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| 2. |
- Lennerstrand, Johan, et al.
(författare)
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A Method for Combined Immunoaffinity Purification and Assay of HIV-1 Reverse Transcriptase Activity Useful for Crude Samples
- 1996
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Ingår i: Analytical Biochemistry. - : Elsevier BV. - 0003-2697 .- 1096-0309. ; 235:2, s. 141-152
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Tidskriftsartikel (refereegranskat)abstract
- Detection of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) activity in crude specimens was greatly enhanced using a novel capture RT assay. Eighteen different monoclonal antibodies (Mabs) raised against purified HIV-1 RT were tested for their ability to bind to HIV-1 RT without affecting its activity. The anti-HIV-1 RT Mabs were immobilized on plastic macrobeads and used as solid carriers in the capture RT assay. The assay system first involved RT's adherence to the immobilized Mabs. Nonspecific enzymes and other impurities were removed by a simple wash after which the RT reaction mixture was added. Substrate and product were finally separated by a wash of the beads. Practically all radioactivity incorporated into DNA (>98%) was recovered on the bead. The Michaelis-Menten constants and the saturation velocity values for the nucleotide substrate were similar for free and immobilized RT. The reaction mechanism for the immobilized RT is discussed. When comparing the function of this assay with more conventional soluble RT assays for samples consisting of recombinant HIV-1 RT mixed with an extract of peripheral blood lymphocytes (PBL), an almost 100-fold higher sensitivity was found. The capture RT assay had the capacity to recover approximately 80% of the RT activity added to an extract of 1 x 10(7) PBL cells/ ml. A strong correlation (r = 0.947) between the results obtained with this assay and a HIV-1 p24 enzyme-linked immunosorbent assay was found, when samples from a collection of 16 HIV strains propagated in cell culture were analyzed.
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| 4. |
- Beamish, A. J., et al.
(författare)
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Changes in adipose tissue distribution and relation to cardiometabolic risk factors after Roux-en-Y in adolescents
- 2023
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Ingår i: Surgery for Obesity and Related Diseases. - : ELSEVIER SCIENCE INC. - 1550-7289 .- 1878-7533. ; 19:10, s. 1154-1161
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Tidskriftsartikel (refereegranskat)abstract
- Background: Roux-en-Y gastric bypass (RYGB) among adolescents with obesity results in signif-icant weight loss; however, depot-specific changes have been understudied.Objective: We hypothesized that visceral adipose tissue (VAT) reduction in adolescents undergoing RYGB would be greater than other depots and associated with improvement in cardiometabolic risk factors.Setting: Three specialized treatment centers in Sweden. Methods: Fifty-nine adolescents underwent dual x-ray absorptiometry before surgery and at 1, 2, and 5 years after RYGB. Changes in body composition in multiple depots (total fat, lean body, gynoid fat, android fat, subcutaneous adipose tissue, and VAT) and cardiometabolic risk factors were assessed using multiple linear regression analysis and generalized estimating equations adjusting for age, sex, and baseline risk factor levels. Data are presented as percent change (95% CI) with regression models showing slopes and estimated P values.Results: At 1 year post-RYGB, a significant reduction was observed across all body composition measures (P , .001) with the greatest reduction observed in VAT (-65.1% [-68.7, -61.8]). From year 1 to 5 years post-RYGB, a regain was observed in all depots except lean body mass (1.2% [.3, 2.7], P 5 .105). A sex-specific difference in overall trajectories was only observed in lean body mass with males consistently having higher mean levels. Change in VAT at 1 year correlated with change in triglycerides (slope: .21 mg/dL/kg, P = .034) and fasting plasma insulin (slope: 44 pmol/L/kg, P = .027). Conclusions: Adiposity measures all decreased after RYGB but poorly predicted change in cardio-metabolic risk. Despite significant reductions at 1 year, a steady regain was observed out to 5 years, with values still well below baseline. Further research should consider control group comparison and extended follow-up.
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| 5. |
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| 6. |
- Dahlgren, T., et al.
(författare)
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Electronic spectra of dithieno analogues of phenanthrene
- 1979
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Ingår i: Chemical Physics. - : Elsevier BV. - 0301-0104. ; 40:3, s. 397-404
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Tidskriftsartikel (refereegranskat)abstract
- The magnetic circular dichroism (MCD) spectra of some dithieno analogues of phenanthrene: benzo [2,1-b;3,4-b′] dithiophene (I) benzo [1,2-b;4,3-b′] dithiophene (II), benzo [1,2-c;3,4-c′] dithiophene (III) and benzo [1,2-b;3,4-b′] dithiophene (IV) are reported. For I–III the spectra corresponding to two different transition moment directions could be obtained from low-temperature linear dichroism spectra. The results compare well with theoretical energies, oscillator strengths, moment directions and MCD B-terms which were obtained from semi-empirical quantum mechanical calculations in the π-electron approximation.
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| 8. |
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| 9. |
- Gronowitz, J S, et al.
(författare)
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Carrier bound templates for single tube reverse transcriptase assays and for combined purification and activity analyses, with special reference to HIV
- 1991
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Ingår i: Biotechnology and applied biochemistry. - 0885-4513 .- 1470-8744. ; 13:1, s. 127-142
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Tidskriftsartikel (refereegranskat)abstract
- Polyriboadenosine (prA) was coupled to polycarbonate macrobeads or magnetic beads. The efficiency of the beads and of prA-Sepharose, after priming with odT, as templates in activity assays of purified AMV- and HIV-reverse transcriptase (RT), using [125I]iododeoxyuridine-triphosphate as substrate, was studied. Although the use of immobilized templates, compared with soluble template, resulted in a decreased total molar turnover, it did not affect the sensitivity of the assay for detecting RT. The utility of the new assay was analyzed by mixing purified AMV- or HIV-Rt with different dilutions of the untreated clinical specimen. This showed that RT activity was unaffected by 100 microliters of an extract of whole blood cells resuspended to their original blood volume and diluted 1/64, and also by 100 microliters of serum diluted 1/64. To improve the utility of the assay at the inhibitory concentrations of clinical specimens, the following procedure was adopted: the sample to be analyzed was incubated with the carrier bound template in order to allow the RT to bind, the carrier was washed to remove inhibitory factors, and the reaction components were then added to determine the amount of bound RT. This procedure greatly enhanced the recovery of RT activity from crude specimens and made the direct detection of HIV-RT possible. The assay is easily automated and useful for RT determination in multiple samples and for determining RT-inhibiting substances such as substrate analogs and antibodies.
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| 11. |
- Janson, A., et al.
(författare)
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A randomized controlled trial comparing intensive non-surgical treatment with bariatric surgery in adolescents aged 13–16 years (AMOS2): Rationale, study design, and patient recruitment
- 2020
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Ingår i: Contemporary Clinical Trials Communications. - : Elsevier BV. - 2451-8654. ; 19
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Tidskriftsartikel (refereegranskat)abstract
- Background: Previous non-randomized studies show similar outcomes in adolescents and adults after bariatric surgery. We describe the study protocol, recruitment, and selected baseline data of patients in a randomized multi-center study, the Adolescent Morbid Obesity Surgery 2 (AMOS2). Methods: Three clinics in Sweden collaborated in designing the study and recruitment of patients from August 1, 2014 to June 30, 2017. Patients were selected among adolescents 13–16 years of age attending third-level obesity care for at least one year. Patients were randomized 1:1 to bariatric surgery (predominantly Roux-en-Y gastric bypass) or intensive non-surgical treatment starting with an eight-week low-calorie-diet. Results: Fifty adolescents (37 girls) were randomized, 25 (19 girls) to bariatric surgery. Mean age was 15.7 years (range 13.3–16.9), weight 122.6 kg (range 95–183.3), Body Mass Index (BMI) 42.6 kg/m2 (range 35.7–54.9) and BMI-SDS 3.45 (range 2.9–4.1). One patient had type 2 diabetes mellitus, and 12/45 (27%) had elevated liver enzymes. There were no significant differences between the groups. For the 39 eligible patients who were offered but declined inclusion, BMI was not different from included patients. However, patients who declined were younger, 15.2 years (p = 0.021). A sex difference was also noted with more of eligible girls, 37/53 (69.8%), than boys, 13/36 (36.1%), wanting to participate in the study (p = 0.002). Conclusions: This clinical trial, randomizing adolescents with severe obesity to bariatric surgery or intensive non-surgical treatment, aims at informing about whether it is beneficial to undergo bariatric surgery in early adolescence. It will also enlighten the outcome of comprehensive non-surgical treatment. The study was registered at www.clinicalTrials.gov number NCT02378259. © 2020
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| 12. |
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| 13. |
- Larsson, P A, et al.
(författare)
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Inhibition of herpes simplex virus replication and protein synthesis by non-smoked tobacco, tobacco alkaloids and nitrosamines
- 1992
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Ingår i: Archives of Oral Biology. - 0003-9969 .- 1879-1506. ; 37:11, s. 969-978
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Tidskriftsartikel (refereegranskat)abstract
- Inhibitory effects of snuff extract and the tobacco chemicals nicotine, anabasine, diethyl-N-nitrosamine (DEN), and the tobacco-specific nitrosamines (TSNA), N-nitrosonornicotine (NNN) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) on herpes simplex virus type 1 (HSV-1) replication in vitro and on HSV-1 protein synthesis in infected cells were analysed. Snuff extract and nicotine caused a significant reduction of HSV-1 attachment to cell membranes whereas anabasine, DEN, NNN and NNK did not affect adsorption of HSV-1. Virus production assays in the presence of snuff added after virus adsorption resulted in a significantly reduced production of virus at low multiplicities of infection (MOI), but at high MOI the inhibitory effect of snuff extract was less pronounced. DEN, NNN and NNK only affected virus production at toxic concentrations. Nicotine and anabasine reduced virus production in non-toxic doses but not at the concentrations present in snuff extract. In HSV-infected cells exposed to snuff extract, the immediate early (α-) infected cell proteins (ICPs) 4 and 27 (as well as the early (β-) ICPs 6 and 8) were markedly increased, whereas the late (γ-) ICPs 5, 11 and 29 were reduced. Nicotine had a less pronounced stimulating effect on the production of α-proteins but no detectable effect on production of β- or -γ-proteins. Anabasine, DEN, NNN and NNK did not affect HSV protein synthesis at non-toxic concentrations. Synthesis of thymidine kinase and DNA polymerase was significantly reduced by snuff extract. Also nicotine and anabasine affected thymidine kinase and DNA polymerase but only at toxic concentrations. The production of the cellular protein actin, which almost disappears a few hours after HSV-1 infection, remained at a significant level in HSV-infected cells exposed to snuff. Thus snuff extract blocks the replicative cycle of HSV at an early stage, which results in an increased production of α-proteins in the infected cells and in prolonged maintenance of cellular functions. This may be of importance for HSV-induced transformation and the development of HSV-associated tumours.
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| 14. |
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| 15. |
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| 16. |
- Neumüller, M, et al.
(författare)
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HIV-1 reverse transcriptase inhibiting antibody titer in serum : relation to disease progression and to core-antibody levels.
- 1992
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Ingår i: Journal of Medical Virology. - : Wiley. - 0146-6615 .- 1096-9071. ; 36:4, s. 283-291
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Tidskriftsartikel (refereegranskat)abstract
- A new assay for detecting inhibition of reverse transcriptase activity (the RT-i REA) was developed. This assay was standardized for screening serum samples for reverse transcriptase inhibiting antibodies (RT-iAb). High specificity (100%) and sensitivity (greater than 98%) were achieved with samples from HIV-negative individuals and HIV-infected individuals. The RT-i REA was also used in a study of the titers of RT-iAb in serum samples obtained from 33 HIV-infected homosexual men. The results confirmed the relation between decreasing RT-iAb levels and progression to late stages of the disease. Furthermore, a falling RT-iAb titer was observed in 14 of 15 individuals experiencing periods of severe clinical symptoms attributed to HIV-activity. In 7 of the patients the decline in RT-iAb titer began prior to severe clinical symptoms. The fall in RT-iAb titer also correlated with a reduction in core Ab level. The core Ab level has previously been reported to be a disease progression marker with considerable prognostic value. However, whereas all patients were positive for RT-iAb, 8 of the 33 patients did not have detectable core Ab. The use of RT-iAb titer as a marker of disease progression is discussed.
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| 17. |
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| 18. |
- Sauerbrei, A., et al.
(författare)
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Screening of herpes simplex virus type 1 isolates for acyclovir resistance using DiviTum® assay
- 2013
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Ingår i: Journal of Virological Methods. - : Elsevier BV. - 0166-0934 .- 1879-0984. ; 188:1-2, s. 70-72
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Tidskriftsartikel (refereegranskat)abstract
- Rapid alternative methods are required to evaluate easily acyclovir (ACV) sensitivity of clinical herpes simplex virus (HSV) isolates. The objective of this study was to screen 54 ACV-sensitive and 41 ACV-resistant clinical HSV-1 isolates, well characterized by phenotypic and genotypic methods, for the phosphorylation activity of the viral thymidine kinase (TK) using a commercially available and modified non-radioactive DiviTum® test on the basis of an indirect enzyme linked immunosorbent assay. The ACV-sensitive HSV-1 isolates had high TK activity values between 31.5±6.4 DiviTum® Units per liter (DU/L) and 487.4±60.1DU/L. The mean activity of all ACV-sensitive isolates was calculated as 212.3±15.7 DU/L. By contrast, the mean activity of all ACV-resistant HSV-1 isolates was significantly lower at 5.5±1.3DU/L. Out of the 41 ACV-resistant HSV-1 isolates, 38 had no or very low phosphorylation activities of the viral TK between 0DU/L and 9.3±3.2DU/L. The remaining three ACV-resistant viral isolates had TK activities between 44.6±5.1DU/L and 80.9±13.3DU/L. In conclusion, the modified DiviTum® test can be used to screen HSV-1 isolates for their sensitivity to ACV. Acyclovir-sensitive HSV-1 isolates show TK activities >30DU/L and ACV-resistant isolates have activity values <10DU/L. However, single ACV-resistant HSV-1 isolates can have TK activity values >30DU/L. These strains are most likely ACV-resistant TK-altered mutants, but no evidence was provided for an alteration of the TK.
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| 19. |
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| 20. |
- Soltani-Frisk, S, et al.
(författare)
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Water-miscible tocopherol is not superior to fat-soluble preparation for vitamin E absorption in cystic fibrosis.
- 2001
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Ingår i: Acta paediatrica (Oslo, Norway : 1992). - 0803-5253. ; 90:10, s. 1112-5
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Vitamin E deficiency is a major problem in cystic fibrosis. Modern pancreatic enzymes may improve the absorption of fat-soluble vitamins to make water dispersion less important. In order to compare the absorption of fat-soluble (F) and water-miscible (W) tocopheryl acetate, equivalent amounts (10 mg/kg body weight) were given to five patients with cystic fibrosis (CF) and five age- and sex-matched healthy controls. Serum was analysed for vitamin E using HPLC before and 1, 2, 3, 4, 6, 8, 10, 24 and 28 h after the oral intake. The median peak concentrations in the sera of controls were 41.9 micromol/L after F and 39.8 micromol/L after W preparations, corresponding values in CF patients being 21.3 and 26.8 micromol/L, and corresponding means +/- SD were 41.6+/-6.7 and 38.4+/-3.3, and 27.1+/-14.5 and 28.8+/-8.3, respectively. Although the area under the curve was lower for W than F preparations in both CF patients and controls, these differences were not significant. CONCLUSION: The results in our study are consistent with those of an earlier study using the same preparation and suggest that it is not necessary to use water-miscible preparation of alpha-tocopheryl acetate in CF patients receiving modern pancreatic enzyme supplementation.
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