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Biomedical subjects

S Nyström

Publications and source records attributed to S Nyström.

At least 19 recordsLinked to original sources
PubMed2002

Ontogenetic development and spatial distribution of the ileal apical sodium-dependent bile acid transporter and the ileal lipid-binding protein in apoE knockout and C57BL/6 mice.

BACKGROUND: Although apoE-/- mice are characterized by hypercholesterolemia, the bile acid enterohepatic circulation, which plays a crucial role in cholesterol homeostasis, has not been examined in these mice. The differences between apoE-/- and C57BL/6 mice in expression of the ileal ASBT and ILBP and in intestinal bile acid absorption were studied. METHODS: The intestinal tissues of the fetal, neonatal and post-weaning mice were processed for immunohistochemistry. Body retention and fecal excretion of 75SeHCAT were measured. The bile acid pool size and its composition were analysed by HPLC. RESULTS: In apoE-/- and C57BL/6 mice, the bile acid pool size was 75 +/- 13 and 78 +/- 13 micromol/ 100 g body weight, respectively, while the ratio of cholic acid/beta-muricholic acid was 1.8 +/- 0.3 and 1.4 +/- 0.3 (P < 0.05), respectively. The daily body retention of 75SeHCAT was 48% = 1.8% in C57 black mice and 58.4% +/- 2.7% in apoE-/- mice (P < 0.05). In both mouse strains, ASBT expression in the small intestine was found in the near-term fetal and post-weaning mice, while ILBP expression was found in all postnatal mice. In the post-weaning mice, ILBP expression was limited to the distal 25%-30% of the small intestine, while ASBT expression was limited to the distal 18%. CONCLUSIONS: The bile acid enterohepatic circulation in apoE-/- mice probably does not differ greatly from that in C57BL/6 mice.

Animals↗
PubMed2000

Differences in surface-exposed antigen expression between Helicobacter pylori strains isolated from duodenal ulcer patients and from asymptomatic subjects.

We have analyzed possible qualitative and quantitative differences in antigen expression between Helicobacter pylori strains isolated from the antrum and different locations in the duodenum of 21 duodenal ulcer (DU) patients and 20 asymptomatic subjects (AS) by enzyme-linked immunosorbent assay (ELISA) and inhibition ELISA. Almost all antral and duodenal strains grown in vitro expressed the N-acetyl-neuroaminyllactose-binding hemagglutinin, flagellins (subunits FlaA and FlaB), urease, a 26-kDa protein, and a neutrophil-activating protein. In 75% of both the DU patients and the AS, antral H. pylori strains expressed either the blood group antigen Lewis y (Le(y)) alone or together with the Le(x) antigen. However, duodenal H. pylori strains of DU patients expressed Le(y) antigen more frequently than corresponding strains of AS (P < 0.05). Presence of Le(y) on H. pylori was related to the degree of active duodenitis (P < 0.05). Duodenal H. pylori strains isolated from AS were significantly more often Lewis nontypeable than duodenal strains of DU patients (P < 0.01). Presence of H. pylori blood group antigen-binding adhesin (BabA) was significantly higher on both antral and duodenal strains isolated from DU patients than on corresponding strains isolated from AS (P < 0.05). BabA-positive duodenal H. pylori strains isolated from DU patients were associated with active duodenitis more frequently than corresponding strains isolated from AS (P < 0.01). Infection with H. pylori strains positive for Le(y) and BabA in the duodenum is associated with development of duodenal ulcer formation.

ABO Blood-Group System↗
PubMed1995

A comparative study of two methods for the measurement of alcohol consumption in the general population.

BACKGROUND: One of the major methodological problems in measuring alcohol consumption in a general population and in selected groups is underreporting. METHODS: The present study is based on a general health questionnaire survey of a random sample of about 4000 adults aged 20-74 years in an inner-city area in each of two major Swedish cities in 1991. The questionnaire included items both about alcohol consumption frequency and the usual amount of intake--the commonly used quantity-frequency (QF) method--and other questions about the consumption during work-days and weekends during a 'normal week'--the period-specific normal week (PSNW) method. RESULTS: With a few exceptions, the reported mean consumption and the proportion of high consumers was higher with the latter approach, irrespective of sex, age, socio-demographic factors, smoking and health status, i.e. for variables which are commonly used as confounders or effect modifiers. The differences between the methods was greater among women. The internal non-response rate was higher with the PSNW method but the non-responders had a comparatively low consumption, when measured with the QF method. CONCLUSION: The PSNW method has higher validity and greater precision for the measurement of alcohol consumption and, thus, is superior to the QF method. The sex differences are notable and warrant further studies focusing on sex-related modes of answering.

Adult↗
PubMed1995

Cerebral dysfunction in fibromyalgia: evidence from regional cerebral blood flow measurements, otoneurological tests and cerebrospinal fluid analysis.

Measurements of regional cerebral blood flow (rCBF), analysis of cerebrospinal fluid, auditory brain stem responses (ABR) and oculomotor tests were performed in 19 patients with fibromyalgia. The results from the rCBF measurements showed a normal flow level with slight but significant focal flow decreases in dorsolateral frontal cortical areas of both hemispheres. The ABR results showed signs of dysfunction at least at the brain stem level and the oculomotor tests showed high frequency of pathology. The cerebrospinal fluid analysis showed discrete changes in the cell differential count. Possible explanations for the involvement of the central nervous system in fibromyalgia are discussed.

Adult↗
PubMed1992

Isoprenoid modification of proteins distinct from membrane acyl proteins in the prokaryote Acholeplasma laidlawii.

Isoprenylation is an important posttranslational modification that affects the activity, subunit interactions and membrane anchoring of different eukaryotic proteins. The small, cell-wall-less prokaryote Acholeplasma laidlawii has more than 20 membrane acyl-proteins enriched in myristoyl and palmitoyl chains. Radioactive mevalonate, a precursor to isoprenoids, was incorporated into several specific membrane proteins of 20 to 45 kDa and two soluble proteins of 23-25 kDa, respectively. No acyl proteins and none of the polar acyl lipids became labelled but these are all labelled by radioactive fatty acids. Mevalonate was incorporated mainly into a minor neutral, non-saponifiable lipid which migrated just above a C30-isoprenoid (squalene) on TLC-plates. The isoprenoid chains could not be released by mild alkaline hydrolysis from most of the isoprenylated proteins, although this procedure releases acyl chains from lipids and all acylated proteins. Isoprenylated proteins were enriched in the detergent phase upon partition with the non-ionic detergent Triton X-114. This behaviour is similar to the acyl proteins of this organism and indicates that the isoprenoid chains give the proteins a hydrophobic character.

Acholeplasma laidlawii↗
PubMed1992

Membrane protein acylation. Preference for exogenous myristic acid or endogenous saturated chains in Acholeplasma laidlawii.

Mycoplasmas are small bacteria without a cell wall, often found as surface parasites on eukaryotic cells. Of the more than 200 membrane proteins from Acholeplasma laidlawii resolved by two-dimensional PAGE, 23 were covalently modified with acyl chains. These acyl proteins had lower pI values than average and were all labelled by different exogenously supplied radioactive fatty acids attached by O-ester bonds. The fatty acids were selectively incorporated in the order myristic acid (14:0) greater than palmitic acid (16:0) greater than stearic acid (18:0) greater than oleic acid (18:1). However, endogenously synthesised saturated fatty acids, most of which were 16:0, were preferred over the supplied ones. A fraction of the exogenous 14:0 was elongated to 16:0. Absence of saturated fatty acids increased the incorporation of 18:1. The maximum extent of modification was one acyl chain for protein T2, on the exterior surface and two acyl chains for protein D12, spanning them membrane. Exogenously supplied fatty acids were incorporated into membrane lipids in proportion to their occurrence. However, the acylated proteins always contained 8-10 times more saturated chains than did the lipids. When exogenously supplied, all A. laidlawii polar membrane lipids could donate acyl chains to the acylated proteins but the neutral fraction (fatty acids and diacylglycerol) was most efficient. An incorporation into the acylated proteins of labelled cysteine, but not glucose or glycerol, was observed. Acylated proteins with different chains interacted similarly with a Triton X-114 detergent phase, and no full-size proteins (or acylated fragments) were released from cells by proteolytic enzymes. The results indicate an anchoring with peptide segments in addition to the acyl chains. Both 14:0 and 16:0 were attached at one end of both T2 and D12, but the N-terminal methionine of T2 was not acylated. The extent of modification and preference for saturated chains in the A. laidlawii membrane acylated proteins is more similar to eukaryotic than to eubacterial proteins.

Acholeplasma laidlawii↗
PubMed1991

Comparison of 30 microgram and 120 microgram gentamicin disks for the prediction of gentamicin resistance in Enterococcus faecalis.

Single strain regression analysis was performed on PDM II medium for E. faecalis with 10, 30 and 120 micrograms gentamicin disks using E. faecalis, strain ATCC 29212 as the reference. This method permits the calculation of zone diameters corresponding to different MIC values for different disk contents. The lack of discrimination between normal low-level resistant strains and high-level resistance using the 10 micrograms disk was confirmed. However, both the 30 micrograms and 120 micrograms disks seemed to provide a separation of the normal low-level gentamicin-resistant population from strains with increased resistance. Since the 30 micrograms disk is used routinely in some countries, there should be no need for an extra high content disk in these laboratories. This was confirmed when 96 clinical isolates of E. faecalis were analysed and the results of routine disk diffusion tests were compared with the MIC values. Two of the strains showed high-level gentamicin resistance (greater than 2000 mg/l) and produced no zone of inhibition. The other 94 isolates showed gentamicin MIC values between 4-16 mg/l, and 72 of the MIC results were 8 mg/l. The zone diameters for these strains ranged between 15 and 25 mm with a mean of 18.2 and a median value of 18 mm. In order to include statistical considerations of the zone size populations for setting of breakpoints, a study of gentamicin zone size distributions was performed for several bacterial species. Inhibition zone diameter values around the 30 micrograms gentamicin disk for 2079 clinical isolates of E. faecalis, 2268 S. aureus, 3201 E. coli and 547 strains of P. mirabilis from different years were plotted as histograms. Tests for agreement with a Gaussian distribution showed that the histograms were slightly peaked and skewed towards higher zone values. Parametric and non-parametric statistical tests were compared and the results showed that means and medians were very similar and that parametric fractile estimations at the lower end of the histogram populations were conservative and could be used in view of a slightly lower rate of false resistance. The 1% parametric fractile of 12 mm was selected as a suitable breakpoint for the identification of normal, low-level resistant isolates of E. faecalis using the standardized disk test of the Swedish Reference Group for Antibiotics.

Drug Resistance, Microbial↗
PubMed1991

Reproduction and level of intelligence.

The study was conducted in a representative Swedish rural-urban population sample of 3,064 persons. The IQ factor was determined directly by a single well established procedure. No systematic association between IQ level and the mean number of children was found.

Adult↗
PubMed1989

Septicaemia with coagulase negative staphylococci in a neonatal intensive care unit. Risk factors for infection, and antimicrobial susceptibility of the bacterial strains.

Septicaemia caused by coagulase negative staphylococci is a problem in the neonatal intensive care units (NICU). The very low birthweight (VLBW) infants are at a special high risk because of their immature host defense. In this study the potential risk factors were compared between the VLBW septicaemia patients and the VLBW infants who had not contracted septicaemia in the NICU. The factor most clearly related with septicaemia was the use of umbilical artery catheters. The strategy against neonatal septicaemia includes restriction of the use of intravascular catheters. Also enhancement of the host defense by immunoglobulin therapy is considered. The coagulase negative staphylococci were multiresistant to antibiotics. The combination of netilmicin and benzylpenicillin covered the bacteria found in septicaemia cases in the NICU, and is now the standard treatment in suspected cases. Coagulase negative staphylococci are treated with vancomycin or netilmicin.

Anti-Bacterial Agents↗