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Biomedical subjects

M Eriksson

Publications and source records attributed to M Eriksson.

At least 181 records · Page 10Linked to original sources
PubMed1997

The effect of plasma low density lipoprotein apheresis on the hepatic secretion of biliary lipids in humans.

BACKGROUND: The liver is a key organ in the metabolism of cholesterol in humans. It is the only organ by which substantial amounts of cholesterol are excreted from the body, either directly as free cholesterol into the bile or after conversion to bile acids. The major part of cholesterol synthesis in the body occurs in the liver. Cholesterol is also taken up by the liver from plasma lipoproteins. The relative contributions of newly synthesised cholesterol and plasma lipoprotein cholesterol to bile acid synthesis and biliary cholesterol secretion, respectively, are not known in detail. AIMS: To determine how a rapid lowering of plasma low density lipoprotein (LDL) and very low density lipoprotein (VLDL) cholesterol influences the biliary secretion rates of cholesterol and bile acids in patients with cholesterol gallstones and complete biliary drainage. In this model with a completely interrupted enterohepatic circulation, the secretion of bile acids equals the new synthesis of bile acids in the liver. PATIENTS: Eight patients with common bile duct stones of cholesterol type undergoing conventional cholecystectomy and choledocholithotomy. METHODS: At operation a balloon occludable Foley catheter attached to a T tube was inserted into the bile duct with the balloon placed just past the distal limb of the T tube. The T tube was allowed to drain the bile externally. One week after the operation the Foley catheter balloon was inflated, creating complete biliary drainage. Twelve hours following the inflation plasma LDL apheresis was carried out for two hours. Bile was collected for 15 minute periods starting one hour before the apheresis and ending two hours after its termination. During the collection of bile, plasma lipids were analysed on several occasions. RESULTS: The plasma level of LDL cholesterol decreased by 26% from (mean (SEM)) 2.19 (0.29) to 1.63 (0.17) mmol/l during the LDL apheresis while high density lipoprotein (HDL) cholesterol in plasma was unaffected. During LDL apheresis apolipoprotein B containing lipoproteins bind to the column, causing a significant decrease of not only plasma LDL but also of VLDL cholesterol. The secretion rate of bile acids decreased significantly by 31% from 131 (38) to 90 (16) mumol/15 minutes (p = 0.045). The output of phospholipids also decreased by 19%. The biliary secretion rate of cholesterol was not, however, affected by the plasma LDL apheresis. CONCLUSIONS: The results suggest that, in patients with cholesterol gallstones and complete biliary drainage, lowering of plasma LDL and VLDL cholesterol reduces the biliary secretion rate--synthesis--of bile acids without affecting the biliary secretion rate of cholesterol.

Adult↗
PubMed1997

Factors associated with birth weight in Sweden: the study of men born in 1913.

STUDY OBJECTIVE: To analyse factors associated with birth weight and to evaluate the validity of obstetrical data. DESIGN: Obstetrical data were retrieved for singleton men born in 1913 and living in Gothenburg, Sweden in 1963. Information on birth weight, maternal age, marital status, parity, social class, proteinuria, gestational age, and place of birth (home or hospital) was obtained from these birth records. SETTING: Sweden. PARTICIPANTS: Fifty year old men living in Gothenburg, Sweden, in 1963. MAIN RESULTS: Obstetrical records were obtained for 524 men (65%). Place of birth, gestational age, maternal age, parity, proteinuria, and marital status were all significantly correlated to birth weight. In multivariate analyses, place of birth, gestational age, parity, and proteinuria influenced birth weight. There was a substantial difference in mean birth weight between hospital deliveries (3352 g) and home deliveries (3817 g), which could be explained only partly by sociodemographic variables. Birth weight increased with parity and gestational age in home delivered babies as well as those delivered in a hospital. CONCLUSIONS: The validity of obstetrical records from 1913 was good. The place of birth (home or hospital) is strongly associated with birth weight and may be a confounding factor in studies of the implications of birth weight for future risk of disease or death.

Aged↗
PubMed1997

PCNA, Ki-67, p53, bcl-2 and prognosis in intraoral squamous cell carcinoma of the head and neck.

Eighty patients with primary intraoral squamous cell carcinomas of the head and neck, with a follow-up of 4-14 years were analysed for clinical outcome in relation to immunohistochemical expression of PCNA, Ki-67, p53, bcl-2 and presence of mutations in the p53 gene. The tumor site was not associated with the different parameters calculated. PCNA and Ki-67 labelling showed median values of 56% and 32%, respectively, and neither antigen was of predictive value. Fifty-five percent of the tumours expressed p53, and 38 (48%) had mutations in the p53 gene. No association between the presence of p53 protein or mutations in the p53 gene and clinical outcome was found. Bcl-2 positivity was detected in a minor fraction (10%) of the tumours.

Adult↗
PubMed1997

Adipose tissue lipoprotein lipase and hormone-sensitive lipase. Contrasting findings in familial combined hyperlipidemia and insulin resistance syndrome.

The metabolism of free fatty acids (FFA) is altered in two common atherosclerosis-promoting disorders: familial combined hyperlipidemia (FCHL) and insulin resistance syndrome (IRS). It has been suggested that these two conditions may have a common etiology. The enzymes lipoprotein lipase (LPL) and hormone-sensitive lipase (HSL) are rate-limiting steps for the turnover of fatty acids in adipose tissue, because they hydrolyze extracellular triglycerides in lipoproteins (LPL) and intracellular triglycerides in adipocytes (HSL). The present study was undertaken to simultaneously determine the activities of LPL and HSL in subcutaneous adipose tissue from male patients with FCHL and IRS. LPL and HSL activity was investigated in 10 nonobese FCHL patients and compared with 10 matched healthy nonobese subjects, and in 8 essentially normolipidemic IRS patients (who did not have overt diabetes mellitus) and compared with 9 nonobese matched control subjects. LPL activity was 43% lower in patients with IRS (P < .0005), as compared with control subjects, but HSL activity was not significantly different in the two groups, On the other hand, HSL activity was decreased by 45% in FCHL patients (P < .01), as compared with control subjects, but LPL activity was not significantly different in FCHL patients and the control group. In conclusion, triglyceride metabolism in adipose tissue is altered in both FCHL and IRS. However, the abnormalities observed involve impaired function of LPL in IRS and impaired function of HSL in FCHL, suggesting separate etiologies for the altered lipolysis in these conditions, at least in male subjects.

Adipose Tissue↗
PubMed1997

No influence of simvastatin treatment on platelet function in vivo in patients with hypercholesterolemia.

Hypercholesterolemia is associated with platelet activation. Reduction of plasma cholesterol levels by the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor simvastatin has been found to improve certain aspects of platelet function in vitro and in vivo, but controlled trials are largely lacking. The present randomized, double-blind, crossover study was performed to evaluate whether 10- to 12-week treatment with simvastatin or placebo affects platelet function in vivo in 23 hypercholesterolemic men. Measurements were performed at rest and during mental stress. Simvastatin treatment reduced plasma total cholesterol levels by 18 +/- 2% and low density lipoprotein cholesterol levels by 26 +/- 2% (P < .001 for both), whereas high density lipoprotein cholesterol levels increased slightly (6 +/- 2%, P < .05). Platelet aggregability as assessed by filtragometry ex vivo was unaffected by simvastatin treatment both at rest and during mental stress. Plasma beta-thromboglobulin levels, which reflect platelet secretion, were also unaltered by simvastatin treatment both at rest (antilog of the mean: 20.2 versus 20.0 ng/mL during placebo) and during mental stress. Moreover, nocturnal excretion of 11-dehydrothromboxane B2 in urine did not differ between placebo and active treatment: 218 versus 216 ng/mmol creatinine, respectively. The corresponding values for urinary excretion of high-molecular-weight beta-thromboglobulin were 1.78 versus 1.92 ng/mmol creatinine. Thus, simvastatin treatment had no clear-cut effect on platelet function, as assessed by four different in vivo related platelet function variables, in hypercholesterolemic men.

Blood Platelets↗
PubMed1997

Is a speculum examination sufficient for excluding the diagnosis of ruptured fetal membranes?

OBJECTIVE: To determine the false negative rate of a sterile speculum examination for the diagnosis of rupture of the membranes in women not in labor and without visible amniotic fluid at speculum examination. Furthermore, possible risks to the mother and the baby after suspected rupture of the membranes were analyzed. STUDY DESIGN: In women not in labor with suspected rupture of the membranes between gestational weeks 34 and 42, a sterile speculum examination was performed. If no amniotic fluid was visible, a test for Diamine oxidase was carried out. The results of tests were not known to the obstetricians or the women. The women were allowed to return home with no further controls if no amniotic fluid was visible at the speculum examination. Neonatal and obstetric outcome was recorded prospectively. RESULTS: Of 27,502 deliveries, 2,099 women not in labor attended the delivery ward for suspected rupture of the membranes after week 34. Amniotic fluid was visualized in 1,580 women. In 519 women in whom no amniotic fluid was seen at the speculum examination, the Diamine oxidase test was negative in 456 and positive in 63. Antibiotics were given to eleven children (2.4%) in the group with a negative Diamine oxidase and to one infant (1.6%) in the positive Diamine oxidase group (p>0.05). No differences in obstetric outcome were recorded. CONCLUSIONS: The false negative rate of a speculum examination for the diagnosis of rupture of the membranes in women without amniotic fluid visible at a speculum examination was 12% when Diamine oxidase was used as the standard for the diagnosis of rupture of the membranes. This study did not show any disadvantages for mothers and infants if the women were sent home after a false negative speculum examination. The value of biochemical methods in the management of women not in labor with rupture of the membranes after thirty-four weeks of gestation could be questioned.

Amine Oxidase (Copper-Containing)↗
PubMed1997

Clinical manifestations and epidemiology of childhood tuberculosis in Stockholm 1976-95.

81 cases of tuberculosis infection (17) and disease (64), seen between 1977 and 1995 at St Göran's Children's hospital, Stockholm, Sweden are reviewed. The incidence of tuberculosis disease increased from 1 to 6/10(5) children/y. The increase was due to immigration from high-prevalence countries, with an incidence of 20/10(5) in a partly segregated suburb. Most of the children were foreign-born. Of the 31 0-4-y-old cases, 19 were born in Sweden, and 7 had received BCG vaccination. For Swedish-born children with Swedish-born parents, the incidence of tuberculosis disease remained stable at < 0.5. 50 patients were symptomatic when first seen (60% pulmonary tuberculosis, 8% military tuberculosis, 25%, cervical adenitis, 15% other extrapulmonary tuberculosis). There was 1 death, and in 2 children complicated tuberculosis courses. Side effects of drug therapy were seen in 5% of the children. In conclusion, tuberculosis remains an important differential diagnosis in children of immigrants from high-prevalence countries for at least 5 y after settlement in Sweden. The practice of delaying BCG vaccination of them until 6 months of age can be disputed.

Adolescent↗
PubMed1997

Practice variation in Swedish primary care.

OBJECTIVE: To study individual practice patterns of physicians working in primary health care for standardized simulated cases on their first visit, and relate them to resource consumption for diagnostic tests, drugs and sick leave from a combined perspective of the health care and social security systems. DESIGN: Postal questionnaire presenting six hypothetical working-age cases with symptoms of ailments common in primary care asking physicians to order diagnostic tests and procedures, drugs, follow-up appointments and sick pay. SETTING: Swedish primary health care centres. SUBJECTS: Two hundred randomly selected physicians. MAIN OUTCOME MEASURES: Activities taken by the physician-diagnostic and laboratory tests ordered, drugs prescribed, length of sick leave and the cost of these actions. RESULTS: Practice patterns varied considerably, corresponding to a six-fold difference in total cost between the "cheapest" and "most expensive" physician. The largest share was loss of production as estimated by the cost of prescribed sick leave. Physicians who practised further away from hospitals and those who had worked more years tended to prescribe more measures. However, this only explained a small portion of the observed variation, which may be due to different physician attitudes to taking risks. CONCLUSION: "Paper" cases of common medical ailments presented to primary care physicians revealed considerable differences in practice style, resulting in six-fold differences in cost of measures prescribed at first visits.

Adult↗
PubMed1997

A prospective follow-up study of acute deep venous thrombosis using colour duplex ultrasound, phlebography and venous occlusion plethysmography.

OBJECTIVE: To study the extent of deep venous thrombosis (DVT) and thrombus regression over time and to compare the results obtained with different diagnostic techniques. EXPERIMENTAL DESIGN: A prospective follow-up study with repeated examinations during a 6-month period. SETTING: Patients studied at clinical vascular laboratories. PATIENTS: Forty patients hospitalised for acute DVT. Thirty-six of these completed the follow-up period. MEASURES: The diagnosis of DVT was confirmed with phlebographic and/or ultrasonographic techniques. The patient were then re-examined with colour duplex ultrasound and venous occlusion plethysmography after one week, 3 months and 6 months and with phlebography after 1 week and 6 months. The extent of DVT and number of occluded segments were determined with phlebographic and ultrasonographic techniques. Venous occlusion plethysmography was used to evaluate the functional degree of outflow obstruction. RESULTS: Colour duplex scanning at 3 months' and 6 months' follow-up showed that 55% and 74% of initially occlusive thrombi, respectively, were recanalized, with thrombus resolution occurring faster and more completely in those initially limited to popliteal and/or calf level. Discrepancies between phlebography and duplex scanning were found in 6% (26/441) of venous segments investigated by both methods, primarily concerning flow in the veins below the knee. CONCLUSIONS: In comparison with phlebography, colour duplex scanning is an accurate method for evaluation and follow-up of patients with DVT. The non-invasive nature of colour duplex scanning makes this method extremely suitable for repeated studies and thus a potentially very valuable tool for both clinical and research studies of circulatory changes involved in acute and chronic DVT.

Adult↗
PubMed1997

Comorbidity of personality disorders and major depression in patients with somatoform pain disorders or medical illnesses with long-standing work disability.

The comorbidity between major depression and personality disorders in patients with long-standing work disability at a rehabilitation clinic was investigated. Sixty patients with a somatoform pain disorder and 66 patients with different medical illnesses were assessed by means of a self rating scale for major depression, and the SCID screen personality disorder questionnaire. In the total series, 27% of the patients had a diagnosis of major depression and 34.9% had at least one personality disorder. Personality disorders were significantly more common in patients with medical illness than in patients with a somatoform pain disorder. There was a high frequency of comorbidity between major depression and personality disorders, especially borderline and avoidant personality disorders. If this is due to a common pathogenetic mechanism, it could explain why SSRIs are effective in both depression and some personality disorders.

Adult↗
PubMed1997

Ribonucleotide reductase--structural studies of a radical enzyme.

Ribonucleotide reductase contains a stable organic free radical essential for its activity located on a tyrosine residue in the small subunit of the enzyme called R2. The substrate binding site is, however, found in the catalytic subunit called R1. A long-range protein-mediated radical transfer pathway appears to be responsible for the delivery of the radical from the tyrosine in R2 to the substrate on R1. The active site is located deep inside the protein in a very stable beta/alpha-barrel structure and a hydrogen bonded system leads from the surface to Cys439 at the active site which is in excellent position to remove a hydrogen from the 3' of the ribose of a bound substrate nucleotide.

Escherichia coli↗
PubMed1997

A new approach to gene therapy.

Since 1975, different virus vectors have been developed in order to carry functional genes for gene transfer. However, no successful clinical trials have been reported so far. Recently, a new method for altering a single basepair of target DNA was reported using chimeric RNA/DNA oligonucleotides. The replacement of the single basepair in the target sequence can reach an efficacy of 20%. In patients with hemophilia A or B, the mutations (coagulation factors VIII and IX) are well characterized. The mutation-repair method using chimeric RNA/DNA oligonucleotides could provide an alternative for the treatment of hemophilia. The repaired cells will produce normal protein, like that of non-mutated cells, and the expression of the protein will be stable as long as the repaired cells survive. Clinically, by increasing the concentration of the functional protein (5-10%), it is hoped that a severe phenotype can be converted into a milder phenotype. The high replacement efficacy of the target sequence and the safety of the method make this a likely and promising approach for gene therapy in the future. However, no correction has been detected for the mutations in the coagulation factor genes factor genes factor IX and von Willebrand factor by this method so far.

Animals↗
PubMed1996

Discovery of an algal mitochondrial carbonic anhydrase: molecular cloning and characterization of a low-CO2-induced polypeptide in Chlamydomonas reinhardtii.

In green unicellular algae, several polypeptides are induced upon exposure to limiting CO2. We report here on the localization and characterization of one of these, a 22-kDa polypeptide in Chlamydomonas reinhardtii. This nuclear-encoded polypeptide is induced in the mitochondria by a lowering of the partial pressure of CO2 in the growth medium from 5% to air CO2 levels. Sequencing of two different cDNA clones coding for the polypeptide identified it as a 20.7-kDa beta-type carbonic anhydrase (CA; carbonate dehydratase, carbonate hydro-lyase, EC 4.2.1.1). The two clones differ in their nucleotide sequences but code for identical proteins, showing that this CA is encoded by at least two genes. Northern blot hybridization reveals that mRNA transcripts are only present in cells transferred to air CO2 levels. A comparison of the deduced amino acid sequence with those of other beta-CAs shows the largest degree of similarity with CA from the cyanobacterium Synechocystis (50% identity and 66% similarity). To our knowledge, this is the first identification and characterization of a mitochondrial CA from a photosynthetic organism.

Amino Acid Sequence↗
PubMed1996

Two conserved tyrosine residues in protein R1 participate in an intermolecular electron transfer in ribonucleotide reductase.

The enzyme ribonucleotide reductase consists of two nonidentical proteins, R1 and R2, which are each inactive alone. R1 contains the active site and R2 contains a stable tyrosyl radical essential for catalysis. The reduction of ribonucleotides is radical-based, and a long range electron transfer chain between the active site in R1 and the radical in R2 has been suggested. To find evidence for such an electron transfer chain in Escherichia coli ribonucleotide reductase, we converted two conserved tyrosines in R1 into phenylalanines by site-directed mutagenesis. The mutant proteins were shown to be enzymatically inactive. In addition, the mechanism-based inhibitor 2'-azido-2'-deoxy-CDP was incapable of scavenging the R2 radical, and no azido-CDP-derived radical intermediate was formed. We also show that the loss of enzymatic activity was not due to impaired R1-R2 complex formation or substrate binding. Based on these results, we predict that the two tyrosines, Tyr-730 and Tyr-731, are part of a hydrogen-bonded network that constitutes an electron transfer pathway in ribonucleotide reductase. It is demonstrated that there is no electron delocalization over these tyrosines in the resting wild-type complex.

Base Sequence↗