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Biomedical subjects

S Eriksson

Publications and source records attributed to S Eriksson.

At least 181 records · Page 10Linked to original sources

Systemic necrotizing vasculitides in severe alpha1-antitrypsin deficiency.

We describe the clinical presentation and outcome in a series of eight patients with systemic necrotizing vasculitis and severe alpha1-antitrypsin (AAT) deficiency followed up at three Swedish hospitals during 1968-92. We also review six other cases reported in the literature during the same period. Diagnosis of severe AAT deficiency was based on the presence of the PiZZ phenotype, or low plasma total trypsin inhibitory capacity, or a low plasma AAT concentration (10-40% of the normal mean value) and presence of the PiSZ or PiFZ phenotype. The diagnosis of systemic vasculitis was biopsy-verified in all eight patients. Pretreatment laboratory findings, treatment protocol, and outcome were reviewed in each of the 14 patients. Of the eight patients in the Swedish series, six had systemic vasculitis of the microscopic polyangiitis form, one had Wegener's granulomatosis, and another had Henoch-Schönlein purpura. In the series as a whole (n = 14), median age at diagnosis was 48 years (range 44-84), the median number of affected organs was eight, and all 14 patients had skin involvement, and either renal or joint involvement (in most cases both); 71% (10/14) had emphysema; 57% (8/14) had hepatic abnormalities (two having cirrhosis, two fibrosis, and one multiple aneurysms in hepatic arteries); one patient who presented with acute ulcerative colitis developed manifest vasculitic syndrome three years later; and 64% (9/14) died, the major cause of death being renal failure. This syndrome, characterized by multiple organ involvement and fatal outcome, has been underdiagnosed. Physicians should be alert to the presence of the PiZ AAT deficiency gene in patients with systemic vasculitis, especially when the course is progressive or when the patient also has emphysema or cirrhosis. Awareness of those features may aid prompt recognition and enable early treatment.

Adult↗

Risk of hepatobiliary disease in adults with severe alpha 1-antitrypsin deficiency (PiZZ): is chronic viral hepatitis B or C an additional risk factor for cirrhosis and hepatocellular carcinoma?

OBJECTIVES: To assess homozygous alpha 1-antitrypsin deficiency (PiZZ) as a risk factor for cirrhosis, hepatocellular carcinoma (HCC) and gallstone disease, and to analyse the respective interrelation-ships and those suggested to exist between PiZZ, alpha 1-antitrypsin and chronic hepatitis B and C. DESIGN/METHODS: This study was based on 31 autopsied adults with severe alpha 1-antitrypsin deficiency diagnosed during the period 1963-94, in the city of Malmö, Sweden. For each autopsied PiZZ individual, four age- and sex-matched controls were selected from the same autopsy register. The autopsy rate during the study period was 57.2% of all deaths in the city and 85% of deaths at the hospital. Relative risks were estimated in terms of Mantel-Haenszel odds ratios (ORmh). RESULTS: In the PiZZ group, we found 13 cases of cirrhosis (ORmh = 8.3; 95% CI, 3.8-18.3; P < 0.0001), 5 cases of HCC (ORmh = 5.0; 95% CI, 1.6-15.8; P = 0.008), and 8 cases of gallstone disease (ORmh = 1.0; 95% CI, 0.4-2.3; P = 0.924), compared with 7, 4 and 29 cases, respectively, in the control group. Stratification of the data by age and sex showed the difference in relative risk of cirrhosis between the PiZZ and control groups to be significant in both sexes, but that of HCC to be significant only in the male subgroup. There was no correlation between PiZZ state and gallstone disease in either sex. All PiZZ patients with cirrhosis and HCC had had negative tests for anti-hepatitis B core antigen and/or hepatitis B surface antigen. Of the homozygotes with cirrhosis or HCC for whom frozen sera were available (54% (7/13) and 60% (3/5), respectively), none had antihepatitis C antibodies, as tested both with ELISA-2 and RIBA-3. The prevalence of cirrhosis was higher in the PiZZ group than in controls for all ages above 50 years (P < 0.05). The occurrence of gallstone disease increased steadily with age in the two populations. CONCLUSIONS: Although males and females with severe alpha 1-antitrypsin deficiency are not at significantly greater risk of gallstone disease, they are at greater risk of cirrhosis and HCC, the risk of HCC being more manifest in males. The risk of cirrhosis or HCC was unrelated to the presence of hepatitis B or C infection.

Adult↗

Incidence and clinical characterization of unprovoked seizures in adults: a prospective population-based study.

In a population-based prospective study of epileptic seizures in adult s aged > 17 years, we identified 563 patients with possible seizures in a period of 34 months. Seizures were unprovoked in 160 patients, an incidence of 56 in 100,000 person-years. There was no difference in incidence between sexes. Age-specific incidences of unprovoked seizures increased sharply in men from age 60 years and in women from age 70 years. The incidence of unprovoked seizures in those aged > 65 years was 139 (men 166, women 116). The cumulative incidence of unprovoked seizures between the ages of 17 and 84 years was 4.6%. The proportion with an identified presumptive cause for unprovoked seizures increased with advancing age. A presumed etiology was identified in 77% of persons aged > 60 years. Stroke was the most common etiology, detected in 30% (incidence 16) and in 45% at ages > 60 years. Tumors were detected in 11% (incidence 6) and Alzheimer's disease was detected in 7% (incidence 4). Eighteen percent of patients were demented. Unprovoked seizures were partial in 68% of cases (incidence 38), and generalized in 16% (incidence 9). Another 13% of patients had generalized seizures, but seizure onset was not witnessed (incidence 7). In 16%, there was a delay of > 1 year from the first unprovoked seizure to initial diagnosis.

Adolescent↗

Physical restraints in geriatric care in Sweden: prevalence and patient characteristics.

OBJECTIVE: Physical restraints are used frequently in geriatric care to promote the safety of frail older patients. This study investigated the prevalence of the use of physical restraints in geriatric care and the way in which patient characteristics are related to the use of physical restraints. DESIGN: A point prevalence study of patients cared for in various types of geriatric settings. SETTING: Eight nursing homes, 15 old people's homes, a somatic geriatric clinic, and a psychogeriatric clinic in a health care district in northern Sweden. PARTICIPANTS: A total of 1325 patients, mean age 82 years, 64% of whom were women. MEASUREMENTS: The Multi-Dimensional Dementia Assessment Scale (MDDAS) was used to measure motor function, vision, hearing, speech, ADLs, behavioral symptoms, psychiatric symptoms, use of psychoactive drugs, and the physical and psychological workload of the staff. In addition, questions concerning the use of physical restraints were added to the instrument. RESULTS: Twenty-four percent of the patients were physically restrained. The highest prevalence was found in nursing homes and psychogeriatric care. Physical restraints were found to relate most strongly to cognitive impairment, impaired ADLs, and speech and walking ability. Ninety-four percent of the restrained patients were cognitively impaired. Other variables relating to the use of physical restraints were psychiatric symptoms and behavioral disturbances. CONCLUSIONS: This study has shown that physical restraints are used frequently in geriatric care in Sweden and that cognitive and physical impairments relate very closely to the use of physical restraints.

Activities of Daily Living↗

Phosphorylation of the anti-hepatitis B nucleoside analog 1-(2'-deoxy-2'-fluoro-1-beta-D-arabinofuranosyl)-5-iodouracil (FIAU) by human cytosolic and mitochondrial thymidine kinase and implications for cytotoxicity.

The capacity of recombinant human cytosolic thymidine kinase (TK1) and bovine mitochondrial thymidine kinase (TK2) to phosphorylate the antiviral analogs 1-(2'-deoxy-2'-fluoro-1-beta-D-arabinofuranosyl)-5-iodouracil (FIAU) and 1-(2'-deoxy-2'-fluoro-1-beta-D-arabinofuranosyl)-5-methyluracil (FMAU) has been analyzed. The Vmax/Km ratios for FIAU and FMAU with TK2 are about 30% of that for deoxythymidine, while the corresponding values for TK1 are 2 and 5%, respectively. Thus, these two analogs are more efficient substrates for TK2 than for TK1, which may be part of the explanation for the mitochondrial toxicity associated with FIAU during treatment of hepatitis B infection.

Animals↗

Collagenous colitis: a retrospective study of clinical presentation and treatment in 163 patients.

BACKGROUND: Data on collagenous colitis have been based on a limited number of patients. AIMS: To obtain more information on this disease from a register set up at Orebro Medical Center Hospital. PATIENTS AND METHODS: Twenty five Swedish hospitals have contributed to this patient register, which comprises 163 histopathologically verified cases. Clinical data were retrospectively analysed. RESULTS: Collagenous colitis followed a chronic intermittent course in most cases (85%) with a sudden onset in 42%. Symptoms were chronic watery diarrhoea, often nocturnal (27%), abdominal pain (41%), and weight loss (42%). Sixty six patients (40%) had one or more associated diseases. Routine laboratory data were mostly normal. The median age at diagnosis was 55 (range 16-86) years, but 25% of the patients were younger than 45 years. Seven patients died of unrelated diseases. The response rate for sulphasalazine was 59%, and 50% and 40% for mesalazine and olsalazine. Prednisolone was most effective with a response rate of 82%, but the required dose was often high and the effect was not sustained after withdrawal. Antibiotics were efficient in 63%. Cholestyramine and loperamide had response rates of 59% and 71% respectively. CONCLUSIONS: Collagenous colitis follows a chronic continuous course. Symptoms can be socially disabling, but the disease does not seem to have a malignant potential. A plan for the treatment of a newly diagnosed patient with collagenous colitis is proposed.

Adolescent↗

A 30-year perspective on alpha 1-antitrypsin deficiency.

The early history of alpha 1-antitrypsin deficiency, in the years between 1962 and 1965, and its impact on the understanding of emphysema abnormalities were reviewed by me in 1989. This report discusses the disease spectrum (including emphysema, liver, and vasculitic diseases) and focuses on the variable clinical expression of the deficiency state. Some new findings that may be relevant to the function of alpha 1-antitrypsin are also considered.

Humans↗

Immunochemical and functional properties of biliary alpha-1-antitrypsin.

Alpha-1-antitrypsin (AAT), the archetype of the serpin (serine proteinase inhibitor) superfamily, is synthesized by hepatocytes and excreted to some extent into bile. The role of intact biliary AAT in gallstone pathogenesis is unsettled, but its 36-residue C-terminal peptide was found to promote cholesterol crystallization in a bile model. The present study showed biliary AAT to have specific properties that differ from serum AAT regarding immunoreactivity, heat stability and antiproteolytical activity. Electrophoretical and immunochemical methods were used to characterize biliary AAT. The level of its inhibitory activity was determined spectrophotometrically. In 18 samples from common bile duct and 12 samples from gallbladder bile, AAT was found to be heat-stable and functionally inactive. Added to the untreated, temperature-inactivated or protease inhibitors containing bile, native AAT became functionally inactive, heat-stable and lost its immunoreactivity. In contrast, heat-inactivated AAT, native albumin, transferrin, alpha-1-antichymotrypsin and IgG were unaffected on being added to bile. AAT in human bile manifests specific biochemical properties, such as functional inactivity and heat stability, that may be consistent with a conformational transition of the serpin molecule induced by the hydrophobic environment, and which must be considered when evaluating its role in gallstone pathogenesis.

Adult↗

Structure-activity relationships for phosphorylation of nucleoside analogs to monophosphates by nucleoside kinases.

The mammalian deoxyribonucleoside kinases thymidine kinase 1 and 2, deoxycytidine kinase and deoxyguanosine kinase phosphorylate deoxyribonucleosides and provide an alternative to de novo synthesis of DNA precursors. Their activities are essential for activation of several chemotherapeutically important nucleoside analogs. These four salvage kinase enzymes exhibit distinct substrate specificities for nucleoside analogs modified in the base and glycon moieties. In this review their. structure-activity relationships are discussed. Alternative routes for phosphorylation of nucleoside analogs are also reviewed, such as the phosphotransfer capacity of 5'-nucleotidase and protein kinases.

Adenosine Kinase↗

Characterization of a peptide antibody against a C-terminal part of human and mouse cytosolic thymidine kinase, which is a marker for cell proliferation.

An affinity-purified anti-TK1 antibody (pAb1) raised against a synthetic peptide (amino acids K211PGEAVAARKLFAPQ225) corresponding to part of the C-terminus of human cytosolic thymidine kinase (TK1) was produced and characterized by enzyme-linked immunosorbent assay, Western immunoblotting and immunoprecipitation as well as by immunostaining of intact cells. pAb1 recognized a single 25 kDa TK1 polypeptide in extracts of human and rodent cells. The protein was localized to the cytoplasm, as studied by immunohistochemistry and there was no staining in G1/G0 cells or mutant cells lacking TK1 activity, while it was high in S-phase and G2 cells. When series of peptides were tested for antibody binding in which alanine was replacing each of the other amino acids one by one, lysines 211 and 220, proline 212 and glutamic acid 214 were found to be important for antibody reactivity. These results indicate that amino acids 211-214, which may form a turn region, constitute a major recognition site for pAb1, and this structure may also be involved in the cell cycle-dependent modification of TK1, pAb1 is a very useful tool for studies of the cell cycle regulation of TK1, and it may be used to identify and quantify rapidly proliferating cells such as tumor cells.

Amino Acid Sequence↗

Inhibition of Alzheimer beta-peptide fibril formation by serum amyloid P component.

A 39-43-amino acid residue-long fragment (beta-peptide) from the amyloid precursor protein is the predominant component of amyloid deposits in the brain of individuals with Alzheimer's disease. Serum amyloid P component (SAP) is present in all types of amyloid, including that of Alzheimer's disease. We have used an in vitro model to study the effects of purified SAP on the fibril formation of synthetic Alzheimer beta-peptide 1-42. SAP was found to inhibit fibril formation and to increase the solubility of the peptide in a dose-dependent manner. At a 5:1 molar ratio of A beta 1-42 peptide to SAP, fibril formation was completely inhibited, and approximately 80% of the peptide remained in solution even after 4 days of incubation. At lower SAP concentrations, e.g. at peptide to SAP ratio of 1000:1, short fibrillar like structures, lacking amyloid characteristics, were formed. These structures frequently contained associated SAP molecules, suggesting that SAP binds to the polymerizing peptide in a reaction which prevented further fibril formation.

Alzheimer Disease↗

Nucleoside triphosphate donors for nucleoside kinases: donor properties of UTP with human deoxycytidine kinase.

The reported higher efficiency of UTP, relative to ATP, as phosphate donor for deoxycytidine kinase (dCK), has been extended and found to apply to both dCyd and dAdo as acceptors. UTP as phosphate donor was shown to follow strictly Michaelis kinetics, with Km = 1 microM, in striking contrast to ATP, which exhibits marked negative cooperativity (Hill coef. = 0.7) with a several-fold higher Kmapp = 15 microM. Phosphate transfer was followed directly with use of mixtures of [gamma-32P]ATP and cold UTP as donors, or with 3H-labeled acceptors and cold donors. With equimolar concentrations of ATP and UTP (50 microM or 1 mM each), and dCyd or dAdo as acceptor, only minimal phosphate transfer occurred from ATP (3-10%). With a 6:1 ratio of ATP:UTP, hence exceeding the intracellular ratio, phosphate transfer from ATP increased, but still did not exceed 25-40% with either dCyd or dAdo as acceptor. Moreover, relative ATP transfer is dependent on the dCyd concentration. We conclude that the major intracellular phosphate donor for dCK is not ATP, but UTP. Preliminary data for human thymidine kinases (TK1 and TK2) exhibit quite different behaviour. The foregoing, together with literature data, are highly relevant to in vitro studies on the properties of the nucleoside kinases, and to the design of chemotherapeutically active nucleoside analogues.

Adenosine Triphosphate↗

Efficient incorporation of anti-HIV deoxynucleotides by recombinant yeast mitochondrial DNA polymerase.

Saccharomyces cerevisiae mtDNA polymerase, isolated as a single 135-kDa recombinant polypeptide, showed high processivity and a capacity of use poly(dA).oligo(dT), poly(rA).oligo(dT), or primed bacteriophage M13 DNA as a template. In a primer extension assay, the enzyme exhibited an intrinsic 3'-5'-exonuclease activity. By optimizing the polymerization reaction conditions, apparent Km and Vmax values could be determined for the incorporation of dTTP, 2'-3'-dideoxy-TTP (ddTTP), 3'-azido-TTP (AZTTP), 3'-fluoro-TTP, dCTP, 2'-3'-dideoxy-CTP, and didehydro(d4)CTP. The yeast mtDNA polymerase used ddTTP, 3'-fluoro-TTP, and ddCTP almost as efficiently as natural deoxynucleoside trisphosphates. Both 3'AZTTP and d4CTP were each significantly less efficient as substrates. Overall, the kinetic data with mtDNA polymerase were very similar to those of the recombinant human immunodeficiency virus reverse transcriptase control. Terminally incorporated AZTTP or ddTTP was not removed by the 3'-5' exonuclease activity of mtDNA polymerase. This may explain the inhibition of mtDNA replication observed in anti-human immunodeficiency virus treatment with dideoxynucleoside analogs for their effects of mtDNA polymerase could be of value in future rational drug design.

Antiviral Agents↗

Cytotoxicity of 3'-azido-3'-deoxythymidine correlates with 3'-azidothymidine-5'-monophosphate (AZTMP) levels, whereas anti-human immunodeficiency virus (HIV) activity correlates with 3'-azidothymidine-5'-triphosphate (AZTTP) levels in cultured CEM T-lymphoblastoid cells.

Activation of the anti-human immunodeficiency virus (HIV) compound 3'-azido-3'-deoxythymidine (AZT) is dependent on its 5'-phosphorylation by cellular nucleoside and nucleotide kinases. Azidothymidine 5'-triphosphate (AZTTP) is considered to be the metabolite responsible for both the anti-HIV effect of AZT, via inhibition of reverse transcriptase, and cytoxicity by interference with cellular DNA polymerases. During the characterization of AZT metabolism in cultured human T-lymphoblastoid CEM cells, a spontaneously occurring variant cell line, CEM/Ag-1, was found that showed approximately 10-fold resistance to AZT growth inhibition as compared to wild type (wt) cells (EC50 = 2 mM as compared to 350 microM for wt cells). CEM/Ag-1 cells had a 3-fold reduced capacity to accumulate azidothymidine monophosphate (AZTMP) compared to wt cells whereas similar levels of AZTTP were found in both cell lines. The intracellular half-life of AZTMP was approximately 70 min in both wt and CEM/Ag-1 cells. A 3-fold lower specific activity of cytoplasmic thymidine kinase was observed in CEM/Ag-1 extracts as compared to wt. The reduced thymidine kinase activity was not correlated to a decreased level of thymidine kinase mRNA. Syncytium formation of CEM/Ag-1 cells infected with HIV-2 as well as HIV-1 antigen production was inhibited at the same concentrations of AZT (approx. 0.01 microM) as were HIV-1 and HIV-2 infected wt cells. Thus, minor decreases in cellular thymidine kinase levels may markedly affect the cytoxicity of AZT but have no major effect on the antiviral activity of AZT. Our results strongly suggest that AZTMP is responsible for a major part of the growth inhibitor effects, while AZTTP mainly mediates the antiviral activity of AZT.

Blotting, Northern↗