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Biomedical subjects

S Nordström

Publications and source records attributed to S Nordström.

At least 19 recordsLinked to original sources
PubMed1997

A multicase family with spondylarthropathies.

Thirty six members of a family with symptoms and signs from the skin and/or the joints were examined clinically and radiologically and HLA typed. Fourteen were classified as having inflammatory joint disease, eight of them with more than one disease within the spondylarthropathy group (SpA). Four had psoriasis of the skin, two of whom had psoriatic arthritis. Ten (five males, five females) had radiological signs of sacroiliitis, eight of them fulfilled the criteria for SpA. Five (four males, one female) with sacroiliitis had radiological signs of spine involvement. One female member was classified as having rheumatoid arthritis. Seven with sacroiliitis were HLA-B27 positive, related to the same haplotype. Two with psoriasis were B27 positive and the other two had another haplotype in common. No single HLA antigen or haplotype was associated with the inflammatory joint manifestations or skin lesions. This suggests involvement of other gene loci or coincidence of multicases.

Adult↗
PubMed1995

Efficient modulation of glucolipid enzyme activities in membranes of Acholeplasma laidlawii by the type of lipids in the bilayer matrix.

It is generally anticipated, but so far not fully shown, that the physical properties of membrane lipid bilayers are governed by the concerted actions of the lipid-synthesizing enzymes. In the membrane of Acholeplasma laidlawii a constant surface charge density, similar phase equilibria, and a nearly constant spontaneous curvature are maintained for the polar lipids. Important for these properties are monoglucosyldiacylglycerol (MGlcDAG) and diglucosyldiacylglycerol (DGlcDAG), forming mainly reversed nonlamellar and lamellar phases, respectively. The syntheses of these lipids (from 1,2-DAG and MGlcDAG) by two consecutively acting, membrane-bound glucosyltransferases have been analyzed in synthetic lipid bilayers of selected physical properties. Both enzymes demanded the presence of activator lipids; for MGlcDAG synthesis a critical fraction of anionic lipids was important, whereas for the DGlcDAG synthesis substantial amounts of a liquid-crystalline phosphatidylglycerol (PG) with a certain chain length were essential. The rates of the syntheses for the two glucolipids increased with decreasing chain length of the DAG and MGlcDAG substrates. The enzymatic formation of DGlcDAG (bilayer-forming) was influenced in a dose-dependent manner by the nonbilayer (curvature) propensities of several amphiphilic and hydrophobic lipids in two different bilayer matrixes. However, the preceding synthesis of the nonlamellar MGlcDAG was only affected to a minor extent by such additives. The mechanism for modulation involved an enhancement of the activating potencies of PG in a cooperative fashion at physiological concentrations for PG.(ABSTRACT TRUNCATED AT 250 WORDS)

Acholeplasma laidlawii↗
PubMed1995

Membrane lipid composition and cell size of Acholeplasma laidlawii strain A are strongly influenced by lipid acyl chain length.

The small, cell-wall-less prokaryote Acholeplasma laidlawii strain A-EF22 could grow with membrane lipids having an average acyl chain length Cn varying over 14.5- almost 20 carbons by exogenous supplementation with selected fatty acids. For 16 < Cn < 18, the cells grew with lipids containing 100% (mol/100 mol) monounsaturated acyl chains, whereas for Cn < 16 and Cn > 18, cell growth only occurred with gradually lower fractions of unsaturated chains. Cn was actively increased and decreased by chain elongation or de novo fatty acid synthesis upon incorporation of short-chain and long-chain fatty acids, respectively. The membrane lipid composition was strongly affected by the acyl chain length and unsaturation, and the metabolic responses are readily explained as a regulation mechanism based on the established phase equilibria of the individual lipids in the A. laidlawii membrane. Monoglucosyldiacylglycerol (Glc-acyl2-Gro) was the dominating lipid with short chains but the fraction of this lipid decreased with increasing Cn, correlating with the decreasing lamellar to nonlamellar phase transition temperatures for this lipid. The fractions of diglucosyldiacylglycerol (Glc2-acyl2Gro) and phosphatidylglycerol (PtdGro), forming lamellar phases only, increased with increasing Cn over the entire chain-length interval. A weaker correlation was usually observed between the relative amount of a lipid and the extent of chain unsaturation; however, the fractions of Glc2-acyl2Gro and PtdGro increased clearly with an increasing degree of unsaturation. Moreover, the synthesis of the nonbilayer-forming lipids acyl2Gro and monoacyl-Glc-acyl2Gro was strongly stimulated by a high degree of chain saturation. Concomitantly, the phase equilibria of Glc-acyl2Gro are shifted towards lamellar phases at the growth temperature. The fraction of the three potentially nonbilayer-forming lipids varied over 10-80% (mol/100 mol) total lipids as a function of the acyl chain composition. The combined molar fractions of the three phospholipids increased strongly with chain unsaturation. However, the fraction of phosphate moieties in the different lipids was constant over the entire chain-length interval. It is concluded that the regulation of the membrane lipid composition aims at maintaining similar phase equilibria and surface charge densities of the lipid bilayer. The size of A. laidlawii cells was changed in a systematic manner and correlated qualitatively with the packing properties of the lipids. Cell diameters were increased by an increase in acyl chain length and saturation, and was affected by additives such an n-dodecane and acyl2Gro.

Acholeplasma laidlawii↗
PubMed1994

Fine mapping of Best's macular dystrophy localizes the gene in close proximity to but distinct from the D11S480/ROM1 loci.

The Best's macular dystrophy (BMD) gene has previously been mapped to the 11q13 region. In this study, recombination data localizes the BMD gene to the 6-cM genetic interval between the markers Fc epsilon RI and D11S480/ROM1 in a large Swedish 12-generation BMD family. Mutation analyses of the candidate gene ROM1 did not reveal any mutations that could explain the disease phenotype. However, one recombination event between intragenic ROM1 polymorphisms and the BMD phenotype was detected. Therefore, it is highly unlikely that mutations in the ROM1 gene cause BMD. Identification of the disease gene will elucidate the pathophysiological mechanism in BMD, which may also be of importance in other retinopathies such as age-related macular degeneration.

Alleles↗
PubMed1993

Variable expression of tapetoretinal degeneration in northern Sweden.

In the county of Västerbotten in northern Sweden, 20 families with 50 diagnosed cases and 53 sporadic cases of tapetoretinal degenerations (TRD), including retinitis pigmentosa (RP), were ascertained. The familial and sporadic cases were traced genealogically as far back as was possible. Ancestors born before 1890 (n = 12,033) were registered on a PC. The analysis of data showed that 7 families (20 cases) and 21 sporadic cases could be traced to ancestors in a parish in the northern part of the county. The results suggest, in that parish, a gene source of an autosomal recessive gene causing TRD, with varying phenotypic expression, including variants of RP.

Female↗
PubMed1992

The gene for Best's macular dystrophy is located at 11q13 in a Swedish family.

A large Swedish family with more than 250 cases of Best's macular dystrophy has been clinically and genetically studied. The gene was traced to a couple born in central Sweden in the 17th century. Highly significant evidence for genetic linkage to DNA markers on chromosome 11q13 was detected. A lod score of 15.12 was obtained at recombination fraction 0.01 with DNA marker INT2 (also called FGF3). The retinally expressed gene ROM1, which maps to the same chromosomal region is a candidate for this genetic disease.

Chromosomes, Human, Pair 11↗
PubMed1989

Genetic genealogical studies of 20 north Swedish families with the rare blood group p.

In the county of Västerbotten in northern Sweden, a large number of individuals with the rare blood group p have been found. The ancestors of all known 31 cases were studied genealogically, and the data showed that about one half of all cases (15 out of 31 in 9 out of 20 families) could be traced to one gene source in the north-eastern part of the county in the middle of the 17th century. In two of the families the parents were first cousins and in three they were second cousins. In the 18th and 17th centuries genealogical connections between the parents were found in another 10 of the families.

Adult↗
PubMed1987

Secondary aortoenteric fistulas--an analysis of 42 cases.

Secondary aortoenteric fistulas are seen with an increasing frequency which parallels the expansion of reconstructive vascular surgery. During a 12-year period 42 cases have been collected from the hospitals, which perform most of the vascular surgery in Sweden (0.7% of vascular operations). Twenty-five were seen after operation for aortic aneurysm, 15 for aortoiliac occlusive disease, one after renal artery ligation (as a part of reconstruction for renovascular hypertension) and one after operation for an iliac pseudoaneurysm. The frequency of complications during and after the primary operation was high. The interval between operation and onset of fistula symptoms was significantly shorter if there had been infectious complications, the median interval was 32 months, the longest being 10 years. The most important symptom was gastrointestinal haemorrhage, consisting of several small bleeds often combined with septic complications. A large number of negative investigations usually preceded the final diagnosis which was made at exploratory laparotomy. After surgery for the fistula the frequency of complications and mortality, were very high. Mortality was 58%, the most common cause of death being a blow out of the aortic stump. Of those leaving hospital, several further operations were performed with a high mortality. Recurrence of the fistula occurred in 16 out of 34 patients who survived surgery. At follow-up (12-74 months after fistula closure) seven patients were still alive.

Adolescent↗
PubMed1987

Thoracolumbar epidural anaesthesia blocks the circulatory response to laryngoscopy and intubation.

Laryngoscopy and endotracheal intubation cause a stress reaction resulting in an increase in heart rate and systemic blood pressure. This haemodynamic response is considered to be due to a sympathetic discharge caused by stimulation of the upper respiratory tract. This stress reaction during laryngoscopy and endotracheal intubation was studied in patients with total thoracolumbar epidural anaesthesia (EDA). Nine patients with thoracolumbar EDA including at least the segments T1 to L2 were compared to seven patients without EDA during induction of general anaesthesia. The epidural anaesthesia was achieved with 2% mepivacaine with adrenaline. General anaesthesia was induced with thiopentone 4-5 mg/kg followed by 100 mg suxamethonium. The highest blood pressure value during the first 2 min after intubation was compared to the value immediately before intubation. The epidural anaesthesia caused a reduction of the mean arterial blood pressure (MAP) by 25%, and a reduction of the heart rate (HR) by 7%, but neither the induction with thiopentone nor the laryngoscopy and intubation caused any changes in mean arterial blood pressure or heart rate. However, in the control group MAP increased 29% and HR 16% following intubation. Thus, the T1-L2 epidural anaesthesia with 2% mepivacaine with adrenaline blocked the blood pressure reaction to laryngoscopy and intubation, and consequently the efferent sympathetic nervous system was completely blocked.

Adult↗
PubMed1984

Clastogenic effects in human lymphocytes of power frequency electric fields: in vivo and in vitro studies.

In vivo and in vitro studies of the clastogenic effects of power frequency electric fields and transient electric currents have been performed. For the in vivo investigation peripheral lymphocytes from twenty switchyard workers were screened for chromosome anomalies. The rates of chromatid and chromosome breaks were found to be significantly increased compared to the rates in 17 controls. Exposure of human peripheral lymphocytes, in vitro, to a 50-Hz current with 1 mA/cm2 current density did not induce any chromosome damage. Exposure to ten 3 mus-long spark discharge pulses with a peak field strength in the samples of 3.5 kV/cm, however, resulted in chromosome breaks at a frequency similar to that induced in lymphocytes in vitro by ionizing radiation at 0.75 Gy. The biological significance of chromosomal damage induced in somatic cells is discussed.

Adult↗
PubMed1983

Reproductive hazards among workers at high voltage substations.

A retrospective study on reproductive hazards was performed among 542 employees at Swedish power plants. Questionnaires were answered by 89% of the employees. Data on pregnancies were checked by studying hospital case records. There was a statistically significant, decreased frequency of "normal" pregnancy outcome, almost exclusively due to an increased frequency of congenital malformations, when the father was a high-voltage switchyard worker. The differences in pregnancy outcome could not be explained by any of the confounding factors analyzed. The total number of children with malformations (26) and the total number of pregnancies in this study, however, were very small.

Abnormalities, Radiation-Induced↗
PubMed1983

Vascular complications in the Ehlers-Danlos syndrome.

The Ehlers-Danlos syndrome is a rare condition, which usually is easily recognized. In one type of this disease, type IV, arterial fragility dominates, and the syndrome may remain undiscovered until the patient has a traumatic or spontaneous arterial rupture. Two cases with a fatal outcome are presented in order to emphasize some important aspects in the management of these patients.

Adult↗
PubMed1982

Hereditary pyrophosphate arthropathy (familial articular chondrocalcinosis) in Sweden.

Genealogical links between three Swedish families with hereditary pyrophosphate arthropathy were found in the 18th century, indicating a possible founder effect, similar to earlier findings in Slovakia, France and Chile. However, no connection between the Swedish and other European families with the disease has so far been found. In accordance with other reported familial aggregations of pyrophosphate arthropathy, the transmission of the disease in the Swedish families appeared to be autosomal dominant with incomplete penetrance and variable expressivity. Severe symptoms related to homozygotic cases reported in some other families were not found in Sweden.

Adult↗