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Biomedical subjects

S Svensson

Publications and source records attributed to S Svensson.

171 records · Page 10Linked to original sources
PubMed1970

Bacteriophage receptor development and synthesis of O-specific side chains after addition of D-galactose to the uridine diphosphate-galactose-4-epimeraseless mutant Salmonella typhimurium LT2-M1.

The formation of complete cell wall core lipopolysaccharide (LPS) and O-antigenic side chains after addition of d-galactose to the uridine diphosphate-galactose-4-epimeraseless mutant, Salmonella typhimurium LT2-M1, has been studied by (i) determination of adsorption rates of smooth and rough specific bacteriophages, (ii) passive hemagglutination inhibition, and (iii) qualitative and quantitative determination of the polysaccharide composition and structure. A rapid synthesis of the complete core LPS and O side chains occurred in bacteria in the log phase and the early stationary phase. Phage C21, which attaches to unsubstituted Rc structures, was adsorbed by the bacteria for only 10 min after the addition of d-galactose. Unsubstituted Rc structures, however, could still be detected after 160 min by immunological and chemical assays. Attachment of the P22 phage, which requires O-specific side chains with more than one repeating unit for adsorption, was demonstrated 10 min after the addition of d-galactose. Attachment of the Felix O-1 phage, which requires a complete core, was observed between 20 and 80 min after the addition of d-galactose. The rough specific phages 6SR and Br2 did not adsorb to the bacteria at any time after the addition of d-galactose. By passive hemagglutination inhibition, the presence of O-specific structures could be demonstrated after 10 min. No antigenic activity of the Ra and Rb structures was observed in the LPS preparations isolated at any time after the addition of d-galactose. Methylation analysis of LPS preparations isolated at 10 and 160 min after the addition of d-galactose showed that the O-specific side chains contained an average of 11 and 15 repeating units, respectively. In the 10-min sample, every 25th "Rc structure" carried a side chain, compared to every 3rd residue in the 160-min sample.

Adsorption↗
PubMedDate not supplied

Mammalian alcohol dehydrogenase - functional and structural implications.

Mammalian alcohol dehydrogenase (ADH) constitutes a complex system with different forms and extensive multiplicity (ADH1-ADH6) that catalyze the oxidation and reduction of a wide variety of alcohols and aldehydes. The ADH1 enzymes, the classical liver forms, are involved in several metabolic pathways beside the oxidation of ethanol, e.g. norepinephrine, dopamine, serotonin and bile acid metabolism. This class is also able to further oxidize aldehydes into the corresponding carboxylic acids, i.e. dismutation. ADH2, can be divided into two subgroups, one group consisting of the human enzyme together with a rabbit form and another consisting of the rodent forms. The rodent enzymes almost lack ethanol-oxidizing capacity in contrast to the human form, indicating that rodents are poor model systems for human ethanol metabolism. ADH3 (identical to glutathione-dependent formaldehyde dehydrogenase) is clearly the ancestral ADH form and S-hydroxymethylglutathione is the main physiological substrate, but the enzyme can still oxidize ethanol at high concentrations. ADH4 is solely extrahepatically expressed and is probably involved in first pass metabolism of ethanol beside its role in retinol metabolism. The higher classes, ADH5 and ADH6, have been poorly investigated and their substrate repertoire is unknown. The entire ADH system can be seen as a general detoxifying system for alcohols and aldehydes without generating toxic radicals in contrast to the cytochrome P450 system.

Alcohol Dehydrogenase↗
PubMedDate not supplied

Reasons for adherence with antihypertensive medication.

BACKGROUND: Hypertension is often insufficiently controlled in clinical practice, a prominent reason for this being poor patient adherence with therapy. Little is known about the underlying reasons for poor adherence. We set out to investigate hypertensive patients' self-reported reasons for adhering to or ignoring medical advice regarding antihypertensive medication. METHODS: Qualitative analysis of semi-structured interviews with 33 hypertensive patients in a general-practice centre and a specialist hypertension unit in Southern Sweden. Blood-pressure measurements and laboratory measurements of antihypertensive medication were performed. RESULTS: Nineteen out of 33 patients were classified as adherent. Adherence was a function of faith in the physician, fear of complications of hypertension, and a desire to control blood pressure. Non-adherence was an active decision, partly based on misunderstandings of the condition and general disapproval of medication, but mostly taken in order to facilitate daily life or minimize adverse effects. Adherent patients gave less evidence of involvement in care than non-adherent patients. There was no obvious relation between reported adherence, laboratory markers of adherence and blood-pressure levels. CONCLUSIONS: The interview is a powerful tool for ascertaining patients' concepts and behaviour. To optimize treatment of hypertension, it is important to form a therapeutic alliance in which patients' doubts and difficulties with therapy can be detected and addressed. For this, effective patient-physician communication is of vital importance.

Adult↗
PubMedDate not supplied

Antagonistic effects of zinc and aluminum on lead inhibition of delta-aminolevulinic acid dehydratase.

In vitro and in vivo studies regarding the influence of metals on delta-aminolevulinic acid dehydratase activity in erythrocytes indicate that a lead concentration of 4 micrometer/l completely inhibits the enzyme. Zinc activates the enzyme both in vitro and in vivo at concentrations greater than 76 micrometer/l. Aluminum has an inhibitory effect at all concentrations in vitro whereas it activates the enzyme in vivo. Zinc and aluminum together activate the enzyme in vivo. The in vitro activation of zinc is inhibited by increasing concentrations of aluminum. Aluminum and lead together depress the enzyme activity in an additive way that can be reactivated by the addition of zinc.

Aluminum↗
PubMedDate not supplied

Glucose and insulin infusion directly after cardiac surgery: effects on systemic glucose uptake, catecholamine excretion, O2 consumption, and CO2 production.

Systemic glucose uptake was studied in 31 patients during 4 hr starting 1 hr after open heart surgery, using the hyperinsulinemic "clamp" technique at different plasma insulin levels and at a glucose concentration of 6 or 10 mmol/liter. Possible metabolic side effects related to the glucose uptake were studied by measurements of urinary catecholamine excretion, O2 consumption, CO2 production, and arterial PCO2. A peak systemic glucose uptake of 7.0 +/- 0.4 mg/kg body weight/min was found at a plasma insulin concentration of 3192 +/- 150 mU/liter and a blood glucose concentration of 10.2 +/- 0.1 mmol/liter. No significant difference was found in urinary catecholamine excretion compared to control patients. O2 consumption was unaltered while a 15% increase in CO2 production was observed.

Adult↗
PubMedDate not supplied

Splanchnic glucose balance and insulin resistance in the early postoperative phase of cardiac surgery.

The splanchnic balance of glucose was studied in the basal state and at three levels of "clamped" hyperinsulinemia (260 +/- 23, 510 +/- 59, 3875 +/- 367 mU/liter) in 24 patients (43-70 years of age), who had undergone coronary surgery about 1 hr previously. The splanchnic balance of glucose in the basal state was negative in all patients (-1.6 +/- 0.3 mg/kg/min) and was changed into a zero-balance within 30 min when 0.15 or 0.3 U/kg/hr of insulin was infused. At an insulin infusion rate of 1.0 U/kg/hr the net splanchnic glucose balance was turned into a significant positive balance of an average 0.9 +/- 0.3 mg/kg/min.

Adult↗