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Biomedical subjects

L Nilas

Publications and source records attributed to L Nilas.

At least 55 records · Page 3Linked to original sources
PubMed1987

Total body bone mineral in healthy adults.

Total body bone mineral (TBBM) was measured by dual photon absorptiometry (DPA) using a gadolinium 153 source in 135 healthy women aged 21 to 77 years and 101 healthy men aged 20 to 74 years. Among several predictor variables, including lean body mass measured by DPA, weight, and height, only normalization for the projected skeletal area (i.e., calculation of the total body bone density) had an appreciable effect on reduction of TBBM variation. In regression analysis of TBBM, raw and normalized, vs. age, a menopause-adjusted age was used for interpretation of data in women. Regardless of the normalization procedure, the best fit of TBBM vs. menopause-adjusted age was obtained by a polynomial regression of the third degree or a combined linear (premenopausal)--exponential (postmenopausal) regression. In men bone loss was linear with age (0.2% to 0.3% per year). In women, no significant premenopausal bone loss was found. The postmenopausal exponential loss was 4%, 0.44%, and 0.03% per year from TBBM 1 year, 10 years, and 20 years after the menopause. This amounts to a negative calcium balance of 100 mg calcium per day during the first postmenopausal year, and returning to zero after 20 years of menopause, when about 20% of premenopausal bone is lost.

Adult↗
PubMed1986

Bone changes occurring spontaneously and caused by estrogen in early postmenopausal women: a local or generalised phenomenon?

Regional values of bone mineral content and bone mineral density were calculated from total body dual photon absorptiometry scans of 52 early postmenopausal women treated with oestrogen for one year and of 52 similar women treated with placebo. The six regions were head, arms, chest, spine, pelvis, and legs. In addition, bone mineral density of the lumbar spine was measured by dual photon absorptiometry and bone mineral content of the forearm by single photon absorptiometry, using separate special purpose scanners. All regions were unchanged after one year of treatment with oestrogen, excluding the lumbar spine, for which values rose. Values for all regions except the lumbar spine fell significantly in the placebo group. The rates of loss ranged from 2% to 8%, with no significant differences among the regions. It is concluded that loss of bone in the early menopause is a generalised phenomenon, affecting all parts of the skeleton. Furthermore, oestrogen prophylaxis for loss of bone is effective in all parts of the skeleton. Finally, it is suggested that the measurement of bone mineral content in the forearm should be used for clinical follow up of bone changes, as this method is superior to others in the ratio of change to precision.

Bone and Bones↗
PubMed1986

Determination of bone turnover by urinary excretion of 99mTc-MDP.

Two methods of estimating bone turnover were investigated. The 24 h whole body retention (WBR) of intravenously injected 99mTc methylene disphosphonate (99mTc-MDP), a precise, accurate, and generally accepted method, was compared with a new, simple, measurement involving assessment of the 24 h urinary excretion (UE) of 99mTc-MDP. The WBR and UE were measured in 50 normal subjects, 10 patients with thyrotoxicosis, and 10 patients with chronic renal failure. The precision was 4.8% and 2.7%, respectively, and the two methods were highly significantly correlated (r = 0.99, SEE = 2.9%, p less than 0.001). In addition, urinary 99mTc-MDP excretions at 0 h-4 h (UE4) and 0 h-8 h (UE8) after injection were calculated in 49 subjects. The estimation of WBR from UE4 or UE8 was considerably poorer than from UE (for UE4: r = -0.83, SEE = 8.7%, and for UE8: r = -0.90, SEE = 6.8%) and the precision of UE4 and UE8 was 7.2% and 7.8%, respectively, and greater than those of both UE and WBR. It is concluded that the UE bone turnover measurement may become a simple, radiation dose-saving method to diagnose and monitor the treatment of metabolic bone diseases.

Adult↗
PubMed1986

Treatment of transsphincteric anal fistulas by the seton technique.

Twenty-one patients with high transsphincteric fistulas treated by the seton technique were re-examined after two to 14 years. None had recurrent fistulas, but 13 (62 percent) had some degree of continence disturbances. All patients with anal deformities had continence disorders.

Adult↗
PubMed1986

Iliac crest biopsy: representativity for the amount of mineralized bone.

The aim of the study was to evaluate the representativity of iliac crest biopsy for the amount of mineralized trabecular and cortical bone in the skeleton. The following data were obtained on bone from 14 necropsies: right sided iliac crest biopsy, lumbar spine biopsy, dry fat free weight of lumbar spine, bone mineral density (BMD) in the lumbar spine and dry fat free weight of cortical and trabecular bone from the left distal forearm. The amount of mineralized cortical and trabecular bone from various sites was compared by linear regression analysis. The results confirm iliac crest biopsy as a good predictor of the amount of trabecular bone, but not of cortical bone. Furthermore, iliac crest biopsy is a better estimate of the amount of trabecular bone in the lumbar spine than spinal BMD.

Adult↗
PubMed1986

The diagnostic validity of local and total bone mineral measurements in postmenopausal osteoporosis and osteoarthritis.

Assessment of different forms of prevention and treatment of bone mineral loss depends upon valid and precise methods to assess bone mass. We have here studied four groups of women: 45 healthy premenopausal women, 37 healthy postmenopausal women, 21 women with osteoarthritis and 20 with hip fractures. Bone mass was measured in the spine and total body by dual photon absorptiometry and in two forearm sites (proximal and distal bone mineral content (BMC) by single photon absorptiometry. The long-term (1 year) reproducibility was 1.2% for proximal BMC, 1.6% for distal BMC, 5.5% for spinal BMC, and 2.1% for total body bone mass (TBBM). In the early postmenopausal years bone mass was mainly reduced in areas with a high content of trabecular bone. In elderly postmenopausal women and women with hip fractures bone mass was almost identical in all four sites studied. The osteoarthritic patients had an 18% reduction of bone mass in the forearms and in TBBM, whereas the spinal bone mass was only reduced by 6%. In all subgroups TBBM could be predicted from the forearm measurements with standard errors of estimates of 9-13%. When the osteoarthritic women were excluded spinal bone mass could be predicted from both forearm measurements with a standard error of 15% (r = 0.74). The distal forearm BMC seems to be a more accurate estimate of spinal bone mass than does the proximal measurement. Of the 20 patients with hip fracture 16 had a distal forearm value below the premenopausal normal range, whereas spinal bone mass was subnormal in only eight (P less than 0.05). We conclude that bone loss is universal in patients with hip fracture and measurements of forearm bone mass will meet most clinical and research demands.

Adult↗
PubMed1986

Representativity of regional to total bone mineral in healthy subjects and 'anticonvulsive treated' epileptic patients. Measurements by single and dual photon absorptiometry.

Dual photon (153Gd) and single photon (125I) absorptiometry were used to measure the regional bone mineral content (BMC) and density (BMD), as well as the total body mineral content (TBBM) and density (TBBD), in sixty-nine healthy subjects and in twenty-three epileptics on phenobarbitone. The BMCs (and BMDs) of all regions were significantly correlated to each other and to the TBBM (and TBBD). No difference in the ability to discriminate between the different study groups was found for the various regions, excepting the BMD of the head. The relationship between the forearm BMC and TBBM was highly significant, and identical in the five groups. The relationships between spinal BMC and forearm BMC, and TBBM differed in the five groups. It is concluded that some local measurement may be used as estimates of the total body bone mineral in some groups of patients with minor metabolic bone disease and healthy subjects.

Adolescent↗
PubMed1986

Cyclic changes in serum cholesterol and lipoproteins following different doses of combined postmenopausal hormone replacement therapy.

Cyclic changes in lipoproteins after sequential oestrogen-progestogen therapy were studied in a group of healthy postmenopausal women treated with three different hormone doses, and followed up for two consecutive cycles by twice weekly examinations (a total of 17 examinations). There was a significant rise in high density lipoprotein (HDL) cholesterol and a significant fall in low density lipoprotein (LDL) cholesterol closely related to the dose of the oestrogen component. Addition of the progestogen, 1 mg of norethisterone acetate, decreased the oestrogen-induced rise in HDL, but HDL levels remained higher than initial values in the high-dose (4 mg) and medium dose (2 mg) groups. The average increases in HDL cholesterol were 13%, 9% and 2% in the high-dose, medium-dose and low-dose (1 mg) groups, respectively, and the corresponding mean decreases in LDL cholesterol were 18%, 15% and 10% respectively. We conclude that postmenopausal treatment with sequentially combined oestrogen-progestogen has no adverse effects on the lipoprotein status.

Cholesterol↗
PubMed1986

Total and local bone mass before and after normalization for indices of bone and body size.

Both single and dual photon absorptiometry are excellent techniques for longitudinal studies, owing to their high precision. Because of large biological variations they are less suited for diagnosing bone disease in single subjects. In a homogeneous group of 161 women, bone mass in the distal forearm, spine, and whole body measured by photon absorptiometry was significantly related to various general indices of body size (r = 0.29-0.59). Normalization procedures for variations of these variables could only reduce the individual variation by 10-20%. Local indices of body size (i.e. bone width or scan area) were no better in the forearm or spine. Normalization for the projected skeletal area of the whole body could reduce the SD of the total body bone mineral (TBBM) from 322 to 126 grams (15-6%). This might imply that the normalized TBBM can be used for diagnostic purposes.

Body Constitution↗
PubMed1986

Iliac crest biopsy: an investigation on certain aspects of precision and accuracy.

We investigated the intraobserver and section to section variation in static and dynamic histomorphometric variables in ten iliac crest biopsies. We also did a comparative study of iliac crest and lumbar spine specimens from 14 cadavers. The ten patients had osteoporosis (spinal crush fractures) and the 14 specimens taken at the necropsies were either normal or osteopenic, without malignant bone disease, bone metastases or metabolic bone disease. The majority of the coefficients of variation (CV%) were between 5 and 15% in the intraobserver analysis and 10 and 30% in the section to section analysis. These results suggest that more sections from each biopsy should be investigated to increase the precision. The correlation of variables from the iliac crest and spine showed poor agreement between resorption and osteoid variables. This fact, combined with a rather low precision of bone dynamic variables in the section to section investigation, raises the question of whether iliac crest biopsy is representative for trabecular bone turnover in the skeleton.

Aged↗
PubMed1985

Uncoupling of bone formation and resorption by combined oestrogen and progestagen therapy in postmenopausal osteoporosis.

10 healthy early postmenopausal women were treated with oestrogen and progestagen for two cycles of 28 days. Serum alkaline phosphatase and bone Gla protein increased during progestagen administration, whereas urinary excretion of calcium and hydroxyproline fell significantly during treatment, independently of progestagen intake. Thus, bone formation increases when progestagen is added to oestrogen treatment, whereas bone resorption may be kept constantly low during oestrogen plus progestagen treatment, leading to a positive calcium balance. This makes possible effective treatment of postmenopausal osteoporosis--treatment of elderly postmenopausal women with substantial bone loss before their bones have fractured or when they have just started to fracture. This study design can be used for easy and rapid screening of potential drugs for the prevention and treatment of postmenopausal bone loss.

Bone Development↗
PubMed1985

Influence of PTH and 1,25(OH)2D on calcium homeostasis and bone mineral content after gastric surgery.

In 57 patients surgically treated for ulcer, we found low 25OHD concentrations, elevated 1,25(OH)2D concentrations, (P less than 0.001), a normal iPTH level, and a not significantly reduced bone mineral content (BMC) measured by single photon absorptiometry. The 25OHD concentrations were highest in patients regularly taking tablets containing vitamin D (P less than 0.05), whereas the 1,25(OH)2D concentrations and the BMC values were not affected by vitamin D intake. The most severe calcium metabolic disturbances were seen in 15 Billroth I resected patients whose BMC was 89.4 +/- 12.4% of normal. Although the dietary intake of calcium and vitamin D complied with the Scandinavian recommendations and calcium absorption was in the lower part of the normal range, the general state of nutrition appears to influence the bone mass of such patients. In the patients as a group, the 1,25(OH)2D concentrations were significantly related to BMC (r = 0.44, P less than 0.001) and biochemical signs of bone resorption (r = 0.68, P less than 0.001) and formation (r = 0.42, P less than 0.001) Conversely, no relationship could be detected between serum iPTH and bone mass or bone turnover. We suggest that the high 1,25(OH)2D concentrations found after gastric resections express a compensatory process leading to an increase in calcium absorption, and that the initial event in this sequence is a trend toward low serum calcium levels. With increased demands on this regulation or lack of precursor for 1,25(OH)2D synthesis, bone mass declines through the action of 1,25(OH)2D and/or PTH.

Adult↗
PubMed1985

Regulation of vitamin D and calcium metabolism after gastrectomy.

Fifteen men, who had undergone Billroth I gastrectomy and 19 men who had undergone Billroth II gastrectomy were studied with respect to vitamin D and other indices of calcium metabolism. The Billroth I group had hypocalcaemia, raised concentration of serum alkaline phosphatase, and reduced bone mineral content. The same biochemical disturbances were found in the Billroth II group, but bone mineral content was normal. In neither of the groups was found signs of increased bone resorption. The calcium absorption was situated in the lower part of the normal range and the fractional absorption and elimination rates were normal. The 25OHD concentrations in both groups were reduced (p less than 0.05-0.01) and the 1.25(OH)2D concentrations raised (p less than 0.01-0.001). The 1,25(OH)2D concentrations were inversely related to bone mineral content, but directly related to signs of bone turnover and calcium absorption. We suggest that the high 1,25(OH)2D concentration is the result of a compensatory process with the aim of preventing hypocalcaemia.

Adult↗
PubMed1985

Comparison of single- and dual-photon absorptiometry in postmenopausal bone mineral loss.

We describe a single photon absorptiometric (SPA) technique, which enables differential estimation of the rates of loss from trabecular and cortical bone. Ten scans are obtained in the forearm: six in an area with about 7% trabecular bone and four scans in the adjacent distal area with a trabecular bone content of 25%. By comparing bone masses of these two sites in 19 postmenopausal and 53 premenopausal women, the postmenopausal trabecular bone loss was estimated to be approximately seven times greater than cortical loss within the first years of cessation of regular vaginal bleeding. On a group basis the bone loss at the distal forearm scan site (by SPA) corresponded closely to the spinal bone loss (by dual-photon absorptiometry). The reproducibility of the two scan sites in the forearm was 1-1.5% (CV%), which makes the method suitable for longitudinal studies. Corrections for variations in fatty tissue covering can be made without deterioration of the reproducibility. The high precision can only be achieved with a good calibration procedure; if calibration is not done the reproducibility error increases two- or threefold.

Adult↗
PubMed1984

Calcium supplementation and postmenopausal bone loss.

A series of 103 early postmenopausal women completed a questionnaire about their dietary calcium intake and were then divided into three groups: those with an intake below 550 mg/day, those with an intake between 550 and 1150 mg/day, and those with an intake above 1150 mg/day. Thereafter they were given a daily supplement of 500 mg calcium for two years and had their bone mineral content measured every three months. Any changes found were taken as an estimate of bone calcium balance. All three groups showed a similar fall in bone mineral content over the two years, indicating that a calcium intake of 1000-2000 g daily is ineffective in preventing bone loss in the early menopause.

Bone and Bones↗
PubMed1984

A selective and simplified radioimmunoassay of 25-hydroxyvitamin D3.

A simple, non-chromatographic and selective assay for determination of 25OHD3 in serum is described. The serum sample is deproteinated with acetonitrile and the supernatant purified over a small prepacked cartridge, Sep-pak. In the eluate from the cartridge, 25OHD3 is measured by radioimmunoassay. The selectivity of the assay for 25OHD3 is improved by adding vitamin D2 to the antiserum; the assay is thus capable of measuring 25OHD3 in serum samples containing up to a ratio of 25OHD2/25OHD3 equal to 150. The simplicity, speed and the small amount of sample needed (0.5 ml) make this method suitable for use in a routine clinical laboratory. Because of its selectivity for 25OHD3 the assay is a necessary prerequisite in the further investigation of metabolic discrimination between vitamins D2 and D3.

Calcifediol↗
PubMed1984

Relationship between local and total bone mineral content after gastric surgery.

We compared the total body bone mineral mass (TBBM), assessed by the dual-photon technique, with the local bone mineral mass (BMC), measured by single-photon absorptiometry, in 27 ulcus patients treated by either gastric resection or parietal cell vagotomy. Except for raised concentrations of serum alkaline phosphatase in the Billroth I resection group, the biochemical findings and the measurements of bone mass (local and total) were normal. A highly significant correlation between local and total body bone mineral mass was found in both patients (r = 0.84) and controls (r = 0.91). Since the relationship between these two measurements is identical in the patient population and in the age-matched control group, it is concluded that the local BMC may be useful to estimate total bone mass after gastric surgery.

Aged↗