, in a cohort of Swedish pregnant women from early to late pregnancy and Mozambican late pregnant women with and without signs of histologic chorioamnionitis. Eleven Swedish women were studied from early pregnancy (week 16-17) to late pregnancy (week 37-38). Amniotic fluid was collected via amniocentesis in early pregnancy and also in late pregnancy during elective Caesarean section. From Mozambican women, amniotic fluid was harvested transmurally through the uterus wall during elective Caesarean section. Half of the group of 30 women showed histological signs of chorioamnionitis and half of the group did not show such signs. A statistical, significant increase in IL-1ra, Il-6 and IL-8 values from early to late pregnancy was seen in the Swedish pregnant women. Among the Mozambican women, no statistically significant increase in the above-mentioned interleukins was observed when comparing women with and without histological signs of chorioamnionitis. Term Swedish and Mozambican women did not show differences in cytokine levels. There were no detectable values of IL-1 beta in either Swedish or Mozambican women. IL-1ra, IL-6 and IL-8 increased in amniotic fluid from the second to the third trimester in the Swedish cohort. No correlation was found between histological chorioamnionitis and elevated cytokine levels of amniotic fluid in term pregnant women not in labour. An equally good cytokine response was found among Swedish and Mozambican third-trimester non-labouring women.

Amniocentesis↗
PubMed1996

Simplified care of women with prolonged or persistent retention of the placenta: the use of paracervical block.

Thirty patients with prolonged or persistent retention of the placenta were randomized to either paracervical block or intravenous cocktail of pethidine and diazepam. When paracervical block worked, the analgesia produced was better than that usually achieved with intravenous cocktail of pethidine and diazepam. From a cost-benefit point of view paracervical block is preferable to intravenous cocktail. No significant side-effects occurred during the trial.

Analgesia, Obstetrical↗
PubMed1995

Molecular analysis of a 66-kDa protein associated with the outer membrane of Lyme disease Borrelia.

A 66-kDa protein (p66) associated with the outer membrane of Lyme disease Borrelia was analysed at the molecular level. The chromosomal genes encoding p66 in B. burgdorferi B31, B. afzelii ACAI, and B. garinii Ip90 were sequenced. Database searches revealed that the p66 gene sequences were homologous to a previously reported gene fragment of unknown function. The deduced amino acid sequences of p66 in different Lyme disease borreliae were 92-94% identical and had no homologs in the databases. Proteolytic cleavage patterns of p66 and a computer-predicted single trans-membrane helix suggested the presence of surface-exposed epitopes on the C-terminus.

Amino Acid Sequence↗
PubMed1995

Expression of truncated and full-length forms of the Lyme disease Borrelia outer surface protein A in Escherichia coli.

The lipidated major outer surface protein, OspA, of the Lyme disease spirochaete may be important in the pathogenesis during Lyme borreliosis. To produce sufficient amounts of purified OspA variants to perform pathogenesis studies in vivo and in vitro, different recombinant OspA expression systems in Escherichia coli were constructed. Recombinant OspA variants were produced as a full-length molecule, as a truncated variant lacking the N-terminal lipidated cysteine, or as a fusion protein with the synthetic dimer of Staphylococcus aureus protein A IgG binding domain (ZZ). In order to produce the full-length protein, four different promoters were evaluated. These were combined with either the OspA original signal sequence or the E. coli Brauns lipoprotein signal sequence, lpp. The most efficient production of the full-length lipidated OspA was mediated by the constitutive beta-lactamase promoter in combination with lipoprotein signal sequences. For production of truncated nonlipidated OspA the S. aureus protein A signal sequence was ligated to the OspA open reading frame. Alternatively, truncated OspA was produced intracellularly using expression vectors that lack signal sequences. Production of nonlipidated protein with a heterologous signal peptide resulted in a soluble protein located mainly in the periplasm and in the culture medium. The full-length lipidated OspA, on the other hand, was associated mainly with the membrane fraction. The production level of the lipidated recombinant OspA was much lower than the level obtained with the truncated ZZ-OspA fusion protein.

Antigens, Surface↗
PubMed1995

Intrauterine death and infections during pregnancy.

OBJECTIVE: To elucidate whether microbial infections are involved in the etiology of intrauterine death. METHODS: One hundred four cases of stillbirth of unknown etiology and 96 age- and parity-matched referents with live births were analyzed with respect to microbial infection by cultures from the placenta, endocervix and internal organs of the fetuses, external sites of the babies and fetuses, and by serology for bacteria, viruses and Toxoplasma gondii. RESULTS: In 17 cases in whom no other infectious agent was diagnosed, Escherichia coli was isolated from the placenta and one or more internal fetal organs. Tests for Treponema pallidum and Toxoplasma gondii were more frequently positive in cases than in referents (O.R. 8.3 and 3.9, respectively). There was no increased risk for intrauterine death in women with human immunodeficiency virus, cytomegalovirus, herpes simplex virus or rubella virus. CONCLUSIONS: Our findings indicate that infections remain an important cause of intrauterine death in Zimbabwe.

Case-Control Studies↗
PubMed1995

Subcutaneous implanted chambers in different mouse strains as an animal model to study genetic stability during infection with Lyme disease Borrelia.

Tissue metal net cages were implanted subcutaneously in BALB/cJ and C3H/Tif mice as an experimental model of Borrelia burgdorferi infection. B. burgdorferi sensu stricto strain Sh2-82 could be isolated up to 14 weeks after the inoculation. However, a significant difference in infectivity between the two mice strains was observed. C3H/Tif mice were more susceptible to developing chronic B. burgdorferi s.s. infections than BALB/cJ mice. Although a B. burgdorferi infection was established, no rearrangements in the ospA and ospB genes were observed in any of the infected mice.

Animals↗
PubMed1995

Premature weaning in east Bhutan: only if mother is pregnant again.

The relationship between breast-feeding and subsequent pregnancy in East Bhutan is examined, against the background of local attitudes to family planning. Ninety-eight mothers who had given birth 30-36 months earlier were interviewed. Semisolid supplementary feeding was introduced at a median age of 3 months. Median total duration of breast-feeding was 28 months, and day and night breast-feeding on demand was continued throughout. Median duration of postpartum amenorrhoea was 12 months, and was associated with the timing of the introduction of supplementary foods. There was a significant association between the occurrence of a subsequent pregnancy and early termination of breast-feeding. The relationships between breast-feeding pattern and pregnancy interval are complex, and their relative influence changes with time. During the first year postpartum, infertility during lactational amenorrhoea is important. During the second year there is a strong negative effect on lactation from the next pregnancy. The only important reason for ceasing to breast-feed within 2 years seems to be a new pregnancy.

Amenorrhea↗
PubMed1995

Subsequent pregnancy affects morbidity of previous child.

A prospective study of 113 children in rural Bhutan registered their morbidity and weight and their mothers' subsequent pregnancies, monthly for 32 months during the children's first 3 years of life. Children whose mothers had a subsequent birth interval of 18-30 months had an incidence of diarrhoea during the subsequent pregnancy 50% higher than their matched cohort whose mothers did not become pregnant (p = 0.02). The relative risk for diarrhoea calculated from pooled child months was 1.51. Children whose mothers became pregnant also tended to have a higher incidence of skin infections. Children, whose mothers were pregnant when they terminated breastfeeding, experienced an increased incidence of diarrhoea around weaning (p = 0.01). Children weaned at the same age from non-pregnant mothers did not show increased morbidity. This study, for the first time, relates observations of children's morbidity directly in time to the occurrence of the mother's subsequent pregnancy, and provides evidence of a causal relationship between a moderately short subsequent birth interval and a concurrent increase in morbidity for the study child.

Bhutan↗
PubMed1995

Reducing maternal mortality in Kigoma, Tanzania.

An intervention programme aiming at a reduction of maternal deaths in the Regional Hospital, Kigoma, Tanzania, is analyzed. A retrospective study was carried out from 1984-86 to constitute a background for an intervention programme in 1987-91. The retrospective study revealed gross under-registration of data and clarified a number of potentially useful issues regarding avoidable maternal mortality. An intervention programme comprising 22 items was launched and the maternal mortality ratio was carefully followed in 1987-91. The intervention programme paid attention to professional responsibilities with regular audit-oriented meeting, utilization of local material resources, schedules for regular maintenance of equipment, maintenance of working skills by regular on-the-job training of staff, norms for patient management, provision of blood, norms for referral of severely ill patients, use of antibiotics, regular staff evaluation, public complaints about patient management, travel distance of all essential staff to the hospital, supply of essential drugs, the need of a small infusion production unit, the creation of culture facilities for improved quality of microbiology findings, and to efforts to stimulate local fund-raising. The results indicate that the maternal mortality ratio fell from 933 to 186 per 100,000 live births over the period 1984-91. Thus it is underscored that the problem of maternal mortality can be successfully approached by a low-cost intervention programme aiming at identifying issues of avoidability and focusing upon locally available problem solutions.

Developing Countries↗
PubMed1995

Genital infections in the aetiology of late fetal death: an incident case-referent study.

Women with prelabour fetal death in the third trimester were recruited in order to study the association between intra-uterine death and maternal genital colonization of bacteria. Fifty-eight women with verified fetal death were compared with a group of 58 women matched for age, parity and gestational length (the first referent group) and with women delivering liveborn neonates (second referent group). Cultures from the vagina, the endocervix, the amniotic fluid, the placenta, the conjunctivae of the newborn and the secretion of gastric aspirate of the newborn were carried out. Blood was taken for haemoglobin, thick film (malaria) and syphilis and HIV serology. Cases were more affected by previous stillbirths than first referents (OR = 11.88). Preterm delivery was significantly more common in cases than in second referents (OR = 57.70). Cases had significantly more often < 3 ANC visits (OR = 2.81). Cases had a lower body mass index than first referents (OR = 2.38). Temperature > or = 37 degrees C was 12 times more frequent in cases than in first referents (OR = 21.20) and four times more frequent than in second referents (OR = 6.60). Average birth weight among stillborns was 1954 g and in liveborns 3223 g (P = 0.001). The corresponding prevalence of LBW was 78% in cases and 0% among second referents (P < 0.001). Histological chorioamnionitis was significantly prevalent in cases than in second referents (OR = 4.97). Syphilis was significantly more common in cases than in first (OR = 7.71) and in second referents (OR = 5.30).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

An incident case-referent study of threatening preterm birth and genital infection.

A total of 53 pregnant Mozambican women identified as having painful uterine contractions in the preterm period were studied and compared to referents, matched for age, parity, and gestational length, without such contractions. Both groups were studied regarding socio-economic and obstetric background factors, current clinical features, and microbiological findings in the lower genital tract. Cases tended to seek antenatal care earlier than referents. Salaried work outside the home was more common among cases (OR = 16.9). It was shown that affected cases had significantly more antenatal card risk factors (OR = 3.4) and that 10 times more cases than referents had elevated body temperature (OR = 16.7). Anaemia was more common among cases than among referents (OR = 3.7) and malaria parasitaemia was over-represented among cases (OR = 12.4). Mid-upper-arm circumference was shorter among cases than among referents (OR = 2.4). Anaerobic bacteria tended to be isolated from endocervix more often among cases than among referents (OR = 2.4). Only one woman in the study was HIV-1-positive. It is concluded that febrile infection is strongly associated with preterm labour and that salaried work outside home, anaemia, and malaria are significant risk factors in the setting studied.

Adolescent↗
PubMed1995

Human milk kappa-casein and inhibition of Helicobacter pylori adhesion to human gastric mucosa.

Readily digested caseins, which account for almost half of the protein content in human milk, are important as nutritional protein for breast-fed infants. It has also been advocated that part of the antimicrobial activity of human milk resides in the caseins, most likely the glycosyated K-casein. Top explore this possibility, we purified K-casein from human milk to homogeneity by a two-step size-exclusion chromatography procedure. Purified human K-casein, in contrast to K-casein purified from bovine milk, effectively inhibited the cell lineage-specific adhesion of fluoroisothiocyanate-labeled Helicobacter pylori to human gastric surface mucous cells. The inhibitory activity was abolished by metaperiodate oxidation and considerably reduced by preincubation with alpha-L-fucosidase but not with alpha-N-acetylneuraminidase or endo-beta-galactosidase. These results strongly support the view that fucose containing carbohydrate moieties of human K-casein are important for inhibition of H. pylori adhesion and, thus, infection. They also suggest that breastfeeding may protect from infection by H. pylori during early life and that species-specific glycosylation patterns, as illustrated by human bovine K-casein, partly determine both the narrow host spectrum of this human gastric pathogen and the capacity to resist infection.

Animals↗
PubMed1995

Expression of the flagellin gene in Borrelia is controlled by an alternative sigma factor.

The flagellin genes from six Borrelia species were cloned, sequenced and characterized at the molecular level. The flagellin genes of two relapsing fever Borrelia species, B. hermsii and B. crocidurae, three Lyme disease genomic species, B. burgdorferi, B. afzelii and B. garinii, and the avian borreliosis agent, B. anserina, were compared and showed an 85-93% sequence identity to each other. Comparison of the fla genes from the different Lyme borreliosis spirochaetes revealed that they were 94-99% identical. Nucleotide sequencing of the fla gene and primer extension on isolated mRNA from both B. hermsii (as transcribed in Escherichia coli) and B. burgdorferi (as transcribed in the natural host) identified the putative transcriptional start points, the ribosomebinding sites and the promoter regions of these genes. The deduced promoter of the Borrelia flagellin gene resembled neither the sigma 70 promoter of prokaryotes, as seen for the genes for the outer-surface proteins A and B in Lyme disease Borrelia and the genes for the variable major proteins 7 and 21 of B. hermsii, nor the sigma 28 consensus promoter region of motility genes from other bacteria. Instead, the promoter of the fla gene in Borrelia has most similarity to the bacteriophage SP01 sigma gp33-34 promoter sequence of Bacillus subtilis.

Amino Acid Sequence↗
PubMed1995

The outer surface proteins of Lyme disease borrelia spirochetes stimulate T cells to secrete interferon-gamma (IFN-gamma): diagnostic and pathogenic implications.

Late stages of borrelia Lyme disease infections may be difficult to diagnose because of unspecific symptoms and unreliable laboratory tests, being too unspecific or insensitive. The T cell immune response was thus evaluated in these patients by using a sensitive ELISPOT T cell assay that detects the secretion of IFN-gamma, i.e. a T helper 1 (Th1) response on the single-cell level. Three subcellular fractions of the Lyme borreliosis strain Borrelia afzelii were used for antigenic stimulation. The outer surface protein (Osp) fraction elicited the strongest response, discriminating between borrelia infections (n = 15) compared with other neurological diseases (n = 10) and normal controls (n = 12) (P = 0.0001). The more heterogeneous sonicated borrelia fraction also elicited a strong response, however, also in some of the controls. The flagellin fraction did not have a similar T cell-stimulating effect. When looking at subgroups of borrelia infections, central nervous system (CNS) infections (n = 7) revealed a lower T cell response in blood (P = 0.0128) compared with other borrelia manifestations (n = 8). Cerebrospinal fluid (CSF) lymphocytes were available from three patients with CNS borreliosis, and all showed a compartmentalization with higher responses to the Osp fraction in CSF compared with blood, also in the two patients without any intrathecal-specific antibody synthesis. The ELISPOT method is feasible for detecting a specific IFN-gamma T cell response in borrelia infections. This Th1 response may well be of pathogenic relevance.

Adolescent↗
PubMed1995

Subsequent pregnancy affects nutritional status of previous child: a study from Bhutan.

In a rural area of Bhutan, anthropometric measurements of 113 children and interviews with their mothers were carried out monthly for 32 months. The purpose of the study was to investigate the effect of a mother's subsequent pregnancy on growth in weight of her last-born child. The children whose mothers had a subsequent birth interval of 18-30 months were matched for date of birth with children whose mothers did not become pregnant. Growth of the children during the subsequent pregnancy was compared with growth during the same period of children whose mothers were not pregnant. A statistically significant reduction of 28% was found (p < 0.05), which was most pronounced in early pregnancy. A similar trend was found for change in mid-upper-arm circumference (p < 0.05). The study provides evidence of a causal relationship between a moderate subsequent pregnancy interval and a concurrent reduction in growth rate for the previous child.

Birth Intervals↗
PubMed1995

Prevalence of Borrelia burgdorferi sensu lato-infected ticks on migrating birds.

The prevalence of Lyme disease Borrelia-infected ticks on migrating birds was studied in Scandinavia. A total of 22,998 birds were caught at eight different bird observatories and examined for ticks. Five different species of ticks were found infesting the birds. The dominant species, Ixodesricinus, constituted 98.3% of the ticks collected. The presence of spirochetes was determined by an immunofluorescence assay of tick larvae and DNA amplification by PCR on all ticks. To determine which Borrelia burgdorferi sensu lato species were present, a species classification was performed by DNA amplification with species-specific 16S rDNA primers and by DNA sequencing (rDNA is DNA coding for rRNA). Flagellin gene sequences of all species of B. burgdorferi sensu lato previously recorded in Europe were observed. Borrelia garinii was the most prevalent Lyme disease Borrelia species in ticks collected from birds arriving from the South or Southeast in the spring, whereas the distribution was more heterogeneous in ticks from birds migrating from the Southwest. These data support the notion that birds are partly responsible for the heterogeneous distribution of Lyme disease Borrelia spirochetes in Europe.

Animals↗
PubMed1995

Transhemispheric exchange of Lyme disease spirochetes by seabirds.

Lyme disease is a zoonosis transmitted by ticks and caused by the spirochete Borrelia burgdorferi sensu lato. Epidemiological and ecological investigations to date have focused on the terrestrial forms of Lyme disease. Here we show a significant role for seabirds in a global transmission cycle by demonstrating the presence of Lyme disease Borrelia spirochetes in Ixodes uriae ticks from several seabird colonies in both the Southern and Northern Hemispheres. Borrelia DNA was isolated from I. uriae ticks and from cultured spirochetes. Sequence analysis of a conserved region of the flagellin (fla) gene revealed that the DNA obtained was from B. garinii regardless of the geographical origin of the sample. Identical fla gene fragments in ticks obtained from different hemispheres indicate a transhemispheric exchange of Lyme disease spirochetes. A marine ecological niche and a marine epidemiological route for Lyme disease borreliae are proposed.

Animals↗