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Biomedical subjects

B Isaksson

Publications and source records attributed to B Isaksson.

At least 19 recordsLinked to original sources
PubMed1992

Anti-neutrophil cytoplasm antibodies, anti-GBM antibodies and anti-dsDNA antibodies in glomerulonephritis.

The diagnostic potential of assays detecting anti-neutrophil cytoplasm antibodies (ANCA), anti-GBM antibodies and anti-dsDNA antibodies was evaluated by examining sera from time of admission in a consecutive series of 455 patients with biopsy verified primary or secondary glomerulonephritis (GN). ANCA were classified into c- and p-ANCA by indirect immunofluorescence (IIF) and ELISAs using alfa-granule extract, proteinase-3, myeloperoxidase (MPO), elastase and lactoferrin. C-ANCA was virtually confined to 64 patients with systemic small vessel vasculitis, 66-74% being c-ANCA positive. P-ANCA against MPO, seen in 47 patients, segregated through many diagnostic categories of primary and secondary severe GN. ANCA against lactoferrin and elastase were rare. Anti-dsDNA positive patients constituted 57% of the 44 ANA-positive patients with systemic lupus erythematosus. It is concluded that the IIF and ELISAs for anti-proteinase-3, anti-MPO, anti-dsDNA and anti-GBM have an acceptable performance and are useful in the primary diagnostic work-up of patients suspected for secondary GN as the majority of such patients will be classified by these assays.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed1992

Reproducibility and validity of 7-day food records.

The reproducibility of the 7-day food record method, as used in The Glostrup Population Studies, has been tested by 40 adult volunteers, mainly hospital staff, recording their dietary intakes in two 7-day periods. To validate the calculated protein intake a 24-h urine specimen was collected from all participants in period II, but for various reasons urine specimens were only obtained from 31 in period I. There were significant differences in the intakes of energy, protein and some vitamins and minerals between the two periods, but the nutrient densities, except for vitamin A, were equal. The mean energy distributions in the diet showed no significant differences between the two periods. The weekly variance ratio (S2within/S2between) was between 0.25 and 0.80 for most nutrients. The only ratios above 1.0 were found for vitamin A, vitamin C, vitamin D, vitamin B12 and chromium, selenium and sodium. The weekly coefficients of variance (CV) were for most nutrients less than 30%. In period II the mean protein intake estimated from the urine samples was 74.7 (+/- 15.9 SD) g/day, whereas the protein intake calculated from the diet records was 70.6 (+/- 18.4) g/day. The average estimated protein intake for the 31 people who collected urine in period I was 72.1 (+/- 18.3) g/day, whereas the calculated intake was 78.0 (+/- 22.7) g/day. In neither period were the mean differences significant.

Adolescent↗
PubMed1991

Synergistic post-antibiotic effect of amikacin and beta-lactam antibiotics on Enterococcus faecalis.

The in-vitro post-antibiotic effect (PAE) of amikacin alone and in combination with ceftazidime, ceftriaxone and piperacillin was studied for two strains of Enterococcus faecalis using a bioluminescent assay of bacterial ATP. The two strains of E. faecalis were resistant to amikacin, ceftazidime and ceftriaxone but sensitive to piperacillin. The bacterial cultures were incubated with the beta-lactam antibiotics for 1 h and concentrations of amikacin between 2-64 mg/l were then added. Thereafter, incubation continued with the combinations for one more hour. After dilution, regrowth was monitored by measuring bacterial ATP every hour. Increasing concentrations of amikacin (2-64 mg/l), ceftazidime (8-32 mg/l) and ceftriaxone (32-128 mg/l) resulted in little or no PAE (0-0.3 h) on these strains. PAEs of 0.5 to 1.6 h resulted from exposure to piperacillin (4-32 mg/l). In combination amikacin and piperacillin increased the PAE to 5.5 h. A synergistic PAE was also seen when the enterococci were exposed to amikacin combined with ceftazidime or ceftriaxone in concentrations close to the MICs of the latter antibiotics.

Amikacin↗
PubMed1991

Synergic post-antibiotic effect of amikacin in combination with beta-lactam antibiotics on gram-negative bacteria.

The post-antibiotic effect (PAE) of amikacin alone and in combination with ceftazidime, ceftriaxone and piperacillin was studied for two strains each of Pseudomonas aeruginosa and Serratia marcescens using a bioluminescent assay of bacterial ATP. Two models were used for combining beta-lactam antibiotics and amikacin: in one model the cultures were incubated with 32 mg/L of ceftazidime, 128 mg/L of ceftriaxone or 32 mg/L of piperacillin for 1 h. Different concentrations of amikacin (0.5-64 mg/L) were then added. Incubation of the combinations continued for one more hour. The antibiotics were eliminated by dilution. In the second model tested, one strain of S. marcescens was simultaneously exposed to amikacin and a beta-lactam antibiotic for 2 h. The PAEs produced by the drugs in combination were longer than the sum of the individual effects of the drugs when they were used alone. Results were equally good with both models. A synergic PAE was also found with amikacin concentrations close to the MIC in combination with low concentrations of ceftazidime, ceftriaxone and piperacillin.

Amikacin↗
PubMed1991

Pharmacodynamics of daptomycin and vancomycin on Enterococcus faecalis and Staphylococcus aureus demonstrated by studies of initial killing and postantibiotic effect and influence of Ca2+ and albumin on these drugs.

The pharmacodynamics of daptomycin and vancomycin on Enterococcus faecalis ATCC 29212 and Staphylococcus aureus ATCC 25923 were investigated by studying the postantibiotic effect (PAE) and initial killing. The influence of Ca2+ and albumin on these drugs was also evaluated. The PAE was studied by use of bioluminescence assay of bacterial ATP. Daptomycin at clinically achievable concentrations produced a dose-dependent PAE on E. faecalis (0.6 to 6.7 h) and S. aureus (1.0 to 6.3 h). The long PAE of daptomycin was seen simultaneously with a potent dose-dependent initial killing assayed by viable count determination. The initial change in bacterial ATP was not as extensive as the decrease in viability. Vancomycin at corresponding concentrations produced shorter PAEs on E. faecalis (0.5 to 1.0 h) and S. aureus (1.3 to 1.8 h). This coincides with a weak non-dose-dependent initial change in viability and intracellular ATP. The MICs of vancomycin were not influenced by different Ca2+ concentrations or by the addition of albumin to the broth. The MICs of daptomycin for both strains were lowered, and the PAEs were prolonged with increasing concentrations of Ca2+ in the broth. The PAE of daptomycin was Ca2+ dependent to the same extent as the MIC was. In the presence of physiological concentrations of albumin and free Ca2+, the PAEs of daptomycin on both strains were reduced and the MICs were increased in comparison with the results obtained in pure Mueller-Hinton broth with approximately the same free Ca2+ concentration. This decrease in daptomycin activity was considered to be due to the albumin binding of daptomycin. Despite the albumin binding of daptomycin, the PAE produced on E. faecalis and S. aureus in the presence of a physiological free Ca2+ concentration was still over 6 h at clinically achievable concentrations.

Albumins↗
PubMed1991

Viral haemorrhagic fever in Sweden: experiences from management of a case.

The first recognized case in Scandinavia with potential man to man transmission of viral haemorrhagic fever occurred in Linköping, Sweden, in January 1990. Following a visit to Kenya a 21-year-old male student suffered a very severe illness including extremely prolonged high grade fever, rash, disseminated intravascular coagulation with thrombocytopenia and severe bleedings. This necessitated one month of intensive care support including respirator treatment. The patient was discharged after 2 1/2 months in good condition, with a partial femoral nerve paresis. About 100 medical personnel were exposed to aerosol or blood before a strict containment regimen was established. No secondary cases occurred.

Adult↗
PubMed1990

An ELISA for the detection of anti-neutrophil cytoplasm antibodies (ANCA).

An enzyme-linked immunosorbent assay (ELISA) has been developed for the detection of circulating anti-neutrophil cytoplasm antibodies (ANCA), which are defined by a diffuse, granular staining of the cytoplasm of alcohol-fixed human neutrophils by indirect immunofluorescence (IIF). Detection of antineutrophil cytoplasm antibodies has a high sensitivity and specificity for active Wegener's granulomatosis (WG) and reflects the effect of treatment. In the present enzyme-linked assay, immunoplates were coated with the cytoplasmic alpha fraction of neutrophils obtained from apparently healthy human donors by nitrogen bomb cavitation and subsequent Percoll gradient centrifugation. Alkaline phosphatase-labelled anti-human IgG was used as a secondary antibody. Diluted sera from 70 patients with WG and 16 patients with other diseases with anti-myeloperoxidase antibodies (anti-MPO) were examined. It is concluded that the ELISA accurately detects IIF ANCA positive patients with WG, is helpful in detecting WG patients in remission, is not influenced by the presence of anti-MPO and may help in detecting ANCA in cases with granulocyte-specific anti-nuclear antibodies since this IIF pattern obscures the IIF ANCA patterns. The ELISA with titration can be carried out in 3.5 h whereas a rapid test just to detect ANCA can be performed in 30 min.

Autoantibodies↗
PubMed1990

Prediction of 24-h energy expenditure and its components from physical characteristics and body composition in normal-weight humans.

The applicability of body composition as estimated by the bioimpedance method to predict energy expenditure (EE) was studied. Ten healthy subjects underwent measurement of body composition and 24-h energy expenditure (24-h EE) twice in a respiration chamber on a fixed program. The 24-h EE and its components, sleeping EE (SEE), basal EE (BEE), and daytime EE, for an individual were very reproducible (coefficient of variation 2.3%, 1.4%, 5.0%, & 3.1%, respectively). The variability of 24-h EE among subjects was 11.4% but only 4.1% when adjusted for differences in lean body mass (LBM). LBM was the best determinant of 24-h EE, BEE, and SEE and accounted for 91-93% of the interindividual variance of EE. The prediction equations were 24EE (kcal/d) = 390 + 33.3 LBM (r2 = 0.93, P = 0.000001), SEE (kcal/h) = 9.8 + 1.1 LBM (r2 = 0.92, P = 0.000001), and BEE (kcal/h) = -3.1 + 1.35 LBM (r2 = 0.91, P = 0.000002). In conclusion, 24EE, BEE, and SEE can be predicted with a high degree of precision from LBM as estimated by bioimpedance in normal-weight subjects.

Adult↗
PubMed1990

Amikacin once daily: a new dosing regimen based on drug pharmacokinetics.

Once-daily dosing of amikacin is a novel therapy regimen which seems pharmacokinetically appropriate for the primary group of patients considered for aminoglycoside therapy. In this study of 29 elderly patients with serious infections, amikacin 11 mg/kg or 15 mg/kg bw was administered as a short-term (30 min) intravenous infusion. The amikacin serum concentration-time profile was best described by a bi-exponential equation with a half-life of about 4.8 h. A triexponential equation was not applicable because the slow terminal elimination phase was not detected during the 24 h dosing interval. In practice, a uni-exponential equation is often used, and this may lead to incorrect conclusions about the elimination rate of amikacin. Amikacin clearance provides more direct information about elimination of amikacin than does serum half-life. Thus, there was a better correlation between the individual amikacin clearances and creatinine clearances (r = 0.89), than between the serum half-lives of amikacin and the creatinine clearances (r = 0.71). For elderly patients a smaller dose of amikacin than the regular daily dose of 15 mg/kg bw, i.e. about 11 mg/kg bw, seems recommendable, when it is given once daily. From the data obtained it is also obvious that once-daily dosing of amikacin does not eliminate the need for checking serum concentrations of the drug.

Aged↗
PubMed1990

The postantibiotic effect of amikacin alone and in combination with piperacillin on gram-negative bacteria.

The in vitro postantibiotic effect (PAE) of amikacin was investigated using a bioluminescent assay of bacterial ATP. Two strains each of Escherichia coli, Pseudomonas aeruginosa and Serratia marcescens were exposed for one hour to different concentrations of amikacin. The aminoglycoside was removed by a 10(-3) dilution and regrowth of bacteria was followed at hourly intervals by monitoring bacterial ATP. The length of the PAE was concentration-dependent and was approximately four to six hours for the three strains at amikacin concentrations normally reached in serum during standard dosing. The PAE of amikacin in combination with 32 mg/l piperacillin on Ps. aeruginosa was also studied. These cultures were incubated with piperacillin for one hour. Thereafter different concentrations of amikacin 0.5-64 mg/l were added and the incubation then continued with the combinations for one more hour. The PAEs produced by the drugs in combination were longer than the sum of the individual effects of the drugs when they were used alone. Knowledge of synergistic PAE could have clinical implications for optimal dosing schedules during combination antimicrobial chemotherapy.

Amikacin↗
PubMed1990

Some errors inherent in a longitudinal dietary survey revealed by the urine nitrogen test.

In the longitudinal population study 'Women in Gothenburg', subgroups of 154, 205 and 331 women in 1968/69, 1974/75 and 1980/81 respectively, were subjected to a dietary interview and collected a 24-h urine specimen for nitrogen analyses. The dietary data demonstrated a continuous increase in intake of energy and protein with time (2030, 2150 and 2350 kcal/d and 73, 77 and 90 g protein/d), while the 'true' protein intake (calculated from 24-h urine nitrogen) was unchanged (75, 73 and 75 g/d). The discrepancies were interpreted as being due to the changes in the dietary questionnaires made before the interviews in 1974/75, and again in 1980/81, changes expected to improve the method. In 1968/69 overweight women (BMI 24-30), as well as obese women (BMI greater than 30), reported a significantly smaller intake of energy and protein than lean women. Their reported protein intake was significantly lower than their 'true' protein intake (69 versus 77 g/d and 73 versus 94 g/d, respectively). Significant underreporting of dietary intake by the overweight and obese women in the studies 1974/75 and 1980/81 was revealed by the urine nitrogen test after correction for the methodological errors of the questionnaires. The results illustrate the necessity of using an independent validation test in dietary surveys.

Adult↗
PubMed1989

[The use of the impedance measurement technic for calculating body fat mass. A validity study].

The body composition of water and fat may be calculated on the basis of measurements of its impedance. Calculations are based on algorithms developed by all measurements of the body compositions of a reference material, by means of standard methods (eg hydrodensiometry, total body water by isotope dilutimetry). A commencial impedance analyser with built-in algorithm for calculation of total body water and body fat mass was evaluated and compared with measurements of the total body water in 42 young men and women. Very good agreement was found (mean values for total water were 34.2 and 33.5, respectively, for women and 46.8 and 47.0, respectively, for men). These calculations of total body water correlated better with the reference values than calculations from four other algorithms published in the literature. Simple anthropometric measurements (skin-fold thickness, BMI) resulted in significantly higher calculations of body fat mass than calculations based on impedance measurement. This study has shown that the technique of impedance measurement has good reliable validity for calculation of the body fat mass and that, on account of its simplicity, the method is suitable for field studies and also individual measurements.

Adipose Tissue↗
PubMed1989

A rapid assay for circulating anti-glomerular basement membrane antibodies in Goodpasture syndrome.

A rapid ELISA for the detection of circulating anti-glomerular basement membrane antibodies in Goodpasture syndrome is described. The specificity of the test was shown to be highly dependent on the antigens used. Using the purified Goodpasture antigen it was possible to shorten the incubation times to 10 min in a routine assay using alkaline phosphatase-labeled second antibodies and the total assay was complete in 30 min. 200 reference sera, 500 sera from patients with various types of glomerulonephritis and 32 sera from patients with Goodpasture syndrome were analyzed by this rapid assay. The assay was able to discriminate between Goodpasture syndrome and other forms of glomerulonephritis. Using enzyme amplification it was possible to further shorten the incubation times to 1 min and the total time of the assay to 6 min.

Anti-Glomerular Basement Membrane Disease↗
PubMed1989

Postantibiotic and bactericidal effect of imipenem against Pseudomonas aeruginosa.

The postantibiotic effect of imipenem on Pseudomonas aeruginosa was studied at different inocula using one ATCC strain and four clinical isolates. The postantibiotic effect was measured using two different methods: viable counts and bioluminescence assay of intracellular bacterial ATP. The postantibiotic effect could be demonstrated with both methods (viable counts 1-2 h, ATP assay 3-5 h) for all strains at an inoculum of 10(6) CFU/ml. When the inoculum was raised to 10(8) CFU/ml, no postantibiotic effect could be observed with either method using routine growth conditions. This disappearance of the postantibiotic effect coincided with a loss of bactericidal effect of imipenem when high inocula were used. Improved oxygenation of the cultures restored the bactericidal and postantibiotic effects of imipenem at high inocula.

Dose-Response Relationship, Drug↗
PubMed1989

Dietary habits and incidence of noninsulin-dependent diabetes mellitus in a population study of women in Gothenburg, Sweden.

Dietary intake as initially estimated in a cross-sectional study has been related to the 12-y incidence of diabetes mellitus in a prospective study of 1462 women. In addition, all 50-y-old women (n = 352) were subjected to an intravenous glucose tolerance test. Because of the sampling procedure and a high participation rate the participants were representative of middle-aged women in the general population. No differences of statistical significance were observed concerning intake of energy and different nutrients. Neither did the number of meals nor the longest time between meals differ between women who developed diabetes and those who did not. Women with impaired glucose tolerance who developed diabetes did not differ from those who did not develop diabetes, concerning dietary intake. Body mass index was significantly higher in women who developed diabetes compared with other women. No specific dietary recommendations can be based on the results of this study.

Adult↗
PubMed1989

The population study of women in Gothenburg 1980-81--the third phase of a longitudinal study. Comparison between participants and non-participants.

A representative population sample comprising 1,462 women was studied in Gothenburg, Sweden in 1968-69, and a third follow-up study was carried out in 1980-81. The participation rates in the baseline study and during the follow-up studies were high. In 1980-81 women in two new age strata, aged 26 and 38, were added. Women who had moved to or from Gothenburg during the study period were not found to differ from those who were living in Gothenburg during the total study period, while there were a few differences of statistical significance between refusers and participants in 1980-81. The mortality among initial refusers was about doubled compared to that of those who participated in the baseline study.

Adult↗