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S Elfving

Publications and source records attributed to S Elfving.

12 recordsLinked to original sources
PubMed1994

Serum ionized calcium, intact PTH and novel markers of bone turnover in bedridden elderly patients.

Chronic immobilization could markedly affect calcium and bone metabolism in elderly people. To investigate this, and to test the theory of 'type II' osteoporosis in bedridden elderly patients with low vitamin D status, 55 such subjects were examined. Serum concentrations of ionized calcium (Ca++), intact parathyrin (PTH) and two novel markers of bone collagen formation (carboxyterminal propeptide of type I procollagen; PICP) and resorption (carboxyterminal crosslinked telopeptide of type I collagen; ICTP) were measured. The effects on these parameters after 40 weeks of supplementation with vitamin D (1000 IU d-1) and/or calcium (1 g d-1) were subsequently prospectively evaluated. Despite low (mean 11.6 nmoll-1) serum 25-hydroxyvitamin D levels (25-OHD), those of 1,25-dihydroxy-vitamin D (1,25-(OH)2D) were mostly normal. Neither correlated with Ca++ or PTH. PTH correlated negatively not only with Ca++ (r = -0.328, P < 0.05) but also with ICTP (r = -0.306, P < 0.05). Mean PICP was normal but ICTP was elevated and tended to correlate positively with Ca++ (r = 0.268, P = 0.06). Vitamin D supplementation did not change PICP or ICTP considerably, despite slightly increased 1,25-(OH)2D and slightly decreased PTH. Ca++ values were normal and remained stable. In conclusion, Ca++ and PTH are poor indicators of vitamin D status in chronically immobilized elderly subjects. Furthermore, the results suggest that the increased bone resorption is not due to 'type II' secondary hyperparathyroidism; rather the resorption is primarily increased. Correction of vitamin D deficiency does not seem to benefit ageing bones unless adequate mechanical loading is provided.

Aged↗
PubMed1993

A programme for assigning target values for external quality assessment schemes in countries with no authorized reference laboratories. Annex. Experiences with deviating results on Ektachem 700 XR.

The use of consensus values in external quality assessment schemes (EQAS) involves several problems and should preferably be replaced with target values obtained by methods of high metrological level. However, such values are difficult to obtain. In the present study we transferred values from the NIST (former NBS) certified reference serum SRM 909 to lyophilized and frozen test sera for various inorganic components using flame absorption or flame emission spectrometry. Enzyme values were assigned by laboratories of members of the former Scandinavian Enzyme Committee. The assignment was based on 2-4 determinations each day through 3 days of experiment. A total of 10 laboratories participated in the work. The results were utilized in a Danish EQAS. One practical concern is the fairly long time (9 months) which was needed for production, collection and compiling all data. To get an impression of how much dry chemistry analysers, e.g, could influence consensus values a Kodak Ektachem 700 XR was studied using lyophilized and frozen sera. The results are reported in the annex. On NIST SRM 909 the values found for sodium(I) were 6% too high even though the findings on frozen human sera were accurate. For aspartate aminotransferase a result three times the target values was found on a human lyophilized serum, while the values on the frozen sera only were slightly too high.

Blood↗
PubMed1992

Calcemic status of geriatric patients: a longitudinal study.

Serum ionized (CaI), total (CaT) and albumin-'corrected' total (CaA) calcium concentrations were measured in 108 geriatric long-term inpatients on admission and again 37 months (mean) later. Mean CaI, especially when pH adjusted, remained extremely stable, indicating well-preserved homeostatic calcemic control even in the terminal years in the elderly. Further, the results indicate that in addition to their previously shown invalidity in interindividual comparisons, CaT and CaA are inferior to CaI and can also be misleading in the detection of slight longitudinal changes in the 'true' calcemic status of an individual geriatric patient.

Aged↗
PubMed1988

No effect on serum lipids by moderate and high doses of vitamin C in elderly subjects with low plasma ascorbic acid levels.

The influence of dietary supplementation with moderate (200 mg/day) and high (2,000 mg/day) doses of vitamin C on serum lipid levels was studied in 27 female long-stay hospital patients characterized by low plasma ascorbic acid levels during the preceding year. The two doses of vitamin C were compared with placebo in a double-blind, cross-over design during randomly determined 6-week periods followed by 2-week washout intervals. No effect was observed on serum cholesterol, HDL cholesterol, and triglyceride levels. Plasma ascorbic acid levels were highly significantly increased (p less than 0.001) by both doses of vitamin C. It is concluded that dietary supplementation with moderate or high doses of vitamin C does not affect serum lipids of persons who have low plasma ascorbic acid levels suggestive of possible marginal deficiency of vitamin C.

Aged↗
PubMed1988

Assessment of calcaemic status in geriatric hospital patients: serum ionized calcium versus albumin-adjusted total calcium.

To evaluate the accuracy of total serum calcium (CaT) and albumin-adjusted total calcium (CaA) determinations in the assessment of calcaemic status in the elderly, serum ionized calcium (CaI), CaT and serum albumin (Alb) concentrations were measured in 558 geriatric hospital patients. As expected, CaT was correlated with Alb (r = 0.316, p less than 0.001) and CaI with serum pH (r = -0.351, p less than 0.001) and they were closely interrelated (r = 0.746, p less than 0.001). Various albumin-adjustment formulas from the literature decreased the correlation of CaT and CaI. Using conventional reference limits for CaT only 12% and 72% of patients with CaI above or below the reference limits for CaI, respectively, were found. This study demonstrates the low sensitivity of total and albumin-adjusted calcium in the detection of slightly or moderately abnormal calcaemic states.

Adult↗
PubMed1987

Serum protein binding of phenytoin, diazepam and propranolol in age-related decrease in renal function.

The serum protein binding of phenytoin, diazepam and propranolol was investigated in vitro in 32 elderly people with an age-related decrease in renal function by a pressure ultrafiltration method at 37 degrees C. The mean age of the patients was 88 +/- 1 years (mean +/- SE), and their mean 51Cr-EDTA clearance 46 +/- 4 ml/min. The main reason for hospitalization of these patients was their age. The free fraction of phenytoin correlated negatively with the serum albumin concentration, and that of propranolol with the alpha 1-acid glycoprotein (alpha 1-AGP) concentration. The free fraction of diazepam did not correlate with either of these binding proteins. In stepwise multiple regression analysis, the most significant variable for phenytoin free fraction was serum albumin concentration, with the serum urea concentration coming in second place. For the diazepam free fraction, the only significant variable was the serum urea level, although in the correlation matrix the correlation with creatinine was also significant. When the effect of serum albumin level was corrected mathematically, the urea level was the best determinant in regression analysis for both the phenytoin and diazepam free fractions. It can be concluded that an age-dependent decrease in renal function increases the free fraction of phenytoin and diazepam and is, together with hypoalbuminaemia, responsible for the increased free fraction of these drugs in the elderly. For propranolol the only important factor is the serum alpha 1-acid glycoprotein concentration.

Aged↗
PubMed1986

Serum C-peptide concentrations and their value in evaluating the usefulness of insulin therapy in elderly diabetics.

Serum C-peptide concentrations were determined in 121 elderly subjects: 25 nondiabetic controls aged 69-86 years, and 96 type 2 (noninsulin-dependent diabetes mellitus) diabetics aged 64-96 years. Forty-seven of the diabetics were treated with tablets, 35 with insulin, and 14 with diet alone. Fasting serum C-peptide concentrations (nmol/l; mean +/- SD) were 0.51 +/- 0.20 for controls; 0.60 +/- 0.16 for diabetics on diet alone; 0.72 +/- 0.33 for diabetics on tablets and 0.46 +/- 0.23 for diabetics on insulin (p less than 0.001 for diabetics on tablets vs. controls and diabetics on tablets vs. diabetics on insulin). The glucagon-stimulated C-peptide concentrations were similar in all groups; the increment after glucagon was less in the diabetic patients on tablets or on insulin than in the nondiabetics. In 10 patients on insulin treatment and with fasting C-peptide of 0.24-1.46 nmol/l an attempt was made to withdraw insulin. In 4 subjects the transfer to tablets was possible. Serum C-peptide level did not predict the outcome of the attempt to change the therapy, but the possibility of an adequate dietary regimen seemed to be important. The results demonstrate a wide range of basal C-peptide concentrations in elderly diabetics on different treatments, which may indicate varying pathogenetic contributions of insulin deficiency and resistance in these patients. Our observations emphasize the necessity for regular re-evaluation of the therapeutic management of elderly diabetic patients.

Aged↗
PubMed1984

External quality assessment of serum drug determinations in the Nordic countries.

A system for external quality assessment of serum drug determinations in the five Nordic countries has been established, and results of several surveys of antiepileptic drug determinations are described. The work was started as a pioneer work of NORDKEM at the time when NORDKEM was founded and was carried out during the years 1977-1979. The problems concerning methodology of drug analyses and, consequently, the problem of setting up quality assessment systems differ clearly from those in connection with the common analyses of clinical chemistry. Especially the quality of control materials is very important. An expert panel of drug specialists is necessary to plan and interpret an external quality assessment program of drug analyses, but it can very well be carried out in connection with other quality assessment programs. The state of the art of antiepileptic drug determinations in the Nordic countries at the time of the surveys was very good. The level of inaccuracy was well below 5%, and the level of imprecision was mainly in the range of 15-20%, although no outliers were excluded during the statistical treatment of the data.

Anticonvulsants↗
PubMed1980

Stress fracture in soldiers: a multifocal bone disorder. A comparative radiological and scintigraphic study.

Forty-two military recruits with suspected stress fractures were evaluated by radiographs and radionuclide images. In 3 cases, both studies were negative. The initial radiograph was negative in 13 patients and positive in 29. Many foci shown by the radionuclide image were negative on the radiograph, particularly in the tarsal region. Thus stress fractures are often multifocal and may remain radiographically negative.

Adult↗