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J C Renier

Publications and source records attributed to J C Renier.

At least 37 records · Page 2Linked to original sources
PubMed1990

[The development of bone mass during a lifetime].

The authors present a reminder of the methods used to evaluate the bone mass and density and, with population studies, specify the profile and significance of the physiological osteopenia in both sexes. Analysis of these studies shows that the age of onset of the bone loss and its percentage vary markedly between the various sites of the skeleton, according to the type of bone, cortical or trabecular. It seems that the "smooth" aspect of the physiological osteopenia curves obtained is women during population studies, essentially results from the disparity between the times of menopause. A general protocol of the physiological osteopenia, synthesizing all data collected with nine different methods of measurement of the mineral bone content, is presented for educational purposes.

Adult↗
PubMed1989

[What is Paget's disease?].

Paget's disease of bone is characterized by the progressive and extensive replacement, in one or several bones, of normal bone tissue by a bone tissue of rough and irregular structure, the excessive and disorderly renewal of which gradually produces hyperdensity and hypertrophy of the bones involved. The condition results from the action of abnormal and overactive osteoclasts containing virus-like intranuclear and intracytoplasmic inclusions. The disease profoundly alters the physiology of bones in the region affected. The viral-looking inclusions that enter the osteoclasts seem to induce a loss of control of bone renewal and remodelling, as shown by histology and radiology. The resorption-formation mechanism persists but it is unbalanced, facilitating bone resorption during two to five years, then bone formation. In that way, subjects with Paget's disease, who have reached the age of physiological osteopenia, show an often important increase in bone density and mass. Paget's disease of bone is a disease grafted on the skeleton: it is partly dependent on the skeletal status of the host. The activity of Paget's disease is evaluated by measuring the ratio of plasma alkaline phosphatase levels to the volumes of normal and pagetic bones; the author suggests a mathematical formula for calculating this ratio.

Alkaline Phosphatase↗
PubMed1989

[Paget's bone disease. Epidemiology and etiology].

Paget's bone disease is a chronic and usually benign bone disorder mainly found in people over fifty. The condition is characterized by excessive bone remodelling related to bone cell overactivity leading to abnormal bone structure. The viral origin of the disease, first proposed on the basis of ultrastructural observations, is now supported by immunocytological and molecular hybridization studies. Genetic and environmental elements may be involved, favouring and modulating the expressivity of this slow virus infection.

Humans↗
PubMed1989

Treatment of Paget's disease of bone with (4-chloro-phenyl) thiomethylene bisphosphonate.

Introduction of antiosteoclastic drugs, calcitonin and etidronate, has profoundly changed the treatment of active Paget's disease of bone. Nevertheless, the use of these drugs is limited in some patients by the occurrence of side-effects or by a resistance to therapy. We report the results of an open, nonrandomized study with a new bisphosphonate, (chloro-4 phenyl) thiomethylene bisphosphonate (Cl-TMBP), given orally to 35 patients with active Paget's disease of bone. At two different dosages this new bisphosphonate induced a significant decrease in disease activity. Patients receiving a mean dosage of 5 mg/kg/d (n = 14) showed a significant reduction of serum alkaline phosphatase levels to 43% of pretherapeutic values (from 499 +/- 91 to 214 +/- 41 IU/l) while hydroxyproline/creatinine ratio decreased to 43% of baseline (from 93 +/- 21 to 40 +/- 11). A second group of patients (n = 21) receiving a mean dosage of 11 mg/kg/d exhibited a similar response: serum alkaline phosphatase activity was reduced to 42% of initial values (from 1384 +/- 209 to 584 +/- 111 IU/l) while hydroxyproline/creatinine ratio fell to 48% of baseline (from 144 +/- 27 to 69 +/- 15). This was accompanied by a reduction in radionuclide uptake in pagetic areas. A prolonged beneficial effect was observed in most patients. In patients receiving the highest dosage significant reduction in serum calcium and rise in parathyroid hormone were observed. Otherwise no clinical or biological side-effect occurred throughout the study.

Aged↗
PubMed1988

[Serum, synovial and intra-articular pharmacokinetics of naproxen after one-gram oral administration in patients with rheumatoid polyarthritis].

After a reminder of the major points of the pharmacokinetics of non-steroid anti-inflammatory drugs, the authors report the results of a multicentric study of the kinetics of naproxen after oral intake of one single dose of 1 gram in patients with rheumatoid arthritis. The half-life is longer in the synovial fluid than in the serum, 23 hours versus 17 hours. The balance point is obtained at the 24th hour and, at that time, the naproxen level in the synovium and the joint fluid are 32 and 60 p. cent, respectively, of the corresponding maximum concentrations.

Administration, Oral↗
PubMed1988

[Introduction to the biomechanics of the lumbar spine].

The first part of this report is devoted to the functional anatomy of the lumbar spine, and reminds of the morphology, structure and proper physiology of each lumbar vertebral component, and then of each flexible element linking the lumbar vertebrae with one another. In this tripod system, the column of vertebral bodies and discs play an essential role, while the two columns of posterior articular processes have a supplementary, but nevertheless effective role in spinal stability and mobility. The intervertebral disc, because of the strong osmotic pressure of the nucleus and the dual direction fibrillar structure of the annulus, is in a pre-stress condition and constitutes a very strong visco-elastic shock-absorber; besides, it is a flexible structure allowing free motion. Under certain circumstances, it is supported by the abdominal wall. The second part of this report shows how spinal mobility in all directions, and absorbing of the load in all body postures, are effected by the lumbar spine.

Biomechanical Phenomena↗
PubMed1988

[Primary hyperparathyroidism. Recent physiopathological data].

Recent advances in the physiology of the parathyroid hormone permit a better demonstration of the mechanisms of inappropriate hypersecretion which characterizes hyperparathyroidism, even through the etiology of primary forms still remains unknown. There have been also some progress achieved understanding and evaluating the impact od hypersecretion on target organs, especially bone and kidney. Some studies give an indication of the therapeutic modalities which would enable to reduce the excess of secretion, to counteract the effect of the hormone on its receptor sites or finally limit its consequences on osteopenia.

Animals↗
PubMed1987

Sarcomatous degeneration in Paget's bone disease.

The authors report 12 cases (8 men and 4 women) of sarcomatous degeneration in Paget's bone disease, with an average age of 72.3 years. Sarcomatous degeneration occurred often in polyostotic Paget's disease, and osteitis deformans was seen in 4 cases. Femur and pelvis were the most affected bones. Pain was a constant feature, whereas tumefaction and fracture were less common. Osteolytic lesions were more frequent than condensed or mixed lesions and radiological signs of malignancy were usually found. Seven cases were histologically classified as osteogenic sarcoma and 3 cases as fibrosarcoma. Electron microscopy was performed on 2 osteogenic sarcomas and in 1 case revealed microcylindrical inclusions in Pagetic osteoclasts and in multinucleated giant tumor cells, but none in mononucleated tumor cells. The average survival time for the patients in this study was only 4.5 months.

Aged↗
PubMed1987

[Pancreatic cytosteatonecrosis].

If cutaneous panniculitis, made of dermo-hypodermic nodules, is the most constant manifestation of pancreatic cytosteatonecrosis, articular and bony localizations are quite frequent and sometimes the first manifestation of the disease. Articular lesions: monoarthritis, oligo-arthritis and mostly polyarthritis, often assume a very inflammatory picture; the synovial fluid is oily or puriform, and has a high content of polynuclear cells or macrophages with a foamy cytoplasm, lipid droplets, triglycerides, non-esterified fatty acids, and pancreatic enzymes; the most typical synovial lesion is a cytosteatonecrosis with adipocytes showing a huge lipidic vacuole. The bony lesions are mostly osteolytic, microgeodic lesions, or more extended ones, pseudo-tumoral without soft tissue invasion: more rarely, there is a periosteal thickening, bony infarctions, or epiphyseal osteonecrosis; these lesions do not always demonstrate a hyperfixation on scintigrams. The physiopathology of these various lesions is usually linked to a diffusion of pancreatic lipases, but other enzymes or enzymatic inhibitors also intervene, as well as a cytotoxic and local inflammatory activity of the fatty acids themselves. Surgical treatment of the pancreatic lesions, when possible, is the only treatment that is truly effective.

Adult↗
PubMed1987

[Serum concentrations of 1,25-dihydroxyvitamin D in cases of osteomalacia, parathyroid dysfunction and idiopathic hypercalciuria].

1,25 dihydroxyvitamin D (1,25(OH)2 D) is the active metabolite of vitamin D and has an essential role in bony metabolism on the regulation of the calcium-phosphorus balance. The circulating level of 1,2(OH)2 D is normally between 25 and 45 pg/ml. Isolation of the fraction to be titrated requires sophisticated purification techniques using high performance chromatography (HPLC). In osteomalacia secondary to a deficiency the mean level of 1,25(OH)2 D is low (14.1 +/- 6.9 pg/ml) because of substratum deficiency. Administration of vitamin D supplements is quickly followed by a supraphysiological increase of the level of active metabolite. The role of the parathyroid hormone on the activity of 1-hydroxylase is illustrated by the results of the titration in parathyroid dysfunctions: decrease of the mean level in hypoparathyroidism (18 +/- 6.9 pg/ml), and on the contrary, a significant increase in hyperparathyroidism (56.6 +/- 15.4 pg/ml) despite of a spread of the individual values. In 18 cases of idiopathic hypercalciuria, we have only observed an increase of 1,25(OH)2 D level, in two cases. Titration of 1,25(OH)2 D complements the calcium-phosphorus evaluation to precise the physiopathogenic mechanism of the disorders observed in various diseases. Its interpretation requires the joint measurement of the substratum level, 25-hydroxyvitamin D, and the evaluation of the parathyroid function.

Adult↗
PubMed1986

[Paget's disease].

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Bone and Bones↗