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Biomedical subjects

F Melsen

Publications and source records attributed to F Melsen.

At least 127 records · Page 7Linked to original sources
PubMed1982

Vitamin D metabolism and osteomalacia in patients with fractures of the proximal femur.

A high frequency of histological osteomalacia (25 per cent) was seen in patients with fractures of the proximal femur. No correlation was found between the levels of circulating 25-hydroxyvitamin D (25-OHD) or 1,25-dihydroxyvitamin D (1,25-(OH)2D) and the bone histomorphometric changes. The serum 25-OHD levels were normal, which excludes a dietary vitamin D deficiency or a reduced hepatic hydroxylation of the vitamin. The mean serum 1,25-(OD)2D concentration was significantly reduced in the whole patient group, but surprisingly the levels were normal in those with histological osteomalacia, indicating that an impaired conversion of 25-OHD to 1,25-(OH)-2D was not the primary cause of the bone disease. A reduced sensitivity to 1,25-(OH)2D might be a possible explanation for the osteomalacia.

Anthropometry↗
PubMed1982

The subchondral bone of the proximal tibial epiphysis in osteoarthritis of the knee.

The trabecular bone of the proximal end of the tibia was assessed as an endoprosthesis-bearing structure. The mass and mineral content as well as the activity of subchondral trabecular bone were determined in osteoarthritis knees with varus or valgus deformity. Bone specimens were taken from the lateral condyle, the medial condyle, and centrally from the intercondylar area of seven varus and four valgus knees. The percentage volume of trabecular bone was determined by histomorphometry. On an additional nine knees, five with varus and four with valgus deformity, as well as ten knees from a normal autopsy material, photon absorptiometric determination of the mineral content of the same areas was performed. On average, the loaded condyle had twice the percentage volume of trabecular bone, and accordingly twice the mineral content, of the unloaded condyle. It was remarkable that the mineral content of the latter was of the same order as the condyles of the normal material.

Aged↗
PubMed1982

Osteon cross-sectional size in the iliac crest: variation in normals and patients with osteoporosis, hyperparathyroidism, acromegaly, hypothyroidism and treated epilepsia.

Cross-sectional osteon size was measured in undecalcified stained sections of iliac crest bone specimens from normal individuals (n = 68) and from patients with spinal osteoporosis (n = 27), primary hyperparathyroidism (n = 23), epilepsia (receiving chronic anti-convulsant therapy) (n = 11), acromegaly (n = 18), and hypothyroidism (n = 12). In each individual the shortest osteon diameter (D) and the corresponding Haversian canal diameter (d) were measured in a minimum of 20 completed secondary osteons by means of a micrometer eyepiece. Among normal males the areas of bone resorbed and formed increased with age (p less than 0.01), owing to an increase in the thickness of bone resorbed (p less than 0.01) and an unchanged thickness of bone formed. Among the females, both the areas of bone resorbed and formed decreased with age (p less than 0.05), owing to a reduction in the thickness of bone resorbed (p less than 0.05) as well as formed (p less than 0.001). Resorbed and formed areas were reduced in the epileptic (p less than 0.01) and acromegalic (p less than 0.01) groups but increased in the hypothyroid group (p less than 0.01) compared to sex- and age-matched controls. Neither the osteoporotic nor the hyperparathyroid group showed any alterations in osteon size. The Haversian canal diameter was slightly increased in the epileptic group but normal in the other patient groups. The observed changes reflect variations in the amount of work performed by osteoclasts and osteoblasts during bone remodelling and may be explained by variations in cellular activity and bone turn-over rates.

Acromegaly↗
PubMed1981

Effects of thyroid hormone(s) on mean wall thickness of trabecular bone packets.

The mean wall thickness of iliac trabecular bone packets was determined in undecalcified iliac crest bone specimens from 14 hypothyroid patients, 14 hyperthyroid patients and 28 age- and sex-matched normal controls. Calcification rate and fractional resorption, formation and labeled surfaces in trabecular bone from the patients were measured by conventional histomorphometric methods after double-labeling with tetracycline. The mean wall thickness was increased in the hypothyroid patients (58,9 microns), while no change was demonstrated in the hyperthyroid group (52,5 microns) as compared to the controls (54,0 microns). Calculated estimates of trabecular bone remodeling at the "Basic Multicellular Unit" level showed longer periods of resorption, formation and total remodeling in the hypothyroid than in the hyperthyroid patients.

Adult↗
PubMed1981

Iliac crest bone mass and remodelling in acromegaly.

Iliac crest bone biopsies from 18 patients with active acromegaly, of whom 11 had received tetracycline double-labelling, were evaluated by quantitative histomorphometry and compared with age- and sex-matched normal controls. A significant increase (P less than 0.01) was found in both cortical (175%) and trabecular (130%) bone mass. In trabecular bone, resorption surfaces and active (tetracycline-labelled) and total formation surfaces were increased (P less than 0.05 and P less than 0.01, respectively) causing an enhanced bone turn-over at tissue level (P less than 0.01). The increased trabecular bone mass indicates a positive net balance per remodelling cycle and, therefore, larger than normal bone remodelling units, which in part may explain the increased bone turn-over at tissue level. The activity of the osteoblasts active in mineralization (the appositional rate) was increased (P less than 0.01) and positively related to the fasting serum growth hormone levels (Rs = 0.69, P less than 0.05). The average activity of active and inactive osteoblasts (bone formation rate at basic metabolic unit (BMU) level) was insignificantly increased. The proportion of active (tetracycline labelled) to nonactive formation surfaces was normal. The bone changes were unrelated to serum levels and urinary excretions of calcium and phosphorus or to renal excretion of total and non-dialyzable hydroxyproline or cAMP.

Acromegaly↗
PubMed1981

Mineral metabolism in chronic renal failure with special reference to serum concentrations of 1.25(OH)2D and 24.25(OH)2D.

This study examines the interrelationship between serum levels of substances important in mineral metabolism including the 3 vitamin D metabolites 25OHD, 24.25(OH)2D and 1.25(OH)2D and static and dynamic histomorphometric measurements of bone remodelling in iliac crest biopsies in 17 patients with chronic renal failure. No correlation was found between the serum values of any of the vitamin D metabolites and the histomorphometric values. However, significant inverse correlations were found between serum calcium and both the osteoid surface extent (P less than 0.05) and osteoid volume (P less than 0.05) in trabecular bone. Serum immunoreactive parathyroid hormone (iPTH) was positively related to trabecular osteoclastic bone resorption. The serum level of 1.25(OH)2D was inversely related to endogenous creatinine clearance (P less than 0.01). These results support the hypothesis that the serum calcium concentration is more important than the serum concentration of vitamin D metabolites for bone remodelling in chronic renal failure.

Bone and Bones↗
PubMed1980

The cranial base in anencephaly and microcephaly studied histologically.

A histological microradiographical analysis was carried out on the cranial base removed at autopsy from three infants--two with microcephalia, one with anencephalia. The histological findings were compared with those from normal individuals of the same age. It was shown that a reduced size of the brain was accompanied by a change in the remodeling pattern of the internal as well as the external surface of the cranial base, leading to a flattening of the cranial base. The findings further suggest that the development of the brain influences the ossification of the chondrocranium.

Anencephaly↗
PubMed1980

Experimental infection of the upper genital tract of female grivet monkeys with Mycoplasma fermentans.

Mycoplasma fermentans inoculated directly into the uterine tubes of female grivet monkeys produced a self-limiting acute salpingitis and parametritis. The inflammation was accompanied by a significant rise in titre of specific indirect haemagglutinating antibodies. Inoculation of M. fermentans into the uterine cavity through the cervical canal without dilatation of the cervix produced practically no signs of inflammation and no antibody response. However, when the intrauterine inoculation of mycoplasmas was followed by currettage of the endometrium, in animals whose uterine tubes had been closed by ligatures, pronounced upper genital-tract inflammation developed, together with a significant antibody response.

Animals↗
PubMed1980

Histomorphometrical determination of bone marrow cellularity in iliac crest biopsies.

The point-count principle is an exact method of bone marrow quantitation but fairly good correlation was found between quantitated and estimated values of the cellularity in iliac crest biopsies, although the latter values were significantly lower. No intraspecimen variation was found, but the cellularity in the individual biopsies varied considerably from field to field, indicating that quantitation and estimation on small samples obtained by aspiration may be misleading. The correlation between the values from undecalcified and decalcified sections was high, but decalcification of the biopsies resulted in an underestimation of the amount of haemopoietic tissue.

Adolescent↗
PubMed1980

Trabecular bone mineralization lag time determined by tetracycline double-labeling in normal and certain pathological conditions.

Quantitative histomorphometric analyses of iliac crest biopsy specimens were performed after tetracycline double-labeling in 41 normal individuals, 20 hyper- and 10 hypothyroid patients, 18 patients with primary hyperparathyroidism, 20 epileptic patients receiving long-term anticonvulsant therapy, and 17 patients after jejunoileal bypass for morbid obesity. The mineralization lag time in trabecular bone or the period of time between apposition and subsequent mineralization of osteoid was calculated from the bone formation rate at BMU level (Basic Multicellular Unit) and the mean width of osteoid seams. The mineralization lag time was 8-52 days (median 21 days) in normal individuals and showed no variation with sex or age. The mineralization lag time was shortened in hyperthyroidism, normal in anticonvulsant bone disease and in primary hyperparathyroidism, and markedly prolonged in hypothyroidism and following jejunoileal bypass. Among all individuals an inverse hyperbolic relation (r = 0.94, p less than 0.001) was found between the mineralization lag time and the average cellular activity of the osteoblasts.

Adult↗
PubMed1980

Experimental acute pyelonephritis in grivet monkeys, provoked by Staphylococcus saprophyticus.

Urinary tract infection by Staphylococcus saprophyticus was provoked in two female grivet monkeys. A non-hemagglutinating strain of S. saprophyticus was injected into the renal pelvis of one of the animals (monkey I), while in the other (monkey II), a hemagglutinating strain of the same species was inoculated into the bladder by suprapubic puncture. In monkey I, massive hematuria and proteinuria were demonstrated during the post-inoculation (p.i.) week, after which the monkey was killed. In monkey II, which was killed after 2 weeks, hematuria and proteinuria were present during the first 5 p.i. days. In both monkeys, S. saprophyticus was isolated in numbers < 10(5) bacteria/ml bladder urine on each p.i. day. Autopsy of monkey I revealed acute pyelonephritis and inflammatory changes in the ureter on the same side on which S. saprophyticus had been inoculated. In monkey II, both kidneys were enlarged and there were signs of acute pyelonephritis. The histopathological examination revealed microabscesses, interstitial infiltration and numerous leukocytes in the tubules. Both the ureters of monkey II were congested and microscopically an acute inflammatory reaction was found. Inflammatory signs were also present in the bladder. Scanning electron microscopy revealed cocci adhering to the epithelial lining of the urinary tract.

Acute Disease↗
PubMed1980

Low serum levels of 1.25-dihydroxyvitamin D and histomorphometric evidence of osteomalacia after jejunoileal bypass for obesity.

Twenty-seven unselected patients were investigated three to eight years after jejunoileal bypass for morbid obesity. The serum levels of calcium, magnesium, and phosphorus, and the renal excretions of calcium and magnesium were reduced. The serum alkaline phosphatase levels were increased. The serum levels of the two vitamin D metabolites 25-hydroxyvitamin D (25-OHD) and 1.25-dihydroxyvitamin D (1.25-(OHD)2D) were reduced and inversely related to the increased serum levels of immunoreactive parathyroid hormones (iPTH). Serum 1.25-(OH)2D correlated positively and serum iPTH inversely with serum concentrations and renal excretion rates of calcium. Iliac crest bone biopsies after in vivo tetracycline double-labelling showed a reduced bone turnover with an increased amount of osteoid due to an increase in both surface extent and mean width of osteoid seams. The increased volume of osteoid was caused by a decreased osteoblastic function with a longer life-span of bone-forming sites and a prolongation of the mineralisation lag time. The amount of trabecular bone was normal. The results indicate an impaired vitamin D metabolism with osteomalacia and secondary hyperparathyroidism.

Adult↗
PubMed1980

1 alpha-hydroxy vitamin D3 treatment of non-dialyzed patients with chronic renal failure. Effects on bone, mineral metabolism and kidney function.

Nine non-dialyzed patients with creatinine clearance below 20 ml/min and histological and biochemical signs of renal osteodystrophy received 1 alpha-hydroxy vitamin D3 for 6 months in a mean daily dosage of 0.9 microgram. The serum concentrations of calcium and phosphate increased, and the serum concentrations of alkaline phosphatase and parathyroid hormone decreased during treatment. Quantitative histological examination of iliac crest bone biopsies showed a marked improvement of uremic bone changes, including normalization of the initial low mineralization rates evaluated by tetracycline uptake in bone. No significant change was seen in bone mineral content in the forearm measured by photon absorptiometry. An accelerated loss of kidney function was observed during the treatment period with 1 alpha-OH-vitamin D3 as compared with control periods before and after the treatment.

Adult↗
PubMed1979

Postmortem findings in three patients treated with intravenous fat emulsions.

Three patients died of intercurrent illness in relation to intravenous nutrition with fat emulsions (20% Intralipid). In two cases, postmortem findings showed milky white, shiny, clotted lumps in the heart, with a fatty acid composition resembling that of fat emulsions. In vitro investigations make it likely that fibrin deposits in hyperlipemic plasma composed the lumps. In two cases, 30- to 50-mu Sudan-positive accumulations were found in the small vessels of the lungs, the cerebrum, and the kidneys.

Aged↗
PubMed1979

Experimental infusion thrombophlebitis. A comparison between glucose and frutcose and 5% and 10% glucose solution.

On the basis of clinical experience it has been claimed that glucose results in a higher incidence of infusion thrombophlebitis than fructose, and that glucose solutions in concentrations higher than 5% are extremely irritant to the venous endothelium. The validity of these two assertions has been investigated by an experimental method based on a quantitative histological study of rabbit-ear veins into which infusions were given under standardized conditions. In two series of experiments, it was shown (1) that fructose solutions caused significantly more inflammatory changes in the veins than did glucose solutions, and (2) that glucose in 10% solutions caused significantly more injury to the veins than 5% solutions, although the difference in the average inflammatory changes was only slight.

Animals↗